native cut flowers · iii foreword postharvest flower fall from various native australian cut...

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Native CutFlowersExtending Postharvest LifeUsing 1-MCP Treatment

A report for the Rural Industries Researchand Development Corporation

by AJ Macnish, DC Joyce, DH Simons and PJ Hofman

October 1999

RIRDC Publication No. 99/155RIRDC Project No. UQ-63A

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© 1999 Rural Industries Research and Development Corporation.All rights reserved.

ISBN 0 642 57979 2ISSN 1440-6845

Native Cut Flowers – Extending Postharvest Life Using 1-MCP TreatmentPublication no. 99/155Project no. UQ-63A.

The views expressed and the conclusions reached in this publication are those of the author and notnecessarily those of persons consulted. RIRDC shall not be responsible in any way whatsoever to any personwho relies in whole or in part on the contents of this report.

This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing theCorporation is clearly acknowledged. For any other enquiries concerning reproduction, contact thePublications Manager on phone 02 6272 3186.

Researcher Contact DetailsAssoc. Prof. David H. SimonsSchool of Land and FoodThe University of QueenslandGatton College QLD 4345

Phone: 07 5460 1231Fax: 07 5460 1455Email: [email protected]

RIRDC Contact DetailsRural Industries Research and Development CorporationLevel 1, AMA House42 Macquarie StreetBARTON ACT 2600PO Box 4776KINGSTON ACT 2604

Phone: 02 6272 4539Fax: 02 6272 5877Email: [email protected]: http://www.rirdc.gov.au

Published in October 1999Printed on environmentally friendly paper by Canprint

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FOREWORD

Postharvest flower fall from various native Australian cut flowers is induced by ethylene. Silverthiosulfate (STS) solution is commonly used to reduce ethylene-induced flower fall, but may bewithdrawn from commercial use due to possible environmental hazards. Recently, an alternativeand novel gaseous anti-ethylene agent, 1-MCP, was developed.

This project aimed to:

• Develop dosing (concentration, duration and temperature) relationships for 1-MCP treatmentof native cut flowers.• Extend the postharvest longevity of various ethylene-sensitive native cut flowers throughtreatment with 1-MCP.• Devise and test practical application systems for 1-MCP treatment.

This report documents a study into the effects of 1-MCP treatment on a variety of nativeAustralian cut flowers. The effects of 1-MCP concentration, treatment duration and treatmenttemperature on the ethylene sensitivity of Grevillea ‘Sylvia’ inflorescences were evaluated. Ascreening study in which the response of a number of native Australian cut flowers to 1-MCP andethylene treatments is also presented. A detailed investigation into the effects of temperature onthe efficacy of 1-MCP treatments on native cut flowers is reported. Finally, several practicalapplication systems for 1-MCP treatment are examined.

This report, a new addition to RIRDC’s diverse range of over 400 research publications, formspart of our Wildflowers and Native Plants R&D program, which aims to improve theprofitability, productivity and sustainability of the Australian wildflower and native plantindustry.

Most of our publications are available for viewing, downloading or purchasing online throughour website:• downloads at www.rirdc.gov.au/reports/Index.htm• purchases at www.rirdc.gov.au/pub/cat/contents.html

Peter CoreManaging DirectorRural Industries Research and Development Corporation

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ACKNOWLEDGMENTS

The authors thank Dr John Faragher of the Victorian Agriculture, Institute for Horticultural Development,

Knoxfield laboratory for his interest and collaboration in this study. Special thanks are also due to Tony Slater

and Dr David Beardsell for their advice and assistance with experiments conducted at the Knoxfield laboratory.

The skilled technical assistance of Victor Roberston, Alison Van Ansem and Srivong Rangsi is gratefully

acknowledged. We thank Allan Lisle for his advice on the statistical analysis of data. We acknowledge Setyadjit

for his assistance with experiments during the early part of this study.

The following people are thanked for provision of cut flowers for experiments: Pamela Barrass, John and

Barbara Bradshaw, Edward Bunker, Christensen Flower Wholesaler, Graham and Ester Cook, Jamie Creer, Ben

Edwards, Brett Gunderson, David and Olive Hockings, Leo Lynch and Sons (Qld) Pty. Ltd., David Matthews, Dr

David Tranter, Philip Watkins and Ken Young.

Financial support from the Rural Industries Research and Development Corporation is gratefully acknowledged.

In particular, special thanks are due to Dr David Evans for his support throughout this study.

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TABLE OF CONTENTSFOREWORD iiiACKNOWLEDGMENTS ivLIST OF ABBREVIATIONS AND SYMBOLS xiiEXECUTIVE SUMMARY xv

1 GENERAL INTRODUCTION 1

1.1 BACKGROUND TO RESEARCH 11.2 GENERAL OBJECTIVES 21.3 REPORT STRUCTURE 3

2 1-MCP TREATMENT PREVENTS ETHYLENE- INDUCED FLOWERABSCISSION FROM GREVILLEA ‘SYLVIA’ INFLORESCENCES 5

2.1 INTRODUCTION 52.2 MATERIALS AND METHODS 6

2.2.1 Plant Material 62.2.2 Chemicals 72.2.3 Treatment chambers 82.2.4 Treatments 102.2.5 Assessments 112.2.6 Experiment design and data analysis 13

2.3 RESULTS 152.3.1 Effect of 1-MCP concentration on the ethylene sensitivity of G. ‘Sylvia’ inflorescences 152.3.2 Effect of 1-MCP pre-treatment duration on ethylene sensitivity of G. ‘Sylvia’ inflorescences 252.3.3 Effect of temperature on 1-MCP pre-treatment efficacy 322.3.4 Effect of 1-MCP pre-treatment on inflorescence physiology 38

2.4 DISCUSSION 45

3 RESPONSES OF A NUMBER OF NATIVE AUSTRALIAN CUT FLOWERS TO 1-MCP AND ETHYLENE TREATMENTS 51


3.2.1 Plant material 523.2.2 Plant material preparation 563.2.3 Chemicals 563.2.4 Treatments 573.2.5 Assessments 583.2.6 Experiment design and data analysis 61

3.3 RESULTS 633.3.1 Treatment of a range of native cut flowers with 1-MCP and ethylene 633.3.2 Treatment of B. heterophylla with 1-MCP, STS and ethylene 108

3.4 DISCUSSION 116

4 EFFECT OF TEMPERATURE ON THE EFFICACY OF 1-MCP TREATMENT OF CUT FLOWERS 125

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4.2.1 Plant material 1264.2.2 Chemicals 1274.2.3 Treatments 1274.2.4 Assessments 1284.2.5 Experiment design and data analysis 128

4.3 RESULTS 1294.3.1 Duration of persistence of 1-MCP pre-treatment effects on G. ‘Sylvia’ inflorescences 1294.3.2 Duration of persistence of 1-MCP and STS pre-treatment effects on flowering C. uncinatum sprigs 135

4.4 DISCUSSION 150

5 COMMERCIAL SCALE 1-MCP TREATMENTS PROTECT GERALDTONWAXFLOWER AGAINST ETHYLENE-INDUCED FLOWER ABSCISSION 153


5.2.1 Plant material and preparation 1515.2.2 Chemicals 1515.2.3 Treatments 1515.2.4 Quality assessment 1585.2.5 Experiment design and data analysis 158

5.3 RESULTS 1595.3.1 Application of 1-MCP inside polyethylene 1595.3.2 Injection of 1-MCP into cartons 1735.3.3 Application of 1-MCP into a coolroom 1835.3.4 Application of 1-MCP in cartons by forced-air cooling 1875.3.5 Slow release of 1-MCP inside cartons 192

5.4 DISCUSSION 197

6 GENERAL DISCUSSION AND CONCLUSIONS 205

6.1 EFFICACY OF 1-MCP TREATMENTS ON CUT FLOWERS 2056.2 EFFICACY OF COMMERCIAL SCALE 1-MCP TREATMENTS 2066.3 EFFECT OF TEMPERATURE ON THE EFFICACY OF 1-MCP TREATMENT 2076.4 DURATION OF PROTECTION AFFORDED BY 1-MCP TREATMENT 2086.5 EFFECT OF TEMPERATURE ON THE DURATION OF PROTECTION AFORDED BY 1-MCP TREATMENT 2096.6 DURATION OF PROTECTION AFFORDED BY STS TREATMENT 2096.7 GENERAL CONCLUSIONS AND RECOMMENDATIONS 210

APPENDICES 213

APPENDIX A LITERATURE REVIEW 213

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1.1 ETHYLENE IN PLANT BIOLOGY 2131.1.1 General roles 2131.1.2 Abscission 2141.1.3 Senescence of vegetative tissue 2161.1.4 Flower senescence 2171.1.5 Fruit ripening and senescence 220

1.2 ETHYLENE BIOSYNTHESIS 2221.3 INHIBITORS OF ETHYLENE BIOSYNTHESIS 224

1.3.1 Aminoethoxyvinylglycine 2241.3.2 Aminooxyacetic acid 225

1.4 ETHYLENE PERCEPTION 2251.5 INHIBITORS OF ETHYLENE PERCEPTION 229

1.5.1 Silver ions 2291.5.2 2,5-Norbornadiene 2311.5.3 Diazocyclopentadiene 2311.5.4 Cyclopropenes 233

1.6 INTERACTION BETWEEN ETHYLENE BIOSYNTHESIS AND PERCEPTION 2391.7 ETHYLENE IN POSTHARVEST HORTICULTURE 241

1.7.1 Gas ripening and degreening 2411.7.2 Acceleration of deterioration 2421.7.3 Ethylene removal 2421.7.4 Biosynthesis inhibition 2441.7.5 Binding inhibition 244

APPENDIX B SUPPORTING AND STATISTICAL DATA 247

APPENDIX C SUMMARY TABLE OF PROJECT ACHIEVEMENTS 329

BIBLIOGRAPHY 331

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LIST OF ABBREVIATIONS AND SYMBOLS

a.i. active ingredient

ACC 1-aminocyclopropane-1-carboxylic acid

ACO ACC oxidase

ACS ACC synthase

Ado-Met S-adenosylmethionine

Ag(S2O3)2 silver thiosulfate

Ag+ silver

AgNO3 silver nitrate

ANOVA Analysis of variance

AOA aminooxyacetic acid

AVG aminoethoxyvinylglycine

ca. approximately

cf. compare

χ2 chi-square

cm centimetre

Co. company

CO2 carbon dioxide

Co2+ cobalt ions

CP cyclopropene

CRD completely randomised design

DACP diazocyclopentadieneoC degrees celsius

DI deionised water

DICA dichloroisocyanurate

3,3-DMCP 3,3-dimethylcyclopropene

E east

e.g. for example

epi epinastic

et al. and others

FID flame ionisation detector

FW fresh weight

g gram

> greater than

≥ greater than or equal to

HCl Hydrochloric acid

hr hour

i.e. that is

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IHD Institute for Horticultural Development

Inc. Incorporated

kd binding dissociation constant

kg kilogram (103 g)

km kilometre

KMnO4 potassium permanganate

KOH potassium hydroxide

< less than

L litre

LSD least significant difference

1-MCP 1-methylcyclopropene

m metre

M molar (moles/L)

MACC 1-(malonylamino) cyclopropane-1-carboxylic acid

µL microlitre (10-6 L)

mg milligram (10-3 g)

mL millilitre (10-3 L)

mm millimetre

mM millimolar (10-3 M)

mol mole

mRNA messenger RNA

MTA methylthioadenosine

MTR methylthioribose

n number of replicates

NaOH sodium hydroxide

Na2S2O3 sodium thiosulfate

NH4SO4 ammonium sulphate

nL nanolitre (10-9 L)

nmol nanomole (10-9 mole)

nor non-ripening

Nr never-ripe

2,5-NBD 2,5-norbornadiene

ns not significant

NSW New South Wales

% percent

± plus or minus

P probability

pers. comm. personal communication

Qld Queensland Registered name

x

RH relative humidity

rin ripening inhibitor

RNA ribonucleic acid

s second

S south

s.e. standard error

SLFE shelf life following ethylene treatment

STS silver thiosulfateTM Trade Mark

UQG The University of Queensland, Gatton College

UV ultra violet

v volume

viz. namely

vs. versus

w weight

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EXECUTIVE SUMMARY

Premature flower fall or abscission and flower senescence (e.g. wilting) are ethylene-related postharvest

problems for a number of cut flowers. Unintentional exposure of these flowers to ethylene, a plant hormone,

reduces their postharvest longevity and marketability. Treatments that inhibit ethylene biosynthesis or action can

be used to protect sensitive horticultural commodities against exposure to ethylene. To date, the most successful

commercial treatment for preventing ethylene-induced flower abscission and senescence is pulsing flower stems

with silver thiosulfate (STS). Because the active ingredient of STS is silver, a heavy metal, legislators in some

countries are considering restricting the commercial use of STS. Recently, researchers in the USA developed an

alternative, novel gaseous inhibitor of ethylene action in plants, 1-methylcyclopropene (1-MCP). 1-MCP

apparently binds irreversibly to ethylene receptors in plant tissue, thereby preventing ethylene action. In studies

conducted overseas, 1-MCP applied at low concentrations has been shown to protect several cut flowers

including carnation, Cymbidium orchid and Geraldton waxflower against exposure to ethylene. A commercial

preparation of 1-MCP, EthylBloc, has been recently produced. EthylBloc is being evaluated by the

Environmental Protection Agency in the USA. It is anticipated that EthylBloc will soon be registered for use on

ornamentals (J. Daly, pers. comm.). In the present study, it was proposed that 1-MCP would prove to be an

effective anti-ethylene treatment for a variety of ethylene sensitive native Australian cut flowers.

The objectives of this study were to:

• Develop dosing (concentration, duration and temperature) relationships for 1-MCP treatment of native cut

flowers.

• Extend the postharvest longevity or vase life of various ethylene-sensitive native cut flowers through

treatment with 1-MCP.

• Devise and test practical application systems for 1-MCP treatment.

Experiments were conducted to determine an effective 1-MCP pre-treatment protocol (viz. concentration, duration

and temperature) for protecting native Australian cut flowers against ethylene. Pre-treatment of Grevillea ‘Sylvia’

inflorescences on day 0 of the experiment with 10 nL 1-MCP/L (10 parts per billion) for 12 hours at 20oC delayed

the onset of flower abscission induced by exposure on day 1 to 10 µL ethylene/L (10 parts per million) for 12 hours

at 20oC. Pre-treatments using lower 1-MCP concentrations (e.g. 5 nL 1-MCP/L for 12 hours at 20oC) and shorter

treatment duration (e.g. 10 nL 1-MCP/L for 3 hours at 20oC) also reduced the sensitivity of G. ‘Sylvia’

inflorescences to exogenous ethylene. These results are consistent with research conducted overseas where similar

1-MCP pre-treatments protected a range of traditional cut flowers, including carnation, snapdragon, Penstemon and

phlox against ethylene.

Pre-treatment on day 0 with 10 nL 1-MCP/L for 12 hours at 20oC protected nine other ethylene-sensitive native

Australian cut flowers (viz. Alloxylon pinnatum, Ceratopetalum gummiferum, Chamelaucium uncinatum ‘Paddy’s

Late’, G. ‘Kay Williams’, G. ‘Sandra Gordon’, Leptospermum petersonii, Telopea speciosissima and Verticordia

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nitens) against exposure on day 1 to 10 µL ethylene/L for 12 hours at 20oC. In addition, 1-MCP pre-treatment

afforded flowering Boronia heterophylla stems with protection against exposure to 10 µL ethylene/L for the longer

duration of 72 hours at 20oC. 1-MCP pre-treatment reduced ethylene-induced floral organ abscission and the

associated loss in vase life. Ethylene-induced floral organ wilting on B. heterophylla and C. gummiferum was also

reduced by 1-MCP pre-treatment. The efficacy of 1-MCP pre-treatment appeared to be similar to reports where

STS treatment prevented ethylene-induced floral organ abscission and senescence from various native cut flowers.

With the exception of C. gummiferum, 1-MCP pre-treatment did not extend the vase lives of flowers not exposed

to ethylene. Thus, 1-MCP appears to be useful as a precautionary treatment for native cut flowers which may be

exposed to exogenous ethylene during the postharvest handling phase.

G. ‘Sylvia’ inflorescences pre-treated with 10 nL 1-MCP/L for 12 hours at 2oC were not protected against ethylene.

Similarly, C. uncinatum sprigs were only protected against exogenous ethylene treatment for ca. 2 days after pre-

treatment with 10 nL 1-MCP/L for 12 hours at 2oC. These results confirm work conducted in the USA, where the

efficacy of 1-MCP was shown to be reduced for cut Penstemon and Kalanchoe flowers pre-treated at 2oC. The

reason why the efficacy of 1-MCP is reduced at low temperature is unclear. Presumably, 1-MCP binding or

diffusion to ethylene receptors is reduced at low temperature.

G. ‘Sylvia’ inflorescences and C. uncinatum sprigs pre-treated on day 0 with 10 nL 1-MCP/L for 12 hours at 20oC

remained insensitive to exogenous ethylene for 2 and ca. 4 days, respectively, after 1-MCP pre-treatment.

Thereafter, exposure of sprigs to ethylene induced flower abscission and reduced vase life. The synthesis of new

ethylene receptors is presumably responsible for the recovery of sensitivity, which appears to be rapid in the

abscission zones of both G. ‘Sylvia’ and C. uncinatum flowers. In contrast to 1-MCP, pre-treatment of C.

uncinatum sprigs with STS (0.5 mM Ag+) for 12 hours at 2 or 20oC afforded longer term protection against

ethylene. Pulsing sprigs with STS provided complete protection against ethylene for the duration of the experiment

(viz. 10 days). Silver in the STS complex is thought to bind to ethylene receptors and thereby block ethylene

action. Based on the results of this study it seems that silver remains as a ‘pool’ in and around flower abscission

zones and binds to new receptors as they are formed.

A number of 1-MCP treatment systems that are potentially suitable for industry were evaluated. Pre-treatment of

C. uncinatum bunches standing in buckets of water inside sealed polyethylene tents with 200 nL 1-MCP/L for

either 6 hours at 20oC or 14 hours at 2 or 20oC effectively reduced ethylene-induced flower abscission. Similarly,

bunches in buckets of water pre-treated with 150 nL 1-MCP/L for 15 hours at 2oC inside a sealed coolroom were

afforded protection against ethylene. Thus, 1-MCP pre-treatment at low temperature is effective when high 1-MCP

concentrations are used. Similarly, the efficacy of 1-MCP pre-treatment of Kalanchoe flowers was reported to be

improved by increasing the pre-treatment temperature from 2 to 24oC and/or increasing the 1-MCP concentration

from 10 to 128 nL/L. Thus, from a practical perspective, effective protection against ethylene can be achieved by

using high 1-MCP concentrations (e.g. 150-200 nL/L) at low temperature. Moreover, high 1-MCP concentrations

take the possibility of small leaks existing from the enclosed structures into account.

1-MCP pre-treatment (200 nL/L) applied at 2oC by forced air movement through cartons or via circulating

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coolroom air through bunches standing in buckets of water also effectively reduced ethylene-induced flower

abscission and the associated loss in vase life. Similar levels of flower abscission and vase lives were found for

sprigs at various sampling position within cartons treated by forced air. This similarity indicates that the movement

of air containing 1-MCP through cartons was uniform.

Injection of 0.2 or 2 µL 1-MCP/L by syringe into cartons containing C. uncinatum bunches that were then held for

24 hours at 2oC did not consistently reduce ethylene-induced flower abscission. One explanation for reduced

efficacy of this treatment is that 1-MCP may have diffused out through the carton wall. To provide sustained

release of 1-MCP, glass tubes with rubber seals containing 1-MCP gas were placed at three positions amongst

bunches inside cartons. The 1-MCP concentration in tubes decreased from 6928 ± 177 µL/L on day 0 to 1793 ±

48 µL/L on day 6 indicating that 1-MCP diffused through the rubber plugs that sealed the tubes. 1-MCP treatment

via this slow release system was fully effective at protecting flowers against ethylene when three tubes were placed

into each carton. When one or two tubes were placed into cartons, only flowers adjacent to tubes were protected

against ethylene. Sustained release of 1-MCP gas from inside cartons promises to be an effective alternative

treatment which, after refinement, may provided extended protection against ethylene.

In summary, 1-MCP treatments developed in this RIRDC sponsored work have potential as a postharvest anti-

ethylene treatments for sensitive native Australian cut flowers. Application of 150-200 nL 1-MCP/L for 3-15

hours duration at 2 or 20oC to native cut flowers inside enclosed coolrooms or tents was completely effective in

reducing ethylene-induced flower abscission. However, compared to STS pulsing, 1-MCP pre-treatment provides

native cut flowers with relatively short term protection against ethylene. Sustained release of 1-MCP from inside

cartons has potential, following refinement, to provide cut flowers with longer term protection against ethylene by

remaining available to bind to newly formed ethylene receptors. This treatment would be easy to use and allow

rapid dispatch of cut flowers to markets by eliminating the need to pre-treat flowers. Additionally, it may appeal to

growers without suitable enclosed treatment structures and those concerned about handling chemicals such as 1-

MCP and STS. Nevertheless, 1-MCP treatments developed in this study are comparatively easy to apply and can

provide protection to sensitive cut flowers where the period of postharvest handling is brief.

1

CHAPTER 1

GENERAL INTRODUCTION

1.1 BACKGROUND TO RESEARCH

There is increasing demand in the international floral trade for native Australian cut flowers as an exotic

alternative to traditional cut flowers such as carnations, roses and chrysanthemums (Joyce et al. 1993). As

a result, the native cut flower industry in Australia has grown considerably over the past 15 years. Native

cut flower exports have increased from $3 million in 1983 to $27 million in 1995/96 (FECA 1996).

However, there has been limited research into the postharvest physiology and horticulture of these flowers

particularly in relation to ethylene (Faragher 1989). Ethylene is a gaseous plant hormone that regulates a

number of growth, development and senescence processes (Abeles et al. 1992). Exposure of several

native cut flowers to ethylene is known to induce floral organ abscission and senescence, thereby reducing

vase life and marketability (Joyce et al. 1993). The deleterious effects of ethylene on ornamentals during

postharvest can, however, be regulated by chemical inhibitors of ethylene biosynthesis or perception

(Sherman 1985).

Ethylene is thought to bind to plants through a membrane-located receptor (Burg and Burg 1967; Sisler et

al. 1980; Bleecker et al. 1988). Inhibitors of ethylene perception are presumed to counteract ethylene by

binding to these receptors and thereby blocking subsequent signal transduction and translation (Sisler

1979, 1991). A number of compounds have been developed over the past 25 years to inhibit ethylene

perception by plants. 2,5-norbornadiene (2,5-NBD) inhibits ethylene perception in a range of ethylene

sensitive plants (Sisler and Pian 1973; Sisler et al. 1983; Sisler and Yang 1984b). However, the

reversible nature of 2,5-NBD binding to ethylene receptors and offensive odour limit its practical use

(Sisler et al. 1986). Another inhibitor of ethylene perception is silver (Ag+) (Beyer 1976). Ag+ in the

silver thiosulfate (STS) complex is used successfully as a postharvest treatment to prevent ethylene-

induced floral organ abscission and senescence from ethylene sensitive cut flowers and potted plants

(Veen 1983; Nowak and Rudnicki 1990). STS solution applied as a pulse moves readily in the

transpiration stream of cut flowers and accumulates in their receptacles (Veen and van de Geijn 1978).

However, Ag+ is a heavy metal and environmental pollutant and as a result, some countries are starting to

restrict its use (Serek et al. 1994a). As a possible alternative to STS, diazocyclopentadiene (DACP) gas

was developed and shown to delay ethylene-induced flower abscission and senescence and fruit ripening

(Sisler and Blankenship 1993a, b; Sisler et al. 1993). However, a major problem with DACP is that it is

only fully effective when irradiated with fluorescent light (Serek et al. 1995b).

Recently, an alternative and novel inhibitor of ethylene perception, 1-methylcyclopropene (1-MCP) gas,

was synthesised (Serek et al. 1994b). 1-MCP inhibits ethylene binding by apparently competing with

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ethylene and binding to the ethylene receptors in an irreversible manner (Sisler and Serek 1997). It has

been shown to prevent ethylene perception in a range of cut flowers (Serek et al. 1995a, c; Porat et al.

1995b; Sisler et al. 1996a), potted flowering plants (Serek et al. 1994b), climacteric fruit (Sisler et al.

1996b; Golding et al. 1998) and non-climacteric fruit (Ku et al. 1999; Porat et al. 1999). 1-MCP is

reportedly as effective as STS in preventing cut flower abscission and senescence, even when applied at

very low concentrations (Serek et al. 1995a). The efficacy of 1-MCP treatment has been shown to be a

relationship between 1-MCP concentration, treatment duration and treatment temperature (Serek et al.

1995a; Reid et al. 1996). 1-MCP is generally considered to be non-toxic at active concentrations and thus

has considerable potential as a commercial treatment for the regulation of ethylene responses in

ornamentals (Sisler and Serek 1997).

1.2 GENERAL OBJECTIVES

The general objectives of this research were to:

1. Develop dosing (concentration, duration and temperature) relationships for 1-MCP treatment of

native cut flowers,

2. Extend the postharvest longevity of a number of ethylene-sensitive native cut flowers through

treatment with 1-MCP,

3. Devise and test practical application systems for 1-MCP treatment.

1.3 REPORT STRUCTURE

This report is divided into six chapters. Chapter one (General Introduction) identifies the problem and

outlines the direction of the investigation. Chapters two, three, four and five report on experiments

conducted. An evaluation of the effects of 1-MCP concentration, treatment duration and treatment

temperature on the ethylene sensitivity of Grevillea ‘Sylvia’ inflorescences is presented in Chapter two.

Chapter three reports on a screening study in which the response of a number of native Australian cut

flowers to 1-MCP and ethylene treatments were examined. Chapter four presents a more detailed

investigation into the effects of temperature on the efficacy of 1-MCP treatments on native cut flowers.

The development and testing of several practical application systems for 1-MCP treatment are presented

in Chapter five. Chapter six is the general discussion, which reviews the findings of this report in relation

to existing literature and outlines the opportunities for future research. A survey of available literature

concerning the content of this report is presented in Appendix A. All supporting and statistical data for

the experimental chapters are shown in appendices 2.1 to 5.42 of Appendix B. A summary table of

achievements of project milestones is presented in Appendix C.

4

CHAPTER 2

1-MCP TREATMENT PREVENTS ETHYLENE-INDUCED FLOWER

ABSCISSION FROM GREVILLEA ‘SYLVIA’ INFLORESCENCES

2.1 INTRODUCTION

Grevillea is the largest genus in the family Proteaceae, containing over 340 species that are mostly native

to Australia (Olde and Marriott 1994). Many Grevillea hybrids have attractive foliage and colourful

inflorescences. Most hybrids have appeal as landscape plants, while some have potential as cut flowers

(Costin and Costin 1988). Presently, use of Grevillea hybrids for cut flowers is limited by a typically

short vase life of less than 1 week (Joyce et al. 1996). The short vase life of Grevillea hybrids is

associated with the fragile nature of inflorescences and rapid perianth abscission (Faragher 1989).

Moreover, exposure of Grevillea inflorescences to exogenous ethylene elicits rapid flower and perianth

abscission and reduces vase life (Joyce and Haynes 1989). Sensitivity of Grevillea hybrids to ethylene

may be reduced by pulse treating inflorescences with STS solution immediately after harvest (Joyce and

Haynes 1989; Vuthapanich et al. 1993).

A novel gaseous inhibitor of ethylene perception, 1-MCP was developed recently (Serek et al. 1994b).

Treatment with 1-MCP at nanomolar concentrations prevented ethylene-induced senescence of cut

carnation flowers (Serek et al. 1995a; Sisler et al. 1996a, b) and abscission from cut Geraldton waxflower

(Serek et al. 1995c), Penstemon (Serek et al. 1995a) and phlox (Porat et al. 1995b) flowers. The 1-MCP

treatment concentration required to prevent ethylene-induced flower senescence and abscission from cut

flowers is inversely related to the treatment time (Serek et al. 1995a; Sisler et al. 1996a) and treatment

temperature (Serek et al. 1995a; Reid et al. 1996). Accordingly, 1-MCP efficacy appears to be mediated

by treatment conditions with respect to its binding to the ethylene receptor.

The fragile nature of Grevillea inflorescences and their sensitivity to exogenous ethylene suggests that

they may benefit, in terms of postharvest longevity, from treatment with 1-MCP. In the present study, 1-

MCP was evaluated as a potential postharvest anti-ethylene treatment for G. ‘Sylvia’ (G. banksii x G.

whiteana hybrid) inflorescences. The 1-MCP treatment variables of concentration, treatment duration and

temperature, were examined in three successive experiments. In addition to basic assessment of vase life

parameters, respiration, ACC concentrations in flowers and ethylene production by inflorescences were

measured.

2.2 MATERIALS AND METHODS

2.2.1 Plant material

5

G. ‘Sylvia’ cut flowers comprised of 1 terminal inflorescence and the supporting stem were harvested

from 5 year old in-ground plants at a commercial nursery near Redland Bay in S.E. Qld (27o 37’S, 153o

18’E). Inflorescences with newly opened flowers at maturity stage 4 (Beal et al. 1995) were cut with

secateurs in the morning (0900-1100 hours) to a length of approximately 30 cm. Leaves were trimmed

from stems. Inflorescences were then placed into styrofoam boxes between layers of newsprint moistened

with deionised (DI) water to minimise moisture loss. Inflorescences were arranged carefully so that they

were separated from each other to avoid mechanical injury. A layer of ice was placed in the bottom of

each box to minimise heating of inflorescences. They were then taken to The University of Qld, Gatton

College (UQG) postharvest laboratory in an air conditioned car within 2 hours of harvest.

At the laboratory, stem ends were recut under DI water to avoid air embolisms by removal of at least 2 cm

from the stem base. Inflorescences were then assigned at random to treatment lots. They were each

placed into individual vases (375 mL capacity) containing a solution of 10 mg available chlorine/L as the

sodium salt of dichloroisocyanurate (DICA), an anti-microbial agent. Smaller vases (100 mL capacity)

were used in experiments examining effects of 1-MCP on inflorescence physiology. Vases were closed

with a piece of low density polyethylene film secured over the opening with a rubber band. This plastic

film minimised evaporation and prevented falling flowers from contaminating the vase solution.

Inflorescences were inserted through slits in the plastic film into the vase solution.

2.2.2 Chemicals

2.2.2.1 1-Methylcyclopropene

1-MCP was synthesised using a modified method of Sisler and Serek (1997), whereby lithium

diisopropylamide was substituted for phenyllithium (E. Sisler, pers. comm.). 1-MCP stock gas was held

in a glass bottle sealed with a rubber port. The volume of gas removed from the bottle with a syringe was

simultaneously replaced with saturated ammonium sulphate (NH4SO4) solution to maintain a constant

concentration by prevention of pressure imbalances. The stock bottle was kept at 4oC in an inverted

position so that the NH4SO4 solution provided an additional seal on the inside of the rubber port. The 1-

MCP concentration in the bottle was quantified by injecting 1 mL samples into a Shimadzu GC-8AIT gas

chromatograph equipped with a flame ionisation detector (FID). The sample was separated in a 1.22 m

long by 3.2 mm internal diameter stainless steel column packed with Chromosorb P-AW with a mesh

range of 80/100 (Appendix 2.1). The gas chromatograph was operated at an oven temperature of 40oC

and an injector/detector temperature of 50oC. High purity nitrogen gas (2.4 kg/cm2) was the carrier gas.

A 97.3 µL iso-butylene/L standard (BOC Gases, β-grade special gas mixture) was used to calibrate the

gas chromatograph (L. Dodge, pers. comm.). The detection limit for 1-MCP was 0.1 µL/L in a 1 mL

sample. The location of 1-MCP on the gas chromatogram was identified by reacting the 1-MCP sample

with 0.1 g elemental iodine in 10 mL absolute ethanol for 1 hour (E. Sisler, pers. comm.). This reaction

‘scrubbed’ or removed 1-MCP from the sample (Appendix 2.2).

6

2.2.2.2 Ethylene

Pure ethylene (BOC Gases) was used in the treatment of inflorescences. A working stock was created by

diluting pure ethylene gas in air inside a glass bottle sealed with a rubber port. Saturated NH4SO4 solution

was used to replace the volume of gas withdrawn. The ethylene stock was held at 20oC in an inverted

position. Ethylene was quantified by injecting 1 mL gas samples into a Shimadzu GC-8AIT FID gas

chromatograph. This gas chromatograph was fitted with a 0.9 m long by 3.5 mm internal diameter glass

column packed with activated alumina with a mesh range of 80/100. The gas chromatograph was

operated at an oven temperature of 90oC and an injector/detector temperature of 120oC. The carrier gas

used was high purity nitrogen (1.2 kg/cm2). A 103 µL ethylene/L standard (BOC Gases, β-grade special

gas mixture) was used for calibration.

2.2.2.3 Propylene

Pure propylene gas (Matheson Gas Products Inc.) was diluted in air in a glass bottle stoppered with a

rubber port. The propylene stock was handled in the same manner described for the ethylene stock

(section 2.2.2.2). Propylene gas was quantified by injecting 1 mL samples into the same gas

chromatograph used to quantify ethylene (section 2.2.2.2). A laboratory made 1000 µL propylene/L

standard was used to calibrate the gas chromatograph. This standard was prepared by diluting pure

propylene gas inside a glass bottle containing high purity nitrogen.

2.2.3 Treatment chambers

Glass 60.5 L volume (length, breadth and height each 39.25 cm) chambers, with removable lids were used

for adminstering 1-MCP, ethylene and propylene treatments. The lids each had a 10 mm diameter hole at

the centre for attachment of a stirring fan and a 75 mm diameter hole to one side for a gas injection and an

ambient air admission port. The latter two apertures were through a rubber plug (Plate 2.1). These holes

were sealed around the stirring fan and rubber plug with Vaseline (petroleum jelly). Stirring fans were

used to mix air in the chambers and eliminate gas concentration gradients. Beakers each containing 10

mL 1M potassium hydroxide (KOH) solution were placed into chambers to reduce the excessive

accumulation of CO2 from respiring inflorescences (Plate 2.1). A filter paper was stood vertically into

each beaker to increase the surface area of KOH. To avoid a reduction in chamber air pressure due to

sorption of CO2 by KOH, air was admitted through a saturated NH4SO4 solution trap (Plate 2.1).

7

Plate 2.1. Treatment chamber showing a glass structure (A), a stirring fan (B), a gas injection portand an ambient air admission port (C), beakers containing 1M KOH (D) and an air admission trap(E).

8

2.2.4 Treatments

2.2.4.1 Effects of 1-MCP concentration, treatment duration and

treatment temperature on cut G. ‘Sylvia’ inflorescences

In a series of three experiments, inflorescences in vases were evenly allocated to treatment chambers each

containing 6 to 8 beakers of 1M KOH solution. Once all inflorescences were inside chambers, lids were

sealed in place with polyethylene tape. Inflorescences were then treated with 1-MCP on day 0 of each

experiment at different concentrations, treatment durations and treatment temperatures. Aliquots of 1-

MCP gas were injected through the gas injection port. Control inflorescences were enclosed in matching

chambers in air with KOH, but without 1-MCP. The fan in each chamber circulated air for 10 minutes

after injection. Inflorescences in chambers were exposed to cool white fluorescent lights providing 6

µmol/m2/s at inflorescence height.

Following 1-MCP treatment, chambers were ventilated by removing their lids either outside the laboratory

or in a fume cupboard. After approximately 10-15 minutes, chambers were returned to the laboratory. All

inflorescences in their vases were removed from chambers and re-randomised within each treatment lot.

Half of the inflorescences from each treatment were then placed back into chambers which were again

sealed. They were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. The ethylene

treatment protocol was based on similar treatments reported by Joyce (1989). Ethylene gas was injected

and the ethylene concentration inside the chambers was checked by gas chromatography. Control

inflorescences were enclosed in matching chambers in air and were not treated with ethylene. Following

ethylene treatment, inflorescences and their vases were removed from chambers and transferred to a vase

life room operating at 20 ± 2oC and 50-70% RH. The room was fitted with overhead cool white

fluorescent lights providing 13 µmol/m2/s at inflorescence height on a 12 hour on/off cycle.

Concentrations of 1-MCP required to protect G. ‘Sylvia’ inflorescences against ethylene were investigated

by treating inflorescences with 5, 10 or 20 nL 1-MCP/L for 12 hours at 20oC. These 1-MCP

concentrations were similar to those used by Serek et al. (1995a) with a range of cut flowers. The effect

of different 1-MCP treatment durations was then investigated by treating inflorescences with 10 nL 1-

MCP/L for 3, 6, 9 or 12 hours at 20oC. Finally, the efficacy of 1-MCP treatment at a range of

temperatures was tested. Inflorescences were placed into vase solutions held at 0, 5, 10 or 20oC. The

stem temperature of an additional inflorescence in a vase placed at each temperature was monitored using

thermocouples. Once the stem had reached the desired temperature, inflorescences were treated with 10

nL 1-MCP/L for 12 hours at each temperature. Control inflorescences enclosed in chambers held at each

temperature remained in air without 1-MCP. Following 1-MCP treatment, inflorescences were transferred

to vases kept at 20oC. When the temperature of inflorescences reached 20oC, they were exposed to

ethylene.

2.2.4.2 Effect of 1-MCP treatment on the physiology of cut G. ‘Sylvia’

9

inflorescences

In two identical experiments, inflorescences were treated on day 0 with 10 nL 1-MCP/L for 12 hours at

20oC as described in section 2.2.4.1. Control inflorescences were enclosed in chambers in air without 1-

MCP. In these experiments, propylene was used to mimic ethylene treatment (Burg and Burg 1967) and

thereby facilitate measurement of ethylene production by inflorescences (McMurchie et al. 1972).

Following 1-MCP treatment, half of the inflorescences from each treatment were exposed on day 1 to 100

µL propylene/L for 12 hours at 20oC. The remaining half of the inflorescences stayed in air without

propylene. At the completion of propylene treatment, inflorescences were placed into a controlled

environment room operating at 20oC and 50% RH under cool fluorescent lights giving 6 µmol/m2/s at

inflorescence height and a 12 hour light period per day.

2.2.5 Assessments

2.2.5.1 Vase life

Inflorescences and their vases were separately weighed daily to allow calculations of relative fresh mass

[% of initial day 0 fresh weight (FW)] and vase solution uptake (mL/g initial FW), respectively. Flower

abscission from inflorescences was determined daily after gently brushing them three times by hand.

Abscission was rated using the following scale: 1 = < 10%, 2 = 10-30%, 3 = 30-50%, 4 = 50-80%, 5 = >

80% abscission relative to the initial number of flowers on a inflorescences (Joyce and Poole 1993).

Flower wilting and discolouration (fading) were assessed daily using the following rating scale: 1

= none/slight, 2 = moderate, 3 = advanced. Opening of flowers was recorded daily using the following

scale: 1 = < 5%, 2 = 5-25%, 3 = > 25% open flowers on an inflorescence. Vase life of inflorescences was

judged as the time in days to loss of visual appeal (viz. > 10% flower abscission and/or moderate flower

wilt and/or moderate discolouration).

2.2.5.2 Measurement of respiration and ethylene production rates

Inflorescences were placed individually with their vases into 2.2 L glass jars. These jars contained either

10 g Purafil (aluminium oxide pellets coated with potassium permanganate) (ethylene scrubber) or 10

mL 1M KOH (CO2 scrubber) solution. All jars were sealed daily with a plastic screw-on lid and held at

20oC for 4 and 8 hours to allow accumulation of CO2 and ethylene, respectively. Three replicates were

used for each treatment.

Headspace gas samples were taken through a sampling port in the lid of each jar using a 1 mL syringe.

Syringes were pumped 5-6 times with air within the jars to stir the air therein before the sample was taken

for analysis. Syringes were likewise flushed several times with ambient air between taking subsequent

samples from different jars. CO2 was quantified with a Shimadzu GC-8AIF gas chromatograph fitted with

a thermal conductivity detector (TCD) and using a 1.5 m long by 1.8 mm internal diameter copper column

10

packed with Porapak R with a mesh size of 80/100. High purity helium gas (2.5 kg/cm2) was the carrier

gas. Column temperature was 25oC and injector/detector temperature was 30oC. CO2 samples were

quantified against a 0.573% CO2 standard (BOC Gases β-grade special gas mixture). Ethylene samples

were quantified as detailed previously (section 2.2.2.2) and using a 0.09 µL ethylene/L standard (BOC

Gases β-grade special gas mixture). The rates of respiration and ethylene production were calculated as

mL CO2/kg FW/hr and µL/kg FW/hr, respectively.

2.2.5.3 Measurement of 1-aminocyclopropane-1-carboxylic acid

ACC concentration in flowers was measured using a modification of the method described by Jobling et

al. (1991). At each sampling time, approximately 2 g of flowers from individual inflorescences were

stripped by hand. These flowers were sealed into plastic bags and immediately frozen in liquid nitrogen (-

196oC). They were then held in a -20oC freezer pending ACC measurement.

A weighed sample (ca. 1 g) of floral tissue was cut up finely with a scalpel. Five mL of acidified

methanol (0.1M HCl in methanol) was added to the tissue in a 110 mL test tube and left to extract for 4

hours at 20oC. Following thorough vortex mixing, a 500 µL aliquot of the sample extract was pipetted

into a 15 mL VenojectTM plain blood serum collection tube, and made up to 800 µL with distilled water.

Each sample extract was prepared in duplicate. One of the duplicates from each sample was spiked with

100 nmol ACC (Sigma Chemical Co.). The extract was neutralised to the phenolphthalein endpoint (pH

8.5-9, pink colour) by dropwise addition of 10% (w/v) KOH. A 200 µL aliquot of 0.1 M mercuric (II)

chloride was added, and the tube was sealed with a rubber septum. Next, a 0.1 mL aliquot of a mixture of

liquid chlorine (White KingTM; 40 g available chlorine/L as sodium hypochlorite) and saturated sodium

hydroxide (NaOH) in a 2:1 ratio (v/v) were injected into the tube. Following vortex mixing, the mixture

was left for 1 hour at 30oC. The concentration of ethylene in a 1 mL sample of headspace gas was

determined by gas chromatography. Initial ACC concentration (nmol/g FW) was calculated, with

correction for the percent recovery of ACC in the spiked samples.

2.2.6 Experiment design and data analysis

In all experiments, inflorescences were arranged in completely randomised designs (CRD). Three to ten

replicate inflorescences were used for each treatment, depending upon the particular experiment. The

effects of 1-MCP concentration and treatment duration were examined as 2 (ethylene) x 4 (1-MCP) or 2

(ethylene) x 5 (1-MCP) factorial experiments, respectively. The influence of temperature on the efficacy

of 1-MCP treatment was determined using a 2 (ethylene) x 2 (1-MCP) x 4 (temperature) factorial

experiment. Inflorescence physiology was examined as 2 (ethylene) x 2 (1-MCP) factorial experiments.

Treatment means ± standard errors were calculated using Microsoft Excel (Version 5.0, Microsoft Inc.)

and are presented for all data. Figures were created using Sigmaplot (Version 2.0, Jandel Corporation)

scientific graphing software. Data were analysed by ANOVA unless otherwise stated using the balanced

ANOVA function of Minitab (Release 11.12, Minitab Inc.) biometrics package. All data from the first

experiment are presented in the main body of this chapter. Thereafter, data for which there were non-

11

significant differences between treatments are presented in appendices.

Flower abscission, wilting and discolouration data from experiments examining the effects of different 1-

MCP concentrations and treatment durations were recorded as the time in days to reach a score of 2 (viz.

> 10% flower abscission, moderate flower wilting and moderate flower discolouration) for ANOVA. The

time in days to reach moderate flower discolouration on inflorescences used in the physiology experiment

was also recorded for ANOVA. Flower abscission data were then analysed as factorial ANOVAs. When

flower abscission from inflorescences was 100%, flower wilting, discolouration and opening

measurements for these inflorescences were by necessity discontinued. Thus, as unbalanced data sets

existed, flower wilting and discolouration data were analysed for the remaining treatments as one-way

ANOVAs. Vase life data from all experiments were analysed as factorial ANOVAs.

In subsequent experiments, all replicates did not reach flower abscission, wilting or discolouration scores

of 2. In the case of flower abscission data, scores were converted to the corresponding percentage and

arcsine transformed to obtain approximately normally distributed data sets for ANOVA (Steel and Torrie

1987). Flower wilting and discolouration data were assigned a binary score, where the absence or

presence of moderate to advanced wilting or discolouration on each inflorescence was recorded as a 0 or 1

score for ANOVA (Narula and Levy 1977). Flower abscission, wilting and discolouration data were then

anlaysed as split plot for time (i.e. sequential days of measurement) ANOVAs. Relative fresh weight,

vase solution uptake, ACC concentration, respiration and ethylene production data were also analysed as

split plot for time ANOVAs. The days of measurement on which no variation between data existed were

excluded from split plot for time ANOVAs. Flower opening was analysed by testing if an association

existed between treatments and opening scores using chi-square (χ2) tests (Conover 1980). Where chi-

square tests were invalid, data were analysed using Fisher’s exact test (Conover 1980) by SAS (Release

6.12, SAS Institute 1996).

Following ANOVA, the least significant difference (LSD) test at P = 0.05 was used to separate treatment

means. LSDs calculated from split plot for time ANOVAs are for comparisons between treatments, rather

than for a particular time within a treatment. LSDs were calculated and presented only when ANOVA

showed significant (P < 0.05) differences between treatments. Differences between treatment means

referred to in the results are significant at P < 0.05 level. LSDs which relate to ANOVAs performed on

data not directly shown in figures are presented in appendices. LSDs from ANOVA on transformed and

binary data sets are not presented as they do not correspond to the base data shown in figures.

2.3 RESULTS

2.3.1 Effect of 1-MCP concentration on the ethylene sensitivity of G. ‘Sylvia’

inflorescences

1-MCP pre-treatment protected G. ‘Sylvia’ inflorescences against ethylene (Plate 2.2). Pre-treatment with

12

5 nL 1-MCP/L for 12 hours at 20oC significantly delayed the onset to flower abscission induced by

exogenous ethylene treatment (Figure 2.1 and Appendix 2.3). Flower abscission from inflorescences not

exposed to exogenous ethylene was significantly reduced by pre-treatment with 5 nL 1-MCP/L.

Increasing the 1-MCP concentration to 10 or 20 nL/L was slightly more effective than pre-treatment with

5 nL/L in protecting inflorescences against exogenous and endogenous ethylene-induced flower

abscission. The decline of relative fresh weight of inflorescences pre-treated with 5 nL 1-MCP/L was

significantly reduced compared to inflorescences not pre-treated with 1-MCP (Figure 2.2). Increasing the

1-MCP concentration to 10 or 20 nL/L did not further reduce the loss of inflorescence relative fresh

weight. The loss of inflorescence relative fresh weight was mainly due to the abscission of flowers. 1-

MCP pre-treatment was equally effective at 5, 10 or 20 nL 1-MCP/L in significantly delaying the onset to

flower wilting from inflorescences exposed to 0 or 10 µL ethylene/L (Figure 2.3 and Appendices 2.3 and

2.4).

Because vase lives of inflorescences were partly based on flower abscission data, pre-treatment with 5 nL

1-MCP/L prevented the exogenous ethylene-induced reduction in vase life (Figure 2.4). Increasing the 1-

MCP concentration to 10 or 20 nL/L was not more effective than 5 nL/L in preventing the loss in vase

life. Vase lives of inflorescences not exposed to ethylene were only significantly extended by pre-

treatment with 10 and 20 nL 1-MCP/L compared to inflorescences not pre-treated with 1-MCP (Figure

2.4). The pronounced counteraction of exogenous ethylene by 1-MCP was reflected in a significant

interaction between 1-MCP pre-treatment and ethylene treatment for flower abscission (Appendix 2.5). It

followed that a significant interaction between 1-MCP pre-treatment, ethylene treatment and time of

measurement for relative fresh weight was also recorded (Appendix 2.6). Likewise, a significant

interaction between 1-MCP pre-treatment and ethylene treatment for vase life data was evident (Appendix

2.7).

There were no consistent effects of 1-MCP or ethylene treatments on flower discolouration (Figure 2.5

and Appendices 2.3 and 2.8). 1-MCP or ethylene treatments did not affect flower opening (Figure 2.6 and

Appendix 2.9). Nevertheless, there were significant differences between treatments on days 2, 3 and 5,

although treatment effects were not consistent. Vase solution uptake by inflorescences tended to increase

initially, then declined over time (Figure 2.7). Inflorescences pre-treated with 1-MCP used vase solution

at higher rates than inflorescences not pre-treated with 1-MCP, in association with the delay of flower

abscission and wilting. These different responses are reflected in a significant interaction between 1-MCP

pre-treatment, ethylene and time of measurement for vase solution uptake data (Appendix 2.10).

13

Plate 2.2. G. ‘Sylvia’ inflorescences on day 2 after pre-treatment on day 0 with 0 (LHS) or 5 nL 1-MCP/L (RHS) for 12 hours at 20oC followed by exposure on day 1 to 10 µL ethylene/L for 12 hoursat 20oC. Note: extensive flower abscission is evident in the control inflorescence (LHS).

14

Abs

ciss

ion

scor

e

1

2

3

4

5

Time (days)

0 1 2 3 4 5 6 7

1

2

3

4

5

+ Ethylene

- Ethylene

Figure 2.1. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from G. ‘Sylvia’ inflorescencestreated on day 0 with 0 (zz), 5 (��), 10 (▲) or 20 (▼) nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC. Remaining inflorescences were held in air without exogenous ethylene. Verticalbars represent standard errors of means (n = 10). Where no vertical bars appear, the standarderror was smaller than the size of the symbol. LSD is presented in Appendix 2.3.

15

Time (days)

0 1 2 3 4 5 6 7

Rel

ativ

e fr

esh

wei

ght (

% in

itial

FW

)

0

20

40

60

80

100

0

20

40

60

80

100+ Ethylene

- Ethylene

Figure 2.2. Relative fresh weight of G. ‘Sylvia’ inflorescences treated on day 0 with 0 (zz), 5 (��), 10(▲) or 20 (▼) nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Remaininginflorescences were held in air without exogenous ethylene. Vertical bars represent standard errorsof means (n = 10). Where no vertical bars appear, the standard error was smaller than the size ofthe symbol. LSD = 5.3%.

16

Wilt

sco

re 1

2

3

Time (days)

0 1 2 3 4 5 6 7

1

2

3

+ Ethylene

- Ethylene

Figure 2.3. Wilting (scores: 1 = none/slight to 3 = advanced) of flowers on G. ‘Sylvia’ inflorescencestreated on day 0 with 0 (zz), 5 (��), 10 (▲) or 20 (▼) nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC. Remaining inflorescences were held in air without exogenous ethylene. Verticalbars represent standard errors of means (n = 10). Where no vertical bars appear, the standarderror was smaller than the size of the symbol. LSD is presented in Appendix 2.3.

17

1-MCP concentration (nL/L)

0 5 10 15 20

Vas

e lif

e (d

ays)

0

1

2

3

4

5

Figure 2.4. Vase life of G. ‘Sylvia’ inflorescences treated on day 0 with 0, 5, 10 or 20 nL 1-MCP/Lfor 12 hours at 20oC. Half of the inflorescences from each of these treatments were then exposed onday 1 to 10 µL ethylene/L for 12 hours at 20oC (●). The other half of the inflorescences were notexposed to exogenous ethylene (■). Vertical bars represent standard errors of means (n = 10). LSD= 0.3.

18

1

2

3

Time (days)

0 1 2 3 4 5 6 7

Dis

colo

urat

ion

scor

e

1

2

3

+ Ethylene

- Ethylene

Figure 2.5. Discolouration (scores: 1 = none/slight to 3 = advanced) of flowers on G. ‘Sylvia’inflorescences treated on day 0 with 0 (zz), 5 (��), 10 (▲) or 20 (▼) nL 1-MCP/L for 12 hours at20oC. Half of the inflorescences from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC. Remaining inflorescences were held in air without exogenousethylene. Vertical bars represent standard errors of means (n = 10). Where no vertical barsappear, the standard error was smaller than the size of the symbol.

19

Ope

ning

sco

re

1

2

3+ Ethylene

Time (days)

0 1 2 3 4 5 6 7

1

2

3- Ethylene

Figure 2.6. Opening (scores: 1 = < 5% to 3 = > 25%) of flowers on G. ‘Sylvia’ inflorescences treatedon day 0 with 0 (zz), 5 (��), 10 (▲) or 20 (▼) nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC. Remaining inflorescences were held in air without exogenous ethylene. Verticalbars represent standard errors of means (n = 10). Significant differences (P < 0.05) betweentreatments existed on days 2, 3 and 5 (Appendix 2.9).

20

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.1

0.2

0.3

Time (days)

0 1 2 3 4 5 6 7

0.0

0.1

0.2

0.3

+ Ethylene

- Ethylene

Figure 2.7. Vase solution uptake by G. ‘Sylvia’ inflorescences treated on day 0 with 0 (zz), 5 (��), 10(▲) or 20 (▼) nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Remaininginflorescences were held in air without exogenous ethylene. Vertical bars represent standard errorsof means (n = 10). LSD = 0.022 mL/g initial FW/day.

21

2.3.2 Effect of 1-MCP pre-treatment duration on ethylene sensitivity of G. ‘Sylvia’

inflorescences

Pre-treatment with 10 nL 1-MCP/L for 3 hours at 20oC significantly delayed the onset of flower abscission

from inflorescences exposed to exogenous ethylene (Figure 2.8 and Appendix 2.11). 1-MCP pre-

treatment for 3 hours also reduced flower abscission from inflorescences not exposed to ethylene.

Increasing the 1-MCP pre-treatment duration to 6, 9 or 12 hours was seemingly more effective than the 3

hour pre-treatment in delaying the onset of flower abscission from inflorescencees exposed to exogenous

ethylene. However, no significant differences between the 3 and 12 hour treatments existed (Appendix

2.11). Endogenous ethylene-induced flower abscission was reduced on days 6 and 7 by increasing the 1-

MCP pre-treatment duration to 12 hours compared to the 3 hour pre-treatment (Figure 2.8).

The decline in relative fresh weight of inflorescences associated with exogenous ethylene-induced flower

abscission was significantly reduced by pre-treatment with 1-MCP for 3 hours (Figure 2.9). However,

there was no further reduction in the decline of inflorescence relative fresh weight by increasing the 1-

MCP pre-treatment to 6, 9 or 12 hours. The loss of inflorescence relative fresh weight from

inflorescences not exposed to exogenous ethylene was reduced most effectively by pre-treatment with 1-

MCP for 12 hours. Pre-treatment with 1-MCP for 3 hours significantly delayed the onset of flower wilting

induced by exposure to exogenous ethylene (Figure 2.10 and Appendix 2.11). The onset of flower wilting

was not further delayed by increasing the 1-MCP pre-treatment duration to 6, 9 or 12 hours. 1-MCP pre-

treatment did not delay the onset of flower wilting from inflorescences not exposed to ethylene.

Pre-treatment of inflorescences with 1-MCP for 3 hours prevented the reduction in vase life associated

with exposure to exogenous ethylene (Figure 2.11). Increasing the 1-MCP pre-treatment duration to 6, 9

or 12 hours was not significantly more effective in preventing the loss in vase life than pre-treatment for 3

hours. However, there was a trend toward extended vase life for inflorescences pre-treated with 1-MCP

for 9 or 12 hours compared to inflorescences pre-treated for 3 hours. 1-MCP pre-treatment did not

significantly extend the vase lives of inflorescences not exposed to ethylene (Figure 2.11). The delay in

the onset of flower abscission primarily for ethylene-treated inflorescences by 1-MCP pre-treatment was

reflected in a significant interaction between 1-MCP pre-treatment and ethylene treatment for flower

abscission (Appendix 2.12). Likewise, a significant interaction between 1-MCP pre-treatment, ethylene

treatment and time of measurement was evident for flower wilting (Appendix 2.11) and relative fresh

weight (Appendix 2.14). As a consequence of the strong influence of flower abscission, a significant

interaction between 1-MCP pre-treatment and ethylene treatment for vase life was recorded (Appendix

2.15).

There was no consistent effect of 1-MCP pre-treatment on flower discolouration (Appendices 2.11, 2.16

and 2.17). 1-MCP pre-treatment did not affect flower opening (Appendices 2.18 and 2.19). There was

more flower opening on days 1 and 2 from inflorescences exposed only to ethylene compared to

inflorescences not exposed to ethylene (Appendix 2.18). However, inflorescences exposed only to

22

ethylene had more open flowers than other treatments on day 0. Inflorescences pre-treated with 1-MCP

maintained higher rates of vase solution uptake throughout the experiment compared to inflorescences

exposed only to ethylene (Figure 2.12). This differential response accounted for the significant interaction

between 1-MCP pre-treatment and time of measurement (Appendix 2.20).

23

Time (days)

0 1 2 3 4 5 6 7

Abs

ciss

ion

scor

e

1

2

3

4

5 - Ethylene

1

2

3

4

5 + Ethylene

Figure 2.8. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from G. ‘Sylvia’ inflorescencestreated on day 0 with 10 nL 1-MCP/L for 0 (zz), 3 (��), 6 (▲), 9 (▼) or 12 (◆) hours at 20oC. Half ofthe inflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for12 hours at 20oC. Remaining inflorescences were held in air without exogenous ethylene. Verticalbars represent standard errors of means (n = 10). Where no vertical bars appear, the standarderror was smaller than the size of the symbol. LSD is presented in Appendix 2.11.

24

Time (days)

0 1 2 3 4 5 6 70

20

40

60

80

100

120

Rel

ativ

e fr

esh

wei

ght (

% in

itial

FW

)

0

20

40

60

80

100

120 + Ethylene

- Ethylene

Figure 2.9. Relative fresh weight of G. ‘Sylvia’ inflorescences treated on day 0 with 10 nL 1-MCP/Lfor 0 (zz), 3 (��), 6 (▲), 9 (▼) or 12 (◆) hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Remaininginflorescences were held in air without exogenous ethylene. Vertical bars represent standard errorsof means (n = 10). Where no vertical bars appear, the standard error was smaller than the size ofthe symbol. LSD = 5.7%.

25

Wilt

sco

re 1

2

3

Time (days)

0 1 2 3 4 5 6 7

1

2

3

+ Ethylene

- Ethylene

Figure 2.10. Wilting (scores: 1 = none/slight to 3 = advanced) of flowers on G. ‘Sylvia’inflorescences treated on day 0 with 10 nL 1-MCP/L for 0 (zz), 3 (��), 6 (▲), 9 (▼) or 12 (◆) hours at20oC. Half of the inflorescences from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC. Remaining inflorescences were held in air without exogenousethylene. Vertical bars represent standard errors of means (n = 10). Where no vertical barsappear, the standard error was smaller than the size of the symbol. LSD is presented in Appendix2.11.

26

1-MCP pre-treatment duration (hr)

0 3 6 9 12

Vas

e lif

e (d

ays)

0

1

2

3

4

5

Figure 2.11. Vase life of G. ‘Sylvia’ inflorescences treated on day 0 with 10 nL 1-MCP/L for 0, 3, 6,9 or 12 hours at 20oC. Half of the inflorescences from each of these treatments were then exposedon day 1 to 10 µL ethylene/L for 12 hours at 20oC (●). The other half of the inflorescences were notexposed to exogenous ethylene (■). Vertical bars represent standard errors of means (n = 10).Where no vertical bars appear, the standard error was smaller than the size of the symbol. LSD =0.8.

27

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.1

0.2

0.3

0.4

0.5

Time (days)

0 1 2 3 4 5 6 7

0.0

0.1

0.2

0.3

0.4

0.5

+ Ethylene

- Ethylene

Figure 2.12. Vase solution uptake by G. ‘Sylvia’ inflorescences treated on day 0 with 10 nL 1-MCP/L for 0 (zz), 3 (��), 6 (▲), 9 (▼) and 12 (◆) hours at 20oC. Half of the inflorescences from eachof these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. The otherhalf of the inflorescences were held in air without exogenous ethylene. Vertical bars representstandard errors of means (n = 10). Where no vertical bars appear, the standard error was smallerthan the size of the symbol. LSD = 0.003 mL/g initial FW/day.

28

2.3.3 Effect of temperature on 1-MCP pre-treatment efficacy

1-MCP pre-treatment (10 nL/L for 12 hours) was equally effective when applied at 0, 5, 10 or 20oC in

significantly reducing exogenous ethylene-induced flower abscission (Figure 2.13 and Appendix 2.21). 1-

MCP pre-treatment at 0, 5 or 10oC did not significantly reduce flower abscission from inflorescences not

exposed to ethylene. Flower abscission from inflorescences pre-treated with 1-MCP at 20oC and that were

not exposed to exogenous ethylene was reduced compared to similar inflorescences not pre-treated with 1-

MCP (Figure 2.13). The decline in inflorescence relative fresh weight associated with exogenous

ethylene-induced flower abscission was significantly reduced by 1-MCP pre-treatment at each temperature

(Figure 2.14). However, as for flower abscission data, 1-MCP pre-treatment did not reduce the loss of

relative fresh weight of inflorescences not exposed to ethylene, except for those pre-treated at 20oC.

Pre-treatment of inflorescences with 1-MCP at each temperature prevented the loss in vase life associated

with exposure to exogenous ethylene (Figure 2.15). 1-MCP pre-treatment at 0, 5 or 10oC did not extend

the vase lives of inflorescences not exposed to ethylene. In contrast, pre-treatment with 1-MCP at 20oC

significantly extended the vase lives of inflorescences not exposed to ethylene (Figure 2.15), presumably

as flower abscission was reduced. The vase lives of inflorescences exposed only to ethylene at 20oC were

consistently short due to rapid flower abscission, and were not affected by the pre-treatment temperature.

Despite the presence of non-significant pre-treatment temperature effects, there were significant

interactions between 1-MCP pre-treatment, ethylene treatment and time of measurement for flower

abscission (Appendix 2.21) and relative fresh weight (Appendix 2.22). As a consequence, a significant

difference between 1-MCP pre-treatment and ethylene treatment for vase life was recorded (Appendix

2.23).

Flower discolouration was not affected by 1-MCP pre-treatment (Appendix 2.24). However, flower

discolouration developed earlier for inflorescences held at 20oC during pre-treatment compared to those

held at 0, 5 or 10oC and reflects the significant interaction between treatment (1-MCP and ethylene) and

pre-treatment temperature (Appendix 2.25). In contrast to earlier experiments, the onset to flower wilting

was not delayed by 1-MCP pre-treatment (Appendix 2.26). Nevertheless, flower wilting was most

advanced on inflorescences pre-treated at 0oC and probably gives rise to the significant interaction

between treatment (1-MCP and ethylene) and pre-treatment temperature (Appendix 2.27). 1-MCP and

ethylene treatments did not affect flower opening (Appendices 2.28 and 2.29). Vase solution uptake by

inflorescences exposed only to ethylene was relatively stable over time, due to flower abscission,

compared to inflorescences not exposed to ethylene (Figure 2.16). This difference in response is reflected

in the presence of a significant pre-treatment temperature, ethylene treatment and time of measurement

interaction (Appendix 2.30).

29

Time (days)

0 1 2 3 4 5 6 7

Abs

ciss

ion

scor

e

1

2

3

4

5- 1-MCP + Ethylene

1

2

3

4

5+ 1-MCP + Ethylene + 1-MCP - Ethylene

0 1 2 3 4 5 6 7

- 1-MCP - Ethylene

Figure 2.13. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from G. ‘Sylvia’ inflorescencespre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 0 (zz), 5 (��), 10 (▲) and 20oC (▼).Half of the inflorescences from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC. The other half of the inflorescences were not exposed to exogenousethylene. Vertical bars represent standard errors of means (n = 5). Where no vertical bars appear,the standard error was smaller than the size of the symbol.

30

20

40

60

80

100

120

Time (days)

0 1 2 3 4 5 6 7

Rel

ativ

e fr

esh

wei

ght (

% in

itial

FW

)

20

40

60

80

100

120

0 1 2 3 4 5 6 7

+ 1-MCP + Ethylene

- 1-MCP + Ethylene

+ 1-MCP - Ethylene

- 1-MCP - Ethylene

Figure 2.14. Relative fresh weight of G. ‘Sylvia’ inflorescences pre-treated on day 0 with 0 or 10 nL1-MCP/L for 12 hours at 0 (zz), 5 (��), 10 (▲) and 20oC (▼). Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. The otherhalf of the inflorescences were not exposed to exogenous ethylene. Vertical bars represent standarderrors of means (n = 5). Where no vertical bars appear, the standard error was smaller than thesize of the symbol. LSD = 14.7%.

31

Pre-treatment temperature (oC)

0 5 10 15 20

Vas

e lif

e (d

ays)

0

1

2

3

4

5

6

7

0

1

2

3

4

5

6

7 + Ethylene

- Ethylene

Figure 2.15. Vase life of G. ‘Sylvia’ inflorescences treated on day 0 with 0 (●) or 10 nL 1-MCP/L(■) for 12 hours at 0, 5, 10 or 20oC. Half of the inflorescences from each of these treatments werethen exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. The other half of the inflorescenceswere not exposed to exogenous ethylene. Vertical bars represent standard errors of means (n = 5).Where no vertical bars appear, the standard error was smaller than the size of the symbol. LSD =1.9 days.

32

Time (days)

0 1 2 3 4 5 6 70 1 2 3 4 5 6 7

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.2

0.4

0.6

0.0

0.2

0.4

0.6 + 1-MCP + Ethylene + 1-MCP - Ethylene

- 1-MCP + Ethylene - 1-MCP - Ethylene

Figure 2.16. Vase solution uptake by G. ‘Sylvia’ inflorescences pre-treated on day 0 with 0 or 10 nL1-MCP/L for 12 hours at 0 (zz), 5 (��), 10 (▲) and 20oC (▼). Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. The otherhalf of the inflorescences were not exposed to exogenous ethylene. Vertical bars represent standarderrors of means (n = 5). Where no vertical bars appear, the standard error was smaller than thesize of the symbol. LSD = 0.043 mL/g initial FW/day.

33

2.3.4 Effect of 1-MCP pre-treatment on inflorescence physiology

Pre-treatment with 10 nL 1-MCP/L for 12 hours at 20oC significantly delayed the onset to flower

abscission and reduced the associated decline of inflorescence relative fresh weight induced by exposure

to 0 or 100 µL propylene/L (Figure 2.17). As a result these responses are manifested as significant

interactions between 1-MCP pre-treatment, propylene treatment and time of measurement for flower

abscission (Appendix 2.31) and relative fresh weight (Appendix 2.32). Vase solution uptake between

days 0 and 1 was lowest for inflorescences pre-treated with 1-MCP (Figure 2.18). In addition, vase

solution uptake between days 1 and 2 was lowest for inflorescences exposed to propylene. These

responses give rise to the significant interactions between 1-MCP pre-treatment and time of measurement

and propylene treatment and time of measurement for vase solution uptake data (Appendix 2.33).

Consequently, the reduction in vase life associated with exposure to propylene treatment was prevented by

pre-treatment with 1-MCP (Table 2.1). However, 1-MCP pre-treatment did not significantly extend the

vase lives of inflorescences not exposed to propylene. Accordingly, a significant interaction between 1-

MCP pre-treatment and propylene treatment for vase life was recorded (Appendix 2.34). 1-MCP pre-

treatment did not affect flower discolouration, opening and wilting compared to inflorescences not pre-

treated with 1-MCP (Appendices 2.35, 2.36, 2.37, 2.38 and 2.39).

34

Abs

ciss

ion

scor

e

1

2

3

4

5

Time (days)

0 1 2 3 4 5 6 7

Rel

ativ

e fr

esh

wei

ght

(%

initi

al F

W)

0

20

40

60

80

100

120

Figure 2.17. Flower abscission (scores:1 = < 10% to 5 = > 80%) and relative fresh weight for G.‘Sylvia’ inflorescences treated with 0 nL 1-MCP/L and 0 µL propylene/L (●), 0 nL 1-MCP/L and100 µL propylene/L (■), 10 nL 1-MCP/L and 0 µL propylene/L (▲) or 10 nL 1-MCP/L and 100 µLpropylene/L (▼). 1-MCP and propylene treatments were each conducted for 12 hours at 20oC onday 0 and 1, respectively. Vertical bars represent standard errors of means (n = 6). Where novertical bars appear, the standard error was smaller than the size of the symbol. LSD for relativefresh weight data = 4.5%.

35

Time (days)

0 1 2 3 4 5 6 7

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.2

0.4

Figure 2.18. Vase solution uptake by G. ‘Sylvia’ inflorescences treated with 0 nL 1-MCP/L and 0µL propylene/L (●), 0 nL 1-MCP/L and 100 µL propylene/L (■), 10 nL 1-MCP/L and 0 µLpropylene/L (▲) or 10 nL 1-MCP/L and 100 µL propylene/L (▼). 1-MCP and propylenetreatments were each conducted for 12 hours at 20oC on day 0 and 1, respectively. Vertical barsrepresent standard errors of means (n = 6). Where no vertical bars appear, the standard error wassmaller than the size of the symbol. LSD = 0.028 mL/g initial FW/day.

36

Table 2.1. Vase life (mean ± s.e.) of G. ‘Sylvia’ inflorescences treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of these treatments were thenexposed on day 1 to 100 µL propylene/L for 12 hours at 20oC. Vase life data followed by the sameletter are not significantly different (LSD = 0.7) at P = 0.05 (n = 6).

Treatment Vase life (days)

No propylene (0 µL/L)

0 nL 1-MCP/L 6.0 ± 0.2 b

10 nL 1-MCP/L 6.3 ± 0.3 b

Plus propylene (100 µL/L)

0 nL 1-MCP/L 2.0 ± 0.0 a

100 nL 1-MCP/L 6.3 ± 0.2 b

Pre-treatment of inflorescences with 1-MCP reduced ethylene production rates compared to inflorescences

exposed only to propylene, which were peduncles without flowers (Figure 2.19). Ethylene production

rates by the peduncles of inflorescences exposed only to propylene remained low until day 4, thereafter

increased until day 6, and then began to decline. Rates of ethylene production by inflorescences pre-

treated with 1-MCP and those not treated with 1-MCP or propylene, slowly increased until day 7 in

association with flower abscission (Figures 2.17 and 2.19). However, there was no significant effect of 1-

MCP pre-treatment on the rate of ethylene production by inflorescences not exposed to propylene

(Appendix 2.40). The respiration rate of all inflorescences declined following initial treatments (Figure

2.19). However, the rate of respiration by inflorescences pre-treated with 1-MCP was maintained at

higher rates than inflorescences exposed only to propylene. The rate of respiration started to increase

after day 5 or 6 for inflorescences pre-treated with 1-MCP and for those not treated with 1-MCP or

propylene, respectively, (Figure 2.19) in association with flower abscission (Figure 2.17). Consequently,

a significant interaction between 1-MCP pre-treatment, propylene treatment and time of measurement was

evident for respiration (Appendix 2.41).

37

Rat

e of

eth

ylen

e pr

oduc

tion

(µL/

kg F

W/h

r)

0

2

4

6

8

Time (days)

2 3 4 5 6 7

Res

pira

tion

rate

(m

g C

O2/

kg F

W/h

r)

0

50

100

150

Figure 2.19. Rates of ethylene production and respiration by G. ‘Sylvia’ inflorescences treated with0 nL 1-MCP/L and 0 µL propylene/L (●), 0 nL 1-MCP/L and 100 µL propylene/L (■), 10 nL 1-MCP/L and 0 µL propylene/L (▲) or 10 nL 1-MCP/L and 100 µL propylene/L (▼). 1-MCP andpropylene treatments were each conducted for 12 hours at 20oC on day 0 and 1, respectively.Vertical bars represent standard errors of means (n = 3). Where no vertical bars appear, thestandard error was smaller than the size of the symbol. Where no vertical bars appear, thestandard error was smaller than the size of the symbol. LSD for ethylene production = 1.3 µL/kgFW/hr and respiration = 16.6 mg CO2/kg FW/hr.

38

In the second experiment examining inflorescence physiology, 1-MCP pre-treatment significantly delayed

the onset of flower abscission from inflorescences exposed to 0 or 100 µL propylene/L (Figure 2.20).

This response accounts for the significant interaction between 1-MCP pre-treatment, propylene treatment

and time of measurement (Appendix 2.42). The ACC contents of 1-MCP pre-treated flowers or those not

treated with 1-MCP or propylene increased to day 5 (Figure 2.20). Flower ACC content increased rapidly

after day 3 and apparently preceded flower abscission (Figure 2.20). However, the ACC content of

flowers was not significantly affected by 1-MCP pre-treatment (Appendix 2.43). 1-MCP pre-treatment

prevented the loss in vase life for inflorescences exposed to propylene (Table 2.2). The vase lives of

inflorescences not exposed to propylene was not extended by 1-MCP pre-treatment. As a result, a

significant interaction for 1-MCP pre-treatment and propylene treatment for vase life was recorded

(Appendix 2.44). In this experiment, flower discolouration and wilting on inflorescences pre-treated with

1-MCP were significantly more advanced than inflorescences not pre-treated with 1-MCP on days 4 and 5

(Appendices 2.45, 2.46 and 2.47). Flower opening was not affected by 1-MCP or propylene treatments

(Appendices 2.45 and 2.48).

39

Abs

ciss

ion

scor

e

1

2

3

4

5

Time (days)

0 1 2 3 4 5

AC

C c

onte

nt (

n m

oles

AC

C/g

FW

)

0

1

2

Figure 2.20. Flower abscission (scores: 1 = < 10% to 5 = > 80%) and ACC content from G. ‘Sylvia’inflorescences treated with 0 nL 1-MCP/L followed by 0 µL propylene/L (zz), 0 nL 1-MCP/Lfollowed by 100 µL propylene/L (��), 10 nL 1-MCP/L followed by 0 µL propylene/L (▲) or 10 nL 1-MCP/L followed by 100 µL propylene/L (▼). 1-MCP and propylene treatments were eachconducted for 12 hours at 20oC on day 0 and 1, respectively. Vertical bars represent the standarderrors of means. Where no vertical bars appear, the standard error was smaller than the size of thesymbol. LSD for ACC is 0.42 n mol/g FW.

40

Table 2.2. Vase life (mean ± s.e.) of G. ‘Sylvia’ inflorescences used in the determination of flowerACC content, which were treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half ofthe inflorescences from each treatment were then exposed on day 1 to 100 µL propylene/L for 12hours at 20oC. Vase life data followed by the same letter are not significantly different (LSD = 0.8)at P = 0.05 (n = 3).


No propylene (0 µL/L)

0 nL 1-MCP/L 4.3 ± 0.2 b

10 nL 1-MCP/L 4.3 ± 0.2 b

Plus propylene (100 µL/L)

0 nL 1-MCP/L 2.0 ± 0.0 a

10 nL 1-MCP/L 4.0 ± 0.0 b

2.4 DISCUSSION

1-MCP pre-treatment was effective at low concentration (5 nL 1-MCP/L for 12 hours at 20oC) and for

short treatment duration (10 nL 1-MCP/L for 3 hours at 20oC) in delaying the onset of flower abscission

from G. ‘Sylvia’ inflorescences subsequently exposed to 10 µL ethylene/L (Figures 2.1 and 2.8).

Endogenous ethylene-induced flower abscission was also reduced by 1-MCP pre-treatment. The loss of

inflorescence relative fresh weight (Figures 2.2 and 2.9) and vase life (Figures 2.4 and 2.11) associated

with exogenous ethylene-induced flower abscission were reduced by 1-MCP pre-treatment. These results

are in agreement with those of other workers who used similar 1-MCP treatments to prevent ethylene-

induced floral organ abscission and senescence from a range of cut flowers (Serek et al. 1995a, b, c; Porat

et al. 1995a, b; Sisler et al. 1996a). In particular, 1-MCP pre-treatment protocols used in the present

study and their efficacy match those used by Serek et al. (1995a). They found that pre-treatment with 10-

20 nL 1-MCP/L for 6 hours protected various cut flowers including carnation, snapdragon and Penstemon

against ethylene.

It is possible that lower 1-MCP concentrations or shorter treatment durations than those used in the

present study could also reduce the ethylene sensitivity of G. ‘Sylvia’ inflorescences, since carnation

flowers can be protected against ethylene by pre-treatment with 0.5 nL 1-MCP/L for 24 hours at 24oC or

250 nL 1-MCP/L for just 5 minutes at 24oC (Sisler et al. 1996a). Nevertheless, the sensitivity of different

plant materials to 1-MCP varies (Sisler and Serek 1997). Protection of G. ‘Sylvia’ inflorescences against

ethylene may require a higher 1-MCP concentration and/or longer treatment duration than for carnations.

Efficacy of 1-MCP pre-treatment was proposed by Serek et al. (1995a) to be an inverse relationship

between 1-MCP concentration and treatment duration. They showed that pre-treatment of Penstemon

flowers with 10 nL 1-MCP/L for 0.5 hours or 5 nL 1-MCP/L for 3 hours were equally effective in

preventing ethylene-induced flower abscission. Accordingly, from a commercial perspective, a range of

effective 1-MCP treatment protocols could be applied depending on the sensitivity of plant tissue to 1-

41

MCP and ethylene and changes in market supply and demand patterns. For example, pre-treatment of cut

flowers with high 1-MCP concentrations for short durations could be used to meet increasing market

demand.

Increasing the 1-MCP concentration to 10 or 20 nL/L or extending the treatment duration to 12 hours

were only slightly more effective in delaying exogenous ethylene-induced flower abscission than a

concentration of 5 nL/L or a treatment duration of 3 hours, respectively (Figures 2.1 and 2.8). This is

consistent with the results of Serek et al. (1995a), who showed that pre-treatment of Penstemon flowers

with 5 or 10 nL 1-MCP/L for 6 hours was slightly more effective in extending flower longevity than a 3

hour pre-treatment. Higher 1-MCP concentrations and/or longer term exposure to 1-MCP may block

additional ethylene receptors, although this does not appear to be critical in providing significantly longer

protection against ethylene. It is assumed that pre-treatment of inflorescences with 5 nL 1-MCP/L for 12

hours at 20oC or 10 nL 1-MCP/L for 3 hours at 20oC blocked almost all available ethylene receptors

(Figures 2.4 and 2.11).

1-MCP pre-treatment (10 nL 1-MCP/L for 12 hours) was equally effective when applied at 0, 5, 10 or

20oC in protecting G. ‘Sylvia’ inflorescences against ethylene (Figure 2.14). These results contrast with

those of Serek et al. (1995a) who reported that pre-treatment of Penstemon flowers with 5 or 20 nL 1-

MCP/L for 6 hours at 2oC did not prevent ethylene-induced flower abscission. Likewise, Reid et al.

(1996) found that 1-MCP treatment of Kalanchoe flowers was not effective when applied at 2oC, possibly

because 1-MCP binding was reduced. However, increasing the 1-MCP concentration and/or the treatment

duration at 2oC was reported by Reid et al. (1996) to improve the efficacy of treatment. It is possible that

the low efficacy of 1-MCP treatment reported by Serek et al. (1995a) and Reid et al. (1996) is related to

an inherent low temperature response of the plant material. Exposure of chilling sensitive plants to low

temperature is proposed to induce membrane phase changes which, in turn, may alter the conformation of

membrane-bound proteins (Lyons 1973). Thus, some degree of conformational change to the membrane-

located protein believed to act as the ethylene receptor may reduce its ability to bind 1-MCP molecules.

However, whilst Kalanchoe is generally regarded as being chilling sensitive, Penstemon are frost tolerant

(Page and Olds 1997). Further, Penstemon flowers were not reported to suffer injury at 2oC (Serek et al.

1995a).

Tropical and sub-tropical flowers are sensitive to chilling at temperatures of 10-15oC (Halevy and Mayak

1981). Because of their sub-tropical origin (Costin and Costin 1988), G. ‘Sylvia’ inflorescences might be

considered chilling sensitive. However, no injury was observed for inflorescences kept at 5oC for 5 days

(Ligawa et al. 1997). Accordingly, 1-MCP pre-treatment may have protected inflorescences against

ethylene as the ethylene receptors were not disturbed by exposure to chilling temperatures. Alternatively,

it is possible that the binding of 1-MCP molecules may have taken place during ventilation of chambers at

the end of 1-MCP treatment. Chambers were ventilated inside a fume cupboard at 20oC for 10-15 minutes

and thus the temperature of inflorescences may have risen while 1-MCP gas was still present. 1-MCP

binding is known to be rapid as carnation flowers pre-treated with 250 nL 1-MCP/L for just 5 minutes

42

were protected against ethylene (Sisler et al. 1996a).

Pre-treatment with 10 nL 1-MCP/L for 12 hours at 20oC protected G. ‘Sylvia’ inflorescences against

propylene treatment (100 µL/L for 12 hours at 20oC). Propylene treatment mimicked ethylene by

inducing flower abscission (Figure 2.17) and reducing vase life (Table 2.1). Consequently, ethylene

production by inflorescences pre-treated with 1-MCP was reduced (Figure 2.18). However, increasing

ethylene production by 1-MCP pre-treated inflorescences was associated with flower abscission. This

result is similar to those of Sisler et al. (1996a), where ethylene production by carnation flowers was

reduced and delayed by 1-MCP pre-treatment compared to flowers exposed only to ethylene. In the

present study, 1-MCP pre-treatment did not reduce the rate of ethylene production by inflorescences not

exposed to propylene. This is in contrast to the findings of Sisler et al. (1996a), where the rate of ethylene

production by carnation flowers not exposed to ethylene was reduced by 1-MCP pre-treatment. The

retention of flowers on inflorescences pre-treated with 1-MCP was presumably responsible for

maintaining higher rates of respiration compared to inflorescences exposed only to ethylene (Figure 2.18).

ACC content of flowers not exposed to propylene increased prior to flower abscission, but was not

affected by 1-MCP pre-treatment (Figure 2.20). Nonetheless, the association between rates of ethylene

production, respiration and natural postharvest flower abscission were similar to results presented by

Joyce et al. (1995). The ACC data provide additional evidence that endogenous ethylene production by

G. ‘Sylvia’ inflorescences may mediate natural postharvest flower abscission.

The vase solution uptake by inflorescences decreased over time presumably as the transpirational surface

area decreased in association with flower abscission and senescence. However, the decrease in vase

solution uptake was delayed for inflorescences pre-treated with 1-MCP because flower abscission and the

associated decrease in transpirational surface area were also delayed (Figures 2.7, 2.12, 2.16 and 2.18). 1-

MCP pre-treatment helped to discriminate between ethylene dependent and ethylene independent

senescence processes in G. ‘Sylvia’ inflorescences. Despite 1-MCP pre-treatment delaying flower wilting

in the first two experiments, there was no consistent effect of 1-MCP pre-treatment on flower wilting in

subsequent experiments. Thus, any potential role of ethylene in flower wilting on G. ‘Sylvia’

inflorescences is unclear. Flower discolouration and opening were not consistently affected by 1-MCP

pre-treatment in any way and, therefore, do not appear to be regulated by ethylene.

Overall, 1-MCP pre-treatment was judged only to be effective in protecting inflorescences against

exogenous ethylene. It did not consistently extend the vase lives of inflorescences not exposed to ethylene

or propylene (Figures 2.4, 2.11, 2.15, Tables 2.1 and 2.2). Nonetheless, 1-MCP pre-treatment was shown

to reduce endogenous ethylene-induced flower abscission in most experiments. Consequently, based on

its demonstrated capacity to block the sensitivity of G. ‘Sylvia’ inflorescences to exogenous ethylene, 1-

MCP pre-treatment may have potential as a postharvest anti-ethylene treatment for sensitive native

Australian cut flowers.

43

CHAPTER 3

RESPONSES OF A NUMBER OF NATIVE AUSTRALIAN CUT

FLOWERS TO 1-MCP AND ETHYLENE TREATMENTS

3.1 INTRODUCTION

Native Australian cut flowers are gaining acceptance in the international ornamentals trade based on a 10-

fold increase in the value of exports between 1980/81 and 1995/96 (FECA 1996). In contrast to

traditional flower crops, there has been limited postharvest research on native cut flowers (Faragher

1989). For example, relationships between exogenous and endogenous ethylene-induced flower

abscission and senescence have not been thoroughly investigated. Nonetheless, ethylene has been

implicated in flower abscission from Chamelaucium uncinatum (Geraldton waxflower) (Joyce 1988,

1989, 1993), Grevillea spp. (Joyce and Haynes 1989), Leptospermum scoparium (tea tree) (Zieslin and

Gottesman 1983), Telopea speciosissima (NSW waratah) (Joyce et al. 1993) and Verticordia nitens

(yellow Morrison) (Joyce and Haynes 1989; Joyce and Poole 1993). Accelerated senescence of Boronia

heterophylla (red boronia) flowers has also been associated with exposure to exogenous ethylene (Joyce

and Haynes 1989).

STS treatment has been shown to inhibit ethylene effects on cut B. heterophylla (Joyce and Haynes 1989),

C. uncinatum (Joyce 1988, 1989, 1993), Grevillea spp. (Joyce and Haynes 1989; Vuthapanich et al.

1993), L. scoparium (Zieslin and Gottesman 1983), T. speciosissima (Joyce et al. 1993) and V. nitens

(Joyce and Haynes 1989; Joyce and Poole 1993). Likewise, the recently developed gaseous inhibitor of

ethylene perception, 1-MCP, might also protect native Australian flowers as it does traditional cut flowers

against ethylene (Serek et al. 1995a, b, c; Porat et al. 1995a, b; Sisler et al. 1996a).

It is proposed that 1-MCP is likely to prove an effective anti-ethylene treatment for ethylene-sensitive

native Australian flowers. The purpose of this screening study was to examine the response in a selection

of native Australian cut flowers to 1-MCP and ethylene treatments. In an associated experiment,

relationships between B. heterophylla flower senescence, exogenous and endogenous ethylene, and 1-

MCP and STS treatments were examined.


Experiments were conducted at The University of Qld, Gatton College (UQG), postharvest laboratory or

at the Victorian Agriculture, Institute for Horticultural Development (IHD), Knoxfield postharvest

laboratory during a visit there by the author. Descriptions and pictures of floral genera used in these

experiments can be found in Wrigley and Fagg (1997).

44


3.2.1.1 Alloxylon pinnatum

Alloxylon pinnatum (Dorrigo waratah; Proteaceae) inflorescences are comprised of a terminal

inflorescence on a stem consisting of approximately 100 flowers. Inflorescences, with 10-20% of flowers

open, were harvested from plants growing near Moss Vale, NSW (34o 33’ S, 150o 23’ E). Hydrated water

absorbent crystals were placed around cut stem ends and the inflorescences were wrapped in plastic

sleeves to minimise water loss. They were placed into a cardboard box and freighted by road to the UQG

laboratory within 36 hours of harvest. In a second experiment, A. pinnatum inflorescences at the same

stage of development as those used in the first experiment were harvested from plants growing near

Maleny in S.E. Qld (26o 46’ S, 152o 51’ E). Inflorescences were packed dry into a cardboard box and

transported to the UQG laboratory by road within 3 hours of harvest.

3.2.1.2 Boronia heterophylla

Flowering Boronia heterophylla (red boronia; Rutaceae) stems were harvested from two cut flower farms

in Western Australia. Stems were packed into commercial flower cartons and air freighted dry either

directly or via a flower exporter in Sydney to the Brisbane airport within 24 or 48 hours of harvest,

respectively. Stems were then taken to the UQG laboratory in an air conditioned car within 2 hours. In

the first experiment, a form of B. heterophylla with small flowers was used. Flowers used in both

experiments arrived at the laboratory with slight flower discolouration (i.e. trace of white on flowers).

3.2.1.3 Cassinia adunca

Flowering Cassinia adunca (Asteraceae) stems with approximately 10-50% of flowers open were

harvested from plants growing near Maleny. Cut stem ends were wrapped in moist newsprint and

transported to the UQG laboratory by road within 3 hours of harvest.

3.2.1.4 Ceratopetalum gummiferum

Flowering Ceratopetalum gummiferum (NSW Christmas bush; Cunoniaceae) stems were harvested from a

farm near Childers in S.E. Qld (25o 14’S, 152o 17’ E). Stems were placed into a cardboard box and

transported dry by road to the wholesale flower market in Brisbane. Stems were then collected and taken

to the UQG laboratory in an air conditioned car. Stems arrived in the laboratory within 48 hours of

harvest.

3.2.1.5 Chamelaucium uncinatum

45

Flowering branches of Chamelaucium uncinatum ‘Paddy’s Late’ (Geraldton waxflower; Myrtaceae) with

> 90% of flowers open were harvested from a farm near Esk in S.E. Qld (27o 14’ S, 152o 25’ E). Cut stem

ends of branches were stood into buckets containing DI water and taken to the UQG laboratory by road

within 1 hour of harvest.

3.2.1.6 Eriostemon scaber

Flowering Eriostemon scaber (Rutaceae) stems were obtained from a farm near Sale in eastern Victoria

(38o 07 S, 147o 04 E). Stems were packed dry into a commercial flower carton and delivered by road to

the IHD laboratory within 24 hours of harvest.

46

3.2.1.7 Grevillea hybrids

Grevillea ‘Kay Williams’ [(G. sessilis x G. pteridifolia) x G. banksii] and G. ‘Misty Pink’ (G. banksii x G.

sessilis) inflorescences (Proteaceae) were harvested from a farm near Gatton in S.E. Qld (27o 34’S 152o

17’E). Inflorescences were selected, harvested and prepared as described in section 2.2.1 and were taken

to the UQG laboratory in an air conditioned car within 30 minutes of harvest. G. ‘Sandra Gordon’ (G.

sessilis x G. pteridifolia) inflorescences were harvested from a nursery near Redland Bay. Inflorescences

were harvested and transported to the laboratory as described in section 2.2.1.

3.2.1.8 Leptospermum spp .

Stems of Leptospermum petersonii (lemon-scented tea tree; Myrtaceae) with > 50% of flowers open were

harvested from a residential garden in Brisbane in S.E. Qld (27o 28’S 153o 01’E). Cut stem ends were

stood into DI water and transported to the UQG laboratory in an air conditioned car within 1 hour of

harvest. Flowering L. scoparium ‘Winter Cheer’ (tea tree) stems were harvested from plants growing near

the IHD laboratory. Cut stem ends were immediately stood into DI water and taken inside the laboratory.

3.2.1.9 Ozothamnus diosmifolius

Flowering Ozothamnus diosmifolius ‘Cooks Tall Pink’ (rice flower; Asteraceae) stems were harvested

from a farm near Helidon in S.E. Qld (27o 33’ S, 152o 08’ E). This cultivar was a fine leaf form of rice

flower. Flowers were harvested at the first sign of flower break or opening. Cut stem ends were stood

into DI water and transported in an air conditioned car to the UQG laboratory within 30 minutes of

harvest.

3.2.1.10 Platysace lanceolata

Flowering Platysace lanceolata (Apiaceae) stems were harvested from plants near Maleny. Cut stem ends

were wrapped in moist newsprint and transported to the UQG laboratory by road within 3 hours of

harvest.

3.2.1.11 Telopea speciosissima

Telopea speciosissima (NSW waratah; Proteaceae) inflorescences were obtained from a farm near

Monbulk in southern Victoria (37o 53’ S, 145o 25’ E). Inflorescences were harvested from clonally

propagated T. speciosissima ‘Shady Lady’ or seed-grown T. speciosissima plants when approximately

47

50% of flowers had opened. Cut stem ends of inflorescences were stood into water and held in a

coolroom at 4oC for approximately 48 hours for inflorescences from clonally propagated plants or

overnight for inflorescences from seed-grown plants. Cut stem ends of all inflorescences were then stood

into DI water and taken to the IHD laboratory in an air conditioned car within 24 (seed-grown) or 48

hours (clonally propagated plants) of harvest.

3.2.1.12 Thryptomene calycina

Flowering Thtyptomene calycina (Grampian’s thryptomene; Myrtaceae) branches were harvested from a

farm near Horsham in western Victoria (36o 43’ S, 142o 12’ E). Branches were packed dry into a

commercial flower carton and delivered to the IHD laboratory by road within 24 hours of harvest.

Branches arrived in the laboratory with approximately 20% of flowers closed.

3.2.1.13 Verticordia nitens

Flowering Verticordia nitens (yellow Morrison; Myrtaceae) stems were bush-picked in Western Australia

and air freighted dry to the Brisbane wholesale cut flower market within 30 hours of harvest. On arrival,

cut stem ends of flowers were stood into water. Stems were then transferred to buckets of DI water and

taken in an air conditioned car to the UQG laboratory within 1 hour.

3.2.1.14 Zieria cytisoides

Flowering Zieria cytisoides (Rutaceae) stems were harvested from a farm near Caboolture in S.E. Qld (27o

05’ S, 152o 57’ E). Cut stem ends were wrapped in moist newsprint and taken to the UQG laboratory by

road within 2 hours of harvest.

3.2.2 Plant material preparation

On arrival at the laboratory, stem ends of flowers which were transported dry (viz. A. pinnatum, B.

heterophylla, C. gummiferum, E. scaber, T. calycina) were recut under DI water (section 2.2.1) and stood

into DI water for 3-6 hours to rehydrate. The stems of all cut flowers were again recut under DI water to a

length of 20-30 cm, removing at least 2 cm of the stem base. Leaves were removed from stem portions

which would otherwise be submerged in vase solution. In the case of O. diosmifolius, all stem ends were

recut under DI water to a length of 30 cm and leaves were removed within 15 cm of the stem base. All cut

flower stems were then randomly assigned to individual vases (300-375 mL volume). Vases contained a

solution of 10 mg available chlorine provided as DICA/L DI water (section 2.2.1). Vase openings were

covered with a piece of plastic film (section 2.2.1) or Parafilm. Stems were inserted through slits in the

film into the vase solution. In a separate study where ethylene production by B. heterophylla stems was

measured, 100 mL capacity vases were used.

3.2.3 Chemicals

48

1-MCP gas was synthesised and quantified according to section 2.2.2.1. Similarly, an ethylene gas stock

was prepared by diluting gas from a pressurised cylinder as described in section 2.2.2.2. The

concentration of the ethylene working stock was determined by gas chromatography (section 2.2.2.2). In

experiments conducted at the IHD laboratory, the concentration of the ethylene working stock was

quantified by injecting 1 mL samples into a Shimadzu GC-8AIT FID gas chromatograph fitted with a 1.83

m long by 2.2 mm internal diameter stainless steel column packed with activated alumina with a mesh

range of 80/100. The column temperature was 140oC and the injector/detector was 180oC. Ethylene

samples were quantified against a 1.1 µL ethylene/L standard (BOC Gases β-grade special gas mixture).

High purity nitrogen was the carrier gas.

3.2.3.1 Silver thiosulfate

A solution of STS was made according to the method of Joyce (1992). STS solutions used to treat flowers

were prepared by pipetting an aliquot of the stock solution into vases containing DI water.

3.2.4 Treatments

3.2.4.1 Treatment of a range of native cut flowers with 1-MCP and ethylene

Flowers in vases were enclosed into 60.5 L glass chambers (section 2.2.3). In experiments conducted at

the IHD laboratory, flowers in vases were placed into 120 L perspex chambers or individually into 30 L

plastic buckets. Potentially excessive accumulation of CO2 concentrations inside glass chambers or

buckets were reduced with KOH solution as previously described (section 2.2.3). In the case of perspex

chambers, 50 mL of 1M KOH was poured onto the chamber base. Perspex chambers consisted of a five

sided perspex tub and a stainless steel base. The tub was sealed by lowering its walls into matching

grooves filled with water on the base. Two inlets in one side of the stainless steel base were connected

and sealed by latex tube for gas injection or sampling. Plastic buckets were sealed with press-on lids. A

rubber septum for gas injection or sampling was positioned through each lid.

In all experiments, once flowers were inside chambers or buckets, the lids were sealed in place. Based on

the results of previous experiments with G. ‘Sylvia’ (Chapter 2) and other cut flowers (Serek et al. 1995a),

flowers were then pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC (section 2.2.4.1).

Chambers and buckets were ventilated outside each laboratory following 1-MCP pre-treatment. Half of

the flowers from each of these treatments were then exposed to 10 µL ethylene/L for 12 hours at 20oC

inside the same chambers or buckets containing 1M KOH solution (section 2.2.4.1). Ethylene

concentrations inside the chambers or buckets was monitored by gas chromatography (sections 2.2.2.2 and

3.2.3). The other half of the flowers were enclosed in matching chambers or buckets in air with KOH, but

without exogenous ethylene. Following ethylene treatment, flowers and their vases were removed from

these containers and transferred to vase life rooms. The vase life room at UQG was operated at the

49

conditions decribed in section 2.2.4.1. The IHD vase life room was maintained at 21 ± 0.5oC and 60%

RH, and was illuminated with overhead cool white fluorescent lights to 10 µmol/m2/s at flower height for

a 12 hour light period each day.

3.2.4.2 Treatment of B. heterophylla with 1-MCP, STS and ethylene

Flowering B. heterophylla stems in vases were pre-treated on day 0 with 0 or 10 nL 1-MCP/L in 60.5 L

glass chambers (section 2.2.3) or pulsed with STS (0.5 mM Ag+) for 12 hours at 20oC. Stems were then

removed from chambers or STS solutions. The portion of stems that had been submerged in STS solution

were rinsed in DI water and placed into standard vase solutions. Half of the stems from each of these anti-

ethylene treatments were then exposed on day 1 to 10 µL ethylene/L for the longer period (cf. section

3.2.4.1) of 72 hours at 20oC. The other half of the stems were held in matching chambers in air with

KOH, but without exogenous ethylene.

3.2.5 Assessments

3.2.5.1 Vase life

All flowers and their vases were weighed separately daily or every second day (section 2.2.5.1). Floral

organ abscission and opening were assessed daily or every second day after gently brushing or tapping

stems three times by hand. Depending on the particular genus, floral organ abscission and opening were

recorded using a rating scale (1 = < 10%, 2 = 10-30%, 3 = 30-50%, 4 = 50-80%, 5 = > 80%) or

as a percentage of the initial number of floral organs present (Table 3.1). Flower opening on Grevillea

spp. inflorescences was rated daily using an alternative scale: 1 = < 5%, 2 = 5-25%, 3 = > 25%

open flowers on an inflorescence. The number of flowers on T. calycina stems which closed during vase

life was expressed as a percentage of the initial number of open flowers.

Table 3.1. Method and frequency of assessing floral organ abscission and opening from native cutflowers.

Flower Abscission Opening

Method Frequency Method Frequency

A. pinnatum percentage daily percentage daily

B. heterophylla a a a a

C. gummiferum score daily a a

C. uncinatum score daily a a

C. adunca a a score daily

E. scaber percentage every second day a a

Grevillea spp. score daily score daily

L. petersonii percentage daily a a

50

L. scoparium percentage b daily a a

O. diosmifolius a a score daily

P. lanceolata score daily a a

T. calycina percentage every second day a a

T. speciosissima percentage daily score every second day

V. nitens score daily a a

Z. cytisoides score daily a a

a Assessment was not made.b Percentage of abscised and senescent flowers.

Wilting at the pedicels and peduncles of C. adunca and O. diosmifolius, flower discolouration (fading)

from Grevillea spp. and flower wilting of other flowers were subjectively determined daily using the

following rating scale: 1 = none/slight, 2 = moderate, 3 = advanced. Discolouration of B.

heterophylla flowers, observed as fading from bright pink to white, was rated daily using the scale of 1 =

0-25%, 2 = 26-50%, 3 = 51-75%, 4 = 76-100% discolouration over the whole stem.

Leaf senescence, evident as chlorosis or necrosis, on flowering stems of C. adunca and O. diosmifolius

was measured as a percentage leaf area affected. In addition, leaf abscission from O. diosmifolius stems

was determined daily and expressed as the length (cm) of stem without leaves, from the stem base to the

lowest leaf. Vase life of all cut flowers examined was judged as the time in days to loss of visual appeal

(Table 3.2).

Table 3.2. Criteria used to determine the end of vase life for native cut flowers.

Flower Criteria

A. pinnatum ≥ 20% perianth abscission and/or ≥ 10% perianth wilting and/or moderate

perianth discolouration

B. heterophylla ≥ 50% of flowers with ≥ 50% discolouration and/or moderate wilting

C. gummiferum > 10% flower abscission and/or moderate sepal wilting

C. uncinatum > 10% flower abscission and/or ≥ 50% of flowers having lost turgor as evidenced

by a decreased angle between petals and the style

C. adunca ≥ 20% leaf senescence and/or moderate pedicel wilting

E. scaber ≥ 10% petal abscission

Grevillea spp. > 10% flower abscission and/or moderate flower wilting and/or moderate flower

discolouration

L. petersonii ≥ 20% flower abscission and/or ≥ 50% of flowers having lost turgor as evidenced

by a decreased angle between petals and the style

L. scoparium ≥ 20% flower abscission and senescence

O. diosmifolius ≥ 20% leaf senescence and/or moderate pedicel wilting

51

P. lanceolata. ≥ 10% flower wilting and/or discolouration

T. calycina ≥ 10% flower closing

T. speciosissima ≥ 20% perianth abscission

V. nitens > 10% flower abscission and/or closing of flowers and/or fading of bracts and/or

pedicel wilting

Z. cytisoides > 10% flower abscission and/or moderate flower wilting

52

3.2.5.2 Ethylene production rates

Parallel sets of 15 cm long flowering and non-flowering B. heterophylla stems in vases were enclosed in

2.2 L glass jars each containing CO2 scrubber (section 2.2.5.2). Additionally, individual flowers were

randomly sampled from flowering stems standing in DI water at 20oC. These detached flowers were

placed singly into 15 mL glass test tubes. Five replicate flowering and non-flowering stems and sets of

detached flowers were used. All jars and tubes were sealed once daily with plastic screw-on lids and

rubber plugs, respectively, and held at 20oC for 10-12 hours. Gas samples were then taken from the

headspace of jars and tubes with a 1 mL syringe. The ethylene concentration was measured by gas

chromatography (section 2.2.5.2).


Following 1-MCP, STS and ethylene treatments, flowers were arranged in a vase life room in a CRD.

There were five to ten replicate stems for each treatment, depending upon the particular experiment. The

responses of a number of cut flowers to 1-MCP and ethylene treatments were examined as 2 (1-MCP) x 2

(ethylene) factorial experiments. A 3 (anti-ethylene agent) x 2 (ethylene) factorial experiment was used to

study the effect of 1-MCP, STS and ethylene treatments on B. heterophylla. Treatment means and

standard errors were calculated using Microsoft Excel (Version 5.0, Microsoft Inc.). Figures were

plotted using Sigmaplot (Version 2.0, Jandel Corporation). Most data were analysed by ANOVA using

the balanced ANOVA function of Minitab (Release 11.12, Minitab Inc.). Data sets from Grevillea spp.

and T. speciosissima experiments showing non-significant differences similar to those reported for G.

‘Sylvia’ in Chapter 2 are presented in appendices. Flower opening from these experiments was analysed

using χ2 tests or Fisher’s exact test by SAS (release 6.12, SAS Institute 1996) (section 2.2.6).

The time in days to reach 10% flower abscission from G. ‘Kay Williams’, G. ‘Misty Pink’ and Z.

cytisoides, or 20% floral organ abscission from L. petersonii, L. scoparium and T. speciosissima was

recorded for ANOVA. Likewise, the time in days to reach moderate wilting of sepals on C. gummiferum,

pedicels on C. adunca and O. diosmifolius and peduncles on O. diosmifolius was calculated. The time in

days to moderate flower discolouration from G. ‘Sandra Gordon’, > 50% flower discolouration from B.

heterophylla (second experiment; section 3.2.4.2) and 10% flower opening from O. diosmifolius were also

recorded for ANOVA. These data were then analysed as 2 x 2 or 3 x 2 factorial ANOVAs depending

upon the particular experiment. In experiments with Grevillea spp., when flower abscission from

inflorescences was 100%, flower wilting, discolouration and opening measurements for these

inflorescences were discontinued (section 2.2.6). Thus, in the case of G. ‘Sandra Gordon’, flower

discolouration of the remaining treatments was analysed as a one-way ANOVA. Ethylene production data

from B. heterophylla was also analysed as one-way ANOVAs.

In experiments where all replicates did not reach the abscission and senescence stages described above,

data were analysed as split plot for time (i.e. sequential days of measurement) ANOVAs as described in

53

section 2.2.6. For this method of ANOVA, score data were converted to a corresponding percentage.

Derived and direct percentage data were then arcsine transformed for ANOVA (Steel and Torrie 1987).

Flower discolouration data from G. ‘Kay Williams’ and G. ‘Misty Pink’ and all remaining wilting data

were recorded for ANOVA as a binary score, where a 0 or 1 score was assigned to each stem to indicate

the absence or presence of moderate to advanced discolouration or wilting (Narula and Levy 1977).

Relative fresh weight and vase solution uptake data from all experiments and leaf abscission from O.

diosmifolius were also analysed as split plot for time ANOVAs.

Treatment means were separated by the LSD test at P = 0.05. For data analysed as split plots for time,

LSDs presented are for between treatments (section 2.2.6). LSDs are presented only when significant

differences (P < 0.05) between treatments existed. Differences at the P < 0.05 level between treatment

means are referred to in the results as significant. LSDs from ANOVAs on derived data not directly

shown in figures are presented in the appendices. LSDs from ANOVA of transformed and binary data

sets are not presented (section 2.2.6).

54

3.3 RESULTS

3.3.1 Treatment of a range of native cut flowers with 1-MCP and ethylene

3.3.1.1 A. pinnatum

Treatment of A. pinnatum inflorescences with 1-MCP or ethylene did not significantly affect perianth

abscission (Figure 3.1 and Appendix 3.1). The change in relative fresh weight of inflorescences was not

affected by 1-MCP pre-treatment (Figure 3.1 and Appendix 3.2). However, inflorescences exposed only

to ethylene lost significantly more relative fresh weight compared to inflorescences not exposed to

ethylene (Figure 3.1 and Appendix 3.2). Vase solution uptake by inflorescences tended to increase with

time (Figure 3.1). Solution uptake by inflorescences exposed to ethylene declined between days 1 and 2.

Thereafter, solution uptake by inflorescences exposed to ethylene was higher than by inflorescences not

exposed to ethylene and is reflected in a significant interaction between ethylene treatment and time of

measurement (Appendix 3.3). There was no significant effect of 1-MCP pre-treatment on solution uptake

by inflorescences (Appendix 3.3). Vase lives of inflorescences were not significantly affected by 1-MCP

or ethylene treatments (Table 3.3 and Appendix 3.4).

In the second experiment with A. pinnatum, perianth abscission was not significantly affected by 1-MCP

or ethylene treatment, although there was a trend toward reduced perianth abscission from inflorescences

that were pre-treated with 1-MCP and subsequently exposed to ethylene (Figure 3.2 and Appendix 3.5).

Perianth abscission of unopened flowers was also reduced. The loss of relative fresh weight from

inflorescences exposed to 0 or 100 µL ethylene/L was significantly reduced by 1-MCP pre-treatment

(Figure 3.2 and Appendix 3.6). Inflorescences exposed only to exogenous ethylene lost most relative

fresh weight.

Vase solution uptake by inflorescences increased to day 3, and thereafter uptake was low by

inflorescences from all treatements (Figure 3.2). Pre-treatment of inflorescences with 1-MCP did not

significantly affect solution uptake (Figure 3.2). Inflorescences exposed to ethylene used vase solution at

lower rates between days 1 and 2 and at higher rates between days 2 and 3 than inflorescences not

exposed to ethylene. These responses are evident as a significant interaction between ethylene treatment

and time of measurement for vase solution uptake (Appendix 3.7). Pre-treatment of inflorescences with 1-

MCP prevented the exogenous ethylene-induced reduction in vase life (Table 3.4 and Appendix 3.8).

Vase lives of inflorescences not exposed to ethylene were marginally extended by pre-treatment with 1-

MCP.

55

Per

iant

h ab

scis

sion

(%

of i

nitia

l num

ber)

0

10

20

30

Rel

ativ

e fr

esh

wei

ght

(%

initi

al F

W)

80

90

100

110

Time (days)

0 1 2 3 4 5 6

Sol

utio

n up

take

(m

L/ g

initi

al F

W/ d

ay)

0.1

0.2

0.3

0.4

Figure 3.1. Perianth abscission, relative fresh weight and vase solution uptake for A. pinnatuminflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/L and 10 µLethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene treatments were each conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent standard errors of means (n = 10). Where no vertical barsappear, the standard error was smaller than the size of the symbol. LSD for relative fresh weightdata = 1.7%. LSD for vase solution uptake data = 0.027 mL/g initial FW/day. (Experiment 1).

56

Table 3.3. Vase lives (mean ± s.e. in days) of native cut flowers which did not respond to 1-MCP or ethylene treatments. Flowers were pre-treated on day0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the flowers from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC. Data within each row were not significantly different at P = 0.05.

Flower No ethylene (0 µL/L) Plus ethylene (10 µL/L)

0 nL 1-MCP/L 10 nL 1-MCP/L 0 nL 1-MCP/L 10 nL 1-MCP/L

A. pinnatum 3.7 ± 0.3 3.3 ± 0.4 2.9 ± 0.4 3.6 ± 0.4

B. heterophylla 5.9 ± 0.8 5.5 ± 0.2 5.0 ± 0.3 4.8 ± 0.3

C. adunca 6.7 ± 1.3 4.8 ± 0.8 5.5 ± 1.1 7.0 ± 1.1

E. scaber 2.9 ± 0.3 3.4 ± 0.3 3.0 ± 0.3 3.3 ± 0.3

L. scoparium ‘Winter Cheer’ 2.8 ± 0.2 3.4 ± 0.2 2.6 ± 0.4 3.0 ± 0.3

O. diosmifolius 7.1 ± 1.0 5.5 ± 0.7 5.3 ± 0.9 7.0 ± 0.8

P. lanceolata 20.4 ± 0.9 19.3 ± 0.6 18.5 ± 0.9 20.1 ± 0.8

T. calycina 3.6 ± 0.3 3.0 ± 0.3 3.0 ± 0.3 2.6 ± 0.3

Z. cytisoides 3.6 ± 0.7 4.8 ± 0.4 2.6 ± 0.6 4.4 ± 1.3

57

Per

iant

h ab

scis

sion

(%

of i

nitia

l num

ber)

0

10

20

30

Rel

ativ

e fr

esh

wei

ght

(% in

itial

FW

)

80

90

100

Time (days)

0 1 2 3 4 5 6 7

Sol

utio

n up

take

(mL/

g in

itial

FW

/day

)

0.1

0.2

0.3

0.4

Figure 3.2. Perianth abscission, relative fresh weight and vase solution uptake for A. pinnatuminflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/L and 10 µLethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene treatments were each conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent standard errors of means (n = 10). Where no vertical barsappear, the standard error was smaller than the size of the symbol. LSD for relative fresh weightdata = 1.9%. LSD for vase solution uptake data = 0.023 mL/g initial FW/day. (Experiment 2).

58

Table 3.4. Vase lives (mean ± s.e. in days) of native cut flowers which responded to 1-MCP and ethylene treatments. Flowers were pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the flowers from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC. Data within each row followed by the same letter are not significantly different at P = 0.05.

Flower No ethylene (0 µL/L) Plus ethylene (10 µL/L) LSD

0 nL 1-MCP/L 10 nL 1-MCP/L 0 nL 1-MCP/L 10 nL 1-MCP/L

A. pinnatum 5.0 ± 0.3 ab 5.8 ± 0.4 b 4.3 ± 0.5 a 5.8 ± 0.1 b 0.9 (n= 10)

C. gummiferum 11.2 ± 1.1 b 15.6 ± 0.9 c 4.9 ± 1.9 a 14.8 ± 1.1 b 3.8 (n = 10)

C. uncinatum ‘Paddy’s Late’ 11.1 ± 0.7 b 11.5 ± 0.2 b 1.0 ± 0.0 a 10.7 ± 0.4 b 1.2 (n = 10)

G. ‘Kay Williams’ 4.1 ± 0.1 b 4.4 ± 0.2 b 1.0 ± 0.0 a 4.3 ± 0.2 b 0.5 (n = 7)

G. ‘Misty Pink’ 4.1 ± 0.2 b 4.1 ± 0.2 b 1.0 ± 0.0 a 3.9 ± 0.2 b 0.5 (n = 10)

G. ‘Sandra Gordon’ 6.0 ± 0.2 b 6.4 ± 0.2 c 2.0 ± 0.0 a 5.8 ± 0.1 b 0.4 (n = 10)

L. petersonii 2.5 ± 0.4 b 3.0 ± 0.6 b 1.4 ± 0.2 a 3.4 ± 0.2 b 1.1 (n = 10)

T. speciosissima 5.1 ± 0.3 ab 5.5 ± 0.2 b 4.3 ± 0.4 a 5.9 ± 0.3 b 0.8 (n = 10)

T. speciosissima ‘Shady Lady’ 2.3 ± 0.4 b 2.5 ± 0.3 b 1.3 ± 0.2 a 2.2 ± 0.4 ab 0.9 (n = 10)

V. nitens 11.0 ± 0.9 b 9.8 ± 0.9 b 1.0 ± 0.0 a 11.3 ± 0.9 b 2.2 (n = 10)

59

3.3.1.2 B. heterophylla

Flower discolouration on flowering B. heterophylla stems was not significantly affected by 1-MCP or

ethylene treatment (Figure 3.3 and Appendix 3.9). However, there was a trend toward more flower

discolouration from stems treated with ethylene as opposed to stems not treated with ethylene (Figure 3.3).

This response is reflected in a significant interaction between ethylene treatment and time of measurement

(Appendix 3.9). Flower wilting was not significantly affected by 1-MCP pre-treatment (Figure 3.3 and

Appendix 3.10). The onset of flower wilting was significantly delayed on stems that received ethylene

treatment. However, wilting of flowers not treated with ethylene or pre-treated with 1-MCP was minor.

Nonetheless, a significant interaction between 1-MCP pre-treatment and ethylene treatment was recorded

(Appendix 3.10). The change in relative fresh weight of stems were not significantly affected by 1-MCP

or ethylene treatments when applied either alone or in combination (Figure 3.3 and Appendix 3.11).

Vase solution uptake by stems fluctuated over time regardless of 1-MCP or ethylene treatment (Figure

3.3). However, solution uptake by stems pre-treated with 1-MCP was less variable compared to stems not

pre-treated with 1-MCP. In addition, stems exposed to ethylene used vase solution at a higher rate

between days 0 and 1 than stems not exposed to ethylene. Collectively, these variable responses resulted

in a significant interaction between 1-MCP pre-treatment, ethylene treatment and time of measurement for

vase solution upatke (Appendix 3.12). 1-MCP and ethylene treatments did not significantly affect vase

lives of stems (Table 3.3 and Appendix 3.13).

60

Dis

colo

urat

ion

scor

e1

2

3

4

Wilt

sco

re

1

2

3

Time (days)

0 2 4 6 8 10 12

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0

1

2

Rel

ativ

e fr

esh

wei

ght

(%

of i

nitia

l FW

)

40

60

80

100

Figure 3.3 Flower discolouration (scores: 1 = 0-25% to 4 = 76-100%), flower wilting (scores: 1 =none/slight to 3 = advanced), relative fresh weight and vase solution uptake of flowering B.heterophylla stems treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/L and 10 µLethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene treatments were each conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent the standard errors of means (n = 8). Where no vertical barsappear, the standard error was smaller than the size of the symbol. LSD for vase solution uptakedata = 0.106 mL/g initial FW/day.

61

3.3.1.3 C. adunca

Leaf senescence and flower opening on C. adunca stems were not significantly affected by 1-MCP or

ethylene treatments (Figure 3.4, Appendices 3.14 and 3.15). However, there was trend toward reduced

flower opening from stems pre-treated with 1-MCP (Figure 3.4). Pedicel wilting from stems pre-treated

with 1-MCP and exposed to ethylene was significantly delayed compared to stems pre-treated with 1-

MCP and not exposed to ethylene (Figure 3.4 and Appendix 3.16). This difference is reflected by a

significant interaction between 1-MCP pre-treatment and ethylene treatment (Appendix 3.17). 1-MCP

pre-treatment apparently slightly reduced peduncle wilting on stems and consequently a significant

interaction between 1-MCP pre-treatment and ethylene treatment was evident (Figure 3.4 and Appendix

3.18).

There was no significant effect of 1-MCP and ethylene treatments on the loss of relative fresh weight of C.

adunca stems (Figure 3.4 and Appendix 3.19). Vase solution uptake by stems increased between days 2

and 4, but thereafter decreased over time (Figure 3.4). The increase in solution uptake by stems between

days 2 and 4 varied according to each of the four treatments tested. Consequently, a significant

interaction between 1-MCP pre-treatment, ethylene treatment and time of measurement was recorded

(Appendix 3.20). Vase lives of stems were not significantly affected by either 1-MCP or ethylene

treatment (Table 3.3 and Appendix 3.21).

62

Leaf

sen

esce

nce

(% o

f lea

f are

a)0

20

40

60

80

Flo

wer

ope

ning

sco

re

12345

Ped

icel

wilt

sc

ore

1

2

3

Ped

uncl

e w

ilt

scor

e

1

2

3

Rel

ativ

e fr

esh

wei

ght

(% in

itial

FW

)

40

60

80

100

Time (days)

0 2 4 6 8 10 12

Sol

utio

n up

take

(m

L/g

initi

al

FW

/2 d

ays)

0

1

2

3

Figure 3.4. Leaf senescence, flower opening (scores: 1 = < 10% to 5 = > 80%), pedicel wilting(scores: 1 = none/slight to 3 = advanced), peduncle wilting (scores: 1 = none/slight to 3 = advanced),relative fresh weight and vase solution uptake for flowering C. adunca stems treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/L and 10 µL ethylene/L (■), 10 nL 1-MCP/L and 0µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatmentswere conducted for 12 hours at 20oC on days 0 and 1, respectively. Vertical bars representstandard errors of the means (n = 10). LSD for pedicel wilting data is presented in Appendix 3.16.LSD for solution uptake data = 0.127 mL/g initial FW/2 days.3.3.1.4 C. gummiferum

Pre-treatment of flowering C. gummiferum stems with 1-MCP prevented exogenous ethylene-induced

63

flower abscission (Figure 3.5). Exposure of stems to ethylene caused moderate levels of flower

abscission, whereas no flower abscission at all was observed from stems not exposed to ethylene (Figure

3.5). This response is reflected in a significant interaction between 1-MCP pre-treatment, ethylene

treatment and time of measurement (Appendix 3.22). Pre-treatment of stems with 1-MCP also

significantly delayed the onset of sepal wilting associated with exposure of stems to 0 or 10 µL ethylene/L

(Figure 3.5, Appendices 3.23 and 3.24). The loss of stem relative fresh weight associated with exogenous

ethylene-induced flower abscission and sepal wilting was significantly reduced by 1-MCP pre-treatment

(Figure 3.5 and Appendix 3.25). Likewise, the decline of relative fresh weight from stems not exposed to

ethylene was significantly greater than from stems pre-treated with 1-MCP, presumably as sepal wilting

was delayed. These responses are evident as significant interactions between 1-MCP pre-treatment and

ethylene treatment and between 1-MCP pre-treatment and time of measurement for relative fresh weight

(Appendix 3.25).

Vase solution uptake by stems fluctuated during the first 7 days of the experiment (Figure 3.5).

Thereafter, solution uptake tended to decrease with time. After day 8, stems pre-treated with 1-MCP used

vase solution at higher rates than stems not pre-treated with 1-MCP. This variation resulted in a

significant interaction for 1-MCP pre-treatment and time of measurement (Figure 3.5 and Appendix 3.26).

1-MCP pre-treatment prevented the exogenous ethylene-induced reduction in vase life (Table 3.4). Vase

lives of stems not exposed to ethylene were significantly extended by 1-MCP pre-treatment. Accordingly,

a significant interaction between 1-MCP pre-treatment and ethylene treatment was evident (Appendix

3.27).

64

Rel

ativ

e fr

esh

wei

ght

(%

of i

nitia

l FW

)

40

60

80

100

Abs

ciss

ion

scor

e

1

2

3

4

5

Wilt

sco

re

1

2

3

Time (days)

0 2 4 6 8 10 12 14 16 18

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.00.20.40.60.81.0

Figure 3.5. Flower abscission (scores: 1 = < 10% to 5 = > 80%), sepal wilting (scores: 1 =none/slight to 3 = advanced), relative fresh weight and vase solution uptake for flowering C.gummiferum stems treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/L and 10 µLethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene treatments were each conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent the standard errors of means (n = 10). Where no vertical barappears, standard errors were smaller than the size of the symbol. LSD for sepal wilting data ispresented in Appendix 3.23. LSD for relative fresh weight data = 5.7%. LSD for vase solutionuptake = 0.046 mL/g initial FW/day.3.3.1.5 C. uncinatum ‘Paddy’s Late’

65

1-MCP pre-treatment protected C. uncinatum ‘Paddy’s Late’ sprigs against exogenous ethylene (Plate

3.1). Pre-treatment with 1-MCP significantly delayed the onset of flower abscission from sprigs that were

exposed to exogenous ethylene (Figure 3.6). Exposure of sprigs only to ethylene caused rapid and

extensive flower abscission. By the end of the experiment, flower abscission from sprigs not exposed to

ethylene was significantly greater than that from sprigs pre-treated with 1-MCP (Figure 3.6). Thus, a

significant interaction for 1-MCP pre-treatment, ethylene treatment and time of measurement was

recorded (Appendix 3.28). As a result of 1-MCP pre-treatment having delayed exogenous ethylene-

induced flower abscission, the associated decline of sprig relative fresh weight was significantly reduced

(Figure 3.6). However, the decline of relative fresh weight from sprigs pre-treated with 1-MCP was not

significantly different from that of sprigs not treated with 1-MCP or ethylene. This response was reflected

in a significant interaction between 1-MCP pre-treatment, ethylene treatment and time of measurement

(Appendix 3.29).

Vase solution uptake by sprigs fluctuated over time (Figure 3.6). Sprigs exposed only to ethylene had the

lowest uptake rate during vase life. However, convergence of the uptake patterns by sprigs from all

treatments towards the end of the experiment probably accounts for the significant interaction between 1-

MCP pre-treatment, ethylene treatment and time of measurement (Figure 3.6 and Appendix 3.30). Vase

life was based partly on flower abscission data (Table 3.2). Thus, the exogenous ethylene-induced loss in

vase life was prevented by pre-treatment with 1-MCP (Table 3.4). 1-MCP pre-treatment did not,

however, significantly extend the vase lives of sprigs which were not exposed to ethylene. This

differential response is manifested in a significant interaction between 1-MCP pre-treatment and ethylene

treatment (Appendix 3.31).

66

Plate 3.1. Flowering C. uncinatum ‘Paddy’s Late’ sprigs on day 2 after treatment on day 0 with 0(control treatment) (LHS) or 10 nL 1-MCP/L (RHS) followed by exposure on day 1 to 10 µLethylene/L. Note: extensive flower abscission is evident in the control sprig (LHS).

67

Abs

ciss

ion

scor

e

1

2

3

4

5

Rel

ativ

e fr

esh

wei

ght

(% o

f ini

tial F

W)

20

40

60

80

100

120

Time (days)

0 2 4 6 8 10 12 14

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.5

1.0

1.5

Figure 3.6. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for flowering sprigs of C. uncinatum ‘Paddy’s Late’ treated with 0 nL 1-MCP/Land 0 µL ethylene/L (zz), 0 nL 1-MCP/L and 10 µL ethylene/L (��), 10 nL 1-MCP/L and 0 µLethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatments wereconducted for 12 hours at 20oC on days 0 and 1, respectively. Vertical bars represent the standarderrors of means (n = 10). Where no vertical bars appear, standard errors are smaller than the sizeof the symbol. LSD for relative fresh weight = 3.5%. LSD for vase solution uptake = 0.052 mL/ginitial FW/day.

68

3.3.1.6 E. scaber

Petal abscission from flowers on E. scaber stems was slightly reduced for stems pre-treated with 1-MCP

compared to stems exposed only to ethylene (Figure 3.7). Exposure of stems to exogenous ethylene

induced petal abscission (Appendix 3.32). Changes in the relative fresh weights of stems were not

significantly altered by 1-MCP or ethylene treatments applied either alone or in combination (Figure 3.7

and Appendix 3.33). Vase solution uptake by stems increased over the short duration of this experiment

(Figure 3.7). Solution uptake by stems pre-treated with 1-MCP was significantly higher between days 0

and 2, but not between days 2 and 4, relative to stems not pre-treated with 1-MCP. As a result, a

significant interaction between 1-MCP pre-treatment and time of measurement for vase solution uptake

was evident (Appendix 3.34). 1-MCP or ethylene treatments applied either alone or in combination did

not significantly affect stem vase life relative to stems not treated with 1-MCP or ethylene (Table 3.3 and

Appendix 3.35).

69

Pet

al a

bsci

ssio

n(%

initi

al n

umbe

r of

pe

tals

and

bud

s)

0

20

40

60

80

100

Rel

ativ

e fr

esh

wei

ght

(%

initi

al F

W)

80

90

100

Time (days)

0 2 4

Sol

utio

n up

take

(m

L/ g

initi

al F

W/ 2

day

s)

0.6

0.8

1.0

1.2

Figure 3.7. Petal abscission, relative fresh weight and vase solution uptake for flowering E. scaberstems of treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/L and 10 µL ethylene/L(■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatments were each conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent standard errors of means (n = 10). LSD for vase solutionuptake data = 0.069 mL/g initial FW/2 days.

70

3.3.1.7 Grevillea hybrids

3.3.1.7.1 G. ‘Kay Williams’

Pre-treatment of G. ‘Kay Williams’ inflorescences with 1-MCP significantly delayed the onset of flower

abscission and reduced the associated loss of relative fresh weight stimulated by exposure to exogenous

ethylene (Figure 3.8 and Appendix 3.36). 1-MCP pre-treatment did not significantly reduce flower

abscission or the loss of relative fresh weight from inflorescences not exposed to ethylene. Accordingly, a

significant interaction between 1-MCP pre-treatment and ethylene treatment for flower abscission was

evident (Appendix 3.37). Likewise, a significant interaction between 1-MCP pre-treatment, ethylene

treatment and time of measurement for relative fresh weight was recorded (Appendix 3.38). Vase solution

uptake by inflorescences pre-treated with 1-MCP was consistently higher during the experiment compared

to inflorescences exposed only to ethylene (Figure 3.8). Despite apparent similarities in the uptake

patterns, significant interactions between 1-MCP and time of measurement and between ethylene

treatment and time of measurement were recorded (Appendix 3.39).

Each of flower discolouration, opening and wilting for inflorescences were not significantly affected by 1-

MCP or ethylene treatment applied either alone or in combination (Appendices 3.40, 3.41, 3.42 and

3.43). As vase life was partly based on flower abscission (Table 3.2), the exogenous ethylene-induced

loss in vase life was prevented by 1-MCP pre-treatment (Table 3.4). However, 1-MCP pre-treatment did

not significantly extend vase life of inflorescences not exposed to ethylene. Thus, a significant interaction

between 1-MCP pre-treatment, ethylene treatment and vase life was evident (Appendix 3.44).

71

Abs

ciss

ion

scor

e

1

2

3

4

5

Rel

ativ

e fr

esh

wei

ght

(%

initi

al F

W)

20

40

60

80

100

120

Time (days)

0 1 2 3 4 5

Sol

utio

n up

take

(m

L/ g

initi

al F

W/d

ay)

0.1

0.2

0.3

0.4

Figure 3.8. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for G. ‘Kay Williams’ inflorescences treated with 0 nL 1-MCP/L and 0 µLethylene/L (zz), 0 nL 1-MCP/L and 10 µL ethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲)or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatments were conducted for12 hours at 20oC on days 0 and 1, respectively. Vertical bars represent the standard errors ofmeans (n = 7). Where no vertical bars appear, standard errors are smaller than the size of thesymbol. LSD for flower abscission is presented in Appendix 3.36. LSD for relative fresh weightdata = 4.0%. LSD for vase solution uptake data = 0.087 mL/g initial FW/day.

72

3.3.1.7.2 G. ‘Misty Pink’

1-MCP pre-treatment protected G. ‘Misty Pink’ inflorescences against exogenous ethylene (Plate 3.2).

Pre-treatment with 1-MCP significantly delayed the onset of flower abscission from inflorescences

exposed to exogenous ethylene (Figure 3.9, Appendix 3.45). 1-MCP pre-treatment did not significantly

reduce flower abscission from inflorescences not exposed to ethylene. Consequently, a significant

interaction between 1-MCP pre-treatment and ethylene treatment was evident (Appendix 3.46). 1-MCP

pre-treatment significantly reduced the exogenous ethylene-induced loss of inflorescence relative fresh

weight (Figure 3.9). However, the decline in relative fresh weight of inflorescences not treated with

ethylene was not reduced by 1-MCP pre-treatment. Thus, this differential response was reflected in a

significant interaction between 1-MCP pre-treatment, ethylene treatment and time of measurement

(Appendix 3.47). Inflorescences exposed only to ethylene used vase solution at lower rates than

inflorescences pre-treated with 1-MCP (Figure 3.9). This difference in solution use pattern was reflected

in significant interactions between 1-MCP pre-treatment and time of measurement and, between ethylene

treatment and time of measurement (Appendix 3.48).

Flower discolouration and wilting were not significantly affected by 1-MCP or ethylene treatments

(Appendices 3.49, 3.50 and 3.51). There were no consistent effects of treatments on flower opening

(Appendices 3.49 and 3.52). Nonetheless, on day 1, flower opening from inflorescences pre-treated with

1-MCP was slightly but significantly reduced compared to inflorescences not pre-treated with 1-MCP

(Appendices 3.49 and 3.52).

Vase lives of inflorescences were partly based on flower abscission (Table 3.2). Accordingly, 1-MCP

pre-treatment prevented the exogenous ethylene-induced reduction in vase life (Table 3.4). 1-MCP pre-

treatment did not significantly extend the vase lives of inflorescences not exposed to ethylene. As a result,

there was a significant interaction between 1-MCP pre-treatment and ethylene treatment (Appendix 3.53).

73

Plate 3.2. G. ‘Misty Pink’ inflorescences on day 2 after treatment on day 0 with 0 (LHS) or 10 nL1-MCP/L (RHS) followed by exposure on day 1 to 10 µL ethylene/L. Note: extensive flowerabscission is evident in the control inflorescence (LHS).

74

Abs

ciss

ion

scor

e

1

2

3

4

5

Rel

ativ

e fr

esh

wei

ght

(% o

f ini

tial F

W)

20

40

60

80

100

120

Time (days)

0 1 2 3 4 5

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.1

0.2

0.3

0.4

Figure 3.9. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for G. ‘Misty Pink’ inflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L(zz), 0 nL 1-MCP/L and 10 µL ethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatments were conducted for 12 hours at20oC on days 0 and 1, respectively. Vertical bars represent the standard errors of means (n = 10).Where no vertical bars appear, standard errors are smaller than the size of the symbol. LSD forflower abscission data is presented in Appendix 3.45. LSD for weight loss data = 5.0%. LSD forvase solution uptake data = 0.022 mL/g initial FW/day.

75

3.3.1.7.3 G. ‘Sandra Gordon’

The onset of flower abscission and associated loss of relative fresh weight from G. ‘Sandra Gordon’

inflorescences exposed to exogenous ethylene were significantly delayed by 1-MCP pre-treatment (Plate

3.3 and Figure 3.10). However, 1-MCP did not significantly reduce flower abscission or the decline of

relative fresh weight from inflorescences not exposed to ethylene (Figure 3.10). Accordingly, there were

significant interactions between 1-MCP pre-treatment, ethylene treatment and time of measurement for

flower abscission (Appendix 3.54) and relative fresh weight (Appendix 3.55). Vase solution uptake by

inflorescences pre-treated with 1-MCP was more highly variable over time compared to inflorescences not

pre-treated with 1-MCP (Figure 3.10). This differential pattern of response resulted in a significant

interaction between 1-MCP pre-treatment and time of measurement for vase solution uptake (Appendix

3.56).

There was slightly, but significantly more flower discolouration on day 7 for inflorescences not treated

with 1-MCP or ethylene compared to inflorescences pre-treated with 1-MCP (Appendices 3.57, 3.58 and

3.59). However, effects of 1-MCP pre-treatment on flower discolouration were not consistent

(Appendices 3.57 and 3.58). Similarly, there were no consistent treatment effects on flower opening

(Appendices 3.57 and 3.60). Flower wilting was not significantly affected by 1-MCP pre-treatment

compared to inflorescences not treated with 1-MCP or ethylene (Appendices 3.57 and 3.61). Pre-

treatment of G. ‘Sandra Gordon’ inflorescences with 1-MCP treatment prevented the exogenous ethylene-

induced loss in vase life (Table 3.4). 1-MCP pre-treatment did not significantly extend vase lives of

inflorescences not exposed to ethylene. As a result, there was a significant interaction between 1-MCP

pre-treatment and ethylene treatment (Appendix 3.62).

76

Plate 3.3. G. ‘Sandra Gordon’ inflorescences on day 5 after treatment on day 0 with 0 (controltreatment) (LHS) or 10 nL 1-MCP/L (RHS) followed by exposure on day 1 to 10 µL ethylene/L.Note: extensive flower abscission is evident in the control inflorescence (LHS).

77

Abs

ciss

ion

scor

e

1

2

3

4

5

Rel

ativ

e fr

esh

wei

ght

(%

initi

al F

W)

20

40

60

80

100

120

Time (days)

0 1 2 3 4 5 6 7

Sol

utio

n up

take

(m

L/ g

initi

al F

W/ d

ay)

0.1

0.2

0.3

0.4

Figure 3.10. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for G. ‘Sandra Gordon’ inflorescences treated with 0 nL 1-MCP/L and 0 µLethylene/L (zz), 0 nL 1-MCP/L and 10 µL ethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲)or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatments were conducted for12 hours at 20oC on days 0 and 1, respectively. Vertical bars represent the standard errors ofmeans (n = 10). Where no vertical bars appear, standard errors are smaller than the size of thesymbol. LSD for weight loss = 3.6%. LSD for vase solution uptake data = 0.051 mL/g initialFW/day.

78

3.3.1.8 Leptospermum spp .

3.3.1.8.1 L. petersonii

Pre-treatment of flowering L. petersonii stems with 1-MCP significantly reduced exogenous ethylene-

induced petal abscission (Plate 3.4, Figure 3.11 and Appendix 3.63). However, 1-MCP pre-treatment did

not significantly reduce petal abscission from stems not exposed to ethylene. 1-MCP pre-treatment

significantly reduced the decline of stem relative fresh weight associated with petal abscission from stems

exposed to exogenous ethylene (Figure 3.11 and Appendix 3.64). Vase solution uptake by stems

increased over time to day 3 and then declined (Figure 3.11). Stems exposed only to ethylene used vase

solution at a lower rate throughout the experiment compared to stems pre-treated with 1-MCP. As a

result, there were significant interactions between 1-MCP pre-treatment and time of measurement and

between ethylene treatment and time of measurement (Appendix 3.65). Because vase life was based on

petal abscission data (Table 3.2), 1-MCP pre-treatment also prevented the exogenous ethylene-induced

loss in vase life (Table 3.4). 1-MCP pre-treatment did not significantly extend vase lives of stems not

exposed to ethylene (Table 3.4 and Appendix 3.63).

3.3.1.8.2 L. scoparium ‘Winter Cheer’

Flower abscission and senescence (flower wilting and discolouration) for L. scoparium ‘Winter Cheer’

stems were not consistently affected by 1-MCP or ethylene treatments, although there was a trend toward

reduced flower abscission and senescence from stems pre-treated with 1-MCP (Figure 3.12 and Appendix

3.66). Exposure of stems to ethylene increased the number of abscised and senescent flowers and,

thereby, significantly reduced stem relative fresh weight (Figure 3.12 and Appendix 3.67). However, 1-

MCP pre-treatment did not significantly reduce the loss of stem relative fresh weight. Vase solution

uptake by stems exposed to ethylene was lower between days 2 and 3 than stems not exposed to ethylene

(Figure 3.12). This variable pattern resulted in a significant interaction for ethylene treatment and time of

measurement for vase solution uptake (Appendix 3.68). Vase life was not significantly affected by 1-

MCP or ethylene treatments (Table 3.3 and Appendix 3.66). Nonetheless, there was a trend toward

reduced vase lives of stems exposed to exogenous ethylene.

79

Plate 3.4. Flowering L. petersonii stems on day 2 after treatment on day 0 with 0 (LHS) or 10 nL 1-MCP/L (RHS) followed by exposure on day 1 to 10 µL ethylene/L. Note: petal abscission is evidentin the control stem (LHS).

80

Pet

al a

bsci

ssio

n (%

initi

al n

umbe

r of

pe

tals

and

bud

s)

0

20

40

60

Rel

ativ

e fr

esh

wei

ght

(% in

itial

FW

)

60

80

100

120

Time (days)

0 1 2 3 4 5 6

Sol

utio

n up

take

(m

L/ g

initi

al F

W/ d

ay)

0

1

2

Figure 3.11. Petal abscission, relative fresh weight and vase solution uptake for flowering L.petersonii stems treated with 0 nL 1-MCP/L and 0 µL ethylene/L (zz), 0 nL 1-MCP/L and 10 µLethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene treatments were conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent the standard errors of means (n = 10). Where no vertical barsappear, standard errors are smaller than the size of the symbol. LSD for petal abscission data ispresented in Table 3.4. LSD for relative fresh weight data = 5.1%. LSD for vase solution uptakedata = 0.111 mL/g initial FW/day.

81

Abs

cise

d an

d se

nesc

ent f

low

ers

(%)

0

20

40

60

Rel

ativ

e fre

sh w

eigh

t (%

initi

al F

W)

50

60

70

80

90

100

Time (days)

0 1 2 3 4

Sol

utio

n up

take

(mL/

g in

itial

FW

/day

)

0.0

0.2

0.4

0.6

0.8

Figure 3.12. Abscised and senescent flowers (% of initial number of open flowers and buds),relative fresh weight and vase solution uptake for flowering stems of L. scoparium ‘Winter Cheer’pre-treated with 0 nL 1-MCP/L and 0 µL ethylene/L (zz), 0 nL 1-MCP/L and 10 µL ethylene/L (��),10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCPand ethylene treatments were conducted for 12 hours at 20oC on days 0 and 1, respectively.Vertical bars represent the standard errors of means (n = 7). Where no vertical bars appear,standard errors are smaller than the size of the symbol. LSD for relative fresh weight data = 3.2%.LSD for solution uptake data = 0.051 mL/g initial FW/day.

82

3.3.1.9 O. diosmifolius

Pre-treatment of flowering O. diosmifolius stems with 1-MCP or ethylene did not significantly affect

pedicel wilting and flower opening (Figure 3.13, Appendices 3.69, 3.70 and 3.71). There was more leaf

senescence on stems treated with 1-MCP or ethylene alone until day 10 compared to stems not treated

with 1-MCP or ethylene or those treated with 1-MCP and ethylene in combination (Figure 3.13 and

Appendix 3.72). Leaf abscission, as indicated by the length of stems with no leaves, was greatest from

stems pre-treated with 1-MCP or from stems not treated with 1-MCP or ethylene (Figure 3.13 and

Appendix 3.73). These responses probably account for the significant interaction between 1-MCP pre-

treatment and ethylene treatment evident for leaf senescence (Appendix 3.72) and leaf abscission

(Appendix 3.73).

The loss of relative fresh weight was reduced from stems treated with 1-MCP or ethylene alone compared

to stems not treated with 1-MCP and ethylene (Figure 3.14). However, the variable pattern of stem

relative fresh weight loss on the last day of the experiment probably accounts for a significant interaction

for 1-MCP pre-treatment, ethylene treatment and time of measurement (Appendix 3.74). Pre-treatment of

stems with 1-MCP did not prevent peduncle wilting (Figure 3.14). Peduncle wilting increased following

exposure to exogenous ethylene compared to stems not exposed to exogenous ethylene (Appendices 3.69

and 3.75). Vase solution uptake by stems declined after day 4 of the experiment (Figure 3.14). Solution

uptake by stems exposed to ethylene was lower between days 0 and 2 relative to stems not exposed to

ethylene. Stems pre-treated with 1-MCP used vase solution at relatively constant rates after day 4 of the

experiment compared to stems not pre-treated with 1-MCP. These initially variable data led to significant

interactions between 1-MCP pre-treatment and time of measurement and between ethylene treatment and

time of measurement (Figure 3.14 and Appendix 3.76). Vase lives of stems were not significantly

affected by 1-MCP or ethylene treatments applied either alone or in combination (Table 3.3 and Appendix

3.77).

83

Ped

icel

w

ilt s

core

1

2

3

Ope

ning

sco

re

1

2

3

4

5

Leaf

sen

esce

nce

(%

of l

eaf a

rea)

0102030405060

Time (days)

0 2 4 6 8 10 12 14

Leng

th o

f ste

mw

ith n

o le

aves

(cm

)

02468

1012

Figure 3.13. Pedicel wilting (scores: 1 = none/slight to 3 = advanced), flower opening (scores: 1 = <10% to 5 = > 80%), leaf senescence and the length of stems without leaves for flowering O.diosmifolius stems treated with 0 nL 1-MCP/L and 0 µL ethylene/L (zz), 0 nL 1-MCP/L and 10 µLethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene treatments were each conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent the standard errors of means (n = 10). Where no vertical barsappear, standard errors are smaller than the size of the symbol. LSD for leaf abscission data = 1.8cm.

84

Ped

uncl

e w

ilt s

core

1

2

3

Time (days)

0 2 4 6 8 10 12 14

Sol

utio

n up

take

(m

L/g

initi

al F

W/2

day

s)

0.0

0.5

1.0

1.5

Rel

ativ

e fr

esh

wei

ght

(% in

itial

FW

)

70

80

90

100

110

Figure 3.14. Relative fresh weight, peduncle wilting (scores: 1= none/slight to 3 = advanced) andvase solution uptake for flowering O. diosmifolius stems pre-treated with 0 nL 1-MCP/L and 0 µLethylene/L (●), 0 nL 1-MCP/L and 10 µL ethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲)or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatment were each conductedfor 12 hours at 20oC on days 0 and 1, respectively. Vertical bars represent standard errors ofmeans (n = 10). LSD for peduncle wilting data is presented in Appendix 3.69. LSD for relativefresh weight data = 3.2%. LSD for solution uptake data = 0.070 mL/g initial FW/2 days.

85

3.3.1.10 P. lanceolata

1-MCP pre-treatment did not significantly affect the loss of relative fresh weight of flowering P.

lanceolata stems during vase life evaluation (Figure 3.15). The loss of stem relative fresh weight was

slightly, but significantly greater from stems treated with ethylene compared to stems not treated with

ethylene (Figure 3.15 and Appendix 3.78). The separation of the pattern of stem relative fresh weight loss

from all treatments towards the end of the experiment probably accounts for the significant interaction

between 1-MCP pre-treatment, ethylene treatment and time of measurement (Appendix 3.78). Vase

solution uptake by stems fluctuated during the experiment, but was highest between days 2 and 4 for all

treatments, particularly for stems pre-treated with 1-MCP (Figure 3.15). A small initial variation in

response (Figure 3.15) was reflected in a significant interaction between 1-MCP pre-treatment and time of

measurement for vase solution uptake (Appendix 3.79). Treatment of stems with 1-MCP or ethylene

either alone or in combination did not significantly affect vase life (Table 3.3 and Appendix 3.80).

86

Rel

ativ

e fr

esh

wei

ght

(% o

f ini

tial F

W)

80

90

100

110

Time (days)

0 4 8 12 16 20

Sol

utio

n up

take

(m

L/g

initi

al F

W/2

day

s)

0

1

2

3

Figure 3.15. Relative fresh weight and vase solution uptake for flowering P. lanceolata stemstreated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/L and 10 µL ethylene/L (■), 10nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP andethylene treatments were each conducted for 12 hours at 20oC on days 0 and 1, respectively.Vertical bars represent standard errors of means (n = 10). Where no vertical bars appear,standard errors are smaller than the size of the symbol. LSD for relative fresh weight data = 2.1%.LSD for vase solution uptake data = 0.156 mL/g initial FW/2 days.

87

3.3.1.11 T. speciosissima

Perianth abscission from clonally propagated T. speciosissima inflorescences exposed to exogenous

ethylene was reduced by 1-MCP pre-treatment (Figure 3.16 and Appendix 3.81). However, when no

ethylene was applied, 1-MCP had no significant effect on perianth abscission (Appendix 3.81). 1-MCP

pre-treatment significantly reduced the loss of relative fresh weight from inflorescences treated with

ethylene (Figure 3.16). 1-MCP pre-treatment did not significantly reduce the loss of relative fresh weight

from inflorescences not treated with ethylene. Accordingly, a significant interaction between 1-MCP pre-

treatment, ethylene treatment and time of measurement was evident for relative fresh weight (Appendix

3.82). Flower opening and vase solution uptake by inflorescences were not significantly affected by 1-

MCP or ethylene treatments (Appendices 3.83, 3.84 and 3.85). Pre-treatment of inflorescences with 1-

MCP did not prevent the loss in vase life (time to 20% perianth abscission) for inflorescences exposed to

ethylene (Figure 3.16, Table 3.4 and Appendix 3.81).

1-MCP pre-treatment protected seed-grown T. speciosissima inflorescences against exogenous ethylene by

significantly delaying the onset of perianth abscission (Plate 3.5 and Figure 3.17). However, 1-MCP pre-

treatment did not significantly reduce perianth abscission from inflorescences not exposed to ethylene. As

a result, a significant interaction between 1-MCP pre-treatment and ethylene treatment was recorded

(Appendix 3.86). Pre-treatment of inflorescences with 1-MCP significantly reduced the loss of relative

fresh weight from inflorescences exposed to 0 or 10 µL ethylene/L (Figure 3.17). These responses

reflected significant interactions between 1-MCP pre-treatment and time of measurement and between

ethylene treatment and time of measurement for relative fresh weight (Appendix 3.87).

1-MCP and ethylene treatments did not consistently affect flower opening and vase solution uptake by

inflorescences (Appendices 3.88, 3.89 and 3.90). The exogenous ethylene-induced loss in vase life

associated with perianth abscission was prevented by 1-MCP pre-treatment (Table 3.4). 1-MCP pre-

treatment did not significantly extend vase lives of inflorescences not exposed to ethylene. Thus, there

was a significant interaction between 1-MCP pre-treatment and ethylene treatment (Appendix 3.86).

88

Per

iant

h ab

scis

sion

(%

of i

nitia

l)

0

20

40

60

80

100

Time (days)

0 1 2 3 4 5 6

Rel

ativ

e fr

esh

wei

ght

(% in

itial

FW

)

60

70

80

90

100

Figure 3.16. Perianth abscission and relative fresh weight for clonally propagated T. speciosissima‘Shady Lady’ inflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L (zz), 0 nL 1-MCP/Land 10 µL ethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µLethylene/L (▼). 1-MCP and ethylene were conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent standard errors of means (n = 10). Where no vertical barsappear, standard errors are smaller than the size of symbols. LSD for relative fresh weight data =2.1%.

89

Plate 3.5. Seed-grown T. speciosissima inflorescences on day 2 after treatment on day 0 with 0(control treatment) (LHS) or 10 nL 1-MCP/L (RHS) followed by exposure on day 1 to 10 µLethylene/L. Note: perianth abscission is evident in the control inflorescence (LHS) as thewhite/yellow separation zones at the base of individual styles.

90

Per

iant

h ab

scis

sion

(%

of i

nitia

l)

0

10

20

30

40

Time (days)

0 1 2 3 4 5 6 7

Rel

ativ

e fr

esh

wei

ght

(%

initi

al F

W)

80

90

100

110

Figure 3.17. Perianth abscission and relative fresh weight for seed-grown T. speciosissimainflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L (zz), 0 nL 1-MCP/L and 10 µLethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene were conducted for 12 hours at 20oC on days 0 and 1, respectively.Vertical bars represent standard errors of means (n = 10). Where no vertical bars appear,standard errors are smaller than the size of symbols. LSD for perianth abscission data is presentedin Table 3.4. LSD for relative fresh weight data = 1.1%.

91

3.3.1.12 T. calycina

Flower abscission from flowering T. calycina stems was slightly greater from stems pre-treated with 1-

MCP than from stems treated only with ethylene (Figure 3.18). These unexpected responses were

reflected in a significant interaction between 1-MCP pre-treatment and ethylene treatment (Appendix

3.91). Flower closing on stems treated with 1-MCP and ethylene in combination or ethylene alone was

higher on day 4 than on stems pre-treated with 1-MCP alone (Figure 3.18). Accordingly, a significant

interaction between 1-MCP pre-treatment and ethylene treatment for flower closing was evident

(Appendix 3.92). The loss of stem relative fresh weight was greatest from stems not treated with 1-MCP

or ethylene (Figure 3.18). 1-MCP pre-treatment did not significantly reduce the decline of relative fresh

weight of stems treated with ethylene (Figure 3.18 and Appendix 3.93). This variable response was

reflected in a significant interaction between 1-MCP pre-treatment and ethylene treatment (Appendix

3.93).

Vase solution uptake by stems exposed only to ethylene or pre-treated with 1-MCP were consistently

higher than that by stems not treated with 1-MCP or ethylene (Figure 3.18). Accordingly, there was a

significant interaction between 1-MCP pre-treatment, ethylene treatment and time of measurement for

vase solution uptake (Appendix 3.94). Vase lives of stems were not significantly affected by 1-MCP or

ethylene treatment applied either alone or in combination (Table 3.3 and Appendix 3.95).

92

Flo

we

r a

bsc

issi

on

(% in

itia

l o

pe

n f

low

ers

)

0123456

Clo

sed

flo

we

rs

(% in

itia

l o

pe

n f

low

ers

)

0

10

20

30

40

Re

lativ

e f

resh

we

igh

t (

% in

itia

l FW

)

70

80

90

100

Time (days)

0 2 4 6

So

lutio

n u

pta

ke (

mL

/g in

itia

l F

W/2

da

ys)

0.5

1.0

1.5

2.0

Figure 3.18. Flower abscission, flower closure, relative fresh weight and vase solution uptake forflowering T. calycina stems treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/Land 10 µL ethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µLethylene/L (▼). 1-MCP and ethylene treatments were each conducted for 12 hours at 20oC on days0 and 1, respectively. Vertical bars represent standard errors of means (n = 10). LSD for relativefresh weight data = 3.3%. LSD for vase solution uptake data = 0.201 mL/g initial FW/2 days.

93

3.3.1.13 V. nitens

Pre-treatment of V. nitens stems with 1-MCP prevented exogenous ethylene-induced flower abscission

(Plate 3.6 and Figure 3.19). There was no flower abscission at all from stems pre-treated with 1-MCP or

from stems not exposed to ethylene. Consequently, there was a significant interaction between 1-MCP

pre-treatment, ethylene treatment and time of measurement (Appendix 3.96). 1-MCP pre-treatment

significantly reduced the decline in relative fresh weight of stems associated with exogenous ethylene-

induced flower abscission (Figure 3.19). However, 1-MCP pre-treatment of stems did not significantly

reduce the decline of relative fresh weight of stems not exposed to ethylene. As a result of the pervading

effect of flower abscission, there was a significant interaction between 1-MCP pre-treatment and ethylene

treatment for relative fresh weight (Appendix 3.97).

Vase solution uptake by stems pre-treated with 1-MCP was consistently higher during the experiment than

that by stems not pre-treated with 1-MCP (Figure 3.19). Accordingly, a significant interaction between 1-

MCP pre-treatment and time of measurement was evident (Appendix 3.98). The exogenous ethylene-

induced reduction in vase life was prevented by pre-treating inflorescences with 1-MCP (Table 3.4). Pre-

treatment of stems with 1-MCP did not extend the vase lives of flowering stems not exposed to ethylene.

Thus, there was a significant interaction between 1-MCP pre-treatment and ethylene treatment for vase

life (Appendix 3.99).

94

Plate 3.6. Flowering V. nitens stems on day 2 after treatment on day 0 with 0 (control) (LHS) or 10nL 1-MCP/L (RHS) followed by exposure on day 1 to 10 µL ethylene/L. Note: flower abscission isevident in the control stem (LHS).

95

Abs

ciss

ion

scor

e

1

2

3

4

5

Rel

ativ

e fr

esh

wei

ght

(% o

f ini

tial F

W)

40

60

80

100

120

Time (days)

0 2 4 6 8 10 12 14

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.1

0.2

0.3

0.4

Figure 3.19. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for flowering V. nitens stems treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0nL 1-MCP/L and 10 µL ethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatments were each conducted for 12hours at 20oC on days 0 and 1, respectively. Vertical bars represent standard errors of means (n =10). Where no vertical bars appear, standard errors are smaller than the size of the symbol. LSDfor relative fresh weight data = 3.6%. LSD for vase solution uptake data = 0.027 mL/g initialFW/day.

96

3.3.1.14 Z. cytisoides

Flower abscission from flowering Z. cytisoides stems was not significantly affected by 1-MCP or ethylene

treatments, when applied alone or in combination (Figure 3.20 and Appendix 3.100). However, there was

a trend toward reduced flower abscission from stems pre-treated with 1-MCP. Stems pre-treated with 1-

MCP and not exposed to ethylene lost significantly less relative fresh weight than stems not pre-treated

with 1-MCP (Figure 3.20). However, the loss of relative fresh weight from stems exposed to ethylene was

not significantly different from stems not exposed to ethylene. This variable response resulted in a

significant interaction between 1-MCP pre-treatment and ethylene treatment (Appendix 3.101).

Vase solution uptake by stems pre-treated with 1-MCP and exposed to ethylene was higher, but erratic

between days 2 and 9 of the experiment relative to stems not pre-treated with 1-MCP or stems not exposed

to ethylene (Figure 3.20). This response probably accounts for the significant interaction between 1-MCP

pre-treatment, ethylene treatment and time of measurement (Appendix 3.102). Flower abscission from

stems was the sole factor in limiting vase life in this experiment (Table 3.2). The vase lives of stems were

not significantly affected by 1-MCP or ethylene treatments (Table 3.3 and Appendix 3.100).

97

Abs

ciss

ion

scor

e

1

2

3

4

5R

elat

ive

fres

h w

eigh

t (%

initi

al F

W)

70

80

90

100

110

Time (days)

0 2 4 6 8 10 12 14 16

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0

1

2

Figure 3.20. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for flowering Z. cytisoides stems treated with 0 nL 1-MCP/L and 0 µL ethylene/L(●), 0 nL 1-MCP/L and 10 µL ethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatments were each conducted for 12hours at 20oC on days 0 and 1, respectively. Vertical bars represent standard errors of means (n =5). Where no vertical bars appear, the standard errors were smaller than the size of the symbol.LSD for relative fresh weight data = 4.9%. LSD for solution uptake data = 0.075 mL/g initialFW/day.

1

3.3.2 Treatment of B. heterophylla with 1-MCP, STS and ethylene

Pre-treatment of B. heterophylla stems with 1-MCP was more effective than STS pre-treatment in

delaying the onset of flower wilting stimulated by exposure to exogenous ethylene (Figure 3.21).

Exposure of stems to 10 µL ethylene/L for the longer period of 72 hours, compared to the 12 hour

exposure duration used previously (section 3.2.4.1), stimulated flower wilting (Figure 3.21) and induced

flower and leaf abscission (> 10% of total number of flowers and leaves) (Plate 3.7). Pre-treatment with

1-MCP did not significantly delay the onset of flower wilting from stems not exposed to ethylene.

Conversely, pre-treatment with STS stimulated flower wilting from stems not exposed to ethylene (Figure

3.21). As a result, there was a significant interaction between the anti-ethylene treatment (1-MCP or

STS), ethylene treatment and time of measurement for flower wilting (Appendix 3.103). Accumulation of

Ag+ from STS solution by stems was 0.25 ± 0.01 µmol Ag+/g initial stem FW (n = 20).

Flower wilting and abscission induced by exposure to ethylene were also reflected by accelerated loss of

stem relative fresh weight (Figure 3.21). 1-MCP and STS pre-treatments significantly reduced the loss of

relative fresh weight from stems exposed to ethylene (Figure 3.21). Loss of stem relative fresh weight was

not significantly reduced by either 1-MCP or STS treatment for stems not exposed to ethylene. Thus, a

significant interaction between the anti-ethylene pre-treatment, ethylene treatment and time of

measurement was recorded (Appendix 3.104).

The exogenous ethylene-induced loss in vase life was prevented by 1-MCP pre-treatment (Table 3.5).

STS pre-treatment did not significantly reduce the loss in vase life, although there was a trend toward

extended vase life for STS-treated stems (Table 3.5). 1-MCP pre-treatment did not significantly extend

the vase lives of stems not exposed to ethylene. In contrast, STS pre-treatment significantly reduced vase

lives of stems not exposed to ethylene. Due to these responses, a significant interaction between the anti-

ethylene treatment and ethylene treatment was recorded (Appendix 3.105).

2

Wilt

sco

re

1

2

3

Time (days)

0 4 8 12 16

- Ethylene + Ethylene

Rel

ativ

e fr

esh

wei

ght

(%

of i

nitia

l FW

)

40

60

80

100

0 4 8 12 16


Figure 3.21. Flower wilting (scores: 1 = none/slight to 3 = advanced) and relative fresh weight forflowering B. heterophylla stems pre-treated on day 0 with 10 nL 1-MCP/L (■), STS (0.5 mM Ag+)(▲) or not pre-treated with 1-MCP or STS (control treatment) (●) for 12 hours at 20oC. Half ofthe stems from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 72hours at 20oC. Vertical bars represent the standard errors of means (n = 10). LSD for relativefresh weight data = 4.2%.

3

Plate 3.7. Flowering B. heterophylla stems on day 7 after treatment on day 1 with 0 nL 1-MCP/Land 0 mM Ag+ (control) (LHS), 10 nL 1-MCP/L (centre) or STS (0.5 mM Ag+) (RHS) followed byexposure on day 1 to 10 µL ethylene/L for 72 hours. Note: flower and leaf abscission are evident inthe control stem (LHS).

4

Table 3.5. Vase life (mean ± s.e.) of flowering B. heterophylla stems pre-treated on day 0 with 0 or10 nL 1-MCP/L or with STS (0.5 mM Ag+) for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 72 hours at 20oC. Datafollowed by the same letters are not significantly different at P = 0.05. LSD = 1.6 days.


No ethylene (0 µL/L)

Control (0 nL 1-MCP/L or 0 mM Ag+) 10.8 ± 0.9 b

10 nL 1-MCP/L 10.0 ± 0.7 b

0.5 mM Ag+ 9.1 ± 0.2 a

Plus ethylene (10 µL/L)

Control (0 nL 1-MCP/L or 0 mM Ag+) 8.2 ± 0.4 a

10 nL 1-MCP/L 10.4 ± 0.5 b

0.5 mM Ag+ 9.7 ± 0.5 a

Pre-treatment of stems with 1-MCP did not significantly affect flower discolouration from stems exposed

to 0 or 10 µL ethylene/L (Figure 3.22 and Appendix 3.106). However, pre-treatment of stems with STS

significantly delayed the onset of flower discolouration from stems not exposed to ethylene (Figure 3.22,

Appendices 3.106 and 3.107). Vase solution uptake by stems pre-treated with STS was lower than stems

pre-treated with 1-MCP when they were not exposed to ethylene (Figure 3.22). In contrast, when stems

were exposed to ethylene, vase solution uptake by stems pre-treated with STS was higher compared to

stems pre-treated with 1-MCP until day 11 of the experiment (Figure 3.22). These different responses

resulted in a significant interaction between the anti-ethylene treatments, ethylene treatments and time of

measurement for vase solution uptake (Appendix 3.108).

5

Dis

colo

urat

ion

scor

e

1

2

3

4

Time (days)

0 4 8 12 16

0.0

0.2

0.4

0.6

0.8

1.0

0 4 8 12 16

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

- Ethylene

- Ethylene

+ Ethylene

+ Ethylene

Figure 3.22. Flower discolouration (scores: 1 = 0-25% to 4 = 76-100%) and vase solution uptakefor flowering B. heterophylla stems pre-treated on day 0 with 10 nL 1-MCP/L (■), STS (0.5 mMAg+) (▲) or not pre-treated with 1-MCP or STS (control treatment) (●) for 12 hours at 20oC. Halfof the stems from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 72hours at 20oC. Vertical bars represent the standard errors of means (n = 10). Where no verticalbars appear, standard errors are smaller than the size of the symbol. LSD for flower discolourationdata is presented in Appendix 3.106. LSD for vase solution uptake data = 0.035 mL/g initialFW/day.

6

Increased rates of ethylene production by detached B. heterophylla flowers were associated with the onset

of flower wilting and advanced stages of flower discolouration (Figure 3.23, Appendices 3.109, 3.110,

3.111 and 3.112). Ethylene production by intact flowering stems fluctuated during vase life (Figure 3.24).

Nonetheless, increased rates of ethylene production were associated with flower wilting (Appendices

3.109 and 3.113). However, the association between changes in flower discolouration and the rate of

ethylene production by inatct flowering stems was less pronounced (Figure 3.24, Appendices 3.110 and

3.114) than for detached flowers. Ethylene production by non-flowering stems of B. heterophylla was

generally low (Figure 3.24). Increased rates of ethylene production by these stems on day 12 were

associated with leaf wilting and disease development.

7

Time (days)

0 2 4 6 8 10 12 14E

thyl

ene

prod

uctio

n ( µ

L/kg

FW

/hr)

0

1

2

3

4

5

6

7

8

Time (days)

0 2 4 6 8 10 12 14

Wilt

/dis

colo

urat

ion

scor

e

1

2

3

4

Time (days)

0 2 4 6 8 10 12 14

1

2

3

4

Figure 3.23. Flower wilting (scores: 1 = none/slight to 3 = advanced) (■), discolouration (scores: 1 =0-25% to 4 = 76-100%) (▲) and ethylene production (bars) by detached B. heterophylla flowersheld at 20oC. Vertical lines represent standard errors of means (n = 5).

8

Time (days)

0 2 4 6 8 10 12E

thyl

ene

prod

uctio

n ( µ

L/kg

FW

/hr)

0

1

2

3

4

5

6

7

8

Time (days)

0 2 4 6 8 10 12

Wilt

/dis

colo

urat

ion

scor

e

1

2

3

4

Time (days)

0 2 4 6 8 10 12

1

2

3

4

Figure 3.24. Flower wilting (scores: 1 = none/slight to 3 = advanced) (■), discolouration (scores: 1 =0-25% to 4 = 76-100%) (▲) and ethylene production by flowering (open bars) or non-flowering(shaded bars) B. heterophylla stems held at 20oC. Vertical lines represent standard errors of means(n = 5).

9

3.4 DISCUSSION

Pre-treatment of nine ethylene-sensitive native Australian cut flowers (viz. A. pinnatum, C. gummiferum,

C. uncinatum, G. ‘Kay Williams, G. ‘Misty Pink’, G. ‘Sandra Gordon’, L. petersonii, T. speciosissima and

V. nitens) with 10 nL 1-MCP/L for 12 hours at 20oC provided protection against subsequent treatment

with ethylene (10 µL/L for 12 hours at 20oC). Exposure of these flowers to this ethylene treatment

protocol induced floral organ abscission and, in turn, reduced vase life (Table 3.4). Wilting of sepals on

cut C. gummiferum stems was also associated with exposure to exogenous ethylene (Figure 3.5). The

efficacy of the 1-MCP treatment protocol used in this study in counteracting ethylene supports the

findings of Serek et al. (1995a). They found that treatment of a range of cut flowers with 10-20 nL 1-

MCP/L for 6 hours prevented ethylene treatment effects.

In general, pre-treatment with 1-MCP did not significantly extend the base level vase lives of flowers not

exposed to exogenous ethylene (Table 3.4). By way of an exception, 1-MCP pre-treatment extended the

base vase lives of C. gummiferum flowers by delaying the onset of sepal wilting. There is limited

published research into the postharvest characteristics of C. gummiferum (Wade and Satyan 1997; Worrall

et al. 1999). The results of the present study indicate that the vase lives of flowers can be limited, at least

in part, by flower abscission and sepal wilting induced by exposure to exogenous ethylene. Moreover,

sepal wilting is likely to be regulated by endogenous ethylene. Presumably as a result of sepal wilting, C.

gummiferum stems that were not exposed to ethylene lost relative fresh weight at a significantly greater

rate than similar stems pre-treated with 1-MCP (Figure 3.5). 1-MCP pre-treatment was therefore

apparently effective in preventing both endogenous and exogenous ethylene effects.

Loss of relative fresh weight associated with flower abscission and senescence for G. ‘Sandra Gordon’

and seed-grown T. speciosissima inflorescences (Figures 3.10 and 3.17) and flower abscission from C.

uncinatum ‘Paddy’s Late’ sprigs (Figure 3.6) not exposed to ethylene were also significantly reduced by

pre-treatment with 1-MCP. These results support earlier assertions by Faragher (1986), Joyce (1993) and

Joyce et al. (1995) that endogenous ethylene may mediate flower senescence and abscission processes in

T. speciosissima, C. uncinatum and G. ‘Sylvia’.

The delay or prevention by 1-MCP pre-treatment of the onset of flower abscission from cut C. uncinatum

sprigs (Figure 3.6) and V. nitens flowers (Figure 3.19) exposed to exogenous ethylene correlates with

reports that STS treatment prevented ethylene-induced flower abscission from cut C. uncinatum (Joyce

1988, 1989, 1993) and V. nitens (Joyce and Poole 1993). Likewise, the prevention of extensive ethylene-

induced flower abscission from inflorescences of Grevillea hybrids by 1-MCP pre-treatment (Figures 3.8,

3.9 and 3.10, respectively) is similar to the results of earlier experiments with G. ‘Sylvia’ (Chapter 2).

Thus, the efficacy of 1-MCP pre-treatment in preventing ethylene-induced flower abscission is common

for a number of Grevillea hybrids. This finding complements those of Joyce and Haynes (1989) and

Vuthapanich et al. (1993) who reported that pre-treatment of hybrid Grevillea spp. with STS prevented

ethylene-induced flower abscission.

10

Exogenous ethylene has been reported to induce flower and petal abscission from L. scoparium stems

(Zieslin and Gottesman 1983) and is suspected to cause similar problems in several other Leptospermum

species (T. Slater, pers. comm.). 1-MCP pre-treatment reduced exogenous ethylene-induced petal

abscission from L. petersonii stems (Figure 3.11). This observation supports the findings of Zieslin and

Gottesman (1983), who reported that STS prevented ethylene-induced flower abscission from L.

scoparium stems. L. petersonii stems not exposed to ethylene were observed to be susceptible to

dessication and wilting of petals. Wilting of L. petersonii petals in this study occurred independently of 1-

MCP treatment. Thus, petal wilting does not appear to be mediated by ethylene. In contrast, wilting of L.

scoparium flowers is thought to be an ethylene-mediated process, at least in drier atmospheres (70% RH)

(Zieslin and Gottesman 1983).

Vase life of L. scoparium was not significantly affected by 1-MCP or ethylene treatments in the present

study (Table 3.3). However, exposure of stems to ethylene tended to reduce vase life as a result of

increased flower abscission. Whilst 1-MCP pre-treatment of stems tended to reduce the number of

abscised and senescent flowers and associated loss of relative fresh weight induced by exposure to

ethylene, no significant differences between treatments existed (Figure 3.12). Exposure of L. scoparium

stems to 10 µL ethylene/L for 48 hours at 21oC is known to induce flower abscission and senescence

(Zieslin and Gottesman 1983). Thus, it is possible that the ethylene treatment protocol chosen for this

study (viz. 10 µL ethylene/L for 12 hours at 20oC) was not optimal for inducing ethylene-induced effects

on cut L. scoparium stems. Accordingly, the protective effect of 1-MCP was minor.

Ethylene production by T. speciosissima flowers increases prior to perianth abscission and is, thus, likely

to regulate perianth abscission from inflorescences (Faragher 1986). Furthermore, treatment of

inflorescences with ethylene or ACC can stimulate perianth abscission (J. Faragher, unpublished data).

Moreover, pre-treatment of inflorescences with STS and AOA can prevent this abscission (J. Faragher,

unpublished data). The results of the present study support these observations in that exposure of

inflorescences to exogenous ethylene caused perianth abscission. 1-MCP pre-treatment of T.

speciosissima inflorescences was shown to reduce ethylene-induced flower abscission (Figure 3.16 and

3.17). 1-MCP pre-treatment was more effective in reducing exogenous ethylene-induced perianth

abscission from seed-grown inflorescences than from clonally propagated inflorescences. It is possible

that the efficacy of 1-MCP pre-treatment of clonally-propagated inflorescences was poorer because of the

48 hour delay between harvest and 1-MCP pre-treatment. Endogenous ethylene production by flowers

may have commenced before 1-MCP pre-treatment, thereby reducing treatment efficacy. 1-MCP

treatment efficacy has been found by Reid et al. (1996) to be reduced when endogenous ethylene

production by plant tissue is high.

1-MCP pre-treatment significantly reduced exogenous ethylene-induced loss of fresh weight and vase life

of A. pinnatum inflorescences as a consequence of reduced perianth abscission, wilting and discolouration

(Figure 3.2 and Table 3.4). However, 1-MCP pre-treatment was only significantly effective in reducing

11

the ethylene-induced loss in vase life for inflorescences used in the second of two similar experiments in

this study. The reasons for the differing responses of A. pinnatum inflorescences to 1-MCP between the

first and second experiments are unclear but may be related to the growing region. Perianth abscission

was found to occur only from opened flowers, while perianth wilting and discolouration was generally

associated with unopened flowers. However, as inflorescences used in both experiments were selected

with similar numbers of open and unopened flowers, it is unlikely that different degrees of flower opening

were responsible for this differential response.

Cut flowers that did not respond to pre-treatment with 10 nL 1-MCP/L for 12 hours at 20oC or exposure to

10 µL ethylene/L for 12 hours at 20oC were B. heterophylla, C. adunca, E. scaber, O. diosmifolius, P.

lanceolata, T. calycina and Z. cytisoides (Table 3.3). Flower wilting and discolouration and stem relative

fresh weight loss from cut B. heterophylla stems were not affected by exposure to 10 µL ethylene/L for 12

hours at 20oC (Figure 3.3). Further, 1-MCP pre-treatment did not extend the vase lives of stems not

exposed to ethylene. This observation is apparently contrary to the findings of Williamson (1996), where

STS treatment extended vase lives of stems not treated with ethylene.

Peduncle and pedicel wilting on C. adunca stems were significantly reduced for stems pre-treated with 1-

MCP and then exposed to ethylene (Figure 3.4). However, the absence of a similar response for stems

pre-treated with 1-MCP and not exposed to ethylene suggests it is unlikely that pedicel wilting is

controlled by ethylene. Likewise, peduncle wilting from flowering O. diosmifolius stems exposed only to

ethylene increased on day 4 of the experiment (Figure 3.14). Pre-treatment with 1-MCP did not prevent

this response. Vase life was not significantly affected by peduncle wilting (Table 3.3). Nonetheless, it is

possible that ethylene is involved in regulation of peduncle wilting. Leaf abscission from a broad leaf

form of O. diosmifolius was prevented by treatment with STS (Johnston 1992). As a result, vase life was

extended. However, STS treatment did not prevent leaf abscission from a fine leaf form of O.

diosmifolius. Thus, despite the variable response of different plant forms to STS treatment, it is

conceivable, in view of apparent ethylene responsiveness, that exogenous ethylene did mediate peduncle

wilting of O. diosmifolius in the present study.

Exposure of E. scaber stems to 1-MCP and ethylene treatments did not affect their vase lives. However,

petal abscission from stems pre-treated with 1-MCP and exposed to ethylene was significantly less than

that from stems exposed only to ethylene (Figure 3.7). Nevertheless, the involvement of ethylene in this

process is unclear since there was an absence of significant differences between other treatments and the

change in level of flower abscission during vase life was only small. P. lanceolata stems were not

sensitive to the ethylene treatment protocol used in this study. This assertion is evidenced by no

significant flower quality changes (e.g. wilting or abscission) or loss of relative fresh weight during vase

life (Figure 3.15). Flower abscission and closure for T. calycina stems were not consistently affected by

exposure to ethylene (Figure 3.18). Therefore, ethylene does not appear to be involved in flower

abscission and senescence of T. calycina. These data tend to support the opinion of Joyce et al. (1993),

who reported that in which applied ethylene gas and STS did not affect flower abscission in this species.

12

Treatment of Z. cytisoides with 1-MCP and ethylene did not significantly affect flower abscission (Figure

3.20) or vase life (Table 3.3). However, stems pre-treated with 1-MCP had somewhat reduced levels of

flower abscission and, in turn, longer vase lives than stems exposed only to ethylene. Thus, it is possible

that flower abscission from Z. cytisoides is an ethylene-mediated process.

Higher vase solution uptake by several flowers (i.e. C. gummiferum, C. uncinatum, E. scaber, G. ‘Kay

Williams’, G. ‘Misty Pink’, L. petersonii, L. scoparium, P. lanceolata and V. nitens) was associated with

1-MCP pre-treatment (Figures 3.5, 3.6, 3.7, 3.8, 3.9, 3.11, 3.12, 3.15 and 3.19, respectively). With the

exception of E. scaber and P. lanceolata, exposure of these flowers to exogenous ethylene induced floral

organ abscission and/or wilting which presumably account for reduced transpiration and solution uptake.

In contrast, 1-MCP pre-treatment delayed floral organ abscission and/or wilting and, thereby, maintained

transpiration and solution uptake. It is unclear why E. scaber and P. lanceolata stems pre-treated with 1-

MCP used vase solution at higher rates compared to stems exposed only to ethylene, as no major changes

in postharvest flower quality were evident. In contrast to these species, solution uptake by A. pinnatum

inflorescences exposed to ethylene was consistently higher than that by similar inflorescences not exposed

to ethylene (Figures 3.1 and 3.2). Unexpectedly, perianth abscission, wilting and discolouration induced

by exposure to ethylene did not reduce solution uptake.

In other flowers, relationships between vase solution uptake and 1-MCP or ethylene treatments over the

duration of the experiments were not clear. Solution uptake by B. heterophylla stems and G. ‘Sandra

Gordon’ inflorescences fluctuated during the experiments (Figures 3.3 and 3.10). This fluctuation

sometimes probably reflected variations in the vase life room temperature and RH (i.e. vapour pressure

deficit). Transpiration and vase solution uptake by cut flowers is known to vary in association with

changes to vapour pressure deficit (Halevy and Mayak 1981). Low solution uptake by C. adunca, O.

diosmifolius and T. calycina stems not treated with 1-MCP or ethylene or by stems exposed only to

ethylene was found to correspond to reduced relative fresh weight, possibly indicating adverse water

relations (Figures 3.4, 3.14 and 3.18). Adverse water relations have been reported to limit vase life of T.

calycina (Jones et al. 1993). It is unclear why Z. cytisoides stems pre-treated with 1-MCP and exposed to

ethylene used solution at highly variable rates compared to stems from other treatments (Figure 3.20).

This different response presumably reflects inherent differences in randomly selected stems.

Exposure of B. heterophylla flowers to 10 µL ethylene/L for the longer period of 72 hours at 20oC

induced flower wilting and abscission and, thereby, reduced stem fresh weight and vase life (Figure 3.21

and Table 3.5). Joyce and Haynes (1989) also found that treatment of B. heterophylla with 10 µL

ethylene/L for 72 hours at 22oC induced rapid loss of stem fresh weight and flower wilting. However,

flower abscission was not reported in that study. In the present study, 1-MCP pre-treatment was more

effective than STS in reducing exogenous ethylene effects. Silver toxicity from STS treatment may have

limited vase life as evidenced by premature flower wilting and delayed flower discolouration (Figures

3.21 and 3.22). Vase solution uptake by stems pre-treated with 1-MCP and STS was consistently higher

13

than that by stems exposed only to ethylene. This relative difference was presumably reflecting delayed

flower wilting and abscission and the associated loss in functional transpirational area (Figure 3.22).

Conversely, premature flower wilting induced by STS pre-treatment when stems were not exposed to

ethylene was reflected in lower vase solution uptake (Figure 3.21 and 3.22).

Pre-treating B. heterophylla stems with STS was reported by Joyce and Haynes (1989) to prevent

exogenous ethylene-induced flower wilting and loss of stem fresh weight. Further, Williamson (1996)

found that treatment of flowers with STS (0.5 mM Ag+ for 10.5 hours at 20oC) extended the vase lives of

stems not exposed to exogenous ethylene by delaying flower wilting. In both these studies, STS treatment

was not reported to be toxic. In the present study, stems were calculated to accumulate 0.25 ± 0.01 µmol

Ag+/g initial FW following STS treatment. Joyce (1988) reported that a safe, effective range for Ag+

uptake by C. uncinatum was 0.1-0.6 µmol Ag+/g stem FW. However, the safe range could vary according

to genotype and/or phenotype. Thus, it is possible that the effective range for B. heterophylla is lower

than that for C. uncinatum. This potential problem highlights a difficulty with using STS treatments. The

effective concentration can be close to those which can cause phytotoxicity (Cameron and Reid 1981). In

contrast, 1-MCP is thought to be completely non-phytotoxic (Serek et al. 1994b).

The finding by Williamson (1996) that treating B. heterophylla with STS extended vase lives of stems not

exposed to exogenous ethylene provides circumstantial evidence that endogenous ethylene is involved in

flower senescence. In the present study, this assertion was supported since increased ethylene production

rates were found to correspond to moderate flower wilting and advanced stages of flower discolouration

(Figure 3.23). The early stages of flower discolouration do not appear to be associated with increased

ethylene production. Thus, flower discolouration of B. heterophylla, as suggested by Williamson (1996),

may not be associated with ethylene production. It is possible that flower discolouration is regulated by

earlier changes in tissue pH and in the carbohydrate content of flowers. Discolouration was delayed when

sucrose was included in vase solutions for B. heterophylla (Williamson 1996). Moreover, treatment of cut

flowers, such as red rose, with solutions containing sucrose is known to delay proteolysis, thereby

delaying increases in tissue pH and pigment changes (Mayak and Halevy 1980). The association between

flower discolouration and ethylene production by intact flowering stems was, however, less pronounced

than that of detached flowers (Figure 3.24). Ethylene production by non-flowering stems of B.

heterophylla was generally low compared to flowering stems, suggesting that flowers are the principal site

of ethylene production.

This study has shown that 1-MCP pre-treatment at a nanomolar concentration level can protect 10

different ethylene sensitive native Australian cut flowers against exposure to exogenous ethylene; viz. A.

pinnatum, B. heterophylla, C. gummiferum, C. uncinatum, G. ‘Kay Williams, G. ‘Misty Pink’, G. ‘Sandra

Gordon’, L. petersonii, T. speciosissima and V. nitens. With the exception of C. gummiferum, 1-MCP did

not afford flowers with protection against endogenous ethylene. Nonetheless, 1-MCP gas, which is

comparatively easy to apply, has potential as a postharvest anti-ethylene treatment for ethylene-sensitive

native Australian cut flowers. In an associated study, increased rates of ethylene production by B.

14

heterophylla flowers were found to be associated with their natural senesecence.

16

CHAPTER 4

EFFECT OF TEMPERATURE ON THE EFFICACY OF 1-MCP

TREATMENT OF CUT FLOWERS

4.1 INTRODUCTION

Ethylene is responsible for regulating a number of processes in plants which have commercial significance

in postharvest horticulture (Abeles et al. 1992). Unintentional exposure to ethylene can reduce the

postharvest life of cut flowers by eliciting abscission and/or accelerating senescence (Reid 1985b). Such

effects of ethylene can, however, be prevented by pre-treating sensitive cut flowers with chemical

inhibitors of ethylene biosynthesis or perception (Sherman 1985).

STS can be used as a treatment to protect sensitive cut flowers and potted flowering plants against

ethylene-induced floral organ abscission and senescence (Veen 1983). Ag+ in the STS complex is thought

to bind and block ethylene receptors thereby preventing ethylene perception (Sisler 1982). However, the

use of STS is being reconsidered in some countries due to possible environmental hazards (Serek et al.

1994a). The recently synthesised novel inhibitor of ethylene perception, 1-MCP gas may have potential

as an alternative treatment for a range of ethylene-sensitive crops (Serek et al. 1994b, 1995a, b; Sisler et

al. 1996a, b).

In contrast to STS, 1-MCP efficacy has been reported to be poor when applied at low temperature. For

example, 1-MCP pre-treatment at 20oC was highly effective in protecting cut Penstemon flowers against

ethylene, but no protection was afforded when applied at 2oC (Serek et al. 1995a). Increasing the

concentration of 1-MCP applied during low temperature treatment improved treatment efficacy to levels

similar to treatment at 20oC (Reid et al. 1996). Reasons for this variable temperature response are

unclear.

Sisler et al. (1996a) reported that 1-MCP molecules bind permanently to ethylene receptors and thus

prevent ethylene action irreversibly. Nonetheless, 1-MCP pre-treated cut carnation flowers, banana and

tomato fruit regain sensitivity to ethylene between 10 and 15 days after 1-MCP treatment (Sisler et al.

1996b; Sisler and Serek 1997). Recovery of competence to respond to ethylene is thought to be due to the

synthesis of ethylene receptors (Sisler and Serek 1997).

Exposure of several native Australian cut flowers including Grevillea hybrids and C. uncinatum to

ethylene elicits rapid flower abscission and, thereby, reduces vase life (Joyce 1988, 1989; Joyce et al.

1993). Therefore, the postharvest longevity of native Australian cut flowers may be extended by

treatment with 1-MCP. However, it is proposed that low 1-MCP concentrations will not protect native cut

17

flowers against ethylene when applied at low temperature. The purpose of this study was to test these

hypotheses by examining the influence of temperature on 1-MCP pre-treatment efficacy in preventing

ethylene-induced flower abscission from two cut flowers, G. ‘Sylvia’ and C. uncinatum. In addition, the

duration of 1-MCP effects for each flower was examined. In the case of C. uncinatum, protection was

compared with the duration of ethylene insensitivity afforded by STS treatment.



4.2.1.1 G. ‘Sylvia’ inflorescences

G. ‘Sylvia’ inflorescences were harvested from plants grown at a nursery near Redland Bay.

Inflorescences were harvested and transported to the laboratory within 2 hours of harvest. They were

prepared for treatment as described in section 2.2.1.

4.2.1.2 C. uncinatum sprigs

Flowering branches of C. uncinatum cultivars ‘Lollypop’, ‘Alba’ and ‘Mid Pink’ were harvested from a

farm near Gatton. Stems were immediately stood into buckets containing DI water and taken to the

laboratory in an air conditioned car within 30 minutes of harvest. Flowering sprigs were cut from stems

with secateurs to 20 cm in length. Thereafter, they were prepared as described for G. ‘Sylvia’

inflorescences (section 2.2.1). Leaves were removed from the lower section of sprigs which were

submerged into vase solution.

4.2.2 Chemicals

The preparation of 1-MCP, ethylene and STS stocks was by procedures outlined in sections 2.2.2.1,

2.2.2.2 and 3.2.3.1, respectively.

4.2.3 Treatments

4.2.3.1 Treatment of G. ‘Sylvia’ inflorescences with 1-MCP

G. ‘Sylvia’ inflorescences standing in individual vases were enclosed in 60.5 L glass chambers, each

containing 6 beakers of KOH solution (section 2.2.3). Inflorescences were pre-treated on day 0 with 10

nL 1-MCP/L for 12 hours at 2 or 20oC. Control inflorescences were kept in other chambers in air with

KOH solution, but without 1-MCP. Different sub-samples of 1-MCP treated inflorescences were then

exposed to 10 µL ethylene/L for 12 hours at 20oC (section 2.2.4.1) daily from day 1 until the end of vase

life (day 5). When not receiving 1-MCP or ethylene treatments, inflorescences were held in a vase life

18

room operating at the same conditions as described in section 2.2.4.1.

4.2.3.3 Treatment of C. uncinatum sprigs with 1-MCP or STS

In three separate experiments, C. uncinatum ‘Lollypop’, ‘Alba’ and ‘Mid Pink’ sprigs were pre-treated on

day 0 with 10 nL 1-MCP/L in chambers with KOH solution or pulsed with STS (0.5 mM Ag+) for 12

hours. Both chemicals were applied to sprigs at 2 or 20oC. Untreated sprigs (i.e. 0 nL 1-MCP/L or 0 mM

Ag+) were also maintained in air at 2 or 20oC. Following these treatments, different sub-samples of sprigs

treated with 1-MCP or STS were exposed to 10 µL ethylene/L for 12 hours at 20oC daily from day 1 until

the end of vase life (ca. day 10). When not receiving 1-MCP, STS or ethylene treatments, sprigs were

kept in the same vase life room used for G. ‘Sylvia’ inflorescences.

4.2.4 Assessments

Flower abscission, wilting, discolouration and opening from G. ‘Sylvia’ inflorescences were assessed

daily using the subjective scales described in section 2.2.5.1. Flower abscission was determined after

gently brushing inflorescences three times by hand. Vase life of inflorescences was based on the same

criteria used in section 2.2.5.1. G. ‘Sylvia’ inflorescences and C. uncinatum sprigs and their vases were

weighed separately daily (section 2.2.5.1). Flower abscission from C. uncinatum sprigs was assessed

daily after gently brushing them three times by hand. Flower abscission was expressed as the percentage

of flowers abscised out of the initial number (Day 0) on a sprig. Vase life of sprigs was judged using the

criteria in section 3.2.5.1.


When flowers were not receiving 1-MCP, ethylene or STS treatments, they were arranged in vase life

rooms in CRDs. There were five replicate inflorescences or sprigs per treatment. The effect of

temperature on the efficacy of 1-MCP treatment of G. ‘Sylvia’ inflorescences was examined as a 2

(temperature) x 8 (treatment) factorial experiment. Treatments consisted of 5 ethylene application times

and 3 controls. In similar studies with C. uncinatum, 2 (temperature) x 11 (treatment), 2 (temperature) x

12 (treatment) or 2 (temperature) x 10 (treatment) factorial experiments were used for ‘Lollypop’, ‘Alba’

and ‘Mid Pink’ sprigs, respectively. In each case, treatments included 2 controls. Remaining treatments

were the different ethylene application times. In all experiments, control treatments were excluded from

ANOVA.

Treatment means ± standard errors were calculated using Microsoft Excel (Version 5.0, Microsoft Inc.).

Figures were prepared using Sigmaplot (Version 2.0, Jandel Corporation). Most data were analysed as

factorial (depending upon the particular experiment) ANOVAs by the balanced ANOVA function of

Minitab (Release 11.12, Minitab Inc.).

Flower abscission score data from G. ‘Sylvia’ were converted to a corresponding percentage. The percent

19

change in flower abscission from G. ‘Sylvia’ and C. uncinatum immediately following ethylene treatment

was recorded. A logistic transformation of this data was then performed for ANOVA (McCullagh and

Nelder 1989). The change in relative fresh weight of G. ‘Sylvia’ inflorescences and C. uncinatum sprigs

immediately after ethylene treatment was calculated for ANOVA. Vase solution uptake data were

analysed as split plot for time ANOVAs. When flower abscission from G. ‘Sylvia’ inflorescences reached

100%, measurement of flower wilting, discolouration and opening was discontinued. Based on the

assumption that no meaningful conclusions could be drawn from statistical analysis of these unbalanced

data sets, ANOVAs were not performed.

The LSD test at P = 0.05 was used to separate treatment means. For vase solution uptake data, LSDs

presented are for comparisons between treatments (rather than for a particular time within a treatment).

LSDs are shown only when significant (P < 0.05) differences between treatments existed. Differences

between treatment means referred to in the results are significant at the P < 0.05 level. LSDs from

ANOVA of derived data not presented in figures are shown in appendices. Data sets which show non-

significant differences are also presented in appendices.

4.3 RESULTS

4.3.1 Duration of persistence of 1-MCP pre-treatment effects on G. ‘Sylvia’

inflorescences

G. ‘Sylvia’ inflorescences pre-treated with 10 nL 1-MCP/L at 2oC were not protected from subsequent

exposure to ethylene as evidenced by rapid flower abscission (Plate 4.1, Figure 4.1 and Appendix 4.1).

Pre-treatment of inflorescences with 1-MCP at 2oC did not reduce the ethylene-induced loss of fresh

weight associated with flower abscission (Figure 4.2 and Appendix 4.2).

In contrast, inflorescences pre-treated with 1-MCP at 20oC were afforded protection against ethylene-

induced flower abscission for 2 days after 1-MCP pre-treatment (Plate 4.1, Figure 4.1 and Appendix 4.1).

Thereafter, ethylene treatment stimulated flower abscission. However, flower abscission from

inflorescences pre-treated with 1-MCP at 20oC was not as rapid following ethylene treatment.

Furthermore, flower abscission was not as complete compared to inflorescences pre-treated with 1-MCP

at 2oC (Figure 4.1 and Appendix 4.1). This differential response reflected a significant interaction

between 1-MCP pre-treatment and pre-treatment temperature (Appendix 4.3). Changes in flower

abscission were also reflected in similar changes in the loss of relative fresh weight from inflorescences

pre-treated with 1-MCP at 20oC (Figure 4.2 and Appendix 4.2). However, the loss of relative fresh weight

from inflorescences pre-treated with 1-MCP at 20oC was significantly less after exposure to ethylene than

from inflorescences pre-treated with 1-MCP at 2oC. Consequently, a significant interaction between 1-

MCP pre-treatment and pre-treatment temperature existed (Appendices 4.2 and 4.4).

Vase solution uptake by inflorescences pre-treated with 1-MCP at 2 or 20oC tended to decrease in

20

association with flower abscission induced by ethylene treatment, presumably as the transpirational area

was reduced (Figure 4.3). A significant interaction between 1-MCP pre-treatment, pre-treatment

temperature and time of measurement for vase solution uptake reflected the differential response of

inflorescences to 1-MCP at 2 and 20oC (Appendix 4.5).

As vase life was partly based on flower abscission, 1-MCP pre-treatment at 2oC did not prevent the

exogenous ethylene-induced loss in vase life (Table 4.1). However, 1-MCP pre-treatment at 20oC

significantly reduced the ethylene-induced loss in vase life for up to 2 days after 1-MCP pre-treatment

(Table 4.1). As a result, there was a significant interaction between 1-MCP pre-treatment and pre-

treatment temperature for vase life (Appendix 4.6). Flower wilting, opening and discolouration were not

affected by 1-MCP pre-treatment at 2 or 20oC (Appendices 4.7, 4.8 and 4.9).

21

Plate 4.1. G. ‘Sylvia’ inflorescences on day 5 after pre-treatment on day 0 with 10 nL 1-MCP/L at20 (LHS) or 2oC (RHS) followed by exposure on day 1 to 10 µL ethylene/L at 20oC. Note: extensiveflower abscission is evident in the inflorescence pre-treated with 1-MCP at 2oC (RHS).

22

0 1 2 3 4 5 6

Time (days)

0 1 2 3 4 5 6

1

2

3

4

5

Abs

ciss

ion

scor

e

1

2

3

4

5

2oC

20oC

2oC

20oC

Control treatments

Control treatments

Sequential treatments


Figure 4.1. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from G. ‘Sylvia’ inflorescences pre-treated with 10 nL 1-MCP/L at 2 or 20oC. Different sub-samples of inflorescences were thensequentially exposed to 10 µL ethylene/L at 20oC days 1 (●), 2 (■), 3 (▲), 4 (▼) or 5 (◆). Controlinflorescences were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC (●), 0 nL1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (■) or 10 nL 1-MCP/L at 2 or 20oC and 0 µLethylene/L at 20oC (▲). 1-MCP and ethylene treatments were each conducted for 12 hours on days0 or 1, respectively, unless otherwise stated. Vertical bars represent standard errors of means (n =5). LSD is presented in Appendix 4.1.

23

Rel

ativ

e fr

esh

wei

ght (

% o

f ini

tial F

W)

20

40

60

80

100

120

Time (days)

0 1 2 3 4 5 6

20

40

60

80

100

120

0 1 2 3 4 5 6

Control treatments

Control treatments



2oC 2oC

20oC 20oC

Figure 4.2. Relative fresh weight of G. ‘Sylvia’ inflorescences pre-treated with 10 nL 1-MCP/L at 2or 20oC. Different sub-samples of inflorescences were then sequentially exposed to 10 µLethylene/L at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼) or 5 (◆). Control inflorescences were treatedwith 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC (●), 0 nL 1-MCP/L at 2 or 20oC and10 µL ethylene/L at 20oC (■) or 10 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC (▲). 1-MCP and ethylene treatments were each conducted for 12 hours on days 0 or 1, respectively, unlessotherwise stated. Vertical bars represent standard errors of means (n = 5). LSD is presented inAppendix 4.2.

24

0.0

0.2

0.4

Time (days)

0 1 2 3 4 5 6

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.2

0.4

0 1 2 3 4 5 6

Control treatments Sequential treatments


2oC 2oC

20oC 20oC

Figure 4.3. Vase solution usage by G. ‘Sylvia’ inflorescences pre-treated with 10 nL 1-MCP/L at2 or 20oC. Different sub-samples of these inflorescences were then sequentially exposed to 10 µLethylene/L at 20oC days 1 (●), 2 (■), 3 (▲), 4 (▼) or 5 (◆). Control inflorescences were treatedwith 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC (●), 0 nL 1-MCP/L at 2 or 20oCand 10 µL ethylene/L at 20oC (■) or 10 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC(▲). 1-MCP and ethylene treatments were each conducted for 12 hours on days 0 or 1,respectively, unless otherwise stated. Vertical bars represent standard errors of means (n = 5).LSD = 0.037 mL/g initial FW/day.

25

Table 4.1. Vase life (mean ± s.e.) of G. ‘Sylvia’ inflorescences pre-treated at 2 or 20oC with 0 or 10nL 1-MCP/L for 12 hours. Different sub-samples of inflorescences pre-treated with 10 nL 1-MCP/L were then treated at 20oC daily until day 5 with 10 µL ethylene/L for 12 hours. Values inparentheses show vase life relative to the longest recorded (%). Data followed by the same lettersare not significantly different (LSD = 1.0) at P = 0.05 (n = 5).

1-MCP treatment Days between 1-MCPpre-treatment andexposure to ethylene

Vase life (days)

Part A: Controltreatments

1-MCP treatment at2oC

1-MCP treatment at20oC

0 nL 1-MCP/L - 4.0 ± 0.4 a (87) 3.6 ± 0.4 a (78)1 2.0 ± 0.0 a (43) 2.0 ± 0.0 a (43)

10 nL 1-MCP/L - 4.6 ± 0.4 a (100) 4.6 ± 0.2 a (100)

Part B: Sequentialtreatments

10 nL 1-MCP/L 1 2.0 ± 0.0 a (43) 4.6 ± 0.4 c (100)2 3.0 ± 0.0 bc (65) 4.2 ± 0.5 c (91)3 3.8 ± 0.2 c (83) 3.8 ± 0.4 c (83)4 4.2 ± 0.4 c (91) 4.4 ± 0.4 c (96)5 4.4 ± 0.4 c (96) 4.6 ± 0.5 c (100)

a Control inflorescences were excluded from the statistical analysis of vase life.

4.3.2 Duration of persistence of 1-MCP and STS pre-treatment effects on flowering C.

uncinatum sprigs

Pre-treatment of C. uncinatum ‘Lollypop’, ‘Alba’ and ‘Mid Pink’ sprigs with 10 nL 1-MCP/L at 2oC

provided protection against exogenous ethylene-induced flower abscission for 1, 2 and 2 days,

respectively (Figures 4.4, 4.5, 4.6 and Appendices 4.10, 4.11, 4.12). Thereafter, flower abscission in

response to ethylene treatment was rapid. Ethylene-induced flower abscission was accompanied by the

loss in sprig relative fresh weight (Figures 4.7, 4.8, 4.9 and Appendices 4.13, 4.14, 4.15). Vase life of

‘Lollypop’, ‘Alba’ and ‘Mid Pink’ sprigs pre-treated with 1-MCP at 2oC was reduced when exposed to

ethylene treatment applied 2, 3 and 3 days after 1-MCP pre-treatment, respectively (Tables 4.2, 4.3, 4.4).

In contrast, flower abscission and associated loss of relative fresh weight from ‘Lollypop’, ‘Alba’ and

‘Mid Pink’ sprigs were low throughout these experiments (10, 11 and 9 days, respectively) from parallel

sets of sprigs pre-treated with STS at 2oC (Figures 4.4, 4.5, 4.6, 4.7, 4.8 and 4.9). Thus, vase life of sprigs

pre-treated with STS was effectively extended relative to sprigs pre-treated with 1-MCP (Tables 4.2, 4.3

and 4.4).

The onset of ethylene-induced flower abscission from ‘Lollypop’, ‘Alba’ and ‘Mid Pink’ sprigs pre-

treated with 1-MCP at 20oC was delayed for 6, 4 and 3 days, respectively (Figures 4.4, 4.5, 4.6 and

Appendices 4.10, 4.11, 4.12). Consequently, the loss of relative fresh weight from sprigs pre-treated with

1-MCP at 20oC was reduced during this period compared to sprigs pre-treated with 1-MCP at 2oC

(Figures 4.7, 4.8, 4.9 and Appendices 4.13, 4.14, 4.15). Thereafter flower abscission and associated loss

26

of relative fresh weight were rapid. Vase life of ‘Lollypop’, ‘Alba’ and ‘Mid Pink’ sprigs pre-treated with

1-MCP at 20oC was not reduced by exposure to ethylene for up to 6, 4 and 3 days after 1-MCP pre-

treatment, respectively (Tables 4.2, 4.3 and 4.4). As found for parallel sets of sprigs pre-treated with STS

at 2oC, those treated with STS at 20oC remained insensitive to ethylene for the duration of the

experiments. There was virtually no flower abscission at all from sprigs pre-treated with STS (Figures

4.4, 4.5 and 4.6) except for ‘Lollypop’, which may have been due to STS phytotoxicity. Furthermore, the

loss of relative fresh weight from sprigs pre-treated with STS was significantly reduced compared to

sprigs pre-treated with 1-MCP (Figures 4.7, 4.8 and 4.9). Accordingly, vase life of sprigs pre-treated with

STS at 20oC was longer than sprigs pre-treated with 1-MCP at 20oC except for ‘Lollypop’ (Tables 4.2, 4.3

and 4.4).

The differential response of ‘Lollypop’, ‘Alba’ and ‘Mid Pink’ sprigs to 1-MCP and STS pre-treatments at

2 or 20oC was reflected in a significant interaction between 1-MCP or STS pre-treatment, time of ethylene

treatment and pre-treatment temperature for flower abscission (Appendices 4.16, 4.17 and 4.18) and loss

of relative fresh weight (Appendices 4.19, 4.20 and 4.21). As a result, there was also a significant

interaction between 1-MCP or STS pre-treatment, time of ethylene treatment and pre-treatment

temperature for vase life of ‘Lollypop’ and ‘Mid Pink’ sprigs (Appendices 4.22 and 4.23). For ‘Alba’

sprigs, a significant interaction between 1-MCP or STS pre-treatment and pre-treatment temperature for

vase life was evident (Appendix 4.24).

27

0 2 4 6 8 10

Time (days)

0 2 4 6 8 10

020406080

100

020406080

100

020406080

100

020406080

100

Flo

wer

abs

ciss

ion

(%)

020406080

100

Control (2oC)

+ 1-MCP (2oC)

+ STS (2oC)

Control (20oC)

+ 1-MCP (2oC)

+ 1-MCP (20oC)

+ 1-MCP (20oC)

+ STS (20oC)

+ STS (2oC) + STS (20oC)

Figure 4.4. Flower abscission from C. uncinatum ‘Lollypop’ sprigs pre-treated on day 0 with 10 nL1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs were then sequentiallyexposed to 10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼), 5 (◆), 6 (��), 7(dd), 8 (UU) or 9 (VV). Control sprigs were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µLethylene/L at 20oC (pp) or 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (●). 1-MCP/STS and ethylene treatments were each conducted for 12 hours on days 0 or 1, respectively,unless otherwise stated. Vertical bars represent standard errors of means (n = 5). Where novertical bars appear, the standard error was smaller than the size of the symbol. LSD is presentedin Appendix 4.10.

28

Time (days)

0 2 4 6 8 10

020406080

100

020406080

100

020406080

100

Flo

wer

abs

ciss

ion

(%)

020406080

100

020406080

100

Control (2oC)

+ 1-MCP (2oC)

+ STS (2oC)

0 2 4 6 8 10

Control (20oC)

+ 1-MCP (2oC) + 1-MCP (20oC)

+ 1-MCP (20oC)

+ STS (2oC) + STS (20oC)

+ STS (20oC)

Figure 4.5. Flower abscission from C. uncinatum ‘Alba’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs were then sequentiallyexposed to 10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼), 5 (◆), 6 (��), 7(dd), 8 (UU), 9 (VV) or 10 (pp). Control sprigs were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µLethylene/L at 20oC ( ) or 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (●). 1-MCP/STS and ethylene treatments were each conducted for 12 hours on days 0 or 1, respectively,unless otherwise stated. Vertical bars represent standard errors of means (n = 5). Where novertical bars appear, the standard error was smaller than the size of the symbol. LSD is presentedin Appendix 4.11.

29

0 1 2 3 4 5 6 7 8 9

Control (2oC)

Time (days)

0 1 2 3 4 5 6 7 8 9

020406080

100

020406080

100

020406080

100

Flo

wer

abs

ciss

ion

(%)

020406080

100

020406080

100

Control (2oC)

+ 1-MCP (2oC)

+ STS (2oC)

+ 1-MCP (2oC)

+ 1-MCP (20oC)

+ 1-MCP (20oC)

+ STS (20oC)+ STS (2oC)

+ STS (20oC)

Figure 4.6. Flower abscission from C. uncinatum ‘Mid Pink’ sprigs pre-treated on day 0 with 10 nL1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs were then sequentiallyexposed to 10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼), 5 (��), 6 (dd), 7(UU) or 8 (VV). Control sprigs were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at20oC (pp) or 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (●). 1-MCP/STS andethylene treatments were each conducted for 12 hours on days 0 or 1, respectively, unless otherwisestated. Vertical bars represent standard errors of means (n = 5). Where no vertical bars appear,the standard error was smaller than the size of the symbol. LSD is presented in Appendix 4.12.

30

0 2 4 6 8 10

406080

100120

Rel

ativ

e fr

esh

wei

ght (

% o

f ini

tial F

W)

406080

100120

406080

100120

406080

100120

Time (days)

0 2 4 6 8 10

406080

100120

Control (2oC)

+ 1-MCP (2oC)

+ STS (2oC)

Control (20oC)

+ 1-MCP (20oC)

+ 1-MCP (20oC)

+ 1-MCP (2oC)


+ STS (20oC)

Figure 4.7. Relative fresh weight of C. uncinatum ‘Lollypop’ sprigs pre-treated on day 0 with 10 nL1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs were then sequentiallyexposed to 10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼), 5 (◆), 6 (��), 7(dd), 8 (UU) or 9 (VV). Control sprigs were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µLethylene/L at 20oC (pp) or 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (●). 1-MCP/STS and ethylene treatments were each conducted for 12 hours on days 0 or 1, respectively,unless otherwise stated. Vertical bars represent standard errors of means (n = 5). Where novertical bars appear, the standard error was smaller than the size of the symbol. LSD is presentedin Appendix 4.13.

31

0 2 4 6 8 10

406080

100120

Rel

ativ

e fr

esh

wei

ght (

% o

f ini

tial F

W)

406080

100120

406080

100120

406080

100120

Time (days)

0 2 4 6 8 10

406080

100120

Control (2oC)

+ 1-MCP (2oC)

+ STS (2oC)

Control (20oC)

+ 1-MCP (20oC)+ 1-MCP (2oC)

+ 1-MCP (20oC)


+ STS (20oC)

Figure 4.8. Relative fresh weight of C. uncinatum ‘Alba’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs were then treated with10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼), 5 (◆), 6 (��), 7 (dd), 8 (UU), 9(VV) or 10 (pp). Control sprigs were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at20oC ( ) or 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (●). 1-MCP/STS andethylene treatments were each conducted for 12 hours on days 0 or 1, respectively, unless otherwisestated. Vertical bars represent standard errors of means (n = 5). Where no vertical bars appear,the standard error was smaller than the size of the symbol. LSD is presented in Appendix 4.14.

32

0 2 4 6 8

406080

100120

Rel

ativ

e fr

esh

wei

ght (

% o

f ini

tial F

W)

406080

100120

406080

100120

406080

100120

Time (days)

0 2 4 6 8

406080

100120

Control (2oC)

+ 1-MCP (2oC)

+ STS (2oC)

Control (20oC)

+ 1-MCP (2oC)

+ 1-MCP (20oC)

+ 1-MCP (20oC)


+ STS (20oC)

Figure 4.9. Relative fresh weight of C. uncinatum ‘Mid Pink’ sprigs pre-treated on day 0 with 10nL 1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs were then treatedwith 10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼), 5 (��), 6 (dd), 7 (UU) or 8(VV). Control sprigs were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC (pp)or 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (●). 1-MCP/STS and ethylenetreatments were each conducted for 12 hours on days 0 or 1, respectively, unless otherwise stated.Vertical bars represent standard errors of means (n = 5). Where no vertical bars appear, thestandard error was smaller than the size of the symbol. LSD is presented in Appendix 4.15.

33

Table 4.2. Vase life (mean ± s.e.) of C. uncinatum ‘Lollypop’ sprigs pre-treated at 2 or 20oC with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+) for 12hours. Different sub-samples of sprigs pre-treated with 10 nL 1-MCP/L or 0.5 mM Ag+ were then treated at 20oC daily until day 9 with 10 µL ethylene/L for 12hours. Values in parentheses show vase life relative to the longest recorded (%). Data followed by the same letters are not significantly different (LSD = 1.9) at P= 0.05 (n = 5).

1-MCP treatment Days between 1-MCP orSTS pre-treatment andexposure to ethylene

Vase life (days)

Part A: Control treatments 1-MCP or Ag+ treatmentat 2oC

1-MCP or Ag+

treatment at 20oC0 nL 1-MCP/L or0 mM Ag+

- 8.6 ± 0.9 z (88) 6.4 ± 0.9 z (65)

1 2.0 ± 0.0 z (20) 2.0 ± 0.0 z (20)


10 nL 1-MCP/L at 2oC 0.5 mM Ag+ at 2oC 10 nL 1-MCP/L at20oC

0.5 mM Ag+ at 20oC

1-MCP or Ag+ 1 7.4 ± 1.0 cd (76) 7.4 ± 0.6 cd (76) 7.2 ± 0.7 cd (73) 3.2 ± 0.5 ab (33)2 3.0 ± 0.0 ab (31) 6.6 ± 0.7 bc (67) 7.6 ± 1.0 cd (78) 2.6 ± 0.6 a (27)3 4.4 ± 0.2 ab (45) 7.6 ± 0.6 cd (78) 6.8 ± 0.5 c (69) 3.8 ± 0.5 ab (39)4 5.0 ± 0.0 bc (51) 9.0 ± 0.4 d (92) 7.8 ± 0.4 cd (80) 3.8 ± 0.5 ab (39)5 5.6 ± 0.4 bc (57) 6.0 ± 0.8 bc (61) 8.0 ± 1.3 cd (82) 5.2 ± 1.2 bc (53)6 5.4 ± 1.0 bc (55) 7.4 ± 0.9 cd (76) 8.8 ± 0.8 d (90) 4.2 ± 0.2 ab (43)7 7.2 ± 0.8 cd (73) 4.8 ± 0.6 b (49) 5.4 ± 0.9 bc (55) 3.2 ± 0.5 ab (33)8 8.0 ± 1.0 cd (82) 4.8 ± 0.6 b (49) 7.6 ± 0.4 cd (78) 3.6 ± 0.4 ab (37)9 9.8 ± 0.2 d (100) 8.2 ± 0.6 cd (84) 7.0 ± 0.5 cd (71) 3.6 ± 0.4 ab (37)

z Control sprigs were excluded from the statistical analysis of vase life.Table 4.3. Vase life (mean ± s.e.) of C. uncinatum ‘Alba’ sprigs pre-treated at 2 or 20oC with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+) for 12 hours.Different sub-samples of sprigs pre-treated with 10 nL 1-MCP/L or 0.5 mM Ag+ were then treated at 20oC daily until day 10 with 10 µL ethylene/L for 12 hours.Values in parentheses show vase life relative to the longest recorded (%). Data followed by the same letters are not significantly different (LSD = 2.6) at P = 0.05(n = 5).

1-MCP treatment Days between 1-MCP or STSpre-treatment and exposure to

Vase life (days)

34

ethylene

Part A: Control treatments 1-MCP or Ag+

treatment at 2oC1-MCP or Ag+

treatment at 20oC0 nL 1-MCP/L or0 mM Ag+

- 6.2 ± 1.4 z (62) 4.4 ± 0.4 z (44)

1 2.0 ± 0.0 z (20) 2.0 ± 0.0 z (20)


10 nL 1-MCP/L at 2oC 0.5 mM Ag+ at 2oC 10 nL 1-MCP/L at20oC

0.5 mM Ag+ at 20oC

1-MCP or Ag+ 1 8.8 ± 1.3 bc (88) 8.6 ± 1.0 bc (86) 8.4 ± 0.5 bc (84) 7.0 ± 0.7 b (70)2 4.4 ± 0.7 a (44) 8.0 ± 1.6 bc (80) 7.2 ± 1.2 bc (72) 6.6 ± 1.3 a (66)3 4.6 ± 0.6 a (46) 10.0 ± 0.8 c (100) 6.2 ± 0.6 a (62) 5.8 ± 0.7 a (58)4 5.4 ± 0.4 a (54) 8.6 ± 1.5 bc (86) 8.0 ± 0.9 bc (80) 8.0 ± 0.4 bc (80)5 5.6 ± 0.4 a (56) 9.0 ± 1.2 bc (90) 6.0 ± 0.0 a (60) 9.6 ± 1.0 c (96)6 7.0 ± 0.0 b (70) 9.8 ± 1.0 c (98) 7.2 ± 0.2 bc (72) 8.2 ± 1.0 bc (82)7 7.8 ± 0.4 bc (78) 9.2 ± 0.7 bc (92) 8.6 ± 0.2 bc (86) 7.0 ± 1.3 b (70)8 7.2 ± 0.8 bc (72) 8.8 ± 1.2 bc (88) 7.4 ± 0.7 bc (74) 7.2 ± 1.0 bc (72)9 6.6 ± 1.2 a (66) 10.0 ± 0.4 c (100) 8.4 ± 0.5 bc (84) 7.2 ± 1.2 bc (72)10 7.6 ± 1.2 bc (76) 9.6 ± 0.5 c (96) 8.2 ± 1.7 bc (82) 9.8 ± 0.6 c (98)

z Control sprigs were excluded from the statistical analysis of vase life.Table 4.4. Vase life (mean ± s.e.) of C. uncinatum ‘Mid Pink’ sprigs pre-treated at 2 or 20oC with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+) for 12hours. Different sub-samples of sprigs pre-treated with 10 nL 1-MCP/L or 0.5 mM Ag+ were then treated at 20oC daily until day 8 with 10 µL ethylene/L for 12hours. Values in parentheses show vase life relative to the longest recorded (%). Data followed by the same letters are not significantly different (LSD = 1.6) at P= 0.05 (n = 5).

1-MCP treatment Days between 1-MCP or STSpre-treatment and exposure toethylene

Vase life (days)

Part A: Controltreatments

1-MCP or Ag+

treatment at 2oC1-MCP or Ag+

treatment at 20oC0 nL 1-MCP/L or - 5.8 ± 0.6 z (78) 4.4 ± 0.2 z (59)

35

0 mM Ag+

1 2.0 ± 0.0 z (27) 2.0 ± 0.0 z (27)


10 nL 1-MCP/L at 2oC 0.5 mM Ag+ at 2oC 10 nL 1-MCP/L at 20oC 0.5 mM Ag+ at 20oC

1-MCP or Ag+ 1 5.4 ± 1.5 ab (73) 5.8 ± 0.5 bc (78) 5.6 ± 0.6 b (77) 4.4 ± 0.2 ab (59)2 3.8 ± 0.5 a (51) 6.4 ± 0.9 bc (86) 4.8 ± 0.4 ab (65) 6.4 ± 0.9 bc (86)3 4.0 ± 0.0 ab (54) 6.8 ± 0.5 bc (92) 5.0 ± 0.0 ab (68) 5.8 ± 0.5 bc (78)4 4.6 ± 0.2 ab (62) 6.6 ± 0.5 bc (89) 4.4 ± 0.2 ab (59) 5.6 ± 0.7 b (76)5 5.4 ± 0.2 ab (73) 5.0 ± 0.5 ab (68) 4.4 ± 0.2 ab (59) 5.0 ± 0.5 ab (68)6 4.8 ± 0.2 ab (65) 4.6 ± 0.4 ab (62) 5.4 ± 0.5 ab (73) 4.6 ± 0.4 ab (62)7 5.0 ± 0.5 ab (68) 6.8 ± 1.0 bc (92) 6.6 ± 0.4 bc (89) 4.4 ± 0.4 ab (59)8 7.4 ± 0.5 c (100) 5.4 ± 0.7 ab (73) 6.4 ± 0.7 bc (86) 6.2 ± 0.8 bc (84)

z Control sprigs were excluded from the statistical analysis of vase life.

1

‘Lollypop’ sprigs pre-treated with STS at 20oC used vase solution at a higher rate between days 0 and 1

than parallel sets of sprigs pre-treated at 2oC and sprigs pre-treated with 1-MCP at 2 or 20oC (Figure

4.10). This response was reflected in a significant interaction between the anti-ethylene agent, pre-

treatment temperature and time of measurement (Appendix 4.25). After day 2, vase solution uptake by

sprigs declined with time and was not affected by 1-MCP or STS pre-treatment. Vase solution uptake by

‘Alba’ sprigs pre-treated with STS was consistently lower and more stable throughout the experiment than

sprigs pre-treated with 1-MCP (Figure 4.11). Furthermore, sprigs pre-treated with 1-MCP and STS at

20oC used less vase solution between days 1 and 2 than parallel sets of sprigs pre-treated at 2oC. As a

result there was a significant interaction between the anti-ethylene agent, the timing of ethylene treatment,

pre-treatment temperature and time of measurement (Appendix 4.26). Vase solution uptake by ‘Mid Pink’

sprigs pre-treated with STS at 2 or 20oC was lower and more consistent throughout the experiment than

sprigs pre-treated with 1-MCP (Figure 4.12). These responses resulted in a significant interaction

between the anti-ethylene agent, the timing of ethylene treatment and time of measurement (Appendix

4.27).

Overall, based on solution volume uptake measured for STS pulsing at 2oC, ‘Lollypop’, ‘Alba’ and ‘Mid

Pink’ sprigs accumulated 0.067 ± 0.003, 0.031 ± 0.005 and 0.054 ± 0.002 µmol Ag+/g sprig FW,

respectively. Accumulation of Ag+ by sprigs of ‘Lollypop’, ‘Alba’ and ‘Mid Pink’ pulsed with STS at

20oC was 0.353 ± 0.010, 0.213 ± 0.006 and 0.160 ± 0.005 µmol Ag+/g sprig FW, respectively.

2

0 2 4 6 8 10

Control treatments

1-MCP treatment

1-MCP treatment

STS treatment

STS treatment

0.0

0.4

0.8

1.2S

olut

ion

upta

ke (

mL/

g in

itial

FW

/day

)

0.0

0.4

0.8

1.2

0.0

0.4

0.8

1.2

0.0

0.4

0.8

1.2

Time (days)

0 2 4 6 8 10

0.0

0.4

0.8

1.2

Control treatments

1-MCP treatment

1-MCP treatment

STS treatment

STS treatment

2oC

2oC

2oC

2oC

2oC

20oC

20oC

20oC

20oC

20oC

Figure 4.10. Vase solution uptake by C. uncinatum ‘Lollypop’ sprigs pre-treated on day 0 with 10nL 1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs from each of thesetreatments were then sequentially exposed to 10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2(■), 3 (▲), 4 (▼), 5 (◆), 6 (��), 7 (dd), 8 (UU) or 9 (VV). Control sprigs were treated with 0 nL 1-MCP/Lat 2 or 20oC and 0 µL ethylene/L at 20oC (pp) or 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at20oC (●). 1-MCP/STS and ethylene treatments were each conducted for 12 hours on days 0 or 1,respectively, unless otherwise stated. Vertical bars represent standard errors of means (n = 5).Where no vertical bars appear, the standard error was smaller than the size of the symbol. LSD =0.142 mL/g initial FW/day.

3

0 2 4 6 8 10

Control treatments

1-MCP treatment

1-MCP treatment

STS treatment

STS treatment

0.0

0.5

1.0

1.5

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.5

1.0

1.5

0.0

0.5

1.0

1.5

0.0

0.5

1.0

1.5

Time (days)

0 2 4 6 8 10

0.0

0.5

1.0

1.5

Control treatments

1-MCP treatment

1-MCP treatment

STS treatment

STS treatment

2oC

2oC

2oC

2oC

2oC

20oC

20oC

20oC

20oC

20oC

Figure 4.11. Vase solution uptake by C. uncinatum ‘Alba’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs from each of thesetreatments were then sequentially exposed to 10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2(■), 3 (▲), 4 (▼), 5 (◆), 6 (��), 7 (dd), 8 (UU), 9 (VV) or 10 (pp). Control sprigs were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC ( ) or 0 nL 1-MCP/L at 2 or 20oC and 10 µLethylene/L at 20oC (●). 1-MCP/STS and ethylene treatments were each conducted for 12 hours ondays 0 or 1, respectively, unless otherwise stated. Vertical bars represent standard errors of means(n = 5). Where no vertical bars appear, the standard error was smaller than the size of the symbol.LSD = 0.184 mL/g initial FW/day.

4

0 2 4 6 8

Control treatments

1-MCP treatment

0.0

0.4

0.8

1.2S

olut

ion

upta

ke (

mL/

g in

itial

FW

/day

)

0.0

0.4

0.8

1.2

0.0

0.4

0.8

1.2

0.0

0.4

0.8

1.2

Time (days)

0 2 4 6 8

0.0

0.4

0.8

1.2

Control treatments

1-MCP treatment

STS treatment

1-MCP treatment 1-MCP treatment

STS treatment

STS treatment STS treatment

2oC

2oC

2oC

2oC

2oC

20oC

20oC

20oC

20oC

20oC

Figure 4.12. Vase solution uptake by C. uncinatum ‘Mid Pink’ sprigs pre-treated on day 0 with 10nL 1-MCP/L or STS (0.5 mM Ag+) at 2 or 20oC. Different sub-samples of sprigs from each of thesetreatments were then sequentially exposed to 10 µL ethylene/L for 12 hours at 20oC on days 1 (●), 2(■), 3 (▲), 4 (▼), 5 (��), 6 (dd), 7 (UU) or 8 (VV). Control sprigs were treated with 0 nL 1-MCP/L at 2 or20oC and 0 µL ethylene/L at 20oC (pp) or 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC(●). 1-MCP/STS and ethylene treatments were each conducted for 12 hours on days 0 or 1,respectively, unless otherwise stated. Vertical bars represent standard errors of means (n = 5).Where no vertical bars appear, the standard error was smaller than the size of the symbol. LSD =0.143 mL/g initial FW/day.

5

4.4. DISCUSSION

The efficacy of 1-MCP pre-treatment applied to cut Penstemon and Kalanchoe flowers at low

temperatures (2oC) and at low concentrations (5-20 nL/L) has been reported as being poor (Serek et al.

1995a; Reid et al. 1996). This assertion was confirmed in the present study. Pre-treatment of G. ‘Sylvia’

inflorescences with 10 nL 1-MCP/L for 12 hours at 2oC did not prevent ethylene-induced flower

abscission (Figure 4.1). This response differs from results presented in section 2.3.3 where pre-treatment

of inflorescences with 10 nL 1-MCP/L for 12 hours at 0, 5, 10 or 20oC afforded similar levels of

protection against ethylene. These contrasting results may reflect the different temperatures at which

chambers were ventilated (i.e. 2 vs. 20oC).

C. uncinatum sprigs pre-treated with 10 nL 1-MCP/L for 12 hours at 2oC were afforded only short term

(ca. 2 days) protection against ethylene (Tables 4.2, 4.3 and 4.4). Pre-treatment of sprigs with 10 nL 1-

MCP/L for 12 hours at 20oC provided comparatively longer term (ca. 4 days) protection against ethylene

(Tables 4.2, 4.3 and 4.4). 1-MCP evidently blocked ethylene receptors during pre-treatment at 2 or 20oC,

since the sprigs were fully protected against ethylene immediately after the pre-treatment.

The reasons why higher 1-MCP concentrations are needed at low temperature are unclear. Poor 1-MCP

binding at low temperature may be due to conformational changes in the membrane-located protein(s) that

is/are the ethylene receptor(s). Conformational changes to membranes and membrane-bound proteins are

proposed to occur at low temperature in chilling sensitive plant tissue (Lyons 1973). In addition, slower

diffusion of 1-MCP molecules to the ethylene receptor may occur at low temperature.

According to Sisler and Serek (1997), plants regain sensitivity to ethylene presumably by producing new

ethylene receptors. An alternative explanation to that tendered above is that exposure to low temperature

treatment may induce rapid receptor synthesis. Mayak and Kofranek (1976) reported that holding cut

carnation flowers at 2oC for several days increased their sensitivity to subsequent ethylene treatment.

Sisler et al. (1996a) also reported that carnation flowers pre-treated with 5 nL 1-MCP/L at 24oC and then

held at 4oC for 4 days had more unbound ethylene receptors than parallel sets of flowers held at 24oC.

However, the duration of pre-treatment at 2oC in the present study was only 12 hours. It is possible that

this was sufficient to induce a temporary ‘stress’ which may have enhanced ethylene sensitivity. Low

temperature stress is also known to enhance ethylene production by chilling-sensitive plant tissue upon

return to warmer temperatures (Wang 1989). Further, the number of ethylene receptors has been recently

proposed to increase in response to enhanced ethylene biosynthesis (Klee and Tieman 1997). However,

G. ‘Sylvia’ and C. uncinatum are not considered chilling sensitive crops (Ligawa et al. 1997; Joyce 1988,

respectively).

Pre-treatment of G. ‘Sylvia’ inflorescences with 10 nL 1-MCP/L at 20oC afforded protection against

ethylene-induced flower abscission for only 2 days after 1-MCP pre-treatment (Table 4.1). This

observation is similar to that discussed above for C. uncinatum, and suggests that synthesis of ethylene

6

receptors in the abscission zones of G. ‘Sylvia’ and C. uncinatum flowers is very rapid. Other

horticultural commodities such as carnation flowers, banana and tomato fruit were reported by Sisler et al.

(1996b) and Sisler and Serek (1997) to remain insensitive to ethylene for 10-15 days after 1-MCP pre-

treatment.

In contrast to 1-MCP pre-treatment , pulsing C. uncinatum sprigs with STS (0.5 mM Ag+) at 2 or 20oC

provided complete protection against ethylene for the duration of experiments (ca. 10 days) (Tables 4.2,

4.3 and 4.4). Minor flower abscission from ‘Lollypop’ sprigs pulsed with STS at 20oC was, however,

associated with the highest accumulation of Ag+ (0.353 µmol Ag+/g sprig FW) during STS pulsing. This

flower abscission associated with STS treatment suggests that sprigs suffered STS phytotoxicity. Uptake

of Ag+ by C. uncinatum above 0.6 µmol Ag+/g sprig FW was shown by Joyce (1988) to be toxic and to

cause flower abscission. The safe and effective range of Ag+ accumulation by C. uncinatum may vary

with genotype. Cameron and Reid (1981) reported that effective STS treatment concentrations are usually

close to the phytotoxic level. Relatively low Ag+ accumulation was observed for sprigs pulsed with STS

at 2oC, presumably because transpiration was reduced at low temperature.

Higher vase solution uptake rates were observed during the pre-treatment period for ‘Lollypop’, ‘Alba’

and ‘Mid Pink’ sprigs which were not enclosed in chambers (i.e. those pre-treated with STS and those not

pre-treated with 1-MCP or STS) (Figures 4.10, 4.11 and 4.12). Possibly, the presence of lower relative

humidity and greater air circulation in the controlled environment rooms caused an increase in the

transpiration and hence solution uptake by these sprigs. Vase solution uptake by ‘Alba’ and ‘Mid Pink’

sprigs tended to decrease and became more stable in association with ethylene-induced flower abscission,

possibly reflecting reduced transpirational surface area.

Earlier workers have shown that effective Ag+ treatments provide long term protection against ethylene.

For example, new growth from pea seedlings following spray pre-treatment with AgNO3 showed no

sensitivity to ethylene, indicating that silver acted systemically (Beyer, 1976). Additionally, STS pre-

treatment prevented ethylene-induced flower abscission from Zygocactus for at least 4 weeks (Cameron

and Reid 1981). Ag+ is presumably retained as a ‘pool’ in or around C. uncinatum flower abscission

zones and may remain available to bind to newly formed receptors.

In the present study, 1-MCP pre-treatment was shown to protect G. ‘Sylvia’, C. uncinatum against

ethylene, thereby extending their postharvest longevity. However, the efficacy of 1-MCP pre-treatment

was reduced at low temperature. STS pre-treatment was shown to provide longer term protection against

ethylene than 1-MCP pre-treatment. The duration of persistence of 1-MCP pre-treatment effects varied

depending on treatment temperature (e.g. 2 vs. 20oC) and genus (e.g. G. ‘Sylvia’ vs. C. uncinatum).

These results highlight the need for research into refining 1-MCP treatments to provide cut flowers with

commercially viable longer term protection against ethylene. Compared with STS, 1-MCP is safe and

easy to apply. Moreover, the results of this study indicate that for cut flowers, effective protection during

the relatively brief but critical period of unrefrigerated export by airplane can be achieved.

7

CHAPTER 5

COMMERCIAL SCALE 1-MCP TREATMENTS PROTECT

GERALDTON WAXFLOWER AGAINST ETHYLENE-INDUCED

FLOWER ABSCISSION

5.1 INTRODUCTION

Native Australian flowers are traded internationally as exotic alternatives to traditional cut flowers such as

roses, carnations and chrysanthemums (Joyce et al. 1993). Geraldton waxflower (Chamelaucium

uncinatum, Myrtaceae) is Australia’s most valuable native cut flower export (FECA 1996). C. uncinatum

stems have small flowers and leaves and are attractive as a filler in floral arrangements or when displayed

alone (Joyce 1993). However, exposure of cut C. uncinatum stems to ethylene elicits flower abscission

thereby reducing postharvest quality and marketability (Joyce 1988, 1989, 1993). Consignments of C.

uncinatum can often reach export destinations suffering from extensive flower abscission due to

unintentional exposure to exogenous sources of ethylene or the accumulation of endogenous ethylene

within cartons (Joyce 1993).

Pulse treating C. uncinatum stems with STS solution prevents ethylene-induced flower abscission (Joyce

1988). STS is presumed to bind to ethylene receptors in plant tissue and block ethylene perception (Sisler

1982). Because Ag+ in STS is a heavy metal and possible environmental risk, legislators in some

countries are reconsidering its commercial use (Serek et al. 1994a). The alternative gaseous inhibitor of

ethylene perception, 1-MCP, is apparently non-toxic and can prevent ethylene-induced flower abscission

from cut phlox (Porat et al. 1995b), Penstemon (Serek et al. 1995a), Kalanchoe (Reid et al. 1996) and C.

uncinatum (Serek et al. 1995c).

It was hypothesised that effective 1-MCP treatments developed by Serek et al. (1995c) for C. uncinatum

under laboratory conditions could be replicated on a commercial scale. The purpose of the present study

was to devise several 1-MCP pre-treatment systems suitable for use on a commercial scale and to test the

efficacy of each system in preventing ethylene-induced flower abscission from C. uncinatum.


5.2.1 Plant material and preparation

Branches of C. uncinatum cultivars ‘CWA Pink’, ‘Fortune Cookie’, ‘Lollypop’ and ‘Purple Pride’ with

50% or more flowers open were harvested from a cut flower farm near Gatton (27o 34’S 152o 17’E) in

8

S.E. Qld. C. uncinatum cultivars ‘Paddy’s Late’ and ‘Alba’ were harvested from farms near Esk (27o

14’S 152o 25’E) in S.E. Qld and Cunnamulla (28o 04’S 145o 40’E) in southern Qld, respectively, and

transported dry to the Gatton farm within 24 hours of harvest. Branches were trimmed to 50 cm in length

and bunched to approximately 350-400 g. Flowering ends of bunches were then treated in a fungicide dip

[1mL Rovral (a.i. iprodione) and 5 mL Cislin (a.i. deltamethrin)/L of rain water] for 20-30 seconds.

5.2.2 Chemicals

1-MCP and ethylene stocks were prepared and quantified as previously described (sections 2.2.2.1 and

2.2.2.2). STS stock solution (8 mM Ag+) was prepared by the grower using the method of Joyce (1992).

STS solutions for the treatment of cut C. uncinatum were diluted to 0.2 mM Ag+.

5.2.3 Treatments

5.2.3.1 Application of 1-MCP inside polyethylene tents

Bunches of ‘CWA Pink’ were stood into buckets of rain water and placed inside a 30m3 polyethylene tent

(dimensions: 5 m long, 3 m wide, 2 m high) positioned inside a covered packing shed (Plate 5.1). The

tent had an opening at one end which permitted access to the inside. An electric fan was placed inside the

tent to stir the air. A bottle containing 1-MCP gas calculated to create a concentration of 200 nL 1-

MCP/L inside the tent was placed inside and opened. The tent opening was then immediately closed and

sealed with polethylene tape for 6 hours. The stirring fan was operated for 15 minutes. During the 6 hour

pre-treatment, temperature around the tent was recorded to be ca. 20oC. Other bunches were either stood

into buckets of water or STS (0.2 mM Ag+) and remained outside the tent.

At the completion of 1-MCP pre-treatment, an exhaust fan was fitted to the rear of the tent and used for

10-15 minutes to expel air and 1-MCP to the outside of the packing shed. Six bunches from each

treatment (1-MCP, STS or water) were randomly selected and packed into individual fibreboard flower

cartons (internal dimensions: 100 cm long, 26.5 cm wide and 8 cm high) lined with blank newsprint.

Bunches were packed so that the flower end was alternated with the cut stem end. Lids of cartons were

secured in place with polyethylene strapping tape. Ventilation holes in the ends of cartons were left open.

Flowering sprigs 20 cm in length were randomly sampled from the remaining bunches from each

treatment and placed immediately into buckets containing DI water. Cartons and sprigs were then taken in

an air conditioned car to the UQG laboratory within 20 minutes.

At the laboratory, cartons were arranged in a CRD inside a controlled temperature room operating at 20oC

and 50% RH. Cartons remained in this room for 6 days under continuous illumination by cool white

fluorescent lights (10 µmol/m2/s at carton height). The cut ends of sprigs were recut under DI water,

removing at least 2 cm from the stem base and placed into 375 mL capacity vases containing the same

solution described in section 2.2.1. All sprigs and their vases were randomly placed into 60.5 L glass

9

chambers each containing 4 jars of 10 mL 1M KOH and a filter paper (section 2.2.3). Chamber lids were

then sealed in place with polyethylene tape. Sprigs were exposed to 10 µL ethylene/L for 12 hours at

20oC (section 2.2.4.1). At the completion of ethylene treatment, sprigs and their vases were transferred to

a vase life room operating at the same conditions as described in section 2.2.4.1. At the end of the 6 day

storage period, cartons were opened and sprigs removed at random from bunches. Stem ends of sprigs

were recut under DI water and placed into vase solutions as described above. Sprigs and their vases were

then taken to the vase life room.

Plate 5.1. Treatment tent showing polyethylene structure (A), stirring fan (B), open bottlecontaining 1-MCP gas (C) and bunches of C. uncinatum (D).

10

In a second experiment, bunches of ‘Fortune Cookie’ were stood into buckets of rain water and taken by

an air conditioned car to the laboratory. Bunches in water were then evenly allocated to two 470 L

volume polyethylene tents. Tents were placed individually inside coolrooms operating at 2 and 20oC.

Additional bunches remained in water or were stood into STS (0.2 mM Ag+) and placed next to each tent.

Tent openings were closed and sealed with polyethylene tape. Stem temperature was monitored with

thermocouples on additional bunches until they reached the desired temperature. Bunches inside tents

were treated with 200 nL 1-MCP/L for 14 hours at 2 or 20oC in the dark. At the completion of 1-MCP

pre-treatment, tents were opened and ventilated outside the laboratory. All bunches were stood into rain

water. Flowering sprigs were pruned from bunches in each treatment at random. The cut ends of sprigs

were recut under DI water, placed into vase solutions and treated with ethylene as described for the first

experiment. All remaining bunches were taken in an air conditioned car to the Gatton farm.

At the farm, bunches were randomly selected from each treatment and packed into flower cartons as

described for the first experiment. Cartons were then returned to the laboratory by car and arranged in a

CRD inside the same 20oC room used for the first experiment. Cartons remained in this room for 6 days.

Sprigs exposed to ethylene and those that were removed from bunches after storage in cartons for 6 days

were placed into vases (section 2.2.1) and kept in the vase life room used in the first experiment.

5.2.3.2 Injection of 1-MCP into cartons

Bunches of ‘Lollypop’ were stood in buckets of rain water to hydrate for 3 hours at 20oC. Bunches were

then packed into two flower cartons. The ventilation holes at each end of cartons were closed with

fibreboard disks and sealed onto the carton with polyethylene tape. A rubber septum was inserted tightly

through one end of the cartons and acted as a gas injection port. Cartons were placed into a coolroom

operating at 2oC. An aliquot of 1-MCP gas was injected through the septum into one carton such that an

internal concentration of 200 nL 1-MCP/L was created. Bunches inside the other carton remained in air

without 1-MCP. After 24 hours, cartons were opened outside the coolroom and sprigs removed from

bunches at 5, 25, 75 and 95 cm from the injection point (Plate 5.2). Sprigs were recut under DI water,

placed in vase solution and treated with ethylene as described in section 5.2.3.1. Following ethylene

treatment, sprigs and their vases were taken to the vase life room. In a second experiment, the same

procedure was applied to bunches of ‘Purple Pride’ with the exception that the 1-MCP concentration was

increased to 2 µL/L.

5.2.3.3 Application of 1-MCP into a coolroom

Bunches of ‘Paddy’s Late’ that had been held dry for 24 hours after harvest were stood into buckets of

rain water and placed at several positions in a coolroom operating at 2oC. Stem temperature of an

additional bunch was monitored with a thermocouple until it reached 2oC. A stock bottle of 1-MCP was

then placed in the centre of the room and opened. The stock was calculated to create a 1-MCP

concentration of 150 nL/L inside the room. Sliding access doors to the room were closed and circulation

11

fans operated for the duration of treatment. Additional bunches were stood into buckets of rain water and

transported to the laboratory. These bunches were placed into a controlled temperature room operating at

2oC. After 15 hours, the room fumigated with 1-MCP was opened and ventilated for 10-15 minutes

before bunches were removed. Bunches from the controlled temperature room at the laboratory were then

removed and taken to the Gatton farm. Bunches from each treatment were then selected at random and

packed into flower cartons as described in section 5.2.3.1. Flowering sprigs from the remaining bunches

in each treatment were removed at random and stood into DI water. Cartons and sprigs were transported

to the laboratory. At the laboratory, cartons were arranged at 20oC (section 5.2.3.1). Cut ends of sprigs

were recut under DI water and placed into vases (section 5.2.3.1). Half of the sprigs from each of these

treatments were then treated with ethylene as described in section 5.2.3.1. The other half of the sprigs

were held in air without exogenous ethylene. Cartons were opened after 6 days and sprigs removed at

random from bunches. Sprigs and their vases were kept in the vase life room.

5.2.3.4 Application of 1-MCP by forced-air cooling

Bunches of ‘Purple Pride’ were stood into buckets of rain water and hydrated for 3 hours. Half of the

bunches were then packed into flower cartons (section 5.2.3.1). Half of the bunches remaining in water

and cartons were then placed into a coolroom operating at 2oC. Bunches in water were placed at several

positions within the room while cartons were arranged against a forced-air cooler. Sliding doors to the

room were closed and the forced-air cooler was operated. The other half of the bunches in water and

cartons remained in air at ca. 20oC. After 3 hours the room was opened and bunches and cartons were

removed and placed at ca. 20oC. The other half of the bunches in water and cartons were then placed into

the coolroom and against the forced-air cooler, respectively. A stock bottle of 1-MCP was opened and

released as described in section 5.2.3.3. The 1-MCP concentration created inside the room was calculated

to be 200 nL/L. After 3 hours the room was opened and ventilated for 10-15 minutes and bunches and

cartons were removed. Bunches in water and cartons from all treatments were then taken to the laboratory

by car. Flowering sprigs were removed at random from bunches in each treatment and prepared for

ethylene treatment. Flowering sprigs were removed from bunches in cartons at 5, 25, 75 and 95 cm from

the carton end furtherest from the forced-air cooler wall (Plate 5.2). Sprigs were prepared for ethylene

treatment as previously described (section 5.2.3.1.). Half of the sprigs from each treatment were then

treated with ethylene (section 5.2.3.1). The other half of the sprigs remained in air without exogenous

ethylene. At the completion of ethylene treatment, sprigs and their vases were transferred to the vase life

room.

5.2.3.5 Slow release of 1-MCP inside cartons

Bunches of ‘Alba’ were stood in buckets of rain water for 7 days at 2oC. Bunches were then packed into

cartons (section 5.2.3.1). Glass 33 mL volume tubes containing 6928 ± 177 µL 1-MCP/L that were sealed

with a rubber septa were included in cartons either at one end only, both ends or at both ends and the

centre of cartons (Plate 5.2). Additional cartons were packed with bunches but without the inclusion of

12

tubes and acted as the control treatment. Cartons were then transported to the laboratory by car and

arranged in a CRD inside a 20oC coolroom (section 5.2.3.1). After 6 days, cartons were opened.

Flowering sprigs were pruned from bunches at 5, 25, 75 and 95 cm from the position of the first tube

(Plate 5.2). Sprigs were then prepared for ethylene treatment as described in section 5.2.3.1. Half of the

sprigs from each treatment were then treated with ethylene (section 5.2.3.1). The other half of the sprigs

remained in air without exogenous ethylene. Following ethylene treatment, all sprigs and their vases were

taken to the vase life room.

Plate 5.2. Commercial flower carton showing fibreboard wall structure (A), flowering C. uncinatumbunches (B), 1-MCP injection point/intake end (C), sprig sampling positions (D1, D2, D3 and D4)and glass tubes containing 1-MCP gas (E1, E2 and E3).

13

5.2.4 Quality assessment

Sprigs and their vases were weighed separately daily during vase life to allow determination of relative

fresh weight and vase solution uptake, respectively. Flower abscission from sprigs was assessed daily

using the 5 point scale described in section 2.2.5.1. Sprig vase life was judged using the same criteria

presented in section 3.2.5.1.

Bunches were weighed individually before being packed into cartons and again at the end of the 6 day

storage period to enable calculation of weight loss. The accumulation of abscised flowers and leaves from

bunches in each carton after the storage period was weighed and expressed as a percentage of the initial

bunch weight. The concentration of 1-MCP gas inside glass tubes used in the final experiment was

quantified before and after the 6 day treatment period by gas chromatography (section 2.2.5.2).

Postharvest longevity was used to describe the time in days from harvest to the end of vase life (section

3.2.5.1) for sprigs from bunches held inside cartons for 6 days.


In all experiments, sprigs were arranged in a CRD in the vase life room. Three to ten replicates were used

for each treatment, depending upon the particular experiment. The application of 1-MCP inside

polyethylene tents was examined in two experiments. The first experiment was a one factor (treatment)

design while the second experiment was a 3 (treatment) x 2 (temperature) factorial design. Injection of 1-

MCP into cartons was examined as 2 (1-MCP) x 4 (position) factorial experiments. A 2 (1-MCP) x 2

(ethylene) factorial experiment was used to study the application of 1-MCP into a coolroom. The efficacy

of 1-MCP treatment applied by forced-air cooling was determined using a 2 (1-MCP) x 2 (ethylene) x 4

(position) factorial experiment. A 4 (1-MCP) x 2 (ethylene) x 4 (position) factorial experiment was used

to study the slow release of 1-MCP inside cartons.

Treatment means ± standard errors were calculated using Microsoft Excel (Version 5.0, Microsoft Inc.).

Figures were created using Sigmaplot (Version 2.0, Jandel Corporation). Most data were analysed as

split plot for time ANOVAs by the balanced ANOVA function of Minitab (Release 11.12, Minitab Inc.).

Bunch weight loss, accumulated abscised flowers and leaves from bunches and sprig longevity data were

analysed as one-way ANOVAs. Flower abscission score data were converted to a corresponding

percentage and arcsine transformed for ANOVA (Steel and Torrie 1987). Treatment means were

separated by the LSD test at P = 0.05. LSDs are presented for between treatments for data analysed as

split plots for time (section 2.2.6). LSDs are only presented when significant (P < 0.05) differences

between treatment means existed. Differences between treatment means at the P < 0.05 level are referred

to in the results as significant. LSDs from ANOVAs of transformed data sets are not presented (section

2.2.6).

5.3 RESULTS

14

5.3.1 Application of 1-MCP inside polyethylene tents

Pre-treatment of C. uncinatum ‘CWA Pink’ bunches with 200 nL 1-MCP/L for 6 hours at 20oC inside a

polyethylene tent protected flowering sprigs against exposure to 10 µL ethylene/L for 12 hours at 20oC

(Plate 5.3). 1-MCP pre-treatment significantly reduced ethylene-induced flower abscission from sprigs

(Figure 5.1). The STS pre-treatment protocol (0.2 mM Ag+ for 6 hours at 20oC) used in this experiment

was only partially effective in reducing ethylene-induced flower abscission compared to 1-MCP pre-

treatment (Figure 5.1). This differential response accounted for the significant interaction between

treatment and time of measurement for flower abscission (Appendix 5.1). The decrease in sprig relative

fresh weight was significantly reduced by 1-MCP or STS pre-treatments (Figure 5.1 and Appendix 5.2).

Solution uptake by sprigs increased to day 2 or 3, then declined over time for sprigs from all treatments

(Figure 5.1). Solution uptake between days 2 and 4 was lowest for sprigs pre-treated with STS and

highest for sprigs pre-treated with 1-MCP. This uptake pattern probably resulted in the significant

interaction between treatment and time of measurement for vase solution uptake (Appendix 5.3). As vase

life was partly based on flower abscission, 1-MCP pre-treatment prevented the ethylene-induced loss in

vase life (Table 5.1 and Appendix 5.4). Vase lives of sprigs pre-treated with STS were only marginally,

but significantly longer than sprigs exposed only to ethylene.

The loss of weight from ‘CWA Pink’ bunches pre-treated with 200 nL 1-MCP/L or 0.2 mM Ag+ for 6

hours at 20oC and held in cartons for 6 days at 20oC was significantly reduced compared to bunches not

pre-treated with 1-MCP or STS (Table 5.2 and Appendix 5.5). Bunches not pre-treated with 1-MCP or

STS accumulated the most abscised flowers and leaves in cartons during storage (Table 5.2). However,

during the subsequent vase life of sprigs taken from these bunches, there was no flower abscission at all.

The loss of sprig relative fresh weight during vase life was greatest from sprigs pre-treated with 1-MCP

compared sprigs pre-treated with STS or those not pre-treated with 1-MCP or STS (Figure 5.2 and

Appendix 5.6). Sprigs pre-treated with 1-MCP used significantly less vase solution between days 6 and 7

(i.e. the first day after storage) than sprigs pre-treated with STS or those not pre-treated with 1-MCP or

STS (Figure 5.2 and Appendix 5.7). Longevity of sprigs pre-treated with 1-MCP or STS were

significantly extended compared to sprigs not pre-treated with 1-MCP or STS (Table 5.2 and Appendix

5.8).

15

Plate 5.3. C. uncinatum ‘CWA Pink’ sprigs on day 2 after treatment on day 0 with 0 nL 1-MCP/L(control) (LHS), STS (0.2 mM Ag+) (centre) or 200 nL 1-MCP/L (RHS) followed by exposure to 10µL ethylene/L on day 1. Note: extensive flower abscission is evident in the control sprig (LHS).

16

Abs

ciss

ion

scor

e

1

2

3

4

5

Time (days)

0 2 4 6 8 10

Sol

utio

n up

take

(m

L/ g

initi

al F

W/ d

ay)

0.0

0.2

0.4

0.6

0.8

Rel

ativ

e fr

esh

wei

ght

(%

of i

nitia

l FW

)

60

80

100

Figure 5.1. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for C. uncinatum ‘CWA Pink’ sprigs pre-treated on day 0 with 200 nL 1-MCP/L(■), STS (0.2 mM Ag+) (▲) or 0 nL 1-MCP/L and 0 mM Ag+ (●) for 6 hours at 20oC. Sprigs fromeach of these treatments were then immediately exposed on day 0 to 10 µL ethylene/L for 12 hoursat 20oC. Vertical bars represent standard errors of means (n = 10). Where no vertical bars appear,the standard error was smaller than the size of the symbol. LSD for relative fresh weight data =2.9%. LSD for solution uptake data = 0.051 mL/g initial FW/day.

17

Table 5.1. Vase life (mean ± s.e.) of C. uncinatum ‘CWA Pink’ sprigs pre-treated on day 0 with 200nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for 6 hours at 20oC. Sprigs werethen immediately exposed on day 0 to 10 µL ethylene/L for 12 hours at 20oC. Data followed by thesame letter are not significantly different (LSD = 1.6) at P = 0.05 (n = 10).


200 nL 1-MCP/L 8.0 ± 0.5 c

0.2 mM Ag+ 3.0 ± 0.1 b

0 nL 1-MCP/L and 0 mM Ag+ 1.2 ± 0.1 a

Table 5.2. Weight loss (mean ± s.e.) and proportion of abscised flowers and leaves from bunches ofC. uncinatum ‘CWA Pink’ pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL1-MCP/L and 0 mM Ag+ for 6 hours at 20oC. Following treatment, bunches were packed intocommercial flower cartons and held for 6 days at 20oC. Longevity (mean ± s.e.) of sprigs frombunches is presented. Data within each column followed by the same letter are not significantlydifferent (LSD = 6.6 and 1.2 for weight loss and longevity, respectively) at P = 0.05 (n = 10).

Treatment Weight loss (% of

initial FW)

Abscised flowers and

leaves (% of initial

FW)

Longevity(days)

200 nL 1-MCP/L 23.5 ± 1.6 a 0.16 9.8 ± 0.5 b

0.2 mM Ag+ 20.1 ± 1.3 a 0.19 9.7 ± 0.5 b

0 nL 1-MCP/L and 0 mM Ag+ 31.6 ± 3.1 b 0.20 7.3 ± 0.3 a

18

Time (days)

6 7 8 9 10 11

Sol

utio

n up

take

(m

L/ g

initi

al F

W/ d

ay)

0.0

0.2

0.4

0.6

0.8

Rel

ativ

e fr

esh

wei

ght

(%

of i

nitia

l FW

)

80

100

120

Figure 5.2. Relative fresh weight and vase solution uptake for C. uncinatum ‘CWA Pink’ sprigsfrom bunches pre-treated on day 0 with 200 nL 1-MCP/L (■), STS (0.2 mM Ag+) (▲) or 0 nL 1-MCP/L and 0 mM Ag+ (●) for 6 hours at 20oC. Bunches were then packed into commercial flowercartons and held for 6 days at 20oC. Vertical bars represent standard errors of means. Where novertical bars appear, the standard error was smaller than the size of the symbol (n = 10). LSD forrelative fresh weight data = 4.0%. LSD for vase solution uptake data = 0.040 mL/g initial FW/day.

19

In the second experiment, pre-treatment of ‘Fortune Cookie’ bunches with 200 nL 1-MCP/L or 0.2 mM

Ag+ for 14 hours at 2 or 20oC inside polyethylene tents prevented ethylene-induced flower abscission from

flowering sprigs (Figure 5.3). Pre-treatment with 1-MCP or STS at 2 or 20oC significantly reduced the

decline in sprig relative fresh weight associated with flower abscission (Figure 5.4). However, the loss in

sprig relative fresh weight after day 6 was most effectively reduced from sprigs pre-treated with 1-MCP

compared to sprigs pre-treated with STS, particularly for sprigs pre-treated at 2oC. These responses

account for the significant interactions between treatment and time of measurement and between pre-

treatment temperature and time of measurement (Appendix 5.9). Solution uptake by sprigs from all

treatments fluctuated over time (Figure 5.5). Sprigs pre-treated with STS used vase solution at the highest

rate until day 5, thereafter, solution uptake was greatest by sprigs pre-treated with 1-MCP. This response

reflects the significant interaction between treatment and time of measurement for vase solution uptake

(Appendix 5.10). As vase life was partly based on flower abscission, 1-MCP and STS pre-treatments at 2

or 20oC prevented the ethylene-induced loss in vase life (Table 5.3). Vase lives of sprigs pre-treated with

STS at 2oC were significantly longer than parallel sets of sprigs pre-treated with 1-MCP (Appendix 5.11).

Bunches pre-treated with 1-MCP at 2oC and then held in cartons for 6 days at 20oC lost significantly more

weight than parallel sets of bunches pre-treated with STS and bunches not pre-treated with 1-MCP or STS

(Table 5.4). Conversely, bunches pre-treated with 1-MCP at 20oC lost significantly less weight than

bunches not pre-treated with 1-MCP or STS. The loss of weight from bunches pre-treated at 20oC was

slightly reduced by STS pre-treatment compared to bunches not pre-treated with STS. As a result, a

significant interaction between pre-treatment and pre-treatment temperature was evident (Appendix 5.12).

The accumulation of abscised flowers and leaves in cartons was greatest from bunches not pre-treated

with 1-MCP or STS at 2 and 20oC and least from bunches pre-treated with STS at 2 and 20oC (Table 5.4).

No flower abscission from sprigs was recorded during the subsequent vase life. Sprigs pre-treated with 1-

MCP or STS at 2oC lost significantly more relative fresh weight during vase life than parallel sets of

sprigs pre-treated at 20oC (Figure 5.6). This reponse probably reflects the significant interactions between

pre-treatment temperature and time of measurement and between pre-treatment and pre-treatment

temperature for relative fresh weight (Appendix 5.13). Vase solution uptake by sprigs not pre-treated with

1-MCP and STS at 2oC was higher between days 1 and 2 than for parallel sets of sprigs pre-treated at

20oC (Figure 5.7). This reponse probably accounts for the significant interactions between pre-treatment

and time of measurement and between pre-treatment temperature and time of measurement for vase

solution uptake (Appendix 5.14). 1-MCP pre-treatment at 2 and 20oC extended the longevity of sprigs

marginally compared to sprigs not pre-treated with 1-MCP, although no significant difference between

these treatments existed (Table 5.3 and Appendix 5.15). STS pre-treatment did not extend the longevity

of sprigs.

20

Time (days)

0 2 4 6 8 10 12

1

2

3

4

5

Abs

ciss

ion

scor

e

1

2

3

4

52oC

20oC

Figure 5.3. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from C. uncinatum ‘FortuneCookie’ sprigs pre-treated on day 0 with 200 nL 1-MCP/L (■), STS (0.2 mM Ag+) (▲) or 0 nL 1-MCP/L and 0 mM Ag+ (control treatment) (●) for 14 hours at 2oC or 20oC. Sprigs from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Verticalbars represent standard errors of means (n = 5). Where no vertical bars appear, the standard errorwas smaller than the size of the symbol.

21

Rel

ativ

e fre

sh w

eigh

t (%

of i

nitia

l FW

)

20

40

60

80

100

Time (days)

0 2 4 6 8 10 12

20

40

60

80

100

2oC

20oC

Figure 5.4. Relative fresh weight of C. uncinatum ‘Fortune Cookie’ sprigs pre-treated on day 0with 200 nL 1-MCP/L (■), STS (0.2 mM Ag+) (▲) or 0 nL 1-MCP/L and 0 mM Ag+ (controltreatment) (●) for 14 hours at 2oC or 20oC. Sprigs from each of these treatments were then exposedon day 1 to 10 µL ethylene/L for 12 hours at 20oC. Vertical bars represent standard errors ofmeans (n = 5). Where no vertical bars appear, the standard error was smaller than the size of thesymbol. LSD = 4.8%.

22

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.4

0.8

1.2

1.6

Time (days)

0 2 4 6 8 10 120.0

0.4

0.8

1.2

1.6

2oC

20oC

Figure 5.5. Vase solution uptake by C. uncinatum ‘Fortune Cookie’ sprigs pre-treated on day 0with 200 nL 1-MCP/L (■), STS (0.2 mM Ag+) (▲) or 0 nL 1-MCP/L and 0 mM Ag+ (controltreatment) (●) for 14 hours at 2oC or 20oC. Sprigs from each of these treatments were then exposedon day 1 to 10 µL ethylene/L for 12 hours at 20oC. Vertical bars represent standard errors ofmeans (n = 5). Where no vertical bars appear, the standard error was smaller than the size of thesymbol. LSD = 0.149 mL/g initial FW/day.

23

Table 5.3. Vase life (mean ± s.e.) of C. uncinatum ‘Fortune Cookie’ sprigs pre-treated on day 0 with200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for 14 hours at 2 or 20oC.Sprigs were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Data followed by thesame letters are not significantly different (LSD = 1.9) at P = 0.05 (n = 5).


2oC

200 nL 1-MCP/L 7.0 ± 0.6 b

0.2 mM Ag+ 9.0 ± 1.0 c

0 nL 1-MCP/L and 0 mM Ag+ 2.0 ± 0.0 a

20oC

200 nL 1-MCP/L 7.6 ± 0.5 bc

0.2 mM Ag+ 8.4 ± 1.0 bc

0 nL 1-MCP/L and 0 mM Ag+ 2.0 ± 0.0 a

Table 5.4. Weight loss (mean ± s.e.) and proportion of abscised flowers and leaves from bunches ofC. uncinatum ‘Fortune Cookie’ pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0nL 1-MCP/L and 0 mM Ag+ for 14 hours at 2 or 20oC. Bunches were then packed into commercialflower cartons and held for 6 days at 20oC. Longevity (mean ± s.e.) of sprigs from bunches ispresented. Data within each column followed by the same letters are not significantly different(LSD = 2.8 and 1.2 for weight loss (n = 6) and longevity (n = 5), respectively) at P = 0.05.

Treatment Weight loss (% ofinitial FW)

Abscised flowers andleaves (% of initialFW)

Longevity(days)

2oC

200 nL 1-MCP/L 14.4 ± 1.3 c 1.04 11.2 ± 0.4 b

0.2 mM Ag+ 9.4 ± 0.7 ab 0.63 9.8 ± 0.5 a

0 nL 1-MCP/L and 0 mM Ag+ 7.6 ± 0.5 a 1.54 10.4 ± 0.7 ab

20oC

200 nL 1-MCP/L 10.7 ± 0.7 b 1.06 10.4 ± 0.2 ab

0.2 mM Ag+ 12.4 ± 1.3 bc 0.39 9.6 ± 0.2 a

0 nL 1-MCP/L and 0 mM Ag+ 16.3 ± 1.0 c 1.16 10.2 ± 0.4 ab

24

Rel

ativ

e fr

esh

wei

ght (

% o

f ini

tial F

W)

80

100

120

Time (days)

7 8 9 10 11 12

80

100

120

2oC

20oC

Figure 5.6. Relative fresh weight of C. uncinatum ‘Fortune Cookie’ sprigs from bunches pre-treated on day 0 with 200 nL 1-MCP/L (■), STS (0.2 mM Ag+) (▲) or 0 nL 1-MCP/L and 0 mMAg+ (control treatment) (●) for 14 hours at 2oC or 20oC. Bunches were then packed intocommercial flower cartons and held for 6 days at 20oC. Vertical bars represent standard errors ofmeans (n = 5). Where no vertical bars appear, the standard error was smaller than the size of thesymbol. LSD = 8.2%.

25

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.2

0.4

0.6

0.8

1.0

Time (days)

7 8 9 10 11 12

0.0

0.2

0.4

0.6

0.8

1.0

2oC

20oC

Figure 5.7. Vase solution uptake by C. uncinatum ‘Fortune Cookie’ sprigs from bunches pre-treated on day 0 with 200 nL 1-MCP/L (■), STS (0.2 mM Ag+) (▲) or 0 nL 1-MCP/L and 0 mMAg+ (control treatment) (●) for 14 hours at 2oC or 20oC. Bunches were then packed intocommercial flower cartons and held for 6 days at 20oC. Vertical bars represent standard errors ofmeans (n = 5). Where no vertical bars appear, the standard error was smaller than the size of thesymbol. LSD = 0.076 mL/g initial FW/day.

26

5.3.2 Injection of 1-MCP into cartons

Injection of 200 nL 1-MCP/L at 2oC into cartons containing ‘Lollypop’ bunches did not prevent ethylene-

induced flower abscission from sprigs (Figure 5.8). Unexpectantly, sprigs not pre-treated with 1-MCP

and sampled 5 cm from the carton end sustained moderate flower abscission. This response probably

accounted for the significant interaction between 1-MCP pre-treatment, sampling position and time of

measurement (Appendix 5.16). Consequently, 1-MCP pre-treatment did not reduce the loss of sprig

relative fresh weight (Figure 5.9). Sprigs not pre-treated with 1-MCP and sampled 25 cm from the end of

the carton lost significantly more relative fresh weight than sprigs sampled 5 cm from the end of the

carton. This reponse probably reflects the significant interaction between 1-MCP pre-treatment, sampling

position and time of measurement (Appendix 5.17). Vase solution uptake by sprigs from all treatments

decreased over time until day 4 (Figure 5.10). Solution uptake by sprigs not pre-treated with 1-MCP and

sampled 25 cm from the end of the carton was lower between days 1 and 2 and between days 4 and 5

compared to sprigs pre-treated with 1-MCP. As a result, a significant interaction between 1-MCP pre-

treatment and sampling position was evident (Appendix 5.18). Because vase life was partly based on

flower abscission, there was no effect of 1-MCP on vase lives of sprigs (Table 5.5).

Injection of 2 µL 1-MCP/L at 2oC into cartons containing ‘Purple Pride’ bunches did not afford flowering

sprigs with protection against ethylene-induced flower abscission (Figure 5.11). Unexpectantly, higher

levels of flower abscission were recorded for sprigs pre-treated with 1-MCP and sampled 25, 75 and 95

cm from the injection point compared to sprigs not pre-treated with 1-MCP. This response probably

accounts for the significant interaction between 1-MCP pre-treatment, sampling position and time of

measurement for flower abscission (Appendix 5.19). With the exception of sprigs sampled 5 cm from the

end of the carton, the loss of relative fresh weight from sprigs pre-treated with 1-MCP was significantly

greater than from sprigs not pre-treated with 1-MCP (Figure 5.12). Accordingly, a significant interaction

between 1-MCP pre-treatment, sampling position and time of measurement for relative fresh weight was

recorded (Appendix 5.20). With the exception of sprigs not pre-treated with 1-MCP and sampled from

each end of the carton (i.e. 5 and 95 cm from the injection end), the use of vase solution by sprigs

decreased over time (Figure 5.13). Vase solution uptake by sprigs pre-treated with 1-MCP was less

variable than that by sprigs not pre-treated with 1-MCP. These responses probably account for the

significant interactions between 1-MCP pre-treatment and time of measurement and between sampling

position and time of measurement (Appendix 5.21). Injection of 1-MCP into cartons prevented the

ethylene-induced loss in sprig vase life (Table 5.6). However, 1-MCP pre-treatment was only fully

effective in protecting sprigs sampled 5 cm from the injection point against ethylene on the basis of

extended vase life. Accordingly, a significant interaction between 1-MCP pre-treatment and sampling

position was recorded for vase life (Appendix 5.22).

27

Abs

ciss

ion

scor

e

1

2

3

4

5

Time (days)

1 2 3 4 5

1

2

3

4

5

- 1-MCP

+ 1-MCP

Figure 5.8. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from C. uncinatum ‘Lollypop’sprigs on bunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L in sealed flower cartons for 24hours at 2oC. Flower abscission is presented for sprigs sampled at 5 (●), 25 (■), 75 (▲) and 95 cm(▼) from the 1-MCP injection point. Sprigs were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC. Vertical bars represent the standard errors of means (n = 5). Where no verticalbars appear, the standard error was smaller than the size of the symbol.

28

Rel

ativ

e fr

esh

wei

ght (

% o

f ini

tial F

W)

40

60

80

100

Time (days)

1 2 3 4 5

40

60

80

100

- 1-MCP

+ 1-MCP

Figure 5.9. Relative fresh weight of C. uncinatum ‘Lollypop’ sprigs from bunches pre-treated onday 0 with 0 or 200 nL 1-MCP/L in sealed flower cartons for 24 hours at 2oC. Relative fresh weightis presented for sprigs sampled at 5 (●), 25 (■), 75 (▲) and 95 cm (▼) from the 1-MCP injectionpoint. Sprigs were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Vertical barsrepresent the standard errors of means (n = 5). Where no vertical bars appear, the standard errorwas smaller than the size of the symbol. LSD = 5.1%.

29

0

1

2

3

Time (days)

1 2 3 4 5

Sol

utio

n up

take

(m

L/ g

initi

al F

W/ d

ay)

0

1

2

3

- 1-MCP

+ 1-MCP

Figure 5.10. Vase solution uptake by C. uncinatum ‘Lollypop’ sprigs from bunches pre-treated onday 0 with 0 or 200 nL 1-MCP/L in sealed flower cartons for 24 hours at 2oC. Solution uptake ispresented for sprigs sampled at 5 (●), 25 (■), 75 (▲) and 95 cm (▼) from the 1-MCP injectionpoint. Sprigs were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Vertical barsrepresent the standard errors of means (n = 5). Where no vertical bars appear, the standard errorwas smaller than the size of the symbol. LSD = 0.130 mL/g initial FW/day.

30

Table 5.5. Vase life (mean ± s.e.) of C. uncinatum ‘Lollypop’ sprigs from bunches pre-treated onday 0 with 0 or 200 nL 1-MCP/L for 24 hours at 2oC inside a commercial flower carton. Sprigswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flowering sprigs weresampled from stems located 5, 25, 75 and 95 cm from the point of 1-MCP injection within a carton(positions 1, 2, 3 and 4, respectively).

Vase life (days)

Treatment Position means (n = 5) Treatment means (n = 20)

0 nL 1-MCP/L 2.0 ± 0.0

Position 1 2.0 ± 0.0




200 nL 1-MCP/L 2.0 ± 0.0





31

1

2

3

4

5 - 1-MCP

Time (days)

1 2 3 4 5 6 7 8

Abs

ciss

ion

scor

e

1

2

3

4

5 + 1-MCP

Figure 5.11. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from C. uncinatum ‘Purple Pride’sprigs on bunches pre-treated on day 0 with 0 or 2 µL 1-MCP/L in sealed flower cartons for 24hours at 2oC. Flower abscission is presented for sprigs sampled at 5 (●), 25 (■), 75 (▲) and 95 cm(▼) from the 1-MCP injection point. Sprigs were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC. Vertical bars represent the standard errors of means (n = 5). Where no verticalbars appear, the standard error was smaller than the size of the symbol.

32

Rel

ativ

e fre

sh w

eigh

t (%

of i

nitia

l FW

)

60

80

100

120

Time (days)

1 2 3 4 5 6 7 8

60

80

100

120

- 1-MCP

+ 1-MCP

Figure 5.12. Relative fresh weight of C. uncinatum ‘Purple Pride’ sprigs from bunches pre-treatedon day 0 with 0 or 2 µL 1-MCP/L in sealed flower cartons for 24 hours at 2oC. Relative freshweight is presented for sprigs sampled at 5 (●), 25 (■), 75 (▲) and 95 cm (▼) from the 1-MCPinjection point. Sprigs were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.Vertical bars represent the standard errors of means (n = 5). Where no vertical bars appear, thestandard error was smaller than the size of the symbol. LSD = 5.0%.

33

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.1

0.2

0.3

0.4

Time (days)

1 2 3 4 5 6 7 8

0.0

0.1

0.2

0.3

0.4

- 1-MCP

+ 1-MCP

Figure 5.13. Vase solution uptake by C. uncinatum ‘Purple Pride’ sprigs from bunches pre-treatedon day 0 with 0 or 2 µL 1-MCP/L in sealed flower cartons for 24 hours at 2oC. Vase solutionuptake is presented for sprigs sampled at 5 (●), 25 (■), 75 (▲) and 95 cm (▼) from the 1-MCPinjection point. Sprigs were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.Vertical bars represent the standard errors of means (n = 5). Where no vertical bars appear, thestandard error was smaller than the size of the symbol. LSD = 0.042 mL/g initial FW/day.

34

Table 5.6. Vase life (mean ± s.e.) of C. uncinatum ‘Purple Pride’ sprigs from bunches pre-treatedon day 0 with 0 or 2 µL 1-MCP/L for 24 hours at 2oC inside a commercial flower carton. Sprigswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flowering sprigs weresampled from stems 5, 25, 75 and 95 cm from the point of 1-MCP injection within a carton(positions 1, 2, 3 and 4, respectively). Data within each column followed by the same letters are notsignificantly different (LSD = 2.1 and 1.0 for position and treatment means, respectively) at P =0.05.

Vase life (days)

Treatment Position means (n = 5) Treatment means (n = 20)

0 nL 1-MCP/L 3.6 ± 0.4 a

Position 1 2.4 ± 0.4 a

Position 2 3.6 ± 0.8 ab

Position 3 2.8 ± 0.8 a

Position 4 5.4 ± 0.9 bc

200 nL 1-MCP/L 5.3 ± 0.4 b

Position 1 7.2 ± 0.4 c

Position 2 5.0 ± 0.5 b



35

5.3.3 Application of 1-MCP into a coolroom

Pre-treatment of ‘Paddy’s Late’ bunches standing in buckets of water with 150 nL 1-MCP/L for 15 hours

at 2oC inside a coolroom significantly reduced ethylene-induced flower abscission from sprigs and the

associated loss of relative fresh weight (Figure 5.14). 1-MCP pre-treatment did not reduce flower

abscission or the associated loss in relative fresh weight from sprigs not exposed to ethylene.

Accordingly, a significant interaction between 1-MCP pre-treatment, ethylene treatment and time of

measurement was recorded for flower abscission (Appendix 5.23) and relative fresh weight (Appendix

5.24). Vase solution uptake by sprigs from all treatments fluctuated over time (Figure 5.14). Sprigs pre-

treated with 1-MCP used significantly more vase solution than sprigs exposed only to ethylene. Vase

solution uptake by sprigs pre-treated with 1-MCP and exposed to ethylene was consistently lower than

sprigs pre-treated only with 1-MCP except between days 5 and 6. These responses probably account for

the significant interactions between 1-MCP pre-treatment and ethylene treatment and between 1-MCP pre-

treatment and time of measurement (Appendix 5.25). 1-MCP pre-treatment prevented the ethylene-

induced loss in vase life (Table 5.7). Vase lives of sprigs not exposed to ethylene were not significantly

extended by 1-MCP pre-treatment. Consequently, a significant interaction between 1-MCP pre-treatment

and ethylene treatment for vase life was evident (Appendix 5.26).

Pre-treatment of bunches with 1-MCP at 2oC followed by storage in cartons for 6 days at 20oC did not

reduce the loss of fresh weight or the accumulation of abscised flowers and leaves in cartons (Table 5.8,

Appendices 5.27 and 5.28). Similarly, flower abscission, the associated loss of relative fresh weight and

vase solution uptake by sprigs during the subsequent vase life were not significantly affected by 1-MCP

pre-treatment (Figure 5.15, Appendices 5.29, 5.30 and 5.31). Longevity of sprigs were not significantly

extended by 1-MCP pre-treatment (Table 5.8 and Appendix 5.32).

36

Abs

ciss

ion

scor

e

1

2

3

4

5

Rel

ativ

e fr

esh

wei

ght

(% o

f ini

tial F

W)

0

20

40

60

80

100

Time (days)

1 2 3 4 5 6 7 8

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.0

0.2

0.4

0.6

0.8

Figure 5.14. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for C. uncinatum ‘Paddy’s Late’ sprigs treated with 0 nL 1-MCP/L and 0 µLethylene/L (●), 0 nL 1-MCP/L and 10 µL ethylene/L (■), 150 nL 1-MCP/L and 0 µL ethylene/L (▲)or 150 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP pre-treatment was conducted on day 0 for15 hours at 2oC. Ethylene treatment was conducted on day 1 for 12 hours at 20oC. Vertical barsrepresent standard errors of means (n = 10). Where no vertical bars appear, the standard errorwas smaller than the size of the symbol. LSD for relative fresh weight data = 5.4%. LSD for vasesolution uptake data = 0.075 mL/g initial FW/day.

37

Table 5.7. Vase life (mean ± s.e.) of C. uncinatum ‘Paddy’s Late’ sprigs pre-treated on day 0 with 0or 150 nL 1-MCP/L for 15 hours at 2oC. Half of the sprigs from each of these treatments were thenexposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters arenot significantly different (LSD = 1.0) at P = 0.05 (n = 10).


0 nL 1-MCP/L

0 µL ethylene/L 4.2 ± 0.5 b

10 µL ethylene/L 2.0 ± 0.0 a

150 nL 1-MCP/L



Table 5.8. Fresh weight loss and proportion of abscised flowers and leaves (mean ± s.e.) frombunches of C. uncinatum ‘Paddy’s Late’ pre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15hours at 2oC and held inside commercial flower cartons for 6 days at 20oC. Longevity (mean ± s.e.)of sprigs from bunches is presented. Data within each column were not significantly different at P= 0.05.

Treatment Weight loss (% of

initial FW)a

Abscised flowers and leaves

(% of initial FW)aLongevity (days)b

0 nL 1-MCP/L 43.4 ± 2.3 15.7 ± 0.2 8.1 ± 0.1

150 nL 1-MCP/L 44.8 ± 1.3 16.5 ± 0.5 8.2 ± 0.1

a n = 6.b n = 10.

38

Abs

ciss

ion

scor

e

1

2

3

4

5

Rel

ativ

e fr

esh

wei

ght

(% o

f ini

tial F

W)

40

60

80

100

Time (days)

7 8 9

Sol

utio

n up

take

(m

L/ g

initi

al F

W/ d

ay)

0.2

0.4

0.6

0.8

Figure 5.15. Flower abscission (scores: 1 = < 10% to 5 = > 80%), relative fresh weight and vasesolution uptake for C. uncinatum ‘Paddy’s Late’ sprigs from bunches pre-treated on day 0 with 0nL 1-MCP/L ( ●) or 150 nL 1-MCP/L (■) for 15 hours at 2oC. Bunches were then packed intocommercial flower cartons and held for 6 days at 20oC. Vertical bars represent standard errors ofmeans (n = 10). Where no vertical bars appear, the standard error was smaller than the size of thesymbol.

39

5.3.4 Application of 1-MCP in cartons by forced-air cooling

Application of 200 nL 1-MCP/L for 3 hours at 2oC into a coolroom containing ‘Purple Pride’ bunches

either standing in buckets of water or in cartons against a forced-air cooler reduced ethylene-induced

flower abscission (Figure 5.16). 1-MCP pre-treatment did not significantly reduce flower abscission from

sprigs not exposed to ethylene. Accordingly, a significant interaction between 1-MCP pre-treatment,

ethylene treatment and time of measurement for flower abscission was recorded (Appendix 5.33). Pre-

treatment with 1-MCP reduced the loss of relative fresh weight of sprigs associated with flower abscission

(Figure 5.17). 1-MCP pre-treatment did not significantly reduce the loss of relative fresh weight from

sprigs not exposed to ethylene. However, sprigs pre-treated against the forced-air cooler and sampled 95

cm from the carton end nearest the coolroom air (or those closest to the forced-air cooler wall) had the

greatest loss of relative fresh weight irrespective of 1-MCP pre-treatment. Thus, these responses probably

account for the significant interaction between 1-MCP pre-treatment, ethylene treatment and sampling

position for relative fresh weight (Appendix 5.34).

Vase solution uptake by sprigs not exposed to ethylene decreased over time (Figure 5.18). In contrast,

vase solution uptake by sprigs exposed to ethylene increased between days 0 and 1 and then declined over

time. This different uptake pattern is reflected in a significant interaction between ethylene treatment and

time of measurement (Appendix 5.35). 1-MCP pre-treatment of bunches standing in water or in cartons

did not extend the vase lives of sprigs not exposed to ethylene (Table 5.9). Vase lives of sprigs from

bunches pre-treated with 0 or 200 nL 1-MCP/L in cartons against a forced-air cooler and not exposed to

ethylene were reduced compared to sprigs sampled from similarly treated bunches standing in buckets of

water. 1-MCP pre-treatment prevented the loss in vase life for sprigs exposed to ethylene. As a result

there were significant interactions between 1-MCP pre-treatment and ethylene treatment and between

ethylene treatment and the pre-treatment vessel (i.e. bucket vs. carton) (Appendix 5.36). There was no

consistent or significant effect of the sampling position on sprig vase life (Table 5.9 and Appendix 5.37).

40

1

2

3

4

5

Abs

ciss

ion

scor

e

1

2

3

4

5

1

2

3

4

5

Time (days)

0 1 2 3 4 5 6 7 8 9

1

2

3

4

5

0 1 2 3 4 5 6 7 8 9

- 1-MCP (bucket)

- 1-MCP (forced-air)

+ 1-MCP (bucket)

+ 1-MCP (forced-air)

- 1-MCP (bucket)


+ 1-MCP (bucket)


- Ethylene

- Ethylene

- Ethylene

- Ethylene

+ Ethylene

+ Ethylene

+ Ethylene

+ Ethylene

Figure 5.16. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from C. uncinatum ‘Purple Pride’sprigs from bunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L in either buckets of water orcartons against a forced air cooler for 3 hours at 2oC. Half of the sprigs from each of thesetreatments were then exposed on day 0 to 10 µL ethylene/L for 12 hours at 20oC. Flower abscissionfrom sprigs held inside cartons against the forced-air cooler is presented for sprigs sampled fromstems 5 (●), 25 (■), 75 (▲) and 95 cm from the carton end closest to the incoming coolroom air (▼).Vertical bars represent the standard errors of means (n = 3). Where no vertical bars appear, thestandard error was smaller than the size of the symbol.

41

40

60

80

100

120

Rel

ativ

e fr

esh

wei

ght (

% o

f ini

tial F

W)

40

60

80

100

120

40

60

80

100

120

Time (days)

0 1 2 3 4 5 6 7 8 9

40

60

80

100

120

0 1 2 3 4 5 6 7 8 9

- 1-MCP (bucket)


+ 1-MCP (bucket)


- 1-MCP (bucket)


+ 1-MCP (bucket)


- Ethylene

- Ethylene

- Ethylene

- Ethylene

+ Ethylene

+ Ethylene

+ Ethylene

+ Ethylene

Figure 5.17. Relative fresh weight of C. uncinatum ‘Purple Pride’ sprigs from bunches pre-treatedon day 0 with 0 or 200 nL 1-MCP/L in either buckets of water or cartons against a forced air coolerfor 3 hours at 2oC. Half of the sprigs from each of these treatments were then exposed on day 0 to10 µL ethylene/L for 12 hours at 20oC. Relative fresh weight of sprigs held inside cartons againstthe forced-air cooler is presented for sprigs sampled from stems 5 (●), 25 (■), 75 (▲) and 95 cmfrom the carton end closest to the incoming coolroom air (▼). Vertical bars represent the standarderrors of means (n = 3). Where no vertical bars appear, the standard error was smaller than thesize of the symbol. LSD = 6.5%.

42

0.00.20.40.60.81.0

0.00.20.40.60.81.0

Sol

utio

n up

take

(m

L/g

initi

al F

W/d

ay)

0.00.20.40.60.81.0

Time (days)

0 1 2 3 4 5 6 7 8 9

0.00.20.40.60.81.0

0 1 2 3 4 5 6 7 8 9

- 1-MCP (buckets)


+ 1-MCP (bucket)


- 1-MCP (buckets)


+ 1-MCP (bucket)



- Ethylene

- Ethylene

- Ethylene

+ Ethylene

+ Ethylene

+ Ethylene

Figure 5.18. Vase solution uptake by C. uncinatum ‘Purple Pride’ sprigs from bunches pre-treatedon day 0 with 0 or 200 nL 1-MCP/L in either buckets of water or cartons against a forced air coolerfor 3 hours at 2oC. Half of the sprigs from each of these treatments were then exposed on day 0 to10 µL ethylene/L for 12 hours at 20oC. Vase solution uptake by sprigs held inside cartons againstthe forced-air cooler is presented for sprigs sampled from stems 5 (●), 25 (■), 75 (▲) and 95 cmfrom the carton end closest to the incoming coolroom air (▼). Vertical bars represent the standarderrors of means (n = 3). Where no vertical bars appear, the standard error was smaller than thesize of the symbol. LSD = 0.068 mL/g initial FW/day.

43

Table 5.9. Vase life (days; mean ± s.e.) of C. uncinatum ‘Purple Pride’ sprigs from bunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L for 3 hours whilestanding in buckets of water or in cartons against a forced air cooler inside a coolroom operating at 2oC. Flowering sprigs were removed at random from bunchesstanding in water or from four positions within each carton (5, 25, 75 and 95 cm from the carton end closest to the incoming coolroom air; positions 1, 2, 3 and 4,respectively) and exposed to 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters are not significantly different (LSD = 1.9 for position data (n =3) and 0.9 for treatment data (n = 12)) at P = 0.05.

Treatment Position 1 Position 2 Position 3 Position 4 Treatment means and s.e.

No 1-MCP Bucket 0 µL ethylene/L z z z z 7.3 ± 0.4 c 10 µL ethylene/L z z z z 1.9 ± 0.1 a Carton 0 µL ethylene/L 6.0 ± 0.6 b 7.3 ± 0.9 c 6.0 ± 1.2 b 5.0 ± 1.0 b 6.1 ± 0.5 bc 10 µL ethylene/L 2.0 ± 0.0 a 2.0 ± 0.0 a 1.7 ± 0.3 a 2.0 ± 0.0 a 1.9 ± 0.1 a

Plus 1-MCP Bucket 0 µL ethylene/L z z z z 6.9 ± 0.2 c 10 µL ethylene/L z z z z 6.7 ± 0.4 bc Carton 0 µL ethylene/L 6.3 ± 0.7 b 5.7 ± 0.9 b 5.7 ± 0.7 b 6.3 ± 0.7 b 6.0 ± 0.3 b 10 µL ethylene/L 5.7 ± 0.7 b 7.3 ± 0.9 c 6.7 ± 0.3 b 6.3 ± 0.3 b 6.5 ± 0.3 bc

z Position means and standard errors are not presented for these treatments as sprigs were randomly sampled from bunches standing in buckets of water.

44

5.3.5 Slow release of 1-MCP inside cartons

Inclusion of a tube containing 1-MCP gas into cartons packed with bunches of ‘Alba’ reduced ethylene-

induced flower abscission and the associated loss of relative fresh weight from sprigs sampled adjacent to

the tube (Figures 5.20 and 5.21). Unexpectantly, the additional of two tubes of 1-MCP gas into cartons

only reduced ethylene-induced flower abscission and the loss of relative fresh weight from sprigs sampled

next to one tube only. However, the inclusion of three tubes of 1-MCP gas into cartons significantly

reduced ethylene-induced flower abscission and the loss of relative fresh weight from sprigs sampled from

all four positions within the carton. The addition of tubes of 1-MCP to cartons did not consistently affect

flower abscission and changes in relative fresh weight from bunches not exposed to ethylene. Based on

these responses, a significant interaction between 1-MCP pre-treatment, ethylene treatment, sampling

position and time of measurement was evident for flower abscission (Appendix 5.38) and relative fresh

weight (Appendix 5.39).

Vase solution uptake by sprigs tended to decrease over time (Figure 5.22). However, in cartons that

contained only one tube of 1-MCP, the vase solution uptake between days 7 and 11 by sprigs sampled 75

cm from this tube was higher than that by sprigs from all other treatments. This response probably reflects

the significant interactions between ethylene treatment, sampling position and time of measurement and

between 1-MCP pre-treatment, ethylene treatment and sampling position for vase solution uptake

(Appendix 5.40). Sprigs from bunches held in cartons with one tube only were slightly, but not

significantly protected against the ethylene-induced loss in longevity (Table 5.10). However, the

inclusion of two or three tubes into cartons prevented the ethylene-induced loss in longevity. There was

no consistent effect of sampling position on sprig longevity. Nevertheless, for sprigs sampled adjacent to

tubes of 1-MCP gas and subsequently exposed to ethylene, there was a trend toward extended longevity

compared to sprigs not exposed to 1-MCP. The addition of tubes of 1-MCP gas into cartons did not

significantly extend the subsequent longevity of sprigs not exposed to ethylene. As a result, there was a

significant interaction between 1-MCP treatment, ethylene treatment and sampling position for longevity

(Appendix 5.41).

45

1

2

3

4

5

1

2

3

4

5

Abs

ciss

ion

scor

e

1

2

3

4

5

Time (days)

6 7 8 9 10 11 12

1

2

3

4

5

6 7 8 9 10 11 12

- 1-MCP

+ 1-MCP (1 tube)

+ 1-MCP (2 tubes)

+ 1-MCP (3 tubes)

- 1-MCP

+ 1-MCP (2 tubes)

+ 1-MCP (3 tubes)

- Ethylene

- Ethylene

- Ethylene

- Ethylene

+ Ethylene

+ Ethylene

+ Ethylene

+ Ethylene

+ 1-MCP (1 tube)

Figure 5.20. Flower abscission (scores: 1 = < 10% to 5 = > 80%) from C. uncinatum ‘Alba’ sprigson bunches pre-treated on day 0 in cartons with 0 (control), 1, 2 or 3 tubes of 1-MCP gas for 6 daysat 20oC. Half of the sprigs from each of these treatments were then exposed on day 6 to 10 µLethylene/L for 12 hours at 20oC. Flower abscission is presented for sprigs sampled 5 (●), 25 (■), 75(▲) and 95 cm from 1-MCP tube 1 (▼). Vertical bars represent the standard errors of means (n =3). Where no vertical bars appear, the standard error was smaller than the size of the symbol.

46

20406080

100120

Rel

ativ

e fr

esh

wei

ght (

% o

f ini

tial F

W)

20406080

100

120

20

406080

100120

Time (days)

6 7 8 9 10 11 12

20406080

100120

6 7 8 9 10 11 12

- 1-MCP

+ 1-MCP (1 tube)

+ 1-MCP (2 tubes)

+ 1-MCP (3 tubes)

- 1-MCP

+ 1-MCP (1 tube)

+ 1-MCP (2 tubes)

+ 1-MCP (3 tubes)





Figure 5.21. Relative fresh weight of C. uncinatum ‘Alba’ sprigs from bunches pre-treated on day 0in cartons with 0 (control), 1, 2 or 3 tubes of 1-MCP gas for 6 days at 20oC. Half of the sprigs fromeach of these treatments were then exposed on day 6 to 10 µL ethylene/L for 12 hours at 20oC.Relative fresh weight is presented for sprigs sampled 5 (●), 25 (■), 75 (▲) and 95 cm from 1-MCPtube 1 (▼). Vertical bars represent the standard errors of means (n = 3). Where no vertical barsappear, the standard error was smaller than the size of the symbol. LSD = 9.4%.

47

0.0

0.2

0.4

0.6

0.8S

olut

ion

upta

ke (

mL/

g in

itial

FW

/day

)

0.0

0.2

0.4

0.6

0.8

0.0

0.2

0.4

0.6

0.8

Time (days)

6 7 8 9 10 11 12

0.0

0.2

0.4

0.6

0.8

6 7 8 9 10 11 12

- 1-MCP

+ 1-MCP (1 tube)

+ 1-MCP (2 tubes)

+ 1-MCP (3 tubes)

- 1-MCP

+ 1-MCP (1 tube)

+ 1-MCP (2 tubes)

+ 1-MCP (3 tubes)


- Ethylene

- Ethylene

- Ethylene

+ Ethylene

+ Ethylene

+ Ethylene

Figure 5.22. Vase solution uptake by C. uncinatum ‘Alba’ sprigs from bunches pre-treated on day 0in cartons with 0 (control), 1, 2 or 3 tubes of 1-MCP gas for 6 days at 20oC. Half of the sprigs fromeach of these treatments were then exposed on day 6 to 10 µL ethylene/L for 12 hours at 20oC. Vasesolution uptake is presented for sprigs sampled 5 (●), 25 (■), 75 (▲) and 95 cm from 1-MCP tube 1(▼). Vertical bars represent the standard errors of means (n = 3). Where no vertical bars appear,the standard error was smaller than the size of the symbol. LSD = 0.059 mL/g initial FW/day.

48

Table 5.10. Longevity (days; mean ± s.e.) of C. uncinatum ‘Alba’ sprigs from bunches pre-treated with 0, 1, 2 or 3 tubes containing 1-MCP for 6 days at 20oC. 1-MCP gas was slowly released from test tubes stoppered with a rubber septa. Immediately following 1-MCP treatment, flowering sprigs were removed from fourpositions (5, 25, 75 and 95 cm from tube 1; positions 1, 2, 3 and 4, respectively) within each carton and half of the sprigs from each position were treated with 10 µLethylene/L at 20oC for 12 hours. Data followed by the same letters are not significantly different (LSD = 2.5 for position data (n = 3) and 1.3 for treatment data (n =12)) at P = 0.05.

Treatment Position 1 Position 2 Position 3 Position 4 Treatment means and s.e.

No 1-MCP (0 tubes)

0 µL ethylene/L 8.7 ± 0.3 ab 6.7 ± 0.7 a 8.3 ± 1.2 ab 8.7 ± 1.2 ab 8.1 ± 0.5 y

10 µL ethylene/L 7.0 ± 0.0 ab 7.0 ± 0.0 ab 6.3 ± 0.3 a 6.7 ± 0.3 a 6.8 ± 0.1 z

Plus 1-MCP

1 tube

0 µL ethylene/L 8.0 ± 0.0 ab 8.7 ± 0.9 ab 9.7 ± 1.9 b 10.3 ± 0.7 b 9.2 ± 0.5 y

10 µL ethylene/L 8.7 ± 1.7 ab 8.7 ± 1.7 ab 6.7 ± 0.3 a 7.0 ± 0.0 ab 7.8 ± 0.6 zy

2 tubes

0 µL ethylene/L 8.0 ± 1.2 ab 8.7 ± 0.3 ab 7.7 ± 0.9 ab 7.7 ± 0.3 ab 8.0 ± 0.3 zy

10 µL ethylene/L 7.0 ± 0.0 ab 6.7 ± 0.3 a 8.0 ± 1.0 ab 11.0 ± 0.6 b 8.2 ± 0.6 y

3 tubes

0 µL ethylene/L 8.0 ± 0.0 ab 8.0 ± 1.2 ab 10.0 ± 1.2 b 8.7 ± 1.5 ab 8.7 ± 0.5 y

10 µL ethylene/L 7.7 ± 0.3 ab 8.0 ± 1.0 ab 9.3 ± 0.7 b 9.3 ± 0.3 b 8.6 ± 0.4 y

1

The loss of weight from bunches of ‘Alba’ during the 6 day treatment period was significantly reduced by

the addition of tubes containing 1-MCP into cartons (Table 5.11 and Appendix 5.41). Similarly, the

accumulation of abscised flowers and leaves in cartons from bunches was significantly reduced by the

inclusion of a tube of 1-MCP (Table 5.11 and Appendix 5.42). The inclusion of 2 or 3 tubes in cartons

was not as effective in reducing flower and leaf abscission as the use of 1 tube. The diffusion of 1-MCP

gas from 33 mL volume tubes was presumably through a 2mm thick rubber septa with a surface area of

56.75 mm2. The concentration in tubes decreased from 6928 ± 177 µL 1-MCP/L on day 0 to 1793 ± 48

µL 1-MCP/L on day 6.

Table 5.11. Weight loss and proportion of abscised flowers and leaves (mean ± s.e.) from C.uncinatum ‘Alba’ bunches pre-treated on day 0 in cartons with 0, 1, 2 or 3 tubes of 1-MCP gas for 6days at 20oC. Data followed by the same letters are not significantly different (LSD = 3.2 and 1.1for weight loss and flower and leaf abscission, respectively) at P = 0.05.

Treatment Weight loss (% of initial FW)a Abscised flowers and leaves (% ofinitial FW)b

No 1-MCP

0 tubes (control) 37.0 ± 1.5 b 9.3 ± 0.7 c

Plus 1-MCP

1 tube 27.4 ± 1.1 a 5.3 ± 0.1 a

2 tubes 27.3 ± 1.0 a 6.5 ± 0.1 b

3 tubes 29.2 ± 0.9 a 6.3 ± 0.3 ab

a n = 18.b n = 3.

5.4 DISCUSSION

Application of 1-MCP inside sealed polyethylene tents or coolrooms containing C. uncinatum reduced

ethylene-induced flower abscission and thus appear to be practical treatments. Pre-treatment of ‘CWA

Pink’ bunches standing in buckets of water with 200 nL 1-MCP/L for 6 hours at 20oC inside a sealed

polyethylene tent reduced flower abscission (Figure 5.1) and associated loss in vase life (Table 5.1)

induced by exposure to 10 µL ethylene/L for 12 hours at 20oC. This result confirms the findings of Serek

et al. (1995c) where pre-treatment of C. uncinatum ‘Wendy’ sprigs with 200 nL 1-MCP/L for 6 hours at

21oC inside sealed perspex chambers reduced ethylene-induced flower and bud abscission. The 1-MCP

concentration used was higher than those used in laboratory experiments (Chapter 4) to take into account

the possibility of small leaks existing from the enclosed tent. 1-MCP pre-treatment was more effective

than STS pre-treatment (0.2 mM Ag+ for 6 hours at 20oC) in reducing ethylene-induced flower abscission

from ‘CWA Pink’ sprigs (Figure 5.1). Joyce (1988, 1989, 1993) showed that pulsing C. uncinatum stems

with STS can reduce ethylene-induced flower abscission. STS treatments were reported to be effective

when the accumulation of Ag+ in C. uncinatum tissue was in the range of 0.1 to 0.6 µmol/g (Joyce 1989).

2

As the STS concentration required to protect C. uncinatum is inversely related to treatment duration

(Joyce 1988, 1989) it is possible that in the present study, the duration of STS pulsing was too short for

the concentration used.

1-MCP and STS pre-treatments were equally effective in reducing the loss of weight and abscission of

flowers and leaves from bunches held dry in cartons for 6 days at 20oC after pre-treatment (Table 5.2).

The postharvest longevity of sprigs from these bunches was extended by 1-MCP and STS pre-treatments

presumably indicating that endogenous ethylene production limited longevity (Table 5.2). These results

are similar to those of Serek et al. (1995c) where 1-MCP pre-treatment reduced flower and bud abscission

from C. uncinatum ‘Wendy’ bunches held dry for 72 hours at 21oC after 1-MCP pre-treatment.

Pre-treatment of ‘Fortune Cookie’ bunches standing in water with 200 nL 1-MCP/L inside sealed

polyethylene tents or 0.2 mM Ag+ for the longer duration of 14 hours were equally effective in preventing

ethylene-induced flower abscission from sprigs when applied at 2 or 20oC (Figure 5.3). Presumably, pre-

treatment with high 1-MCP concentration at low temperature can afford C. uncinatum with protection

against ethylene. Pre-treatment of C. uncinatum with the low 1-MCP concentration of 10 nL/L for 12

hours at 2oC did not provide long term protection against ethylene (Chapter 4). Reid et al. (1996)

reported that the 1-MCP treatment concentration required to protect cut Kalanchoe flowers against

ethylene was inversely related to treatment temperature. For example, the efficacy of 1-MCP pre-

treatment applied to Kalanchoe flowers at 2oC was improved by increasing the 1-MCP concentration from

10 to 128 nL/L.

Pre-treatment of ‘Fortune Cookie’ bunches with STS at 2oC was more effective than 1-MCP in preventing

the ethylene-induced loss in sprig vase life (Table 5.3). As both 1-MCP and STS pre-treatments

prevented flower abscission, the termination of vase life was based entirely on flower wilting.

Accordingly, in this experiment it appears that STS was more effective than 1-MCP in delaying flower

wilting. Conversely, 1-MCP pre-treatment was more effective than STS pre-treatment in extending the

postharvest longevity of sprigs from bunches held dry in cartons for 6 days at 20oC after pre-treatments

(Table 5.4). Abscission of flowers and leaves from bunches during storage was more effectively reduced

by STS pre-treatment compared to 1-MCP (Table 5.4). It is possible that rapid synthesis of new ethylene

receptors during storage in association with endogenous ethylene production could initiate flower and leaf

abscission from 1-MCP pre-treated tissue. Sprigs pre-treated with STS may retain Ag+ in and around

flower abscission zones that binds to newly formed receptors thereby reducing flower abscission for the

duration of vase life (Chapter 4). Nonetheless, the data clearly indicate that 1-MCP pre-treatment of C.

uncinatum can be effective at a range of temperatures. This 1-MCP treatment system when operated at

2oC caused little disruption to the normal postharvest handling process for C. uncinatum because

flowering bunches could be cooled to around 2oC in a coolroom whilst being hydrated in buckets of water

and receiving 1-MCP treatment.

Pre-treatment of ‘Paddy’s Late’ bunches with 150 nL 1-MCP/L for 15 hours at 2oC inside a coolroom was

3

effective in reducing ethylene-induced flower abscission (Figure 5.14) and the loss in vase life (Table

5.7). This further confirms that 1-MCP pre-treatment is effective when applied at high concentrations at

low temperature. 1-MCP did not extend the vase lives of sprigs not exposed to ethylene (cf. Chapter 3).

1-MCP pre-treatment did not reduce the loss of weight or abscission of flowers and leaves from bunches

that were held dry for 6 days at 20oC in cartons after pre-treatment (Table 5.8).

Application of 1-MCP by forced-air cooling into cartons containing ‘Purple Pride’ bunches was equally

effective as treating bunches standing in buckets of water inside a coolroom. Sprigs sampled from

different positions within cartons sustained minimal flower abscission (Figure 5.16) and had similar vase

lives (Table 5.9). Thus, movement of air containing 1-MCP through cartons was uniform. Based on these

results C. uncinatum bunches could be packed into cartons and rapidly cooled by forced-air cooling while

receiving 1-MCP treatment.

Injection of 200 nL 1-MCP/L into sealed cartons containing ‘Lollypop’ bunches was not effective in

preventing ethylene-induced flower abscission (Figure 5.8). It is possible that 1-MCP diffused out

through the carton walls before it effectively spread within the carton. Increasing the concentration of 1-

MCP injected into cartons containing ‘Purple Pride’ bunches to 2 µL/L only provided protection against

ethylene to sprigs sampled closest to the injection point (Table 5.6). However, unlike forced-air cooling

where air containing 1-MCP is drawn through the carton, diffusion of 1-MCP applied as a single injection

appears to be poor. It is possible that by making multiple injections of 1-MCP at different locations on

cartons the efficacy of this system will improve. However, this process will involve added handling and

may prove time consuming.

1-MCP treatment by sustained release from tubes inside cartons containing ‘Alba’ bunches was only fully

effective at protecting flowers from ethylene when three tubes were placed into each carton (Table 5.10).

However, protection against ethylene was afforded for some sprigs sampled adjacent to tubes in other

treatments, as evidenced by reduced flower abscission and extended sprig longevity. This alternative

system is based on principles devised by Saltveit (1978) and Poole and Joyce (1993) whilst investigating

simple ethylene gassing systems. 1-MCP apparently diffused through the rubber septa in tubes and into

the carton atmosphere slowly over the 6 day treatment period. According to Poole and Joyce (1993) this

system can maintain relatively constant concentrations in the surrounding atmosphere for long periods of

time. Furthermore, it is compatible with ventilation systems such as forced air cooling which limit CO2

and ethylene accumulation.

The sustained release treatment system may, upon refinement, improve the efficacy of 1-MCP treatment in

providing longer term protection of C. uncinatum against ethylene. It is hypothesised that a sustained

release of 1-MCP around flowers will permit 1-MCP binding to newly formed ethylene receptors in the

abscission zones of C. uncinatum flowers. Thus, the period of protection against ethylene may be

extended. A slow release treatment would be comparatively easy to use and allow rapid dispatch of cut

flowers to markets by eliminating the need to pre-treat flowers. Additionally, it may be a viable treatment

4

for growers without suitable enclosed treatment structures and those concerned about handling chemicals

such as 1-MCP.

In the present study, the efficacy of laboratory scale 1-MCP treatments with C. uncinatum were shown to

be reproducible on a commercial scale. Consequently, several 1-MCP application systems can be

recommended for use by the native Australian cut flower industry. The release of 1-MCP into sealed tents

and coolrooms for short (i.e. 3 hours) or long (i.e. 15 hours) duration at a range of temperatures are highly

effective in protecting C. uncinatum standing in water against ethylene. Similarly, application of 1-MCP

to bunches in cartons via forced air cooling appears to be viable alternative approach. Sustained release

of 1-MCP gas from inside cartons promises to be the most effective treatment which, after refinement,

may provide extended protection against ethylene. While it has been shown that 1-MCP treatment of

several C. uncinatum cultivars reduces ethylene damage, it is anticipated that these application systems

would protect other sensitive native Australian cut flowers against ethylene.

6

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22

APPENDICES

APPENDIX A LITERATURE REVIEW

1.1 ETHYLENE IN PLANT BIOLOGY

Ethylene is a simple, gaseous hydrocarbon molecule comprised of two carbon and four hydrogen atoms

with one double bond (Abeles et al. 1992). It is a plant hormone which has profound effects on processes

of growth, development and senescence (Fluhr and Mattoo 1996). Active in trace amounts, the effects of

ethylene on plants are often spectacular and commercially important (Pratt and Goeschl 1969). Changes

in the rate of ethylene synthesis by plants is commonly associated with specific stages of their

development. Additionally, ethylene biosynthesis can also be stimulated in response to a variety of abiotic

and biotic stresses. These stresses include temperature extremes, water stress, mechanical wounding,

pathogen infection and exposure to chemicals or other hormones (Abeles et al. 1992). This review

examines the roles of ethylene in plant biology and the various approaches to regulate ethylene in

postharvest horticulture.

1.1.1 General roles

Ethylene is responsible for eliciting and coordinating a range of processes in plants. These processes

include seed germination (Ketring 1977; Taylorson 1979), geotropism (Zobel 1973; Jackson 1979) and

altered shoot growth and differentiation, including the seedling ‘triple response’ (Goeschl et al. 1966) and

petiole epinasty (Bradford and Yang 1980; Reid et al. 1981). Altered root growth and differentiation

(Jackson 1985), including adventitious rooting (Robbins et al. 1985) and senescence of vegetative organs

(Mattoo and Aharoni 1988) are also regulated by ethylene. Additionally, ethylene is associated with

flower induction (Burg 1962), flower sex determination (Abeles et al. 1992), flower opening (Reid et al.

1989), flower senescence (Nichols 1966; Halevy and Mayak 1981; Woltering and Van Doorn 1988),

abscission of plant organs (Sexton et al. 1985) and fruit ripening (Kidd and West 1945; Burg and Burg

1962). The involvement of ethylene in abscission, vegetative and flower senescence and fruit ripening are

discussed below in more detail.

1.1.2 Abscission

Abscission is the process where plant organs, including leaves, fruit, flowers, flower parts and buds, are

shed (Sexton et al. 1985). Abscission involves separation of a narrow arrangement of cells called the

separation layer within a generally anatomically distinct abscission zone. The cells of abscission zones

are typically smaller and less vacuolated than adjacent cells. The stele which branches in the zone

normally lacks lignified fibres (Sexton et al. 1985). According to Sexton et al. (1985), the process of

23

abscission involves activation of cell wall hydrolases and/or mechanical rupture, such as in the shedding

of bark, which weaken the walls of cells in the abscission zone. Enzymes most commonly associated with

abscission are cellulases and pectinases (Sexton et al. 1985). Commencement of abscission is associated

with increased respiration (Marynick 1977) and stimulation of RNA and protein synthesis (Holm and

Abeles 1967; Abeles et al. 1979). Ethylene has been implicated in the induction and acceleration of

abscission (Sexton et al. 1985; Reid 1985a). However, ethylene is probably not the universal regulator of

abscission, as evidenced by a poor correlation between endogenous ethylene and natural abscission in

some plant species (Addicott 1982; Abeles et al. 1992).

Current evidence suggests that abscission is a two stage process controlled by the interaction of auxin and

ethylene (Beyer and Morgan 1971; Addicott 1982; Sexton and Roberts 1982; Reid 1985a; Brown 1997).

In the first stage, or the lag phase, high auxin flux from the subtending organ (i.e. leaf, flower or fruit)

across the abscission zone maintains it in a state that is insensitive to ethylene. Thus, abscission is

inhibited. During the second stage, or the separation phase, a decline in the auxin flux from the

subtending organ causes the abscission zone to become sensitive to ethylene. Accordingly, abscission of

the organ occurs. It was deduced that the relative flux of auxin across the abscission zone influenced

abscission more than the absolute auxin concentration. Decrease in auxin source or sink strength, and

flux, have been reported to lead to greater sensitivity to ethylene and the abscission of flowers and fruit

(Roberts et al. 1984; Brown 1997).

Flower and leaf abscission from a number of plants is accelerated by exposure to exogenous ethylene

(Abeles et al. 1992). An association of elevated endogenous ethylene production by flowers with floral

organ abscission provides evidence that ethylene regulates natural abscission (Abeles et al. 1992). For

example, during and following pollination of cyclamen flowers, the rate of endogenous ethylene

production increased and corolla abscission occurred (Halevy et al. 1984). Woltering and Van Doorn

(1988) suggest that the senescence process in flowers of horticultural importance can be classified into

two groups, those that abscise or those that wilt. Plant families which contained flowers that abscised

exhibited the greatest sensitivity to ethylene.

Abscission of some immature and mature fruit can be induced by exposure to exogenous ethylene.

Moreover, Brady and Spiers (1991) reported that endogenous ethylene and/or 1-aminocyclopropane-1-

carboxylic acid (ACC; the immediate precursor of ethylene) concentrations were often higher during

periods of abscission. Exogenously supplied or endogenously produced ethylene synchronised separation

at abscission zones in raspberries. Conversely, treatment with aminoethoxyvinylglycine (AVG), an

inhibitor of ethylene synthesis, prevented raspberry fruitlet abscission (Burdon and Sexton 1990). Sexton

and Roberts (1982) determined that the activity of several cell wall degrading enzymes, including

cellulase and polygalacturonase, was regulated by ethylene.

Treatment of plant tissue with inhibitors of ethylene synthesis (e.g. rhizobitoxine) or perception (e.g. Ag+)

suggests that ethylene is involved in natural abscission processes of some plant species. For instance,

abscission of Zygocactus and snapdragon flowers was prevented by STS (Cameron and Reid 1981) and

24

rhizobitoxine analogues (Wang et al. 1977), respectively. Thus, inhibition was evident even in the

absence of exogenously supplied ethylene.

Assertions that ethylene is not the sole regulator of abscission are based on observations that treatment of

a number of plants with ethylene did not induce leaf or flower abscission and that abscission proceeded in

the absence of ethylene (Addicott 1982; Abeles et al. 1992). Accordingly, it has been claimed that the

role of ethylene in abscission is not clear (Sexton et al. 1985). However, Reid (1985a) and Brown (1997)

propose that regulation of ethylene sensitivity by the auxin flux from the subtending organ could account

for the absence of abscission in the presence of ethylene during stage 1.

1.1.3 Senescence of vegetative tissue

Vegetative tissue senescence is usually associated with loss of protein, starch and chlorophyll and leads to

tissue death (Mattoo and Aharoni 1988). Evidence that ethylene is involved in vegetative senescence has

been based on studies where exogenous or endogenous ethylene was correlated with leaf senescence both

on intact plants and of detached leaf tissue. Ethylene is associated with senescence of vegetative tissue in

a number of plant species (Mattoo and Aharoni 1988). For example, ethylene treatment of tobacco leaf

discs stimulated increased respiration, ethylene production and chlorophyll degradation, and thus

senescence (Aharoni and Lieberman 1979). Also, ethylene synthesis inhibitors such as AVG inhibited the

rise in ethylene production and delayed chlorophyll degradation. Exogenous ethylene has also been

reported to increase the rate of degradation of chlorophyll, RNA and protein in lettuce leaf tissue (Aharoni

1989). Aharoni and Lieberman (1979) suggested that endogenous ethylene may regulate senescence in

combination with other plant hormones including, auxin and cytokinin.

Ethylene production by and respiration of tobacco leaf discs increased during the rapid phase of

chlorophyll degradation (Aharoni et al. 1979b). Aharoni et al. (1979a) found that increased ethylene

production coincided with the advanced stages of natural senescence of tobacco leaves, but it was unclear

whether ethylene stimulated senescence. However, Gepstein and Thimann (1981) reported that increased

ethylene production preceded chlorophyll degradation of oat leaf segments. The relationship between

ethylene production and chlorophyll degradation appears to vary according to plant species and the

experimental system (viz. intact vs. excised tissue). Nevertheless, it appears that endogenous ethylene

does regulate a number of events during vegetative senescence (Aharoni and Lieberman 1979; Gepstein

and Thimann 1981). However, in other species, including cotton plants and an ethylene resistant mutant

of Arabidopsis thaliana, senescence of vegetative organs was shown to proceed in the absence of

exogenous or endogenous ethylene (McAfee and Morgan 1971; Zacarias and Reid 1990). Thus,

senescence may also be regulated by increasing sensitivity of the tissue to ethylene.

1.1.4 Flower senescence

Flower senescence, like senescence of other organs is a highly regulated developmental process. A series

25

of co-ordinated biochemical and physiological changes lead to termination of floral organ life (Nooden

1988; Van Altvorst and Bovy 1995). Senescence of floral organs is associated with the visual changes of

petal wilting and discolouration, and attendant biochemical changes. Biochemical changes include

increased activity of hydrolytic enzymes, degradation of starch and chlorophyll and loss of cellular

compartmentation (Van Altvorst and Bovy 1995). In some flowers, physiological changes that include

surges in respiration and ethylene biosynthesis accompany senesence (Halevy 1986). In many plant

species, flower senescence is accelerated and regulated by ethylene (Woltering and Van Doorn 1988).

Halevy (1986) suggested that flowers can be classified as climacteric or non-climacteric based on the

presence or absence, respectively, of increased rates of respiration and ethylene production associated

with senescence.

Most research into ethylene-mediated flower senescence has been on cut carnation (Dianthus

caryophyllus), which is an excellent ‘model’ flower (Reid 1995). Senescence of cut carnation flowers is

characterised by wilting of petals accompanied by a climacteric increase in autocatalytic ethylene

production (Nichols 1966). Exposure of flowers to ethylene stimulates ethylene biosynthesis, initiates and

hastens flower senescence (Nichols 1968) and induces the loss of proteins, phospholipids and polar fatty

acids (Trippi and Paulin 1984). Attendant changes in membrane permeability of cut carnation flowers

exposed to ethylene led to loss of cellular compartmentation, as evidenced by mixing of cytoplasmic and

vacuolar contents (Trippi and Paulin 1984). Borochov and Faragher (1983) found that ethylene

application to cut carnation flowers elicited an earlier increase in membrane permeability. Ethylene has

also been implicated in stimulating the swelling of the ovary of cut carnations (Nichols 1968, 1976) and

mobilisation of carbohydrates from the petals to the developing ovary.

Additional evidence that ethylene mediates cut carnation flower senescence is provided from studies using

inhibitors of ethylene biosynthesis and perception. Treatment of cut carnation flowers with

aminooxyacetic acid (AOA), an inhibitor of ethylene biosynthesis, delayed flower senescence and

endogenous ethylene production (Fujino et al. 1980). Likewise, treatment with STS, an inhibitor of

ethylene perception, also prevented flower senescence (Veen 1979a). Woodson and Lawton (1988)

reported that several mRNAs expressed in senescing petals of cut carnation flowers exposed to ethylene

appeared to be related to the increase in ethylene production. These mRNAs were found to be similar to

those that accumulated during natural senescence. Woodson et al. (1993) speculated that these mRNAs

encoded for ACC synthase and ACC oxidase enzymes which were functionally important to the

biochemical changes that occurred during senescence.

Application of exogenous ethylene to a number of other ornamentals, including Ipomoea tricolor (Kende

and Baumgartner 1974; Kende and Hanson 1976), Tradescantia (Suttle and Kende 1980), Petunia

(Whitehead et al. 1983), Hibiscus rosa-sinensis (Woodson et al. 1985) and various orchids such as

Vanda, Cattleya and Cymbidium (Goh et al. 1985), also stimulates endogenous ethylene production and

flower senescence. In contrast, the senescence of some flowers proceeds in the absence of ethylene

(Woltering and van Doorn 1988). These flowers include Chrysanthemums (Woltering 1987), Iris and

26

Gladiolus (Woltering and van Doorn 1988) and non-pollinated Cyclamen (Halevy et al. 1984) and

Dendrobium orchids (Ketsa and Luangsuwalai 1996).

1.1.4.1 Pollination-induced senescence

Pollination of many flowers, including orchids, carnation and Petunia, is accompanied by a sudden rise in

the rate of endogenous ethylene production. This surge induces rapid flower senescence (Stead 1992).

Ethylene has been implicated in coordinating a range of postpollination development events, including

petal senescence (Nichols 1977), pigment changes (Woltering and Somhorst 1990), floral organ

abscission (Stead 1992) and ovary growth and development (Zhang and O’Neill 1993).

In many species of orchids, endogenous ethylene production rates increase after pollination, emasculation

or exposure to ethylene and signal the onset of flower senescence (Stead 1992). Orchid flower senescence

is characterised by rapid wilting and/or anthocyanin breakdown or synthesis depending upon the particular

species. The pollination signal responsible for inducing increased rates of ethylene production was

proposed by Burg and Dijkman (1967) to be auxin, on the basis that orchid pollen contains substantial

amounts of auxin. Furthermore, application of auxin to the stigmas of Phalaenopsis flowers mimicked the

effect of pollination on ethylene production (Zhang and O’Neill 1993). However, Reid et al. (1984)

reported that auxin had no effect on the senescence of carnation flowers.

In cut carnation flowers, pollination induces irreversible petal wilting and stimulates a sequential increase

in the rate of ethylene production by stigmas, ovaries, receptacles and finally petals (Nichols et al. 1983).

This sequence is possibly due to ethylene and ACC translocation from the stigma to other flower organs.

However, Reid et al. (1984) showed that ethylene produced by the stigmas of flowers was not involved in

petal senescence. They proposed that ACC was the stimulus for the pollination response. Radioactively

2-14C-labelled ACC applied to the stigma of pollinated Petunia flowers was transported to the petals

where radioactively 14C-labelled ethylene was produced (Reid et al. 1984). Whitehead et al. (1983)

established that Petunia and carnation pollen contained ACC which could be converted to ethylene in the

stigma. However, Hoekstra and Weges (1986) showed that AVG-treated Petunia stigmas produced less

ethylene following pollination, indicating that ACC synthesis by the stigmatic tissue was necessary for

increased ethylene production. This finding was confirmed by Pech et al. (1987), who reported that

pollination led to an increase in ACC synthase activity in Petunia styles.

In a study of cut carnation flowers, Nichols et al. (1983) discovered that pollen produced little or no

ethylene. They suggested that the increased rate of ethylene production may be due to an interaction

between the pollen and stigmatic tissue, possibly as a wound response from the growing pollen tubes as

reported by Gilissen (1977). Stead (1992) suggested that the quantity of pollen-borne ACC was not

sufficient to sustain ethylene production at rates exhibited following pollination. Nevertheless, pollen-

borne ACC may contribute to the initiation of autocatalytic ethylene production by the stigma. Larsen et

al. (1993) speculated that the interorgan signalling responsible for triggering postpollination events may

27

be initiated by a recognition process between pollen tubes and stigmatic tissue, and not by wounding.

Thus, ethylene may act in interorgan communication following pollination because of its capacity to

diffuse through intercellular spaces (Larsen et al. 1993).

There is also an arguement that pollination stimulates the activity of other compounds such as short-chain

fatty acids which, in turn, increase the sensitivity of flowers to ethylene (Whitehead and Halevy 1989).

Increases in the endogenous concentrations of octanoic acid and other short-chain fatty acids were found

in the gynoecia and perianths of Phalaenopsis flowers and corollas of Petunia following pollination

(Whitehead and Halevy 1989; Halevy et al. 1996). Furthermore, application of octanoic acid to the

stigmas of AOA-treated Phalaenopsis flowers enhanced their sensitivity to ethylene (Halevy et al. 1996).

These observations support the view that these compounds are transported to floral organs where they

enhance ethylene sensitivity leading to flower senescence (Whitehead and Halevy 1989; Halevy et al.

1996).

1.1.5 Fruit ripening and senescence

Fruit ripening is a special case of organ senescence during which a series of biochemical and

physiological changes, such as loss of chlorophyll, softening, colouring and sweetening, take place (Pratt

and Goeschl 1969). Fruit have been classified as climacteric or non-climacteric based on their respiratory

activity during ripening (Biale 1964). Climacteric fruit, such as bananas and tomatoes, are characterised

by elevated rates of respiration at the onset of ripening. This burst is accompanied by distinct structural

and compositional changes. In contrast, non-climacteric fruit show no changes in respiration that can be

associated with marked changes in structure and composition. Ethylene production by climacteric fruit

increases at the onset of ripening. This increase is thought to regulate the initiation of biochemical and

physiological changes associated with ripening, including the increase in respiration (Burg and Burg

1962). Burg and Burg (1962) and Reid and Pratt (1970) proposed that the capacity of climacteric fruit to

produce ethylene autocatalytically following exposure to exogenous or endogenous ethylene further

distinguished them from non-climacteric fruit.

Treatment of climacteric banana fruit with propylene (an ethylene analogue) was shown by McMurchie et

al. (1972) to induce a rapid increase in the rate of respiration and ethylene production by fruit, and an

acceleration of ripening. However, no increase in the rate of ethylene production by non-climacteric

lemon fruit treated with propylene was observed, although the rate of respiration increased and degreening

was accelerated. These findings led McMurchie et al. (1972) to propose that two systems regulate

ethylene production in higher plants. System 1 operated in climacteric, non-climacteric fruit and

vegetative tissue and was responsible for basal and wound-induced ethylene production. System 2

occurred in climacteric fruit only, and was proposed to be responsible for the autocatalytic increase in

ethylene production during ripening.

The internal ethylene content of climacteric fruit such as bananas remains relatively constant throughout

28

fruit growth and development. However, at the onset of ripening, a sharp increase in ethylene production

precedes or accompanies the climacteric increase in respiration (Burg and Burg 1965). The accelerated

production rate may be required to raise the internal content of ethylene to a stimulatory level or to initiate

an autocatalytic response once the tissue became sensitive to the still relatively low endogenous level of

ethylene (Burg and Burg 1965). Treatment of climacteric fruit with ethylene or compounds which mimic

ethylene action, prematurely induce increased respiration and ethylene production and accelerate ripening

and senescence (Burg and Burg 1962, 1967; McMurchie et al. 1972). The threshold exogenous ethylene

concentration required to initiate ripening of mature climacteric fruit is generally in the range of 0.1-1.0

µL/L (Burg and Burg 1962).

Treatment of apple fruit with AVG or tomato fruit with Ag+ delays ripening, further confirming that

ethylene is responsible for initiating ripening (Masia et al. 1998; Saltveit et al. 1978; Atta-Aly et al.

1987). Additionally, in climacteric fruit, treatment with Ag+ halts the ripening process even after it is well

advanced. Thus, the continual presence of ethylene is necessary for ongoing co-ordination of ripening

(Tucker and Brady 1987). Some fruit become more sensitive to ethylene as they mature or ripen (Burg

and Burg 1965; Peacock 1972). For example, tomato fruit do not ripen in the presence of ethylene unless

they are close to full maturity (McGlasson et al. 1975). Conversely, cantaloupe and banana fruit ripen in

the presence of ethylene at any maturity stage, although higher concentrations of ethylene are required to

initiate ripening of immature fruit (McGlasson and Pratt 1964; Pratt and Goeschl 1969).

Ripening of non-climacteric fruit is generally ethylene-independent. Exposure of non-climacteric fruit to

exogenous ethylene usually stimulates increased respiration. However, upon removal of ethylene, the

respiration rate decreases rapidly (Biale 1964). Non-climacteric fruit do not produce ethylene in response

to exposure to ethylene (McMurchie et al. 1972). Nevertheless, some non-climacteric fruit are still

sensitive to ethylene. For example, ethylene treatment causes colour changes in the flavedo of citrus fruit,

as evidenced by accelerated chlorophyll degradation (Purvis and Barmore 1981) and enhanced carotenoid

synthesis (Stewart and Wheaton 1972). Similarly, softening of non-climacteric strawberry fruit was

accelerated by low levels of ethylene that accumulated inside punnets sealed with polyethylene film (Wills

and Kim 1995).

1.2 ETHYLENE BIOSYNTHESIS

Ethylene is produced by a variety of organisms, including bacteria, fungi and higher plants, as part of their

development and/or in response to various environmental stimuli (Abeles et al. 1992). Determination of

the sequence of events in ethylene biosynthesis by higher plants has been the focus of intense research

over the past 20 years. Ethylene biosynthesis in higher plants has been reviewed in detail by Lieberman

(1979), Yang and Hoffman (1984), Kende (1993) and Fluhr and Mattoo (1996).

The primary sequence of ethylene biosynthesis involves conversion of methionine to S-

adenosylmethionine (AdoMet) which then forms ACC and finally ethylene (Figure 1.1). The ethylene

29

biosynthetic pathway also has links to other pathways. The methionine cycle is responsible for

replenishing this sulfur containing amino acid in order to sustain metabolic pathways, including ethylene

biosynthesis (Adams and Yang 1977). Adams and Yang (1977) found that methionine levels in apple

tissue were low and suspected that it must be reformed in order to maintain ethylene biosynthesis. They

confirmed this theory by showing that the sulfur group of methylthioadenosine, a degradation product of

the conversion of methionine to AdoMet, was hydrolysed to methylthioribose and then cycled back to

form methionine. The conjugation of ACC with malonate to form 1-(malonylamino) cyclopropane-1-

carboxylic acid (MACC) is also closely linked to the ethylene biosynthetic pathway (Yang et al. 1990). It

is still unclear what regulates the accumulation of MACC. Fluhr and Mattoo (1996) suggest that

conversion of ACC to MACC may contribute to the regulation of ACC accumulation and, hence, ethylene

formation.

Catalysis of each step in the ethylene biosynthetic pathway is enzyme mediated. The conversion of

methionine to AdoMet is catalysed by AdoMet synthetase (Yu and Yang 1979). ACC synthase (ACS) is

responsible for catalysing the conversion of AdoMet to ACC (Adams and Yang 1979). ACS plays a

major role in regulating ethylene biosynthesis, particularly during autocatalysis (positive feedback) or

autoinhibition (negative feedback) where ACS is stimulated or inhibited, respectively (Yang and Hoffman

1984). ACS is regarded as being the major rate-limiting enzyme in ethylene biosynthesis (Picton et al.

1995). The conversion of ACC to ethylene, is catalysed by an oxidative enzyme called ACC oxidase

(ACO). ACO is also considered rate limiting. It was formerly known as the ethylene forming enzyme

(EFE; Adams and Yang 1979).

Methionine

S-adenosyl methionine

Methylthioadenosine

1-aminocyclopropane-1-carboxylic acid

Ethylene

AdoMet synthetase

ACC synthase

ACC oxidase

+

MACC

Methioninecycle

Figure 1.1. Metabolic pathway of ethylene biosynthesis in higher plants (after Fluhr and Mattoo1996).

30

1.3 INHIBITORS OF ETHYLENE BIOSYNTHESIS

Two inhibitors of ethylene biosynthesis which have received considerable attention in literature are AVG

and AOA. Both inhibit pyridoxal phosphate-dependent enzymes, such as ACS (Yang 1981). The

conversion of ACC to ethylene by ACO has been shown to be inhibited by the presence of cobalt ions and

by high temperature (Yang and Hoffman 1984). Treatment of mung bean hypocotyls (Yu and Yang 1979)

and oat leaves (Gepstein and Thimann 1981) with cobalt ions greatly inhibited ethylene production and

associated senescence. Accumulation of ACC in mung bean hypocotyls treated with cobalt ions

corresponded to reduced ethylene production, indicating that ACO activity was inhibited (Yu and Yang

1979). ACO activity is also inhibited in mung bean and apple fruit tissue exposed to high temperatures

(e.g. 35oC), as evidenced by accumulation of ACC and reduced ethylene production (Yu et al. 1980).

1.3.1 Aminoethoxyvinylglycine

Rhizobitoxine is a phytotoxin produced by the Rhizobium japonicum bacteria and inhibits ethylene

biosynthesis (Owens et al. 1971). AVG is an analogue of rhizobitoxine that has been shown to be a very

effective inhibitor of ethylene-related processes in plants (Amrhein and Wenker 1979; Lieberman 1979).

AVG prevents the conversion of AdoMet to ACC by inhibiting ACS (Boller et al. 1979). Ripening of

preclimacteric pear fruit was delayed by vacuum infiltration with AVG (Wang and Mellenthin 1977).

This inhibition was reversed by exposure of fruit to ethylene. AVG was less effective in delaying ripening

of more mature pear fruit, presumably as endogenous ethylene levels were high (Ness and Romani 1980).

Vacuum infiltration of apple fruit with AVG delayed ripening and reduced ethylene production (Bramlage

et al. 1980). Similarly, spraying apple fruit with AVG preharvest inhibited postharvest ethylene

production and thereby delayed ripening (Masia et al. 1998). AVG can also extend the life of ethylene-

sensitive cut flowers (Cook et al. 1985; Gladon and Spear 1984). It inhibits ethylene production by cut

carnation flowers (Baker et al. 1977; Cook et al. 1985).

1.3.2 Aminooxyacetic acid

AOA prevents ethylene synthesis in plant tissue by inhibiting ACS and thereby blocking conversion of

methionine to ethylene (Yu et al. 1979). Much research with AOA has focused on cut flowers, as it is

effectively incorporated into flowers as a vase solution additive. Fujino et al. (1980), Broun and Mayak

(1981), Gladon and Spear (1984) and Woltering and Sterling (1986) tested AOA as a vase solution

additive for cut carnation flowers. They found that pulse or continuous AOA treatment extended flower

longevity and delayed and reduced ethylene production and respiration. However, a practical drawback

with using AOA or other inhibitors of ethylene biosynthesis is their ineffectiveness in inhibiting

senescence when flowers were exposed to exogenous ethylene. Further, because AVG and AOA do not

inhibit the conversion of ACC to ethylene, their effectiveness is limited by the level of ACC already

31

present in the tissue (Yang and Hoffman 1984).

1.4 ETHYLENE PERCEPTION

Burg and Burg (1967) first speculated that ethylene binds to a receptor in plant tissue. They suggested

ethylene binds to a protein-bound transition metal on the basis that olefins such as ethylene are known to

form complexes with metals. This hypothesis was further developed by Sisler (1977), who proposed that

ethylene binds to a metal in the receptor and withdraws electrons. The consequent ligand substitution

process releases ethylene from the receptor and initiates an action response. There is now substantial

belief that ethylene action is by binding to high affinity, saturable and specific receptors (Sisler 1979;

Bleecker et al. 1988; Sisler and Blankenship 1993a). However, attempts to isolate and purify these

receptors have so far failed. This section will review evidence in support of the existence of ethylene

receptors.

Ethylene binding to plant tissue has been demonstrated by displacing 14C-labelled ethylene with

unlabelled ethylene (Sisler 1979, 1982). Sisler (1979) estimated the number of binding sites in tobacco

leaves to be 4000/cell or a concentration of 3.5 x 10-9 M. Inhibitors of ethylene action or perception, such

as 2,5-NBD and silver nitrate (AgNO3), were shown to displace 14C-labelled ethylene in a detergent

extract of mung bean sprouts (Sisler 1982).

Various compounds mimic ethylene action upon association with the putative ethylene receptor (Burg and

Burg 1967). These analogues include, in order of biological activity, propylene, carbon monoxide and

acetylene (Abeles et al. 1992). In mimicking ethylene action, they have been used to characterise ethylene

perception and to facilitate measurement of endogenous ethylene synthesised by plants (McMurchie et al.

1972).

Some bound ethylene dissociates rapidly from receptors in plant tissue, whilst dissociation of remaining

ethylene is slow (Sisler 1979). Sisler (1979) interpreted these kinetics to indicate that more than one type

of receptor existed. Following its partial purification from mung bean sprouts, Sisler (1980) reported that

the receptor appears to be a membrane-bound protein. Based on these observations, Sisler and Yang

(1984a) reconsidered the ethylene action model proposed by Sisler (1977). Ethylene molecules were

believed to associate with the receptor in a reversible manner and upon dissociation a signal is activated.

This signal then mediates changes in gene transcription and in turn the synthesis of specific proteins.

These proteins are predominantly catabolic enzymes associated with plant tissue senescence (Reid and

Wu 1991). Synthesis of novel mRNAs, proteins and enzymes are associated with ethylene responses

(Christoffersen and Laties 1982; Reid 1985a).

Researchers have recently adopted molecular and genetic approaches to identify the ethylene receptor.

Identification of genes that are expressed in association with ethylene responses has been made possible

through selection of ethylene-insensitive mutants of the ‘model’ plant, Arabidopsis thaliana, and tomato

32

plants. A number of mutants affecting ethylene responses in A. thaliana seedlings have been identified

using the ‘triple response’ bioassay. Upon exposure to ethylene normal seedlings are characterised by

having (i) a short and thick hypocotyl, (ii) a short root, and (iii) an exaggerated apical hook. Ethylene

binding and signal transduction mutants show other phenotypes.

Bleecker et al. (1988) isolated etr1 mutant A. thaliana seedlings, which are dominant and insensitive to

ethylene compared to wild type seedlings. They claimed that the ETR1 gene acted as the ethylene

receptor. Four etr1-related ethylene insensitive mutants have also been isolated, and the associated genes

(ETR2, EIN4, ERS1 and ERS2) all share sequence homology with ETR1 (Hua et al. 1995, 1998; Sakai et

al. 1998). A further series of ethylene insensitive mutants (ein2, ein3, ein5, ein6 and ein7) have been

recently isolated in A. thaliana, providing evidence that ethylene perception and signal transduction in

plants is a highly regulated process (Ecker 1995). Alternatively, the recessive mutant, ctr1, which

expressed the ‘triple response’ in the absence of ethylene was identified (Kieber et al. 1993). Thus, CTR1

was reported to repress ethylene responses as its mutant (ctr1) has a constitutive ethylene response. The

CTR1 gene encodes a putative serine/threonine protein kinase which is closely related to the Raf protein

kinase family found in animals (Kieber et al. 1993).

Evidence that ETR1, a membrane-bound protein, is the ethylene receptor is based on observations that

etr1 mutants bound less 14C-labelled ethylene than wild type seedlings (Bleecker et al. 1988). Further

evidence that the ETR1 gene codes for the ethylene receptor has been based on double mutant analysis

between (i) ctr1 and ein1 mutants, in which the ctr1 phenotype was displayed, and (ii) ctr1 and ein3

mutants, where the ein3 phenotype was shown (Kieber et al. 1993). Kieber et al. (1993) and Ecker (1995)

suggested that the CTR1 gene acts downstream of the EIN1 and ETR1 genes. The ETR1 gene encodes for

a protein composed of an amino-terminal domain which was demonstrated to bind ethylene when the

ETR1 gene was expressed in yeast (Schaller and Bleecker 1995). The carboxyl-terminal region of the

ETR1 protein consists of a putative histidine kinase domain and a receiver domain, and exhibits sequence

homology to the bacterial two component regulators (Chang et al. 1993). Such proteins are sensors and

transducers of a variety of signals in response to environmental stimuli. Hua and Meyerowitz (1998)

suggested that since the amino-terminal domains of ETR2, EIN4 and ERS2 are similar to that of ETR1,

they may also bind ethylene and act as receptors. They also suggested that these receptors may act either

independently or as a complex when binding ethylene in plants.

A genetic pathway for ethylene signal transduction has been deduced from double mutant analyses. It is

proposed by Sakai et al. (1998) that ETR1, ETR2, ERS1, ERS2 and EIN4 act upstream of CTR1 which is

upstream of EIN2, EIN3, EIN5, EIN6 and EIN7 (Figure 1.2). By analogy with the bacterial two-

component regulators, the ethylene signal transduction pathway has been proposed to involve the

phosphorylation of the receptor-related proteins in a cascade. It is thought that CTR1 is inactivated and,

in turn, downstream proteins are activated and a response is elicited (Ecker 1995). Reid (1995) linked the

ethylene perception models proposed by Sisler (1977) and Ecker (1995), in suggesting that binding of an

ethylene molecule to the receptor activates protein phosphorylation, causing ligand substitution and

33

activation of responses.

Ethylene

ETR1ETR2ERS1ERS2EIN4

CTR1 EIN2

EIN3EIN5EIN6EIN7

Ethylene response

Figure 1.2. Proposed sequence of gene action in the ethylene signal transduction pathway (Hua etal. 1998; Hua and Meyerowitz 1998).

In contrast to A. thaliana, a number of tomato mutants have been selected at later vegetative and

reproductive stages (Rick and Butler 1956; Tigchelaar et al. 1978). Tomato mutants in which fruit

ripening was delayed included the Never-ripe (Nr), ripening inhibitor (rin) and non-ripening (nor)

mutants, while the epi mutant ripened in the absence of ethylene. The discovery of the putative ethylene

receptor proteins in A. thaliana ethylene insensitive mutants has been reported by Lanahan et al. (1994) to

be consistent with similar receptors in mutant tomato plants. In tomato seedlings the Nr mutants remain

insensitive to ethylene. Thus, both the seedling triple response and flower abscission are not observed

following ethylene treatment (Lanahan et al. 1994). However, rin and nor mutants display the normal

seedling triple response when exposed to ethylene. These observations indicate that the Nr mutation

affects a range of plant ethylene responses, while rin and nor mutations specifically affect fruit ripening.

ETR1-homologous genes have been isolated from tomato and share sequence homology with the Nr

mutation. Thus, the signalling components required for a range of ethylene responses may be similar in a

variety of plants (Yen et al. 1995).

34

1.5 INHIBITORS OF ETHYLENE PERCEPTION

As outlined above, substantial evidence exists to support the concept that ethylene action inhibitors act by

preventing ethylene perception by plant tissue. Signal transduction and gene activation are inhibited by

binding to and blocking of ethylene receptors. Various inhibitors have been reported to bind to the

ethylene receptors in either a reversible or irreversible manner (Sisler and Serek 1997).

1.5.1 Silver ions

Beyer (1976) was first to discover the inhibitory effects of Ag+ against ethylene action in plants. Ag+

applied as a foliar spray of AgNO3 prevented the ‘triple’ response in etiolated pea seedlings, leaf

abscission from cotton plants and senescence of Cattleya orchid flowers exposed to exogenous ethylene.

New growth of pea seedlings was also protected from ethylene by treatment with 240 mg AgNO3/L,

suggesting that Ag+ acted systemically (Beyer 1976).

Mayak et al. (1977) reported that Ag+ also has anti-microbial properties, as evidenced by reduced

microbial populations in the vase solutions holding cut carnation flower stems pre-treated with AgNO3.

Halevy and Kofranek (1977) found that placing stem ends of cut carnation flowers into AgNO3 solution

was not as effective in extending vase life as dipping or spraying flower heads with the same solution.

Veen and van de Geijn (1978) showed that a different form of Ag+, the anionic STS complex (Ag(S2O3)2)

was more mobile in plant tissue than the cationic AgNO3. STS is made by combining AgNO3 and

Na2S2O3 solutions. This complex moved rapidly up cut carnation flower stems to the receptacle and was

effective in preventing ethylene-induced flower senescence. However, Veen and van de Geijn (1978) also

reported that treatment of cut carnation flowers with high STS concentrations caused phytotoxicity.

Ag+ is believed to bind to ethylene receptors and thereby block ethylene action, as evidenced by lower

ethylene binding in mung bean sprouts following their treatment with Ag+ (Sisler 1982). Sisler et al.

(1986) showed that in vivo ethylene binding by cut carnation flower petals was inhibited by Ag+ provided

in the form of STS. Veen (1979a, b) reported that STS treatment of cut carnation flowers prevented the

typical climacteric increase in ethylene production and suggested that by blocking the ethylene receptor,

Ag+ may inhibit the autocatalytic increase in ethylene production. In apparent contrast, STS treatment has

been shown to enhance ethylene production of some plant tissue (Aharoni et al. 1979a), including

Leptospermum scoparium flowers (Zieslin and Gottesman 1983). In such instances, it was proposed that

Ag+ inhibited the negative feedback mechanism of ethylene biosynthesis.

Much of the applied research with STS has been conducted with ornamentals. Ag+ is a chronic poison

and is, therefore, not suitable for practical treatment of edible fruit and vegetables. Reid et al. (1980)

found that pulsing cut stems of carnation flowers with 1-4 mM Ag+ in the STS complex for just 10

minutes was effective in delaying their senescence. A minimum concentration of 0.5 µmol Ag+/stem was

required for maximum vase life. Greater than 5 µmol Ag+/stem was toxic, resulting in discolouration of

35

flower petals. Reid et al. (1980) reported that STS treatment had commercial potential as the relationship

between concentration and treatment time could be tailored to suit particular needs and to deliver an

optimal level of Ag+ to the plant tissue.

STS is currently used widely on a commercial scale (Nowak and Rudnicki 1990). It prevents a range of

ethylene-induced disorders in ornamentals (Veen 1983). These include: flower senescence (petal wilt) of

Gypsophila paniculata (Woltering and Van Doorn 1988; Van Doorn and Reid 1992); floral organ

abscission from cut sweet pea (Mor et al. 1984), Petunia (Lovell et al. 1987), Geraldton waxflower (Joyce

1989) and from potted plants including Geranium and Bougainvillea (Cameron and Reid 1983); leaf

abscission from mistletoe (Joyce et al. 1990); and, leaf and berry abscission from English holly (Joyce et

al. 1990). Cameron and Reid (1981) reported that the protective ability of STS against ethylene was

retained for at least 4 weeks in the treatment of Zygocactus, thereby making commercial application useful

for preventing ethylene responsiveness during transit and retail display. However, as mentioned earlier, a

potential problem with using Ag+ is the risk of phytotoxicity. The usual effective concentrations can be

close to those that are toxic (Cameron and Reid 1981).

36

1.5.2 2,5-Norbornadiene

2,5-NBD was the first cyclic olefin shown to be an effective inhibitor of ethylene responses in plant tissue

(Sisler and Pian 1973). 2,5-NBD inhibits ethylene action in tobacco (Sisler and Pian 1973), pea

hypocotyls (Sisler and Yang 1984b) and cut carnation flowers (Sisler et al. 1983; Sisler et al. 1986; Wang

and Woodson 1989). Treatment of these tissues involved pipetting 2,5-NBD liquid onto filter paper

which then vaporised into a sealed chamber (Sisler et al. 1985).

Sisler et al. (1985) found that higher concentrations of 2,5-NBD were required to prevent abscission of

citrus leaf explants challenged with increased ethylene concentrations. For example, 2000 µL 2,5-NBD/L

was sufficient to protect citrus leaf explants from 2 µL ethylene/L, while 8000 µL 2,5-NBD/L was

required to afford similar protection when explants were subsequently exposed to 10 µL ethylene/L.

Lineweaver-Burk plots constructed by Sisler et al. (1985) demonstrated that 2,5-NBD competed with

ethylene for the ethylene receptor. However, binding was reversible, with the inhibitory effect only being

maintained when 2,5-NBD was constantly present. Further, 2,5-NBD has an unpleasant odour and may be

a carcinogen (Sisler et al. 1986).

Liu et al. (1985) reported that 2,5-NBD inhibited malonylation of ACC in tomato fruit. Ethylene

production, ACC content and ACS and ACO activities were rapidly reduced when cut carnation flowers

producing autocatalytic ethylene were exposed to 2,5-NBD (Wang and Woodson 1989). Removal of

flowers from treatment with 2,5-NBD resulted in recovery of ethylene biosynthesis. Liu et al. (1985) and

Wang and Woodson (1989) both proposed that in each situation, 2,5-NBD, by binding to the ethylene

receptor, disrupted the feedback mechanism involved in ethylene biosynthesis. Conversely, 2,5-NBD was

shown to enhance ethylene production in winter squash by stimulating ACS transcription (Nakajima et al.

1990).

1.5.3 Diazocyclopentadiene

Treatment of cut carnation flowers with DACP gas, a di-cyclic olefin, was reported by Sisler et al. (1993)

to effectively inhibit ethylene-induced senescence. Irradiation of DACP under fluorescent lights was

found to be around 5000 times more effective than non-irradiated DACP in the treatment of cut carnation

flowers (Sisler et al. 1993). Similarly, Sisler and Blankenship (1993b) reported that the ripening of

tomato fruit was delayed by DACP treatment in the presence of fluorescent light. Only a slight delay was

observed for fruit treated with DACP in the dark. Sisler and Blankenship (1993a, b) and Sisler et al.

(1993) suggested that DACP irradiated with visible light gives rise to active unidentified compounds that

block ethylene action in an apparently irreversible manner. Serek et al. (1994a) reported that 1 µL

DACP/L was as effective as STS in preventing leaf and flower bud abscission and extending the longevity

of potted roses. Binding assays using rose petals also indicated that DACP binding to the ethylene

receptor was permanent. According to Serek et al. (1994a), DACP was presumed to attach covalently to

the receptor when the diazo group decomposed. Tomato fruit treated with DACP for 24 hours at 25oC

37

remained insensitive to ethylene for 10 days (Sisler and Blankenship 1993b). Fruit transferred to 14.5oC

immediately after treatment did not respond to ethylene for 20 days. This difference was thought to be

due to more rapid synthesis of new receptors at the higher temperature.

Sisler and Blankenship (1993b) also reported that DACP in delaying ripening, also reduced ethylene

production by green mature tomato fruit. However, when fruit regained sensitivity to ethylene the surge in

climacteric ethylene production was greatly enhanced. Sisler and Lallu (1994) found that DACP retarded

ripening of tomato fruit even when applied at advanced ripening stages. Ethylene production of pink and

red fruit treated with DACP initially decreased, then, after 3-4 days rose to elevated levels. Moreover,

Mathooko et al. (1995) reported that ethylene production by pink stage tomato fruit rapidly decreased in

response to DACP treatment due to the inhibition of ACS and ACO activities and slightly increased

MACC content. Mathooko et al. (1995) proposed that DACP, by binding to the ethylene receptors,

disrupted the positive feedback mechanism of ethylene biosynthesis. Conversely, Tian et al. (1997) found

that ethylene production by the non-climacteric strawberry fruit was stimulated by DACP due to an

increase in ACC content of tissues and the prevention of the negative feedback mechanism of ethylene

production.

38

1.5.4 Cyclopropenes

Some synthetic gaseous cyclopropenes, including cyclopropene (CP), 3,3-dimethylcyclopropene (3,3-

DMCP) and 1-methylcyclopropene (1-MCP) (Figure 1.3) have recently been shown to prevent ethylene

responses in plant tissue by binding to the ethylene receptor (Sisler et al. 1996a). Complete protection of

banana fruit against ethylene was afforded by treatment with 0.7 nL CP/L or 0.7 µL 3,3-DMCP/L for 24

hours (Sisler et al. 1996a). Likewise, treatment of cut carnation flowers with 1 nL CP/L or 0.5-1.0 µL

3,3-DMCP/L for 24 hours provided protection against ethylene (Sisler et al. 1996a). Banana fruit at 24oC

remained insensitive to ethylene for 11-12 days after treatment with CP and for 5 days after treatment with

3,3-DMCP, before ripening normally (Sisler et al. 1996a). CP and 3,3-DMCP appear to bind strongly to

the ethylene receptor, possibly as a result of the highly strained nature of the molecules (Sisler et al.

1996a). Sisler et al. (1996a) proposed that a stearic and/or inductive effect due to the two methyl groups

of 3,3-DMCP may hinder binding and hence require higher concentrations. Both CP and 3,3-DMCP are

relatively stable gases at room temperature, although 3,3-DMCP was reported to be comparatively more

stable than CP (Sisler and Serek 1997). A number of ethylene-induced responses in cut flowers, potted

flowering plants and fruit are prevented by treatment with the gaseous cyclopropene, 1-MCP (Sisler and

Serek 1997). The rapidly expanding literature on the use of 1-MCP in postharvest horticulture is

reviewed below.

cyclopropene 3,3-dimethylcyclopropene

CH3 CH3

CH3

1-methylcyclopropene

Figure 1.3. Chemical structure of cyclopropene, 3,3-dimethylcyclopropene and 1-methylcyclopropene.

39

1.5.4.1 1-Methylcyclopropene

1.5.4.1.1 Introduction

1-MCP is a recently developed gaseous ethylene binding inhibitor in plant tissue (Serek et al. 1994b).

Sisler et al. (1996a) reported that 1-MCP is the first gaseous irreversible inhibitor of ethylene perception

that is effective in the dark. 1-MCP is a simple organic compound, being comprised of four carbon and

six hydrogen atoms (Figure 1.3). It is generally accepted as being non-toxic and is active at nanomolar

concentrations, making it an extremely promising candidate for commercial use (Sisler and Serek 1997).

1-MCP is a very stable gas at room temperature.

1.5.4.1.2 Mode of action

1-MCP molecules bind to ethylene receptors in a competitive and irreversible manner (Sisler et al.

1996a). Whilst 1-MCP occupies the receptor, ethylene cannot bind and elicit an action (Sisler and Serek

1997). Low binding constants were obtained in competition assays between 1-MCP and ethylene in

carnation [Kd = 2.1 nL/L (Serek et al. 1995a)] and rose petals [Kd = 8 nL/L (Serek et al. 1994b)]. Thus,

ethylene receptors are effectively blocked by a very low 1-MCP concentration. Serek et al. (1994b) used

Lineweaver-Burk plots to discern the effects of ethylene concentration relationships for bud and flower

abscission from begonia plants treated with 0 or 5 nL 1-MCP/L. The plots confirmed that 1-MCP

competes with ethylene for the ethylene receptor. Sisler et al. (1996a) treated cut carnation flowers with

1-MCP labelled with tritium. Efflux diffusion rates of this compound from flower tissues were very low,

even after 7 days, suggesting that 1-MCP binds permanently to the ethylene receptor.

Sisler (1977, 1991) proposed that ethylene initiates an action response by binding to and subsequently

being released from a metal in the receptor. On the other hand, it was claimed by Sisler and Serek (1997)

that the highly strained 1-MCP molecule binds very strongly to the receptor. It remains bound to the

metal in the receptor and an action response is not completed.

40

1.5.4.1.3 Synthesis and detection

1-MCP can be synthesised by reacting a solution of phenyllithium in a solvent of 70% cyclohexane and

30% ether with 3-chloro-2-methylpropene (Sisler and Serek 1997). The resulting solution contains

lithium chloride as a precipitate and the lithium salt of 1-MCP in solution. This solution remains stable

for several months if held in a sealed glass tube stored at -20oC (Sisler and Serek 1997). Earlier variations

of this synthesis procedure are described by Fisher and Applequist (1965) and Magid et al. (1971). The

concentration of 1-MCP can be quantified by gas chromatography using a hydrocarbon separation column

and calibration against butane (Sisler and Serek 1997). No detection limits for the determination of 1-

MCP concentration by gas chromatography are provided in the literature. Nakatsuka et al. (1997)

indicated that 1-MCP concentrations of 10–20 nL/L used for treatment of tomato fruit were estimated by

diluting samples from the stock solution.

1.5.4.1.4 Responses of plant tissue to 1-MCP

Numerous accounts in the literature show that 1-MCP is highly potent in preventing ethylene-related

processes in plant tissues (Table 1.1). Sisler et al. (1996a) reported that the concentration of 1-MCP

required to provide cut carnation flowers with full protection against ethylene is inversely related to

treatment time. For example, treatment of cut carnation flowers at 24oC with as little as 0.5 nL 1-MCP/L

for 24 hours or 250 nL 1-MCP/L for just 5 minutes afforded a similar level of protection against ethylene.

However, the effective 1-MCP concentration appears to vary according to the plant tissue or organ.

Banana fruit and cut carnation flowers required a pre-treatment of 0.5 nL 1-MCP/L for 24 hours at 24oC,

while tomato fruit required 7 nL 1-MCP/L for 24 hours at 24oC for complete protection against ethylene

(Sisler et al. 1996b). Higher concentrations may be needed for growing vegetative tissue. As

demonstrated with pea seedlings, 40 nL 1-MCP/L for 6 hours at 24oC was required to completely inhibit

ethylene action (Sisler and Serek 1997). Reasons for this variable response are still unclear. Several

researchers have investigated the inhibitory properties of 1-MCP at higher (micromolar) concentrations

(Abdi et al. 1998; Golding et al. 1998).

Table 1.1. Ethylene-related plant processes reported to be inhibited by 1-methylcyclopropenetreatment.

Ethylene-related process Plant material Reference

Flower abscission Potted flowering begoniaplants

Serek et al. (1994b)

Cut Penstemon flowers Serek et al. (1995a)Cut phlox flowers Porat et al. (1995b)

Leaf, flower bud and flowerabscission

Potted flowering rose plants Serek et al. (1994b)

Cut Geraldton waxflower Serek et al. (1995c)Potted flowering miniaturerose plants

Serek et al. (1996)

41

Leaf abscission and yellowing Epipremnum pinnatumcuttings

Muller et al. (1997)

Flower senescence (flower wilt) Cut Phalaenopsis flowers Porat et al. (1995a)Cut Petunia flowers Serek et al. (1995d)

Flower senescence (flower closure) Potted flowering Kalanchoeblossfeldiana plants

Serek et al. (1994b)

Flower senescence (petal in-rolling)

Cut carnation flowers Serek et al. (1995a)Sisler et al. (1996a)

Fruit ripening Banana fruit Sisler et al. (1996b)Golding et al. (1998)

Tomato fruit Sisler et al. (1996b)Nakatsuka et al. (1997)

Apple fruit Song et al. (1997)Plum fruit Abdi et al. (1998)Strawberry fruit Ku et al. (1999)Orange fruit Porat et al. (1999)

Chilling-induced fruit ripening Pear fruit Lelievre et al. (1997)

Inhibition of growth Pea seedlings Sisler et al. (1996b)Epinasty Tomato plants Cardinale et al. (1995)

1.5.4.1.5 Influence of temperature on 1-MCP treatment efficacy

The efficacy of 1-MCP treatment of cut Penstemon flowers was reported by Serek et al. (1995a) to be

temperature dependent. 1-MCP treatments of 5 or 20 nL 1-MCP/L for 6 hours were highly effective at

20oC. However, they did not protect Penstemon flowers when applied at 2oC. Reid et al. (1996) reported

that higher concentrations of 1-MCP and/or longer treatment times at 2oC were required to achieve

complete inhibition of ethylene action in Kalanchoe flowers. Sisler and Serek (1997) suggested that the

binding of 1-MCP molecules to ethylene receptors is reduced at low temperature. However, no

explanation of the possible mechanism(s) involved were offered. One can speculate that the reduced

efficacy of 1-MCP treatment at low temperature is due to decreased rates of diffusion of 1-MCP gas into

the plant tissue or poorer binding kinetics. From a scientific and commercial perspective, a greater

understanding of this attribute of 1-MCP is needed.

1.5.4.1.6 Effect of 1-MCP on various physiological responses

Porat et al. (1995a) reported that application of 1-MCP to Phalaenopsis orchid flowers effectively

inhibited the pollination-induced increase in ethylene production. Sisler et al. (1996a) showed that 1-

MCP delayed the time to peak ethylene production by cut carnation flowers compared to flowers treated

only with ethylene. Moreover, the rate of ethylene production was reduced compared to flowers that were

not treated with ethylene or 1-MCP. Sisler et al. (1996a) proposed that 1-MCP treatment irreversibly

prevented autocatalytic production of ethylene. Lelievre et al. (1997) examined Passe-Crassane pear fruit

42

which require chilling treatment to stimulate ACS and ACO activity and to produce ethylene for ripening.

Treatment with 4 µL 1-MCP/L at 2oC reduced ethylene production, ACS and ACO activities. In addition,

1-MCP prevented chilling-induced accumulation of ACS and ACO mRNA transcripts. Nakatsuka et al.

(1997) also found that 1-MCP prevented increases in abundance of ACS and ACO mRNAs in ripening

tomato fruit, and thereby reduced the activity of ACS and ACO. Nakatsuka et al. (1997) demonstrated

that 1-MCP interferes with the positive feedback mechanism of ethylene biosynthesis, as proposed earlier

by Sisler et al. (1996a). Treatment of apple fruit with 1-MCP also prevented the typical climacteric rise

of respiration and ethylene and volatiles production (Song et al. 1997). However, 1-MCP treatment was

not effective in preventing ripening of the high ethylene producing feijoa fruit (Reid et al. 1996).

Abdi et al. (1998) demonstrated that 1-MCP delayed the onset of and reduced the rates of both respiration

and ethylene climacterics in climacteric and in suppressed-climacteric varieties of plum treated with

propylene. Golding et al. (1998) similarly reported delayed respiration and ethylene climacterics and also

delayed onset of volatile production in banana fruit treated with 1-MCP. However, in contrast to the

findings of Abdi et al. (1998) with plum fruit, 1-MCP treatment enhanced peak rates of ethylene

production by banana fruit (Golding et al. 1998). Enhanced rates of ethylene production were taken by

Golding et al. (1998) to indicate disruption of the negative feedback mechanism of ethylene biosynthesis.

They suggested that 1-MCP may block the feedback regulation by binding irreversibly to receptors

involved in feedback regulation and/or preventing malonylation of ACC. The enhanced ethylene

production by 1-MCP-treated bananas may be due to over-stimulation of ACS gene transcription.

1.5.4.1.7 Duration of 1-MCP effects on plant tissue

It is has been claimed that 1-MCP molecules bind irreversibly to ethylene receptors in plant tissues (Sisler

et al. 1996b). Evidence that 1-MCP binding is irreversible is based on binding studies with petal explants

and the insensitivity of 1-MCP-treated tissue to ethylene. For example, Sisler et al. (1996b) found that cut

carnation flowers treated with 5 nL 1-MCP/L for 6 hours were insensitive to ethylene applied 10 days

later. Similarly, Song et al. (1997) found that apple fruit treated with 500 nL 1-MCP/L on day 0 were still

insensitive to ethylene treatment on day 11. However, by virtue of the limited frequency of ethylene

treatments, these experiments did not establish that flowers and fruit remain insensitive to ethylene

permanently.

In more detailed investigations, 1-MCP-treated cut carnation flowers, banana and tomato fruit regained

sensitivity to ethylene at various times after 1-MCP treatment (Sisler and Serek 1997). Cut carnation

flowers treated with 1-MCP remained insensitive to ethylene for 12-15 days at 24oC. Sisler and Serek

(1997) also stated that for many cut flowers, the period of protection against ethylene afforded by 1-MCP

exceeds the normal display life. For these cut flowers, longevity is determined by deterioration processes

mediated by factors other than ethylene. Banana and tomato fruits treated with 1-MCP regained their

competency to respond to ethylene after 10-12 days (Sisler et al. 1996b). The ability of 1-MCP-treated

plant tissue to regain the capacity to respond to ethylene was suggested to be due to the synthesis of new

43

ethylene receptors (Sisler and Serek 1997)1. Thus, one can conclude that the efficacy of 1-MCP treatment

will vary according to genotype, possibly being most limited by the apparent synthesis of new receptors.

1.5.4.1.8 Effect of tissue age or development stage on 1-MCP efficacy

Sisler et al. (1996a) reported that older cut carnation flowers displaying early senescence symptoms (petal

in-rolling) required a higher concentration of 1-MCP (5 nL/L for 6 hours at 24oC) than young flowers (2.5

nL/L for 6 hours at 24oC) to prevent ethylene-induced senescence. This may have been due to the

presence of higher levels of endogenous ethylene in the tissue which competed with 1-MCP molecules for

the ethylene receptors. Nakatsuka et al. (1997) reported that 1-MCP treatment of tomato fruit at the pink

stage only slightly inhibited ripening, compared to treatment at the green stage, as evidenced by colour

development and ethylene production. Ripening of banana fruit was not inhibited by 1-MCP once

autocatalytic ethylene production had commenced (i.e. 24 hours after treatment with propylene) (Golding

et al. 1998). Klee and Tieman (1997) claim that plant tissues produce new ethylene receptors in

association with increased ethylene synthesis. This may help explain why higher concentrations of 1-

MCP are required to completely inhibit ethylene-related responses in older tissues.

1.6 INTERACTION BETWEEN ETHYLENE BIOSYNTHESIS AND PERCEPTION

Binding of ethylene to its receptor was speculated by Aharoni et al. (1979) to elicit a feedback signal

which would serve to stimulate or inhibit ethylene production (Figure 1.4). It is now established that

ethylene biosynthesis is regulated by positive and negative feedback mechanisms (Kende 1993). Positive

feedback regulation (autocatalysis) of ethylene biosynthesis is a common feature of fruit ripening and

flower senescence (Yang and Hoffman 1984). Exposure of plant tissue to exogenous or endogenous

ethylene stimulates an increase in ethylene production which is preceded and/or accompanied by increased

ACS and ACO activity (Yang and Hoffman 1984). Negative feedback regulation (autoinhibition) of

ethylene biosynthesis has been associated with a number of fruit and vegetative tissues (Yang and

Hoffman 1984). In this case, exogenous ethylene suppresses endogenous ethylene production (Vendrell

and McGlasson 1971) and the accumulation of ACS transcripts (Nakajima et al. 1990). Liu et al. (1985)

reported that ethylene is also capable of negative feedback regulation of its own production by promoting

conjugation of ACC to MACC in green mature tomato fruit.

1 In a recent publication obtained at the time of going to press, Sisler and Serek (1999) also suggested that1-MCP may diffuse from receptors.

44

Methionine

S-adenosyl methionine

1-Aminocyclopropane-1-carboxylic acid

Ethylene

Perception by ethylene receptor

Signal transduction

Methylthioadenosine

AdoMet synthetase

ACC synthase

ACC oxidase

+

Altered gene expression

Methionine cycle

MACC

MACC transferase

Regulation of ethylene biosynthesis

Protein synthesis

Response

Figure 1.4. Schematic representation of the interaction between ethylene biosynthesis andperception in higher plants (after Fluhr and Mattoo 1996; Picton et al. 1995; Van Altvorst andBovy 1995).

The interaction between ethylene biosynthesis and perception has been studied through the use of ethylene

action inhibitors. The binding of ethylene action inhibitors to ethylene receptors is thought to stimulate

autocatalysis of ethylene production by blocking negative feedback signals (Aharoni et al. 1979; Atta-Aly

et al. 1987), thereby preventing malonylation of ACC (Liu et al. 1985) or stimulating ACS transcription

(Nakajima et al. 1990). Alternatively, ethylene action inhibitors, by binding to the ethylene receptors, can

cause autoinhibition of ethylene production by blocking positive feedback regulation signals which

otherwise stimulate the stimulation of ACS and ACO activity (Wang and Woodson 1989) or reduce

malonylation of ACC to MACC (Philosoph-Hadas et al. 1985). Despite increasing knowledge, the

interaction between ethylene biosynthesis and perception is not fully understood.

1.7 ETHYLENE IN POSTHARVEST HORTICULTURE

1.7.1 Gas ripening and degreening

Ethylene treatment has been widely and effectively used by commercial operators to accelerate peel

45

degreening of early season citrus fruit since the 1920s (Sherman 1985). Citrus fruit, despite being non-

climacteric, are sensitive to ethylene as evidenced by enhanced chlorophyll degradation (Purvis and

Barmore 1981) and synthesis of carotenoid pigments (Stewart and Wheaton 1972). There is evidence that

low endogenous ethylene levels are associated with natural peel degreening (Jahn et al. 1973). Treatment

of citrus fruit with at least 5 µL ethylene/L in commercial ripening rooms promotes rapid and uniform

degreening (Jahn et al. 1973).

Soon after the discovery that ethylene treatment accelerated degreening of citrus fruit, commercial

operators started to use the same technology to ripen a range of climacteric fruit, including tomatoes,

bananas and mangoes (Abeles et al. 1992). Treating climacteric fruit with ethylene is an effective means

of inducing rapid, uniform and predictable ripening. Treating fruit usually involves injecting ethylene gas

from a pressurised cylinder as a ‘shot’ or ‘trickle’ into a specially constructed ripening room or generating

ethylene gas inside the room by catalytic conversion of ethanol (Sherman 1985). For example, banana

fruit are generally treated with up to 1000 µL ethylene/L at 14.5 to 20oC for 24 hours or on two or three

consecutive days until fruit show the first sign of colour change (CSIRO 1972; New and Marriott 1974).

According to Inaba and Nakamura (1988), such high ethylene concentrations saturate the fruit and induce

fruit of variable maturity and ripening stage to ripen evenly. The ethylene concentration or temperature of

treatment can be manipulated to control the rate of fruit ripening (CSIRO 1972). The clear benefit of

using ethylene treatments in commercial postharvest horticulture is facilitation of the orderly marketing of

citrus, tomato, banana and mango fruit (Sherman 1985).

1.7.2 Acceleration of deterioration

Ethylene stimulates a range of responses in fruit, vegetables and ornamentals at concentrations as low as

0.1-1.0 µL/L (Burg and Burg 1962). Ethylene is a component of the ambient atmosphere and can range in

concentration from 0.001-0.005 µL/L in rural areas to around 0.5 µL/L in urban environments (Abeles et

al. 1992). The main sources of ethylene are anthropogenic (e.g. exhaust fumes from combustion engines,

ballasts of fluorescent lights, and leaks from ripening rooms) or biogenic (e.g. ripening and senescing fruit

and vegetables) (Reid 1985b).

Due to the enclosed nature of postharvest handling environments and retail outlets, ethylene tends to

accumulate to levels which are biologically active. Exogenous ethylene can, therefore, induce a range of

detrimental responses which reduce the postharvest life of fruit, vegetables and ornamentals (Abeles et al.

1992). Exposure of climacteric fruit to ethylene hastens ripening and, in turn, senescence and

deterioration (Burg and Burg 1962). In many fruit and vegetables, unintentional exposure to ethylene

accelerates chlorophyll degradation, abscission of leaves, softening and undesirable flavours, and creates

conditions suitable for further deterioration by pathogens (Kader 1985). Exposure of many cut flowers of

horticultural importance to ethylene stimulates rapid deterioration processes such as abscission or

senescence of floral organs and attached leaves (Woltering and Van Doorn 1988). Accordingly,

techniques which remove, avoid or inhibit ethylene are of considerable commercial importance in

preventing the deleterious effects of ethylene (Reid 1985b). Some of these techniques are described

46

below.

1.7.3 Ethylene removal

Removal of ethylene gas from the postharvest environment is a strategy to protect sensitive produce from

exogenous ethylene. Ethylene can be removed from storage areas by periodic or slow constant ventilation

with fresh air or by scrubbing it from the storage atmosphere with compounds that trap or convert ethylene

to inactive products (Sherman 1985). Potassium permanganate (KMnO4) sorbed onto a suitable large

surface area carrier, such as vermiculite, perlite, silica gel, expanded glass or a commercial formulation

using aluminium oxide pellets (Purafil), delayed ripening of banana (Scott et al. 1970), avocado (Hatton

and Reeder 1972) and kiwifruit (Ben-Arie and Sonego 1985). KMnO4 based scrubbers oxidise ethylene to

carbon dioxide (CO2) and water. In this process, the colour changes from purple to brown as MnO4 is

reduced to MnO2 (Reid 1985b). However, the disadvantages of using KMnO4 based scrubbers are

relatively high cost (Saltveit 1980), low effectiveness at very low or high ethylene concentrations (Ben-

Arie and Sonego 1985) and toxicity concerns regarding its safe handling and disposal (Abeles et al.

1992). Ethylene can also be sorbed onto porous beds and oxidised to CO2 in the presence of a platinum

catalyst and elevated temperature (Sherman 1985; Wojciechowski 1989). However, a major problem with

this approach is the energy costs associated with removing heat generated by the platinum catalyst (Abeles

et al. 1992).

Ultraviolet (UV) light can initiate the destruction of ethylene and other hydrocarbons produced by

ripening bananas (Scott et al. 1971). Scott and Wills (1973) demonstrated that irradiating air with UV

light at wavelengths of 185 nm and 254 nm generated ozone that oxidised the ethylene in the air.

However, few commercial scale UV scrubbers have been developed. Alternatively, the recent

development of a liquid electrode plasma system which reduces ethylene into simple and safe by-products

may have commercial potential (Graham et al. 1998). This system was shown to reduce up to 75% of

ethylene in an air stream containing 1 µL ethylene/L.

Ethylene production by plants can also be lowered by a number of plant growth promoting rhizobacteria

that contain ACC deaminase, which catalyses the cleavage of ACC (Glick et al. 1994, 1998). Most

research has focused on Pseudomonas putida, which effectively lowers endogenous ethylene levels in

plant roots by hydrolysing plant ACC. This in turn, can promote longer root growth in various agronomic

crops (Hall et al. 1996). Another soil bacterium, Mycobacterium paraffinicum, has been reported to

remove ethylene from the soil by oxidation (Abeles et al. 1992). Application of ethylene-consuming

bacteria to remove ethylene from postharvest horticulture environments has yet to be developed. Sherman

(1985) speculated that the function of such organisms could possibly be enhanced by genetic engineering.

1.7.4 Biosynthesis inhibition

Effective prevention of a range of ethylene responses in plants through treatment with AOA and AVG has

47

been discussed earlier in this review. AOA is currently used as a commercial anti-ethylene treatment for

cut carnations in The Netherlands (W. van Doorn, pers. comm.). A more recent approach to inhibiting

ethylene biosynthesis in plants has involved isolation and cloning of genes in the ethylene biosynthetic

pathway (Kende 1993; McKeon et al. 1995). ACS and ACO genes have been cloned from various plants.

An ACS antisense gene expressed in tomato plants was found to prevent normal fruit ripening in air by

inhibiting ethylene biosynthesis (Oeller et al. 1991). Likewise, fruit from tomato plants genetically

transformed by insertion of antisense ACO genes produced lower rates of ethylene and displayed delayed

ripening. As an alternative approach, Klee et al. (1991) cloned the gene encoding ACC deaminase from

Pseudomonas sp. and expressed it in tomato plants. The ripening of fruit from these plants was delayed

and their ethylene production was reduced considerably. The use of molecular techniques to inhibit

ethylene biosynthesis may have profound commercial implications in the future.

1.7.5 Binding inhibition

As discussed earlier, a number of compounds that inhibit ethylene binding and, thus, its downstream

actions have been developed for use in commercial horticulture. Some have already seen commercial

application. STS is widely used as a commercial anti-ethylene treatment for a range of cut flowers and

potted flowering plants (Veen 1983; Nowak and Rudnicki 1990). However, because the active ingredient

of STS is Ag+, a heavy metal, its commercial use is restricted to ornamentals. Legislators in some

countries are considering restricting the commercial use of STS because of environmental concerns (Serek

et al. 1994a). Ag+ is a recognised environmental pollutant which makes handling and disposal of STS

solutions and of treated tissues problematical (Serek et al. 1994a). The use of Ag+ retrieval systems

similar to those used in film processing (Cooley 1988), whereby the Ag+ can be recovered from used STS

solution, may have potential for application in the cut flower industry (Veen 1987).

Researchers have been recently seeking alternative anti-ethylene strategies suitable for commercial use.

The discovery by Sisler and Pian (1973) of the gaseous cyclic olefin 2,5-NBD, has led to the investigation

of several similar compounds as possible alternatives to STS. 2,5-NBD is an effective inhibitor, but its

unpleasant odour and toxicity have prevented practical use (Sisler et al. 1986). DACP showed promise as

an STS alternative (Sisler and Blankenship 1993a; Serek et al. 1994a). From a commercial perspective,

DACP treatment has several drawbacks. It is explosive at high concentration, unstable at room

temperature, only completely effective when treatment is conducted in the presence of light, and relatively

high concentrations are required to overcome ethylene responses (Serek et al. 1995b).

Prevention of ethylene-induced responses in fruit and ornamentals treated with synthetic cyclopropenes

has been recently reported (Sisler et al. 1996a). A gaseous cyclopropene, 1-MCP, is particularly effective

at low concentrations and is generally accepted as being non-toxic. 1-MCP is a most likely candidate for

commercial use in the future (Sisler and Serek 1997). A commercial preparation of 1-MCP, EthylBloc

has been recently produced. EthylBloc is being evaluated by the Environmental Protection Agency in

the USA. It is anticipated that EthylBloc will soon be registered for use on ornamentals (J. Daly, pers.

48

comm.). However, as discussed earlier in this review, apparent limitations are associated with the use of

1-MCP as an anti-ethylene treatment. Namely, the sometimes limited duration of its inhibitory effects

(Sisler et al. 1996b) and its apparently poor binding at low temperatures (Serek et al. 1995a; Reid et al.

1996; Sisler and Serek 1997). These issues are among those investigated in the present study on native

Australian cut flowers.

50

APPENDIX B SUPPORTING AND STATISTICAL DATA

Appendix 2.1. Gas chromatogram of a 1-methylcyclopropene sample. Peaks 1 and 4 are unknowncompounds. Peak 2 represents 1-methylcyclopropene, while peak 3 is cyclohexane.

51

Appendix 2.2. Gas chromatogram of a 1-methylcyclopropene sample reacted with 0.1 g elementaliodine in 10 mL absolute ethanol for 1 hour. Note: peak 2 is no longer present (cf. Appendix 2.1),indicating the usual location of the 1-methylcyclopropene peak.

52

Appendix 2.3. Time in days to > 10% flower abscission (score = 2), moderate flower discolouration(score = 2) and wilting (score = 2) of G. ‘Sylvia’ inflorescences treated on day 0 with 0, 5, 10 or 20nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of these treatments werethen exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letterare not significantly different at P = 0.05 (n = 10). LSDs = 0.7 (abscission) and 0.6 (wilting) days.

Treatment Abscission Discolouration Wilting

No ethylene (0 µL/L) Control (0 nL 1-MCP/L) 4.1 ± 0.1 b 3.7 ± 0.2 4.7 ± 0.3 a 5 nL 1-MCP/L 5.3 ± 0.3 cd 4.1 ± 0.1 5.7 ± 0.2 b 10 nL 1-MCP/L 4.7 ± 0.3 bc 3.8 ± 0.1 5.5 ± 0.3 b 20 nL 1-MCP/L 5.3 ± 0.3 cd 4.1 ± 0.2 5.6 ± 0.3 bPlus ethylene (10 µL/L) Control (0 nL 1-MCP/L) 2.1 ± 0.1 a z z

5 nL 1-MCP/L 5.3 ± 0.2 cd 4.0 ± 0.0 5.7 ± 0.2 b 10 nL 1-MCP/L 5.2 ± 0.1 c 3.9 ± 0.1 5.9 ± 0.1 b 20 nL 1-MCP/L 5.9 ± 0.3 d 4.0 ± 0.0 6.0 ± 0.0 b

z Treatments were excluded from analysis as all flowers had abscised.

Appendix 2.4. ANOVA table for wilting of flowers on G. ‘Sylvia’ inflorescences treated on day 0with 0, 5, 10 or 20 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F PTreatment 6 10.8857 1.8143 4.07 0.002Error 63 28.1000 0.4460Total 69 38.9857

Appendix 2.5. ANOVA table for flower abscission from G. ‘Sylvia’ inflorescences treated on day 0with 0, 5, 10 or 20 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP concentration (A) 3 75.737 25.246 42.57 0.000Ethylene (B) 1 1.013 1.013 1.71 0.195A x B 3 22.038 7.346 12.39 0.000Error 72 42.700 0.593Total 79 141.488

53

Appendix 2.6. ANOVA table for relative fresh weight of G. ‘Sylvia’ inflorescences treated on day 0with 0, 5, 10 or 20 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 3 102450.8 34150.3 64.57 0.000Ethylene (B) 1 7098.6 7098.6 13.42 0.000A x B 3 24403.1 8134.4 15.38 0.000Rep (A B) 72 38079.2 528.9 6.70 0.000Day (C) 6 375997.3 62666.2 794.45 0.000A x C 18 26399.8 1466.7 18.59 0.000B x C 6 5302.2 883.7 11.20 0.000A x B x C 18 26441.0 1468.9 18.62 0.000Error 432 34076.2 78.9Total 559 640248.2

Appendix 2.7. ANOVA table for vase life of G. ‘Sylvia’ inflorescences treated on day 0 with 0, 5, 10or 20 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP concentration (A) 3 18.1375 6.0458 46.81 0.000Ethylene (B) 1 3.6125 3.6125 27.97 0.000A x B 3 9.3375 3.1125 24.10 0.000Error 72 9.3000 0.1292Total 79 40.3875

Appendix 2.8. ANOVA table for discolouration of flowers on G. ‘Sylvia’ inflorescences treated onday 0 with 0, 5, 10 or 20 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 2.9. Summary of chi-square test for an association between treatments (1-MCPconcentrations and ethylene) and opening scores (scores: 1 = < 5% to 3 = > 25%) for G. ‘Sylvia’inflorescences treated on day 0 with 0, 5, 10 or 20 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC.

Days Chi-square df P0 z 14.359 7 0.1141 z 16.314 14 0.3972 24.557 14 0.0393 31.183 14 0.0054 16.435 12 0.1725 z 22.418 12 0.0016 8.889 6 0.1807 z 7.368 5 0.416z Fisher’s exact test was performed where the chi-square test was invalid.

54

Appendix 2.10. ANOVA table for vase solution uptake by G. ‘Sylvia’ inflorescences treated on day0 with 0, 5, 10 or 20 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP concentration (A) 3 0.303517 0.101172 17.51 0.000Ethylene (B) 1 0.258505 0.258505 44.73 0.000A x B 3 0.014804 0.004935 0.85 0.469Rep (A B) 72 0.416095 0.005779 3.28 0.000Day (C) 6 1.847170 0.307862 174.75 0.000A x C 18 0.125643 0.006980 3.96 0.000B x C 6 0.337070 0.056178 31.89 0.000A x B x C 18 0.063954 0.003553 2.02 0.008Error 432 0.761087 0.001762Total 559 4.127847

Appendix 2.11. Time in days to > 10% flower abscission (score = 2), moderate flowerdiscolouration (score = 2) and wilting (score = 2) from G. ‘Sylvia’ inflorescences treated on day 0with 10 nL 1-MCP/L for 0, 3, 6, 9 or 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Data followed bythe same letter are not significantly different at P = 0.05 (n = 10). LSDs = 1.1 (abscission), 0.7(discolouration) and 1.3 (wilting) days.

Treatment Abscission Discolouration Wilting

No ethylene (0 µL/L) Control (0 nL 1-MCP/L) 3.5 ± 0.5 b 3.9 ± 0.1 ab 4.6 ± 0.6 b 10 nL 1-MCP/L, 3 hr 4.6 ± 0.5 bc 4.5 ± 0.4 b 5.3 ± 0.6 b 10 nL 1-MCP/L, 6 hr 4.7 ± 0.4 c 4.2 ± 0.1 ab 4.8 ± 0.5 b 10 nL 1-MCP/L, 9 hr 4.5 ± 0.3 bc 4.1 ± 0.2 ab 4.1 ± 0.3 b 10 nL 1-MCP/L, 12 hr 4.5 ± 0.6 bc 4.9 ± 0.3 b 4.5 ± 0.4 bPlus ethylene (10 µL/L) Control (0 nL 1-MCP/L) 1.1 ± 0.1 a z 1.0 ± 0.0 a 10 nL 1-MCP/L, 3 hr 3.8 ± 0.4 bc 4.3 ± 0.3 b 5.1 ± 0.5 b 10 nL 1-MCP/L, 6 hr 4.7 ± 0.4 c 3.5 ± 0.2 a 4.6 ± 0.5 b 10 nL 1-MCP/L, 9 hr 5.0 ± 0.4 c 4.2 ± 0.2 ab 5.1 ± 0.5 b 10 nL 1-MCP/L, 12 hr 5.7 ± 0.3 c 4.6 ± 0.4 b 4.8 ± 0.3 bz Treatment excluded from analysis as all flowers had abscised.

Appendix 2.12. ANOVA table for flower abscission from G. ‘Sylvia’ inflorescences treated on day 0with 10 nL 1-MCP/L for 0, 3, 6, 9 or 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP contact time (A) 4 99.440 24.860 16.13 0.000Ethylene (B) 1 2.250 2.250 1.46 0.230A x B 4 38.200 9.550 6.20 0.000Error 90 138.700 1.541Total 99 278.590

55

Appendix 2.13. ANOVA table for wilting of flowers on G. ‘Sylvia’ inflorescences treated on day 0with 10 nL 1-MCP/L for 0, 3, 6, 9 or 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 2.14. ANOVA table for relative fresh weight of G. ‘Sylvia’ inflorescences treated on day0 with 10 nL 1-MCP/L for 0, 3, 6, 9 or 12 hours at 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 2.15. ANOVA table for vase life of G. ‘Sylvia’ inflorescences treated on day 0 with 10 nL1-MCP/L for 0, 3, 6, 9 or 12 hours at 20oC. Half of the inflorescences from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


56

1

2

3

Time (days)

0 1 2 3 4 5 6 7

Dis

colo

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1

2

3

+ Ethylene

- Ethylene

Appendix 2.16. Discolouration (scores: 1 = none/slight to 3 = advanced) of flowers on G. ‘Sylvia’inflorescences treated on day 0 with 10 nL 1-1-MCP/L for 0 (zz), 3 (��), 6 (▲), 9 (▼) and 12 (◆)hours at 20oC. Half of the inflorescences from each of these treatments were then exposed on day 1to 10 µL ethylene/L for 12 hours at 20oC. The other half of the inflorescences were held in airwithout exogenous ethylene. Vertical bars represent standard errors of means (n = 10). Where novertical bars appear, the standard error was smaller than the size of the symbol. LSD is presentedin Appendix 2.11.

Appendix 2.17. ANOVA table for discolouration of flowers on G. ‘Sylvia’ inflorescences treated onday 0 with 10 nL 1-MCP/L for 0, 3, 6, 9 or 12 hours at 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


57

1

2

3

Time (days)

0 1 2 3 4 5 6 7

Ope

ning

sco

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1

2

3

+ Ethylene

- Ethylene

Appendix 2.18. Opening (scores: 1 = < 5% to 3 = > 25%) of flowers on G. ‘Sylvia’ inflorescencestreated on day 0 with 10 nL 1-1-MCP/L for 0 (zz), 3 (��), 6 (▲), 9 (▼) and 12 (◆) hours at 20oC.Half of the inflorescences from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC. The other half of the inflorescences were held in air withoutexogenous ethylene. Vertical bars represent standard errors of means (n = 10). Where no verticalbars appear, the standard error was smaller than the size of the symbol. Significant differences (P< 0.05) between treatments existed on days 0, 1 and 2 (Appendix 2.19).

Appendix 2.19. Summary of chi-square test for an association between treatments (1-MCPtreatment duration and ethylene) and opening scores (scores: 1 = < 5% to 3 = > 25%) for G.‘Sylvia’ inflorescences treated on day 0 with 10 nL 1-MCP/L for 0, 3, 6, 9 or 12 hours at 20oC. Halfof the inflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/Lfor 12 hours at 20oC.

Days Chi-square df P0 37.500 9 0.0001 55.692 18 0.0002 53.301 18 0.0003 11.380 16 0.7854 z 13.942 16 0.6425 7.619 8 0.4716 9.643 8 0.4107 z 16.364 8 0.101z Fisher’s exact test was performed where the chi-square test was invalid.Appendix 2.20. ANOVA table for vase solution uptake by G. ‘Sylvia’ inflorescences treated on day

58

0 with 10 nL 1-MCP/L for 0, 3, 6, 9 or 12 hours at 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 2.21. ANOVA table for flower abscission from G. ‘Sylvia’ inflorescences treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 0, 5, 10 or 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flowerabscission score data were arcsine transformed for ANOVA.

Source of variation DF SS MS F PTemperature (A) 3 0.04451 0.01484 0.36 0.7801-MCP (B) 1 21.30883 21.30883 520.29 0.000Ethylene (C) 1 16.28499 16.28499 397.62 0.000A x B 3 0.20754 0.06918 1.69 0.178A x C 3 0.04151 0.01384 0.34 0.798B x C 1 16.38125 16.38125 399.97 0.000A x B x C 3 0.27306 0.09102 2.22 0.094Rep (A B C) 64 2.62117 0.04096 5.65 0.000Day (D) 7 17.39076 2.48439 342.69 0.000A x D 21 0.08774 0.00418 0.58 0.934B x D 7 7.12472 1.01782 140.40 0.000C x D 7 5.95978 0.85140 117.44 0.000A x B x D 21 0.19655 0.00936 1.29 0.175A x C x D 21 0.06973 0.00332 0.46 0.982B x C x D 7 6.05461 0.86494 119.31 0.000A x B x C x D 21 0.23704 0.01129 1.56 0.056Error 448 3.24783 0.00725Total 639 97.53162

59

Appendix 2.22. ANOVA table for relative fresh weight of G. ‘Sylvia’ inflorescences treated on day0 with 0 or 10 nL 1-MCP/L for 12 hours at 0, 5, 10 or 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 2.23. ANOVA table for vase life of G. ‘Sylvia’ inflorescences treated on day 0 with 0 or10 nL 1-MCP/L for 12 hours at 0, 5, 10 or 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F PTemperature (A) 3 5.850 1.950 0.88 0.4581-MCP (B) 1 72.200 72.200 32.45 0.000Ethylene (C) 1 45.000 45.000 20.22 0.000A x B 3 5.700 1.900 0.85 0.470A x C 3 1.500 0.500 0.22 0.879B x C 1 42.050 42.050 18.90 0.000A x B x C 3 10.850 3.617 1.63 0.192Error 64 142.400 2.225Total 79 325.550

60

Dis

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1

2

3+ 1-MCP + Ethylene

0 1 2 3 4 5 6 7

1

2

3- 1-MCP + Ethylene

+ 1-MCP - Ethylene

Time (days)

0 1 2 3 4 5 6 7

- 1-MCP - Ethylene

Appendix 2.24. Discolouration (scores: 1 = none/slight to 3 = advanced) of flowers on G. ‘Sylvia’inflorescences pre-treated with 0 or 10 nL 1-MCP/L for 12 hours at 0 (zz), 5 (��), 10 (▲) and 20oC(▼). Half of the inflorescences from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC. The other half of the inflorescences were not exposed to exogenousethylene. Vertical bars represent standard errors of means (n = 5). Where no vertical bars appear,the standard error was smaller than the size of the symbol.

Appendix 2.25. ANOVA table for discolouration of flowers on G. ‘Sylvia’ inflorescences treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 0, 5, 10 or 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.Flower discolouration score data were converted to a binary score for ANOVA.

Source of variation DF SS MS F PTemperature (A) 3 0.7556 0.2519 2.48 0.065Treatment (B) 2 0.4111 0.2056 2.03 0.137A x B 6 1.4111 0.2352 2.32 0.039Rep (A B) 48 9.0667 0.1889 1.86 0.005Day (C) 2 20.8444 10.4222 102.79 0.000A x C 6 0.5778 0.0963 0.95 0.464B x C 4 0.5222 0.1306 1.29 0.280A x B x C 12 1.6556 0.1380 1.36 0.198Error 96 9.7333 0.1014Total 179 44.9778

61

1

2

3+ 1-MCP + Ethylene

Time (days)

0 1 2 3 4 5 6 7

Wilt

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1

2

3- 1-MCP + Ethylene

+ 1-MCP - Ethylene

0 1 2 3 4 5 6 7

- 1-MCP - Ethylene

Appendix 2.26. Wilting (scores: 1 = none/slight to 3 = advanced) of flowers on G. ‘Sylvia’inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 0 (zz), 5 (��), 10 (▲)and 20oC (▼). Half of the inflorescences from each of these treatments were then exposed on day 1to 10 µL ethylene/L for 12 hours at 20oC. The other half of the inflorescences were not exposed toexogenous ethylene. Vertical bars represent standard errors of means (n = 5). Where no verticalbars appear, the standard error was smaller than the size of the symbol.

Appendix 2.27. ANOVA table for wilting of flowers on G. ‘Sylvia’ inflorescences treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 0, 5, 10 or 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flowerwilting score data were converted to a binary score for ANOVA.

Source of variation DF SS MS F PTemperature (A) 3 4.85000 1.61667 25.03 0.000Treatment (B) 2 0.22500 0.11250 1.74 0.179A x B 6 3.17500 0.52917 8.19 0.000Rep (A B) 48 15.10000 0.31458 4.87 0.000Day (C) 3 6.18333 2.06111 31.91 0.000A x C 9 0.55000 0.06111 0.95 0.487B x C 6 0.74167 0.12361 1.91 0.082A x B x C 18 1.72500 0.09583 1.48 0.104Error 144 9.30000 0.06458Total 239 41.85000

62

Ope

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1

2

3+ 1-MCP + Ethylene

0 1 2 3 4 5 6 7

1

2

3- 1-MCP + Ethylene

+ 1-MCP - Ethylene

Time (days)

0 1 2 3 4 5 6 7

- 1-MCP - Ethylene

Appendix 2.28. Opening (scores: 1 = < 5% to 3 = > 25%) of flowers on G. ‘Sylvia’ inflorescencespre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 0 (zz), 5 (��), 10 (▲) and 20oC (▼).Half of the inflorescences from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC. The other half of the inflorescences were not exposed to exogenousethylene. Vertical bars represent standard errors of means (n = 5). Where no vertical bars appear,the standard error was smaller than the size of the symbol. No significant differences (P > 0.05)between treatments were observed (Appendix 2.29).

Appendix 2.29. Summary of chi-square test for an association between treatments (1-MCPtreatment temperature and ethylene) and opening scores (scores: 1 = < 5% to 3 = > 25%) for G.‘Sylvia’ inflorescences treated on day 0 with 10 nL 1-MCP/L for 12 hours at 0, 5, 10 or 20oC. Halfof the inflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/Lfor 12 hours at 20oC.

Days Chi-square df P0 z 14.873 15 0.7191 z 29.559 30 0.3082 39.910 30 0.1073 22.975 22 0.4034 z 10.000 22 0.9935 z 23.043 22 0.3316 z 16.000 22 0.9717 z 19.000 22 0.924z Fisher’s exact test was performed where the chi-square test was invalid.Appendix 2.30. ANOVA table for vase solution uptake by G. ‘Sylvia’ inflorescences treated on day

63

0 with 0 or 10 nL 1-MCP/L for 12 hours at 0, 5, 10 or 20oC. Half of the inflorescences from eachtreatment were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 2.31. ANOVA table for flower abscission from G. ‘Sylvia’ inflorescences treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC. Flower abscission scoredata were arcsine transformed for ANOVA.

Source of variation DF SS MS F P1-MCP (A) 1 8.17554 8.17554 1618.71 0.000Propylene (B) 1 5.40153 5.40153 1069.47 0.000A x B 1 5.87952 5.87952 1164.11 0.000Rep (A B) 20 0.10101 0.00505 1.69 0.042Day (C) 7 3.46264 0.49466 165.10 0.000A x C 7 2.81713 0.40245 134.32 0.000B x C 7 2.10954 0.30136 100.59 0.000A x B x C 7 2.10477 0.30068 100.36 0.000Error 140 0.41945 0.00300Total 191 30.47113

Appendix 2.32. ANOVA table for relative fresh weight of G. ‘Sylvia’ inflorescences treated on day0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.


64

Appendix 2.33. ANOVA table for vase solution uptake by G. ‘Sylvia’ inflorescences treated on day0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.


Appendix 2.34. ANOVA table for vase life of G. ‘Sylvia’ inflorescences treated on day 0 with 0 or10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatment were thenexposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 32.667 32.667 98.00 0.000Propylene (B) 1 24.000 24.000 72.00 0.000A x B 1 24.000 24.000 72.00 0.000Error 20 6.667 0.333Total 23 87.333

65

Dis

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1

2

3

Ope

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1

2

3

Time (days)

0 1 2 3 4 5 6 7

Wilt

sco

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1

2

3

Appendix 2.35. Flower discolouration (scores: 1 = none/slight to 3 = advanced), opening (scores: 1= < 5% to 3 = > 25%) and wilting (scores: 1 = none/slight to 3 = advanced) from G. ‘Sylvia’inflorescences treated with (●) 0 nL 1-MCP/L and 0 µL propylene/L, (■) 0 nL 1-MCP/L and 100µL propylene/L, (▲) 10 nL 1-MCP/L and 0 µL propylene/L or (▼) 10 nL 1-MCP/L and 100 µLpropylene/L. 1-MCP and propylene treatments were each conducted for 12 hours at 20oC on day 0and 1, respectively. Vertical bars represent standard errors of means (n = 6).

Appendix 2.36. Time in days to moderate flower discolouration (score = 2) from G. ‘Sylvia’inflorescences treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each treatment were then exposed on day 1 to 100 µL propylene/L for 12 hoursat 20oC.

Treatment Discolouration0 µL propylene/L 0 nL 1-MCP/L 6.0 ± 0.3 10 nL 1-MCP/L 6.5 ± 0.2100 µL propylene/L 0 nL 1-MCP/L z

10 nL 1-MCP/L 6.3 ± 0.2z Treatment excluded from analysis as all flowers had abscised.Appendix 2.37. ANOVA table for discolouration of flowers on G. ‘Sylvia’ inflorescences treated on

66

day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from eachtreatment were then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.


Appendix 2.38. Summary of chi-square test for an association between treatments (1-MCP andpropylene) and opening scores (scores: 1 = < 5% to 3 = > 25%) for G. ‘Sylvia’ inflorescences treatedon day 0 with 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.

Days Chi-square df P0 y y y

1 2.667 3 0.4462 4.200 6 0.6503 1.667 4 0.7974 2.500 4 0.6455 z 3.154 4 0.8116 2.400 2 0.3017 2.400 2 0.301z Fisher’s exact test was performed where the chi-square test was invalid.y Chi-square test could not be calculated as all inflorescences were of an equal score.

Appendix 2.39. ANOVA table for wilting of flowers on G. ‘Sylvia’ inflorescences treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC. Flower wilting score datawere converted to a binary score for ANOVA.

Source of variation DF SS MS F PTreatment (A) 2 0.05556 0.02778 0.50 0.616Rep (A) 15 2.50000 0.16667 3.00 0.020Day (B) 1 0.11111 0.11111 2.00 0.178A x B 2 0.05556 0.02778 0.50 0.616Error 15 0.83333 0.05556Total 35 2.55556

Appendix 2.40. ANOVA table for ethylene production by G. ‘Sylvia’ inflorescences treated on day0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.


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Appendix 2.41. ANOVA table for respiration by G. ‘Sylvia’ inflorescences treated on day 0 with 0or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatment were thenexposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.


Appendix 2.42. ANOVA table for flower abscission from G. ‘Sylvia’ inflorescences treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC. Flower abscission scoredata were arcsine transformed for ANOVA.


Appendix 2.43. ANOVA table for ACC contents of flowers from G. ‘Sylvia’ inflorescences treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from eachtreatment were then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.


Appendix 2.44. ANOVA table for vase life of G. ‘Sylvia’ inflorescences used in the determination offlower ACC content, which were treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC.Half of the inflorescences from each treatment were then exposed on day 1 to 100 µL propylene/Lfor 12 hours at 20oC and then used to measure ACC.

Source of variation DF SS MS F P1-MCP (A) 1 3.0000 3.0000 18.00 0.003Propylene (B) 1 5.3333 5.3333 32.00 0.000A x B 1 3.0000 3.0000 18.00 0.003Error 8 1.3333 0.1667Total 11 12.6667

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Appendix 2.45. Discolouration (scores: 1 = none/slight to 3 = advanced), opening (scores: 1 = < 5%to 3 = > 25%) and wilting (scores: 1 = none/slight to 3 = advanced) of flowers from G. ‘Sylvia’inflorescences used in the determination of flower ACC content, which were treated with (zz) 0 nL1-MCP/Land 0 µL propylene/L, (��) 0 nL 1-MCP/L and 100 µL propylene/L, (▲) 10 nL 1-MCP/Land 0 µL propylene/L, or (▼) 10 nL 1-MCP/L and 100 µL propylene/L. 1-MCP and propylenetreatments were each conducted on day 0 and day 1, respectively, for 12 hours at 20oC. Verticalbars represent the standard errors of means.

Appendix 2.46. ANOVA table for discolouration of flowers from G. ‘Sylvia’ inflorescences treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from eachtreatment were then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC. Flowerdiscolouration score data were converted to a binary score for ANOVA.


Appendix 2.47. ANOVA table for wilting of flowers from G. ‘Sylvia’ inflorescences treated on day

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0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC. Flower wilting score datawere converted to a binary score for ANOVA.


Appendix 2.48. Summary of chi-square test for an association between treatments (1-MCP andpropylene) and opening scores (scores: 1 = < 5% to 3 = > 25%) for G. ‘Sylvia’ inflorescences treatedon day 0 with 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 100 µL propylene/L for 12 hours at 20oC.

Days Chi-square df P0 y y y

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2 3.771 3 0.2873 y y y

4 z 1.286 2 1.0005 z 2.250 2 1.000z Fisher’s exact test was performed where the chi-square test was invalid.y Chi-square test could not be calculated as all inflorescences were of an equal score.

Appendix 3.1. ANOVA table for perianth abscission from A. pinnatum inflorescences pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. (Experiment1). Perianth abscission percentage data were arcsine transformed for ANOVA.


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Appendix 3.2. ANOVA table for relative fresh weight of A. pinnatum inflorescences pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. (Experiment 1).


Appendix 3.3. ANOVA table for vase solution uptake by A. pinnatum inflorescences pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. (Experiment 1).


Appendix 3.4. ANOVA table for vase life of A. pinnatum inflorescences pre-treated on day 0 with 0or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. (Experiment 1).

Source of variation DF SS MS F P1-MCP (A) 1 0.225 0.225 0.15 0.699Ethylene (B) 1 0.625 0.625 0.42 0.521A x B 1 3.025 3.025 2.04 0.162Error 36 53.500 1.486Total 39 57.375

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Appendix 3.5. ANOVA table for perianth abscission from A. pinnatum inflorescences pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 100 µL ethylene/L for 12 hours at 20oC.(Experiment 2). Perianth abscission percentage data were arcsine transformed for ANOVA.


Appendix 3.6. ANOVA table for relative fresh weight of A. pinnatum inflorescences pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. (Experiment 2).


Appendix 3.7. ANOVA table for vase solution uptake by A. pinnatum inflorescences pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. (Experiment 2).


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Appendix 3.8. ANOVA table for vase life of A. pinnatum inflorescences pre-treated on day 0 with 0or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. (Experiment 2).


Appendix 3.9. ANOVA table for flower discolouration on flowering B. heterophylla stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flowerdiscolouration score data were arcsine transformed for ANOVA.


Appendix 3.10. ANOVA table for flower wilting on flowering B. heterophylla stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower wiltingscore data were converted to a binary score for ANOVA.


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Appendix 3.11. ANOVA table for relative fresh weight of flowering B. heterophylla stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thethese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.12. ANOVA table for vase solution uptake by flowering B. heterophylla stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.13. ANOVA table for vase life of flowering B. heterophylla stems pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.14. ANOVA table for senescence of leaves on flowering C. adunca stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Leaf senescencepercentage data were arcsine transformed for ANOVA.


Appendix 3.15. ANOVA table for flower opening on flowering C. adunca stems pre-treated on day0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower opening score datawere arcsine transformed for ANOVA.


Appendix 3.16. Time in days to moderate pedicel wilting (score = 2) for flowering C. adunca stemsof pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from eachof these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Datafollowed by the same letters are not significantly different (LSD = 2.5) at P = 0.05.

Treatment Time (days)No ethylene (0 µL/L) 0 nL 1-MCP/L 7.8 ± 1.1 ab 10 nL 1-MCP/L 5.4 ± 0.8 a

Plus ethylene (10 µL/L) 0 nL 1-MCP/L 7.1 ± 0.8 ab 10 nL 1-MCP/L 9.1 ± 0.8 b

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Appendix 3.17. ANOVA table for pedicel wilting of flowering C. adunca stems pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation df SS MS F P1-MCP (A) 1 0.400 0.400 0.05 0.821Ethylene (B) 1 22.500 22.500 2.94 0.095A x B 1 48.400 48.400 6.32 0.017Error 36 275.800 7.661Total 39 347.100

Appendix 3.18. ANOVA table for peduncle wilting of flowering C. adunca stems pre-treated on day0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Peduncle wilting score datawere converted to a binary score for ANOVA.


Appendix 3.19. ANOVA table for relative fresh weight of flowering C. adunca stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.20. ANOVA table for vase solution uptake by flowering C. adunca stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.21. ANOVA table for vase life of flowering C. adunca stems pre-treated on day 0 with 0or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatments were thenexposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.22. ANOVA table for flower abscission from flowering C. gummiferum stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flowerabscission score data were arcsine transformed for ANOVA.


Appendix 3.23. Time in days to moderate sepal wilting (score = 2) from flowering C. gummiferumstems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems fromeach of these treatments were then exposed on day 1 to 10 µL ethylene for 12 hours at 20oC. Datafollowed by the same letters are not significantly different (LSD = 3.3) at P = 0.05.

Treatment Time (days)No ethylene (0 µL ethylene/L) 0 nL 1-MCP/L 11.2 ± 1.1 a 10 nL 1-MCP/L 15.5 ± 0.9 b

Plus ethylene (10 µL ethylene/L) 0 nL 1-MCP/L 10.3 ± 1.4 a 10 nL 1-MCP/L 14.8 ± 1.1 bAppendix 3.24. ANOVA table for sepal wilting on flowering C. gummiferum stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these

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treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.25. ANOVA table for relative fresh weight of flowering C. gummiferum stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.26. ANOVA table for vase solution uptake by flowering C. gummiferum stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.27. ANOVA table for vase life of flowering C. gummiferum stems pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.28. ANOVA table for flower abscission from flowering C. uncinatum ‘Paddy’s Late’sprigs pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the sprigs fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.Flower abscission score data were arcsine transformed for ANOVA.


Appendix 3.29. ANOVA table for relative fresh weight of flowering C. uncinatum ‘Paddy’s Late’sprigs pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the sprigs fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.30. ANOVA table for vase solution uptake by flowering C. uncinatum ‘Paddy’s Late’sprigs pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the sprigs fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.31. ANOVA table for vase life of flowering C. uncinatum ‘Paddy’s Late’ sprigs pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the sprigs from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.32. ANOVA table for petal abscission from flowering E. scaber stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Petal abscissionpercentage data were arcsine transformed for ANOVA.


Appendix 3.33. ANOVA table for relative fresh weight of flowering E. scaber stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.34. ANOVA table for vase solution uptake by flowering E. scaber stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.35. ANOVA table for vase life of flowering E. scaber stems pre-treated on day 0 with 0or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatments were thenexposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.36. Time in days to > 10% flower abscission (score = 2) from G. ‘Kay Williams’inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene for 12hours at 20oC. Data followed by the same letters are not significantly different (LSD = 0.5) at P =0.05.

Treatment Time (days)No ethylene (0 µL/L) 0 nL 1-MCP/L 4.3 ± 0.2 b 10 nL 1-MCP/L 4.4 ± 0.2 b

Plus ethylene (10 µL/L) 0 nL 1-MCP/L 1.0 ± 0.0 a 10 nL 1-MCP/L 4.3 ± 0.2 b

Appendix 3.37. ANOVA table for flower abscission from G. ‘Kay Williams’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.38. ANOVA table for relative fresh weight of G. ‘Kay Williams’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.39. ANOVA table for vase solution uptake by G. ‘Kay Williams’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.40. Flower discolouration (scores: 1 = none/slight to 3 = advanced), flower opening(scores: 1 = < 5% to 3 = > 25%) and flower wilting (scores: 1 = none/slight to 3 = advanced) from G.‘Kay Williams’ inflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L (zz), 0 nL 1-MCP/Land 10 µL ethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲), or 10 nL 1-MCP/L and 10 µLethylene/L (▼). 1-MCP and ethylene treatments were conducted for 12 hours at 20oC on days 0and 1, respectively. Vertical bars represent the standard errors of means (n = 7). Where novertical bars appear, standard errors are smaller than the size of the symbol.

Appendix 3.41. ANOVA table for flower discolouration from G. ‘Kay Williams’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.Flower discolouration score data were arcsine transformed for ANOVA.


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Appendix 3.42. Summary of chi-square test for an association between treatment (1-MCP andethylene) and opening scores (scores: 1 = < 5% to 3 = > 80%) for G. ‘Kay Williams’ inflorescencespre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescencesfrom each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Days Chi-square df P0 5.000 4 0.2871 1.400 2 0.4972 0.525 2 0.7693a 2.100 2 0.5414 b b b

5 b b b

a Fisher’s exact test was performed where the chi-square test was invalid.b Chi-square test could not be calculated as all inflorescences were of an equal score.

Appendix 3.43. ANOVA table for flower wilting from G. ‘Kay Williams’ inflorescences pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flowerwilting score data were converted to a binary score for ANOVA.


Appendix 3.44. ANOVA table for vase life of G. ‘Kay Williams’ inflorescences pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.45. Time in days to > 10% flower abscission (score = 2) from G. ‘Misty Pink’inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene for 12hours at 20oC. Data followed by the same letters are not significantly different (LSD = 0.6) at P =0.05.

Treatment Time (days)No ethylene (0 µL/L) 0 nL 1-MCP/L 4.1 ± 0.2 b 10 nL 1-MCP/L 4.2 ± 0.2 bPlus ethylene (10 µL/L) 0 nL 1-MCP/L 1.0 ± 0.0 a 10 nL 1-MCP/L 4.0 ± 0.2 b

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Appendix 3.46. ANOVA table for flower abscission from G. ‘Misty Pink’ inflorescences pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from eachtreatment were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.47. ANOVA table for relative fresh weight of G. ‘Misty Pink’ inflorescences treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.48. ANOVA table for vase solution uptake by G. ‘Misty Pink’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.49. Flower discolouration (scores: 1 = none/slight to 3 = advanced), wilting (scores: 1 =none/slight to 3 = advanced) and opening (scores: 1 = < 5% to 3 = > 25%) from G. ‘Misty Pink’inflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L (zz), 0 nL 1-MCP/L and 10 µLethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲), or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene treatments were conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent the standard errors of means (n = 10). No significantdifferences (P > 0.05) between treatments existed for flower opening data except on day 1(Appendix 3.52).

Appendix 3.50. ANOVA table for flower discolouration from G. ‘Misty Pink’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.Flower discolouration score data were arcsine transformed for ANOVA.


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Appendix 3.51. ANOVA table for flower wilting from G. ‘Misty Pink’ inflorescences pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower wiltingscore data were converted to a binary score for ANOVA.


Appendix 3.52. Summary of chi-square test for an association between treatment (1-MCP andethylene) and opening scores (scores: 1 = < 5% to 3 = > 25%) for G. ‘Misty Pink’ inflorescencespre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescencesfrom each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Days Chi-square df P0 2.219 6 0.8551 8.459 3 0.0372 2.222 3 0.5283 z z z

4 z z z

5 z z z

z Chi-square test could not be calculated as all inflorescences were of an equal score.

Appendix 3.53. ANOVA table for vase life of G. ‘Misty Pink’ inflorescences pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each treatmentwere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.54. ANOVA table for flower abscission from G. ‘Sandra Gordon’ inflorescences on thelast day of the experiment. Inflorescences were pre-treated on day 0 with 0 or 10 nL 1-MCP/L for12 hours at 20oC. Half of the inflorescences from each of these treatments were then exposed onday 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower abscission score data were arcsinetransformed for ANOVA.


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Appendix 3.55. ANOVA table for relative fresh weight of G. ‘Sandra Gordon’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.56. ANOVA table for vase solution uptake by G. ‘Sandra Gordon’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.57. Flower discolouration (scores: 1 = none/slight to 3 = advanced), opening (scores: 1=< 5% to 3 = > 25%) and wilting (scores: 1 = none/slight to 3 = advanced) from G. ‘Sandra Gordon’inflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L (zz), 0 nL 1-MCP/L and 10 µLethylene/L (��), 10 nL 1-MCP/L and 0 µL ethylene/L (▲) or 10 nL 1-MCP/L and 10 µL ethylene/L(▼). 1-MCP and ethylene treatments were conducted for 12 hours at 20oC on days 0 and 1,respectively. Vertical bars represent the standard errors of means (n = 10). LSD for flowerdiscolouration data is presented in Appendix 3.57. No significant differences (P > 0.05) betweentreatments existed for flower opening data, except on day 2 (Appendix 3.60).

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Appendix 3.58. Time in days to moderate flower discolouration (score = 2) for G. ‘Sandra Gordon’inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene for 12hours at 20oC. Data followed by the same letters are not significantly different (LSD = 0.3) at P =0.05.

Treatment Time (days)No ethylene (0 µL/L) 0 nL 1-MCP/L 6.0 ± 0.1 ab 10 nL 1-MCP/L 6.4 ± 0.2 bPlus ethylene (10 µL/L) 0 nL 1-MCP/L z

10 nL 1-MCP/L 5.8 ± 0.1 az Treatment was excluded from statistical analysis as all flowers had abscised.

Appendix 3.59. ANOVA table for flower discolouration from G. ‘Sandra Gordon’ inflorescencespre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescencesfrom each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation df SS MS F PTreatment 2 1.8667 0.9333 4.20 0.026Error 27 6.0000 0.2222Total 29 7.8667

Appendix 3.60. Summary of chi-square test for an association between treatment (1-MCP andethylene) and opening scores (scores: 1 = none/slight to 3 = advanced) for G. ‘Sandra Gordon’inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC.

Days Chi-square df P0 b b b

1 2.165 3 0.5392a 12.894 6 0.0183a 3.077 3 1.0004a 3.077 3 1.0005 b b b

6 b b b

7 b b b

a Fisher’s exact test was performed where the chi-square test was invalid.b Chi-square test could not be calculated as all inflorescences were of an equal score.

Appendix 3.61. ANOVA table for flower wilting from G. ‘Sandra Gordon’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.Flower wilting score data were converted to a binary score for ANOVA.


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Appendix 3.62. ANOVA table for vase life of G. ‘Sandra Gordon’ inflorescences pre-treated on day0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the inflorescences from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.63. ANOVA table for petal abscissiona from flowering L. petersonii stems of pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 12.500 12.500 8.38 0.007Ethylene (B) 1 1.125 1.125 0.75 0.392A x B 1 4.500 4.500 3.02 0.093Error 28 41.750 1.491Total 31 59.875a Petal abscission data is equivalent to vase life data.

Appendix 3.64. ANOVA table for relative fresh weight of flowering L. petersonii stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.65. ANOVA table for vase solution uptake by flowering L. petersonii stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.66. ANOVA table for flower abscission and senescencea from flowering L. scoparium‘Winter Cheer’ stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half ofthe stems from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 1.8360 1.8360 2.41 0.133Ethylene (B) 1 0.8332 0.8332 1.09 0.306A x B 1 0.0489 0.0489 0.06 0.802Error 24 18.2619 0.7609Total 27 20.9800a Flower abscission and senescence data is equivalent to vase life data.

Appendix 3.67. ANOVA table for relative fresh weight of flowering L. scoparium ‘Winter Cheer’stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.68. ANOVA table for vase solution uptake by flowering L. scoparium ‘Winter Cheer’stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems fromeach of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.69. Time in days to moderate pedicel (score = 2) and peduncle wilting (score = 2) and >10% flower opening (score = 2) on flowering O. diosmifolius stems pre-treated on day 0 with 0 or 10nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatments were thenexposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters arenot significantly different at P = 0.05. LSD for peduncle wilting = 1.1.

Assessment No ethylene (0 µL ethylene/L) Plus ethylene (10 µL ethylene/L)0 nL 1-MCP/L 10 nL 1-MCP/L 0 nL 1-MCP/L 10 nL 1-MCP/L

Pedicel wilting 9.0 ± 0.6 8.8 ± 0.5 8.7 ± 0.7 9.7 ± 0.5Flower opening 6.1 ± 1.0 6.0 ± 0.3 5.8 ± 0.6 5.2 ± 0.4Peduncle wilting 6.0 ± 0.5 b 5.3 ± 0.4 ab 4.6 ± 0.3 a 4.7 ± 0.4 a

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Appendix 3.70. ANOVA table for pedicel wilting of flowering O. diosmifolius stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.71. ANOVA table for flower opening on O. diosmifolius stems pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.72. ANOVA table for leaf senescence on flowering O. diosmifolius stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Leaf senescencepercentage data were arcsine transformed for ANOVA.


Appendix 3.73. ANOVA table for leaf abscission from flowering O. diosmifolius stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.74. ANOVA table for relative fresh weight of flowering O. diosmifolius stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.75. ANOVA table for peduncle wilting from flowering O. diosmifolius stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.76. ANOVA table for vase solution uptake by flowering O. diosmifolius stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each ofthese treatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.77. ANOVA table for vase life of flowering O. diosmifolius stems pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.78. ANOVA table for relative fresh weight of flowering P. lanceolata stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.79. ANOVA table for vase solution uptake by flowering P. lanceolata stems pre-treated with 0 or 10 nL 1-MCP/L for 12 hours at 20oC on day 0. Half of the stems from each ofthese treatments were then exposed to 10 µL ethylene/L for 12 hours at 20oC on day 1.


Appendix 3.80. ANOVA table for vase life of flowering P. lanceolata stems pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.81. ANOVA table for perianth abscissiona from clonally propagated T. speciosissima‘Shady Lady’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC.Half of the inflorescences from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 3.025 3.025 3.000 0.092Ethylene (B) 1 4.225 4.225 4.19 0.048A x B 1 1.225 1.225 1.21 0.278Error 36 36.300 1.008Total 39 44.775a Perianth abscission data is equivalent to vase life data.

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Appendix 3.82. ANOVA table for relative fresh weight of clonally propagated T. speciosissima‘Shady Lady’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC.Half of the stems from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for12 hours at 20oC.


Ope

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Appendix 3.83. Flower opening (scores: 1 = < 5% to 3 = 25%) and vase solution uptake for clonallypropagated T. speciosissima ‘Shady Lady’ inflorescences treated with 0 nL 1-MCP/L and 0 µLethylene/L (●), 0 nL 1-MCP/L and 10 µL ethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲),or 10 nL 1-MCP/L and 10 µL ethylene/L (▼). 1-MCP and ethylene treatments were eachconducted for 12 hours at 20oC on days 0 and 1, respectively. Vertical bars represent standarderrors of means (n = 10). LSD for vase solution uptake data = 0.054 mL/g initial FW/2 days.

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Appendix 3.84. Summary of chi-square test for an association between treatment (1-MCP andethylene) and opening scores (scores: 1 = < 5% to 3 = 25%) for clonally propagated T. speciosissimainflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC.

Days Chi-square df P0 5.518 6 0.4792 3.436 6 0.7524 2.222 3 0.5286 3.077 3 0.380

Appendix 3.85. ANOVA table for vase solution uptake by clonally propagated T. speciosissima‘Shady Lady’ inflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC.Half of the inflorescences from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC.


Appendix 3.86. ANOVA table for perianth abscissiona from seed-grown T. speciosissimainflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 10.0000 10.0000 11.84 0.001Ethylene (B) 1 0.4000 0.4000 0.47 0.496A x B 1 3.6000 3.6000 4.26 0.046Error 36 30.4000 0.8444Total 39 44.4000a Perianth abscission data is equivalent to vase life data.

Appendix 3.87. ANOVA table for relative fresh weight of seed-grown T. speciosissimainflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of thestems from each of these treatments on day 1 were then exposed to 10 µL ethylene/L for 12 hours at20oC.


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Ope

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Appendix 3.88. Flower opening (scores: 1 = < 5% to > 25%) and vase solution uptake for seed-grown T. speciosissima inflorescences treated with 0 nL 1-MCP/L and 0 µL ethylene/L (●), 0 nL 1-MCP/L and 10 µL ethylene/L (■), 10 nL 1-MCP/L and 0 µL ethylene/L (▲), or 10 nL 1-MCP/L and10 µL ethylene/L (▼). 1-MCP and ethylene treatments were each conducted for 12 hours at 20oCon days 0 and 1, respectively. Vertical bars represent standard errors of means (n = 10). Nosignificant differences (P > 0.05) between treatments for flower opening data existed except on day2 (Appendix 3.89). LSD for vase solution uptake data = 0.021 mL/g initial FW/2 days.

Appendix 3.89. Summary of chi-square test for an association between treatment (1-MCP andethylene) and opening scores (scores: 1 = < 5% to > 25%) for seed-grown T. speciosissimainflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC.

Days Chi-square df P0 5.583 6 0.4712a 28.092 9 0.0014 12.229 6 0.0576 9.730 6 0.137a Fisher’s exact test was performed where the Chi-square test was invalid.

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Appendix 3.90. ANOVA table for vase solution uptake by seed-grown T. speciosissimainflorescences pre-treated on day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of theinflorescences from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 12hours at 20oC.


Appendix 3.91. ANOVA table for flower abscission from flowering T. calycina stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower abscissionpercentage data were arcsine transformed for ANOVA.


Appendix 3.92. ANOVA table for closure of flowers from flowering T. calycina stems treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower closurepercentage data were arcsine transformed for ANOVA.


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Appendix 3.93. ANOVA table for relative fresh weight of flowering T. calycina stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.94. ANOVA table for vase solution uptake by flowering T. calycina stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.95. ANOVA table for vase life of flowering stems of T. calycina pre-treated on day 0with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatmentswere then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.96. ANOVA table for flower abscission from flowering V. nitens stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower abscissionscore data were arcsine transformed for ANOVA.


Appendix 3.97. ANOVA table for relative fresh weight of flowering V. nitens stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.98. ANOVA table for vase solution uptake by flowering V. nitens stems pre-treated onday 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.99. ANOVA table for vase life of flowering V. nitens stems pre-treated on day 0 with 0or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of these treatments were thenexposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.100. ANOVA table for flower abscissiona from flowering Z. cytisoides stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation df SS MS F P1-MCP (A) 1 11.250 11.250 3.44 0.082Ethylene (B) 1 2.450 2.450 0.75 0.400A x B 1 0.450 0.450 0.14 0.716Error 16 52.400 3.275Total 19 66.550a Flower abscission data is equivalent to vase life data.

Appendix 3.101. ANOVA table for relative fresh weight of flowering Z. cytisoides stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 3.102. ANOVA table for vase solution uptake by flowering Z. cytisoides stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L for 12 hours at 20oC. Half of the stems from each of thesetreatments were then exposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 3.103. ANOVA table for flower wilting from flowering B. heterophylla stems pre-treatedon day 0 with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+) for 12 hours at 20oC. Half ofthe stems from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 72hours at 20oC. Flower wilting score data were converted to a binary score for ANOVA.

Source of variation DF SS MS F PTreatment (A) 2 16.4704 8.2352 120.55 0.000Ethylene (B) 1 1.6667 1.6667 24.40 0.000A x B 2 15.5444 7.7722 113.77 0.000Rep (A B) 54 23.0889 0.4276 6.26 0.000Day (C) 8 38.5926 4.8241 70.62 0.000A x C 16 7.1296 0.4456 6.52 0.000B x C 8 0.2667 0.0333 0.49 0.865A x B x C 16 2.7222 0.1701 2.49 0.001Error 432 29.5111 0.0683Total 539 134.9926

Appendix 3.104. ANOVA table for relative fresh weight of flowering B. heterophylla stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+) for 12 hours at 20oC.Half of the stems from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for72 hours at 20oC.

Source of variation DF SS MS F PTreatment (A) 2 5903.0 2951.5 161.14 0.000Ethylene (B) 1 23413.7 23413.7 1278.33 0.000A x B 2 13243.1 6621.6 361.52 0.000Rep (A B) 54 46640.9 863.7 47.16 0.000Day (C) 11 150542.7 13685.7 747.20 0.000A x C 22 2580.2 117.3 6.40 0.000B x C 11 1685.5 153.2 8.37 0.000A x B x C 22 1038.2 47.2 2.58 0.000Error 594 10879.6 18.3Total 719 255927.0

Appendix 3.105. ANOVA table for vase life of flowering B. heterophylla stems pre-treated on day 0with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+) for 12 hours at 20oC. Half of the stemsfrom each of these treatments were then exposed on day 1 to 10 µL ethylene/L for 72 hours at 20oC.

Source of variation DF SS MS F PTreatment (A) 2 7.600 3.800 1.14 0.329Ethylene (B) 1 4.267 4.267 1.28 0.264A x B 2 32.133 16.067 4.80 0.012Error 54 180.600 3.344Total 59 224.600

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Appendix 3.106. Time in days to > 50% flower discolouration (score = 3) on flowering B.heterophylla stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+)for 12 hours at 20oC. Half of the stems from each of these treatments were then exposed on day 1 to10 µL ethylene for 72 hours at 20oC. Data followed by the same letters are not significantlydifferent (LSD = 1.1) at P = 0.05.

Treatment Time (days)No ethylene (0 µL ethylene/L) 0 nL 1-MCP/L 4.6 ± 0.3 a 10 nL 1-MCP/L 4.8 ± 0.4 a 0.5 mM Ag+ 7.0 ± 0.5 b

Plus ethylene (10 µL ethylene/L) 0 nL 1-MCP/L 4.5 ± 0.4 a 10 nL 1-MCP/L 4.2 ± 0.2 a 0.5 mM Ag+ 5.1 ± 0.5 a

Appendix 3.107. ANOVA table for flower discolouration from flowering B. heterophylla stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+) for 12 hours at 20oC.Half of the stems from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for12 hours at 20oC.

Source of variation df SS MS F PAgent (1-MCP or STS) (A) 2 31.033 15.517 9.63 0.000Ethylene (B) 1 11.267 11.267 6.99 0.011A x B 2 8.633 4.317 2.68 0.078Error 54 87.000 1.611Total 59 137.933

Appendix 3.108. ANOVA table for vase solution uptake by flowering B. heterophylla stems pre-treated on day 0 with 0 or 10 nL 1-MCP/L or pulsed with STS (0.5 mM Ag+) for 12 hours at 20oC.Half of the stems from each of these treatments were then exposed on day 1 to 10 µL ethylene/L for72 hours at 20oC.

Source of variation DF SS MS F PAgent (1-MCP or Ag+) (A) 2 0.44624 0.22312 5.71 0.006Ethylene (B) 1 0.00039 0.00039 0.01 0.920A x B 2 1.43496 0.71748 18.36 0.000Rep (A B) 54 2.10978 0.03907 12.31 0.000Day (C) 11 13.37318 1.21574 383.06 0.000A x C 22 0.60994 0.02772 8.74 0.000B x C 11 0.02513 0.00228 0.72 0.720A x B x C 22 0.35653 0.01621 5.11 0.000Error 594 1.88522 0.00317Total 719 20.24139

Appendix 3.109. Ethylene production by detached flowers or flowering stems of B. heterophylla atdifferent stages of wilting. The number of measurements at each wilting stage or score are shownin parentheses. Data followed by the same letters are not significantly different at P = 0.05. LSDfor ethylene production by individual flowers and flowering stems = 1.8 and 1.3 µL/kg FW/hr,respectively.

Flower wilt score Ethylene production (µL/kg FW/hr)Individual flowers Flowering stems

1 (none/slight) 1.3 ± 0.5 a (n = 59) 2.0 ± 0.4 a (n = 54)2 (moderate) 5.8 ± 1.1 b (n = 4) 2.9 ± 0.2 ab (n = 3)3 (advanced) 5.2 ± 1.1 b (n = 7) 3.4 ± 0.5 b (n = 8)Appendix 3.110. Ethylene production by detached flowers or flowering stems of B. heterophylla atdifferent stages of discolouration. The number of measurements at each discolouration stage or

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score are shown in parentheses. Data followed by the same letters are not significantly different atP = 0.05. LSD for ethylene production by individual flowers and flowering stems = 2.3 and 1.3µL/kg FW/hr, respectively.

Flower discolouration score Ethylene production (µL/kg FW/hr)Individual flowers Flowering stems

1 (0-25%) 0.9 ± 0.2 a (n = 16) 2.2 ± 0.5 a (n = 17)2 (26-50%) 1.2 ± 0.6 a (n = 18) 1.8 ± 0.4 a (n = 19)3 (51-75%) 2.1 ± 0.7 ab (n = 20) 2.6 ± 1.1 a (n = 29)4 (76-100%) 3.6 ± 1.3 b (n = 16) z

z Flowers did not reach a discolouration score of 4.

Appendix 3.111. ANOVA table for ethylene production by detached B. heterophylla flowerssampled at different stages of wilting on a 3 point scale.

Source of variation df SS MS F PWilting 2 159.56 78.78 41.38 0.000Error 67 129.17 1.93Total 69 288.73

Appendix 3.112. ANOVA table for ethylene production by detached B. heterophylla flowerssampled at different stages of discolouration on a 4 point scale

Source of variation df SS MS F PDiscolouration 3 71.04 23.68 7.18 0.000Error 66 217.69 3.30Total 69 288.73

Appendix 3.113. ANOVA table for ethylene production by flowering B. heterophylla stems whenflowers were at different stages of wilting on a 3 point scale

Source of variation df SS MS F PWilting 2 14.293 7.146 7.31 0.001Error 62 60.589 0.977Total 64 74.881

Appendix 3.114. ANOVA table for ethylene production by flowering B. heterophylla stems whenflowers were at different stages of discolouration on a 4 point scale.

Source of variation df SS MS F PDiscolouration 2 8.03 4.01 3.72 0.030Error 62 66.85 1.08Total 64 74.88

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Appendix 4.1. Change in flower abscission (scores: 1 = < 10% to 5 = > 80%) after exposure toethylene for G. ‘Sylvia’ inflorescences pre-treated on day 0 with 10 nL 1-MCP/L for 12 hours at 2or 20oC. Different sub-samples of these inflorescences were then treated daily until day 5 with 10µL ethylene/L for 12 hours at 20oC. Data followed by the same letters are not significantly different(LSD = 1.7) at P = 0.05 (n = 5). A logistic transformation of flower abscission data was performedprior to ANOVA.

Days between 1-MCP pre-treatment andexposure to ethylene

Flower abscission

1-MCP at 2oC 1-MCP at 20oC1 2.1 ± 0.0 d -5.3 ± 0.0 a2 2.1 ± 0.0 d -3.4 ± 1.2 b3 2.1 ± 0.04 d -2.1 ± 1.4 b4 1.9 ± 0.10 cd 0.3 ± 0.5 c5 1.7 ± 0.08 cd 0.8 ± 0.4cd

Appendix 4.2. Loss of relative fresh weight after exposure to ethylene from G. ‘Sylvia’inflorescences pre-treated on day 0 with 10 nL 1-MCP/L for 12 hours at 2 or 20oC. Different sub-samples of these inflorescences were then treated daily until day 5 with 10 µL ethylene/L for 12hours at 20oC. Data followed by the same letters are not significantly different (LSD = 15%) at P =0.05 (n = 5). A logistic transformation of relative fresh weight data was performed prior toANOVA.

Days between 1-MCP pre-treatment andexposure to ethylene

Loss of fresh weight (%)

1-MCP at 2oC 1-MCP at 20oC1 69 ± 2.1 cd 2 ± 1.4 a2 75 ± 3.6 d 11 ± 7.1 a3 72 ± 2.0 cd 34 ± 11 b4 61 ± 3.3 cd 45 ± 5.0 bc5 59 ± 3.7 c 38 ± 5.0 b

Appendix 4.3. ANOVA table for flower abscission from G. ‘Sylvia’ inflorescences pre-treated with10 nL 1-MCP/L for 12 hours at 2 or 20oC. Different sub-samples of these inflorescences were thentreated daily until day 5 with 10 µL ethylene/L for 12 hours at 20oC. A logistic transformation offlower abscission data was performed prior to ANOVA.

Source of variation DF SS MS F PTemperature (A) 1 190.109 190.109 101.09 0.000Treatment (B) 4 57.137 14.284 7.60 0.000A x B 4 71.906 17.977 9.56 0.000Error 40 75.220 1.881Total 49 394.372

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Appendix 4.4. ANOVA table for the loss of relative fresh weight from G. ‘Sylvia’ inflorescencespre-treated with 10 nL 1-MCP/L for 12 hours at 2 or 20oC. Different sub-samples of theseinflorescences were then treated daily until day 5 with 10 µL ethylene/L for 12 hours at 20oC. Alogistic transformation of relative fresh weight data was performed prior to ANOVA.

Source of variation df SS MS F PTemperature (A) 1 2.09408 2.09408 155.68 0.000Time of ethylene treatment (B) 4 0.21605 0.05401 4.02 0.008A x B 4 0.55457 0.13864 10.31 0.000Error 40 0.53804 0.01345Total 49 3.40274

Appendix 4.5. ANOVA table for vase solution uptake by G. ‘Sylvia’ inflorescences pre-treated with10 nL 1-MCP/L for 12 hours at 2 or 20oC. Different sub-samples of these inflorescences were thentreated daily until day 5 with 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F PTreatment (A) 4 0.061322 0.015330 7.43 0.000Temperature (B) 1 0.045499 0.045499 22.04 0.000A x B 4 0.031394 0.007848 3.80 0.010Rep (A B) 40 0.082558 0.002064 3.41 0.000Day (C) 4 0.584569 0.146142 241.51 0.000A x C 16 0.243258 0.015204 25.13 0.000B x C 4 0.032175 0.008044 13.29 0.000A x B x C 16 0.062012 0.003876 6.41 0.000Error 160 0.096819 0.000605Total 249 1.239606

Appendix 4.6. ANOVA table for vase life of G. ‘Sylvia’ inflorescences pre-treated with 10 nL 1-MCP/L for 12 hours at 2 or 20oC. Different sub-samples of these inflorescences were then treateddaily until day 5 with 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F PTemperature (A) 1 8.820 8.820 13.57 0.001Treatment (B) 4 9.800 2.450 3.770 0.011A x B 4 11.88 2.970 4.570 0.004Error 40 26.00 0.650Total 49 56.50

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0 1 2 3 4 5 6

Time (days)

0 1 2 3 4 5 6

Wilt

sco

re

1

2

3

1

2

3

Control treatments

Control treatments



2oC 2oC

20oC 20oC

Appendix 4.7. Flower wilting (scores: 1 = none/slight to 3 = advanced) on G. ‘Sylvia’ inflorescencespre-treated with 10 nL 1-MCP/L at 2 or 20oC. Different sub-samples of these inflorescences werethen sequentially exposed to 10 µL ethylene/L at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼) or 5 (◆).Control inflorescences were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC(●), 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (■) or 10 nL 1-MCP/L at 2 or 20oCand 0 µL ethylene/L at 20oC (▲). 1-MCP and ethylene treatments were each conducted for 12hours on days 0 or 1, respectively, unless otherwise stated. Vertical bars represent standard errorsof means (n = 5).

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0 1 2 3 4 5 6

Time (days)

0 1 2 3 4 5 6

Ope

ning

sco

re

1

2

3

1

2

3



2oC

20oC

2oC

20oC

Appendix 4.8. Flower opening (scores: 1 = < 5% to 3 = > 25%) on G. ‘Sylvia’ inflorescences pre-treated with 10 nL 1-MCP/L at 2 or 20oC. Different sub-samples of these inflorescences were thensequentially exposed to 10 µL ethylene/L at 20oC on days 1 (●), 2 (■), 3 (▲), 4 (▼) or 5 (◆).Control inflorescences were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC(●), 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (■) or 10 nL 1-MCP/L at 2 or 20oCand 0 µL ethylene/L at 20oC (▲). 1-MCP and ethylene treatments were each conducted for 12hours on days 0 or 1, respectively, unless otherwise stated. Vertical bars represent standard errorsof means (n = 5).

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0 1 2 3 4 5 6

Time (days)

0 1 2 3 4 5 6

Dis

colo

urat

ion

scor

e

1

2

3

1

2

3Control treatments Sequential treatments


2oC 2oC

20oC 20oC

Appendix 4.9. Flower discolouration (scores: 1 = none/slight to 3 = advanced) on G. ‘Sylvia’inflorescences pre-treated with 10 nL 1-MCP/L at 2 or 20oC. Different sub-samples of theseinflorescences were then sequentially exposed to 10 µL ethylene/L at 20oC on days 1 (●), 2 (■), 3(▲), 4 (▼) or 5 (◆). Control inflorescences were treated with 0 nL 1-MCP/L at 2 or 20oC and 0 µLethylene/L at 20oC (●), 0 nL 1-MCP/L at 2 or 20oC and 10 µL ethylene/L at 20oC (■) or 10 nL 1-MCP/L at 2 or 20oC and 0 µL ethylene/L at 20oC (▲). 1-MCP and ethylene treatments were eachconducted for 12 hours on days 0 or 1, respectively, unless otherwise stated. Vertical barsrepresent standard errors of means (n = 5).

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Appendix 4.10. Change in flower abscission (%) after exposure to ethylene from C. uncinatum‘Lollypop’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2or 20oC. Different sub-samples of sprigs from each of these treatments were then treated daily untilday 9 with 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters are notsignificantly different (LSD = 0.9) at P = 0.05 (n = 5). A logistic transformation of flower abscissiondata was performed prior to ANOVA.

Days between 1-MCP orSTS pre-treatment andexposure to ethylene

10 nL 1-MCP/L on day 0 0.5 mM Ag+ on day 0

2oC 20oC 2oC 20oC

1 -3.5 ± 0.2 a -3.3 ± 0.1 a -3.5 ± 0.1 a -2.2 ± 0.6b2 -2.2 ± 0.6 de -3.6 ± 0.1 a -3.5 ± 0.1 a -3.4 ± 0.1 a3 -2.2 ± 0.5 b -3.5 ± 0.2 a -3.3 ± 0.2 ab -1.9 ± 0.6 b4 3.4 ± 0.2 e -3.6 ± 0.1 a -3.4 ± 0.1 a -3.6 ± 0.1 a5 3.3 ± 0.1 e -3.1 ± 0.6 ab -3.6 ± 0.2 a -3.1 ± 0.1 ab6 3.2 ± 0.3 e -3.3 ± 0.1 a -3.5 ± 0.1 a -3.1 ± 0.4 ab7 1.4 ± 0.4 d 0.4 ± 0.6 c -3.2 ± 0.4 ab -3.2 ± 0.4 a8 3.3 ± 0.3 e 0.9 ± 0.3 cd -2.4 ± 0.4 b -3.0 ± 0.3 ab9 3.7 ± 0.1 e 2.9 ± 0.3 e -3.5 ± 0.1 a -2.9 ± 0.1 ab

Appendix 4.12. Change in flower abscission (%) after exposure to ethylene from C. uncinatum‘Alba’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or20oC. Different sub-samples of sprigs from each of these treatments were then treated daily untilday 10 with 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters are notsignificantly different (LSD = 1.6) at P = 0.05 (n = 5). A logistic transformation of flower abscissiondata was performed prior to ANOVA.



2oC 20oC 2oC 20oC

1 -3.3 ± 0.2 ab -3.2 ± 0.1 ab -3.4 ± 0.1 ab -3.5 ± 0.1 ab2 -1.7 ± 0.6 bc -2.8 ± 0.7 ab -3.6 ± 0.1 ab -3.2 ± 0.3 ab3 0.5 ± 1.2 cd -3.1 ± 0.4 ab -3.3 ± 0.2 ab -3.2 ± 0.4 ab4 -4.2 ± 0.8 c -2.8 ± 0.5 ab -3.0 ± 0.1 ab -3.3 ± 0.1 ab5 0.8 ± 0.2 cd 0.2 ± 0.3 cd -1.9 ± 0.4 bc -3.2 ± 0.3 ab6 0.9 ± 1.1 cd -1.7 ± 0.3 bc -2.8 ± 0.1 ab -3.6 ± 0.1 ab7 -0.5 ± 0.7 c -2.4 ± 0.3 ab -2.8 ± 0.9 ab -2.1 ± 0.6 b8 -1.3 ± 0.5 bc -0.8 ± 0.9 bc -2.4 ± 0.7 ab -3.8 ± 0.1 a9 0.2 ± 1.3 cd 0.9 ± 0.6 cd -3.4 ± 0.1 ab -3.4 ± 0.1 ab10 1.3 ± 1.0 d -0.7 ± 1.2 bc -3.8 ± 0.1 a -3.7 ± 0.1 a

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Appendix 4.13. Change in flower abscission (%) after exposure to ethylene from C. uncinatum‘Mid Pink’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2or 20oC. Different sub-samples of sprigs from each of these treatments were then treated daily untilday 8 with 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters are notsignificantly different (LSD = 1.0) at P = 0.05 (n = 5). A logistic transformation of flower abscissiondata was performed prior to ANOVA.



2oC 20oC 2oC 20oC

1 -2.7 ± 0.4 b -3.6 ± 0.1 ab -3.8 ± 0.1 a -3.6 ± 0.2 ab2 -2.1 ± 0.5 bc -3.7 ± 0.1 ab -3.8 ± 0.2 a -3.7 ± 0.2 a3 3.1 ± 0.4 f -3.3 ± 0.1 ab -3.8 ± 0.2 a -3.6 ± 0.1 ab4 2.7 ± 0.3 ef -1.2 ± 0.7 c -3.6 ± 0.1 ab -3.6 ± 0.2 ab5 3.3 ± 0.4 f 2.0 ± 0.6 e -3.5 ± 0.1 ab -3.7 ± 0.1 a6 3.2 ± 0.6 f 1.5 ± 1.0 de -3.7 ± 0.2 a -3.0 ± 0.2 ab7 2.1 ± 0.7 e 0.9 ± 0.3 d -3.3 ± 0.4 ab -2.9 ± 0.3 ab8 3.7 ± 0.1 f 2.9 ± 0.5 ef -3.9 ± 0.2 a -3.4 ± 0.3 ab

Appendix 4.14. Loss of relative fresh weight after exposure to ethylene from C. uncinatum‘Lollypop’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2or 20oC. Different sub-samples of sprigs from each of these treatments were then treated daily untilday 9 with 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters are notsignificantly different (LSD = 13.5%) at P = 0.05 (n = 5). A logistic transformation of relative freshweight data was performed prior to ANOVA.

Days between1-MCP orSTS pre-treatment andexposure toethylene

Loss of fresh weight (% of initial FW)

1-MCP at 2oC 1-MCP at 20oC STS at 2oC STS at 20oC

1 -2.6 ± 0.3 ab -0.1 ± 0.5 ab 0.2 ± 2.1 b 15.3 ± 4.8 c2 24.8 ± 2.4 cd 1.4 ± 0.8 b 1.9 ± 1.1 bc 10.6 ± 1.6 bc3 4.3 ± 2.9 bc 2.0 ± 0.5 bc 0.9 ± 0.4 b 10.1 ± 2.2 bc4 54.5 ± 3.6 e 5.7 ± 1.3 bc 0.8 ± 0.3 b 2.9 ± 2.0 bc5 52.7 ± 1.5 e 10.8 ± 4.7 bc 5.3 ± 1.5 bc 3.3 ± 1.4 bc6 47.4 ± 6.4 e 3.1 ± 2.2 bc 1.4 ± 0.9 b 1.7 ± 2.2 b7 40.2 ± 4.6 de 30.6 ± 7.0 d 9.1 ± 1.5 bc 6.6 ± 1.7 bc8 44.1 ± 8.5 e 18.4 ± 13.3 cd 9.2 ± 6.8 bc 2.2 ± 13.8 bc9 44.0 ± 4.3 de 32.9 ± 5.2 de 5.1 ± 2.9 bc 9.5 ± 9.5 bc

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Appendix 4.15. Loss of relative fresh weight after exposure to ethylene from C. uncinatum ‘Alba’sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC.Different sub-samples of sprigs from each of these treatments were then treated daily until day 10with 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters are not significantlydifferent (LSD = 12.5%) at P = 0.05 (n = 5). A logistic transformation of relative fresh weight datawas performed prior to ANOVA.

Days between 1-MCP or STS pre-treatment andexposure toethylene



1 -0.9 ± 0.7 a 0.7 ± 0.4 ab -0.2 ± 0.2 ab 3.5 ± 0.8 ab2 14.0 ± 4.9 bc 4.4 ± 3.0 ab -0.5 ± 0.6 a 0.8 ± 1.2 ab3 31.0 ± 6.5 cd 8.2 ± 2.0 ab 1.5 ± 1.0 ab 6.4 ± 1.2 ab4 24.1 ± 7.5 bc 8.4 ± 3.3 ab 0.2 ± 0.6 ab 8.2 ± 4.9 ab5 28.8 ± 3.4 c 2.7 ± 5.7 c 10.0 ± 3.1 ab 6.4 ± 1.8 ab6 29.8 ± 7.7 c 5.7 ± 2.1 ab 3.3 ± 1.4 ab 0.3 ± 0.9 ab7 25.6 ± 6.4 c 0.2 ± 0.8 ab 6.4 ± 4.8 ab 3.6 ± 2.6 ab8 12.1 ± 6.7 b 19.7 ± 8.1 bc 0.8 ± 2.9 ab 1.6 ± 3.2 ab9 19.4 ± 9.8 bc 32.8 ± 6.2 cd 0.9 ± 1.0 ab 3.4 ± 1.3 ab10 42.5 ± 9.4 d 15.8 ± 9.5 bc 2.9 ± 0.5 ab 4.0 ± 1.0 ab

Appendix 4.16. Loss of relative fresh weight after exposure to ethylene from C. uncinatum ‘MidPink’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or20oC. Different sub-samples of sprigs from each of these treatments were then treated daily untilday 8 with 10 µL ethylene/L for 12 hours at 20oC. Data followed by the same letters are notsignificantly different (LSD = 10.1%) at P = 0.05 (n = 5). A logistic transformation of relative freshweight data was performed prior to ANOVA.

Days between1-MCP or STSpre-treatmentand exposure toethylene



1 0.7 ± 2.0 a 0.6 ± 0.8 a -1.6 ± 0.4 a 0.7 ± 0.8 a2 6.0 ± 1.1 ab 4.7 ± 1.8 ab 1.7 ± 0.5 ab 4.8 ± 2.2 ab3 37.1 ± 2.5 d 2.0 ± 0.2 ab 1.0 ± 0.3 a 4.2 ± 1.0 ab4 53.0 ± 2.9 e 17.1 ± 4.6 bc 2.4 ± 1.0 ab 6.4 ± 4.1 ab5 51.7 ± 3.5 e 45.2 ± 4.9 de 0.6 ± 1.8 a 0.8 ± 0.4 a6 48.1 ± 4.5 e 41.4 ± 10.9 de 7.3 ± 3.3 ab 12.0 ± 8.2 b7 40.6 ± 6.5 de 36.1 ± 4.1 d 9.2 ± 5.4 ab 23.0 ± 5.9 c8 52.6 ± 0.8 e 50.7 ± 3.5 e 19.5 ± 3.5 bc 12.4 ± 5.0 bc

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Appendix 4.17. ANOVA table for flower abscission from C. uncinatum ‘Lollypop’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Differentsub-samples of sprigs from each of these treatments were then treated daily until day 9 with 10 µLethylene/L for 12 hours at 20oC. A logistic transformation of flower abscission data was performedprior to ANOVA.

Source of variation df SS MS F PTime of ethylene treatment (A) 8 168.232 21.029 40.92 0.000Agent - 1-MCP or STS (B) 1 417.666 417.666 812.74 0.000Temperature 1 107.103 107.103 208.41 0.000A x B 8 202.257 25.282 49.20 0.000A x C 8 102.320 12.790 24.89 0.000B x C 1 166.483 166.483 323.96 0.000A x B x C 8 75.087 9.386 18.26 0.000Error 144 74.002 0.514Total 179 1313.151

Appendix 4.18. ANOVA table for flower abscission from C. uncinatum ‘Alba’ sprigs pre-treated onday 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Different sub-samplesof sprigs from each of these treatments were then treated daily until day 10 with 10 µL ethylene/Lfor 12 hours at 20oC. A logistic transformation of flower abscission data was performed prior toANOVA.


Appendix 4.19. ANOVA table for flower abscission from C. uncinatum ‘Mid Pink’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Differentsub-samples of sprigs from each of these treatments were then treated daily until day 8 with 10 µLethylene/L for 12 hours at 20oC. A logistic transformation of flower abscission data was performedprior to ANOVA.


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Appendix 4.20. ANOVA table for relative fresh weight of C. uncinatum ‘Lollypop’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Differentsub-samples of sprigs from each of these treatments were then treated daily until day 9 with 10 µLethylene/L for 12 hours at 20oC. A logistic transformation of relative fresh weight data wasperformed prior to ANOVA.


Appendix 4.21. ANOVA table for relative fresh weight of C. uncinatum ‘Alba’ sprigs pre-treatedon day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Different sub-samples of sprigs from each of these treatments were then treated daily until day 10 with 10 µLethylene/L for 12 hours at 20oC. A logistic transformation of relative fresh weight data wasperformed prior to ANOVA.


Appendix 4.22. ANOVA table for relative fresh weight of C. uncinatum ‘Mid Pink’ sprigs pre-treated on day 0 with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Differentsub-samples of sprigs from each of these treatments were then treated daily until day 8 with 10 µLethylene/L for 12 hours at 20oC. A logistic transformation of relative fresh weight data wasperformed prior to ANOVA.


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Appendix 4.23. ANOVA table for vase life of C. uncinatum ‘Lollypop’ sprigs pre-treated on day 0with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Different sub-samples ofsprigs from each of these treatments were then treated daily until day 9 with 10 µL ethylene/L for12 hours at 20oC.

Source of variation DF SS MS F PTemperature (A) 1 46.006 46.006 20.27 0.000Time of ethylene treatment (B) 8 75.111 9.389 4.14 0.000Agent - 1-MCP or STS (C) 1 101.250 101.250 44.61 0.000A x B 8 77.644 9.706 4.28 0.000A x C 1 211.250 211.250 93.08 0.000B x C 8 59.400 7.425 3.27 0.002A x B x C 8 101.400 12.675 5.59 0.000Error 144 326.800 2.269Total 179 998.861

Appendix 4.24. ANOVA table for vase life of C. uncinatum ‘Mid Pink’ sprigs pre-treated on day 0with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Different sub-samples ofsprigs from each of these treatments were then treated daily until day 10 with 10 µL ethylene/L for12 hours at 20oC.


Appendix 4.25. ANOVA table for vase life of C. uncinatum ‘Alba’ sprigs pre-treated on day 0 with10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Different sub-samples of sprigsfrom each of these treatments were then treated daily until day 8 with 10 µL ethylene/L for 12hours at 20oC.


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Appendix 4.26. ANOVA table for vase solution uptake by C. uncinatum ‘Lollypop’ sprigs pre-treated with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Different sub-samplesof sprigs from each of these treatments were then treated daily until day 9 with 10 µL ethylene/Lfor 12 hours at 20oC.

Source of variation df SS MS F PTime of ethylene treatment (A) 8 1.12132 0.14016 2.93 0.005Agent - 1-MCP or STS (B) 1 21.38160 21.38160 447.18 0.000Temperature (C) 1 1.31512 1.31512 27.50 0.000Rep (A B C) 144 6.88529 0.04781 5.47 0.000A x B 8 1.28480 0.16060 3.36 0.001A x C 8 0.80220 0.10027 2.10 0.040B x C 1 1.53361 1.53361 32.07 0.000A x B x C 8 1.90354 0.23794 4.98 0.000Day (D) 8 50.31703 6.28963 719.06 0.000A x D 64 4.75692 0.07433 8.50 0.000B x D 8 0.70690 0.08836 10.10 0.000C x D 8 0.31651 0.3956 4.52 0.000A x B x D 64 1.16415 0.01819 2.08 0.000A x C x D 64 0.61191 0.00956 1.09 0.292B x C x D 8 1.28136 0.16017 18.31 0.000A x B x C x D 64 0.65813 0.01028 1.18 0.168Error 1162 10.07650 0.00875Total 1619 106.11690

Appendix 4.27. ANOVA table for vase solution uptake by C. uncinatum ‘Alba’ sprigs pre-treatedwith 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Different sub-samples ofsprigs from each of these treatments were then treated daily until day 10 with 10 µL ethylene/L for12 hours at 20oC.


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Appendix 4.28. ANOVA table for vase solution uptake by C. uncinatum ‘Mid Pink’ sprigs pre-treated with 10 nL 1-MCP/L or STS (0.5 mM Ag+) for 12 hours at 2 or 20oC. Different sub-samplesof sprigs from each of these treatments were then treated daily until day 8 with 10 µL ethylene/Lfor 12 hours at 20oC.


Appendix 5.1. ANOVA table for flower abscission from C. uncinatum ‘CWA Pink’ sprigs onbunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0mM Ag+ for 6 hours at 20oC. Sprigs from each of these treatments were then exposed on day 0 to10 µL ethylene/L for 12 hours at 20oC. Flower abscission score data were arcsine transformed forANOVA.


Appendix 5.2. ANOVA table for relative fresh weight of C. uncinatum ‘CWA Pink’ sprigs onbunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0mM Ag+ for 6 hours at 20oC. Sprigs from each of these treatments were then exposed on day 0 to10 µL ethylene/L for 12 hours at 20oC.


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Appendix 5.3. ANOVA table for vase solution uptake by C. uncinatum ‘CWA Pink’ sprigs onbunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0mM Ag+ for 6 hours at 20oC. Sprigs from each of these treatments were then exposed on day 0 to10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.4. ANOVA table for vase life of C. uncinatum ‘CWA Pink’ sprigs on bunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for 6hours at 20oC. Sprigs from each of these treatments were then exposed on day 0 to 10 µLethylene/L for 12 hours at 20oC.


Appendix 5.5. ANOVA table for weight loss from C. uncinatum ‘CWA Pink’ bunches pre-treatedon day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for 6 hours at20oC. Bunches were then held inside commercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F PPre-treatment 2 417.97 208.98 7.21 0.006Error 15 435.08 29.01Total 17 853.05

Appendix 5.6. ANOVA table for relative fresh weight of C. uncinatum ‘CWA Pink’ sprigs onbunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0mM Ag+ for 6 hours at 20oC. Bunches were then held inside commercial flower cartons for 6 daysat 20oC.

Source of variation DF SS MS F PPre-treatment (A) 2 3815.54 1907.77 129.24 0.000Rep (A) 27 9336.46 345.79 23.42 0.000Day (B) 4 5636.05 1409.01 95.45 0.000A x B 8 112.27 14.03 0.95 0.479Error 108 1594.30 14.76Total 149 20494.61

Appendix 5.7. ANOVA table for solution uptake by C. uncinatum ‘CWA Pink’ sprigs on bunchespre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for6 hours at 20oC. Bunches were then held inside commercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F PPre-treatment (A) 2 0.072098 0.036049 5.62 0.005Rep (A) 27 0.389678 0.014433 2.25 0.002Day (B) 4 1.377567 0.344392 53.71 0.000A x B 8 0.090946 0.011368 1.77 0.090Error 108 0.692519 0.006412Total 149 2.622809

Appendix 5.8. ANOVA table for vase life of C. uncinatum ‘CWA Pink’ sprigs on bunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for 6

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hours at 20oC. Bunches were then held inside commercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F PPre-treatment 2 40.067 20.033 10.86 0.000Error 27 49.800 1.844Total 29 89.867

Appendix 5.9. ANOVA table for relative fresh weight of C. uncinatum ‘Fortune Cookie’ sprigs onbunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0mM Ag+ for 14 hours at 2 or 20oC. Sprigs from each of these treatments were then exposed on day1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.10. ANOVA table for solution uptake by C. uncinatum ‘Fortune Cookie’ sprigs onbunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0mM Ag+ for 14 hours at 2 or 20oC. Sprigs from each of these treatments were then exposed on day1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.11. ANOVA table for vase life of C. uncinatum ‘Fortune Cookie’ sprigs on bunchespre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for14 hours at 2 or 20oC. Sprigs from each of these treatments were then exposed on day 1 to 10 µLethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F PTreatment (A) 2 249.800 124.900 59.48 0.000Temperature (B) 1 0.000 0.000 0.00 1.000A x B 2 1.800 0.900 0.43 0.656Error 24 50.400 2.100Total 29 302.000

Appendix 5.12. ANOVA table for weight loss from C. uncinatum ‘Fortune Cookie’ bunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for 14hours at 2 or 20oC. Bunches were then held inside commercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F PPre-treatment (A) 2 16.698 8.349 1.44 0.253

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Temperature (B) 1 62.647 62.647 10.81 0.003A x B 2 236.339 118.170 20.39 0.000Error 30 173.867 5.796Total 35 489.551

Appendix 5.13. ANOVA table for relative fresh weight of C. uncinatum ‘Fortune Cookie’ sprigs onbunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0mM Ag+ for 14 hours at 2 or 20oC. Bunches were then held inside commercial flower cartons for 6days at 20oC.

Source of variation DF SS MS F PPre-treatment (A) 2 590.42 295.21 17.16 0.000Temperature (B) 1 45.27 45.27 2.63 0.108A x B 2 2914.97 1457.48 84.73 0.000Rep (A B) 24 18336.39 764.02 44.41 0.000Day (C) 4 7361.65 1840.41 106.99 0.000A x C 8 183.65 22.96 1.33 0.236B x C 4 441.13 110.28 6.41 0.000A x B x C 8 39.51 4.94 0.29 0.969Error 96 1651.43 17.20Total 149 31564.42

Appendix 5.14. ANOVA table for solution uptake by C. uncinatum ‘Fortune Cookie’ sprigs onbunches pre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0mM Ag+ for 14 hours at 2 or 20oC. Bunches were then held inside commercial flower cartons for 6days at 20oC.

Source of variation DF SS MS F PPre-treatment (A) 2 0.56653 0.28326 45.09 0.000Temperature (B) 1 0.00546 0.00546 0.87 0.354A x B 2 0.13475 0.06737 10.73 0.000Rep (A B) 24 1.12908 0.04704 7.49 0.000Day (C) 4 3.94153 0.98538 156.86 0.000A x C 8 0.12936 0.01617 2.57 0.014B x C 4 0.06893 0.01723 2.74 0.033A x B x C 8 0.07223 0.00903 1.44 0.191Error 96 0.60306 0.00628Total 149 6.65092

Appendix 5.15. ANOVA table for vase life of sprigs from C. uncinatum ‘Fortune Cookie’ bunchespre-treated on day 0 with 200 nL 1-MCP/L, STS (0.2 mM Ag+) or 0 nL 1-MCP/L and 0 mM Ag+ for14 hours at 2 or 20oC. Bunches were then held inside commercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F PPre-treatment (A) 2 6.0667 3.0333 3.31 0.054Temperature (B) 1 1.2000 1.2000 1.31 0.264A x B 2 0.6000 0.3000 0.33 0.724Error 24 22.0000 0.9167Total 29 29.8667

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Appendix 5.16. ANOVA table for flower abscission from C. uncinatum ‘Lollypop’ sprigs onbunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L in sealed flower cartons for 24 hours at2oC. Sprigs from each of these treatments were sampled from 4 positions within cartons andexposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower abscission score data werearcsine transformed for ANOVA.

Source of variation DF SS MS F P1-MCP (A) 1 0.085841 0.085841 39.49 0.000Position (B) 3 0.311065 0.103688 47.70 0.000A x B 3 0.364608 0.121536 55.91 0.000Rep (A B) 32 0.626030 0.019563 9.00 0.000Day (C) 3 0.046461 0.015487 7.12 0.000A x C 3 0.028614 0.009538 4.39 0.006B x C 9 0.103688 0.011521 5.30 0.000A x B x C 9 0.121536 0.013504 6.21 0.000Error 96 0.208677 0.002174Total 159 1.896521

Appendix 5.17. ANOVA table for relative fresh weight of C. uncinatum ‘Lollypop’ sprigs onbunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L in sealed flower cartons for 24 hours at2oC. Sprigs from each of these treatments were sampled from 4 positions within cartons andexposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.18. ANOVA table for vase solution uptake by C. uncinatum ‘Lollypop’ sprigs onbunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L in sealed flower cartons for 24 hours at2oC. Sprigs from each of these treatments were sampled from 4 positions within cartons andexposed on day 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 5.19. ANOVA table for flower abscission from C. uncinatum ‘Purple Pride’ sprigs onbunches pre-treated on day 0 with 0 or 2 µL 1-MCP/L in sealed flower cartons for 24 hours at 2oC.Sprigs from each of these treatments were sampled from 4 positions within cartons and exposed onday 1 to 10 µL ethylene/L for 12 hours at 20oC. Flower abscission score data were arcsinetransformed for ANOVA.


Appendix 5.20. ANOVA table for relative fresh weight of C. uncinatum ‘Purple Pride’ sprigs onbunches pre-treated on day 0 with 0 or 2 µL 1-MCP/L in sealed flower cartons for 24 hours at 2oC.Sprigs from each of these treatments were sampled from 4 positions within cartons and exposed onday 1 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.21. ANOVA table for vase solution uptake by C. uncinatum ‘Purple Pride’ sprigs onbunches pre-treated on day 0 with 0 or 2 µL 1-MCP/L in sealed flower cartons for 24 hours at 2oC.Sprigs from each of these treatments were sampled from 4 positions within cartons and exposed onday 1 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 5.22. ANOVA table for vase life of C. uncinatum ‘Purple Pride’ sprigs on bunches pre-treated on day 0 with 0 or 2 µL 1-MCP/L in sealed flower cartons for 24 hours at 2oC. Sprigs fromeach of these treatments were sampled from 4 positions within cartons and exposed on day 1 to 10µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 28.900 28.900 10.80 0.002Position (B) 3 10.600 3.533 1.32 0.285A x B 3 42.500 14.167 5.30 0.004Error 32 85.600 2.675Total 39 167.600

Appendix 5.23. ANOVA table for flower abscission from C. uncinatum ‘Paddy’s Late’ sprigs onbunches pre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Half of the sprigsfrom each of these treatments were then exposed on day 0 to 10 µL ethylene/L for 12 hours at 20oC.Flower abscission score data were arcsine transformed for ANOVA.


Appendix 5.24. ANOVA table for relative fresh weight of C. uncinatum ‘Paddy’s Late’ sprigs onbunches pre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Half of the sprigsfrom each of these treatments were then exposed on day 0 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 5.25. ANOVA table for vase solution uptake by C. uncinatum ‘Paddy’s Late’ sprigs onbunches pre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Half of the sprigsfrom each of these treatments were then exposed on day 0 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.26. ANOVA table for vase life of C. uncinatum ‘Paddy’s Late’ sprigs on bunches pre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Half of the sprigs from each ofthese treatments were then exposed on day 0 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.27. ANOVA table for weight loss from C. uncinatum ‘Paddy’s Late’ bunches pre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Bunches were then held insidecommercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F P1-MCP 1 9.86 9.86 0.56 0.464Error 18 316.90 17.61Total 19 326.76

Appendix 5.28. ANOVA table for abscised flowers and leaves from C. uncinatum ‘Paddy’s Late’bunches pre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Bunches were thenheld inside commercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F P1-MCP 1 0.6502 0.6502 2.09 0.286Error 2 0.6235 0.3118Total 3 1.2737

Appendix 5.29. ANOVA table for flower abscission from C. uncinatum ‘Paddy’s Late’ bunchespre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Bunches were then held insidecommercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 0.01091 0.01091 0.43 0.519Rep (A) 18 0.90827 0.05046 2.00 0.076Day (B) 1 1.29908 1.29908 51.46 0.000A x B 1 0.00085 0.00085 0.03 0.857Error 18 0.45439 0.02524Total 39 2.67350Appendix 5.30. ANOVA table for relative fresh weight of C. uncinatum ‘Paddy’s Late’ bunchespre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Bunches were then held insidecommercial flower cartons for 6 days at 20oC.

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Source of variation DF SS MS F P1-MCP (A) 1 36.65 36.65 2.22 0.154Rep (A) 18 6231.70 346.21 20.95 0.000Day (B) 1 1379.49 1379.49 83.47 0.000A x B 1 0.00 0.00 0.00 0.988Error 18 297.49 16.53Total 39 7945.32

Appendix 5.31. ANOVA table for vase solution uptake by C. uncinatum ‘Paddy’s Late’ bunchespre-treated on day 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Bunches were then held insidecommercial flower cartons for 6 days at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 0.01710 0.01710 1.40 0.252Rep (A) 18 1.16493 0.06472 5.31 0.000Day (B) 1 0.70562 0.70562 57.88 0.000A x B 1 0.01133 0.01133 0.93 0.348Error 18 0.21943 0.01219Total 39 2.11841

Appendix 5.32. ANOVA table for vase life of C. uncinatum ‘Paddy’s Late’ bunches pre-treated onday 0 with 0 or 150 nL 1-MCP/L for 15 hours at 2oC. Bunches were then held inside commercialflower cartons for 6 days at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 0.0500 0.0500 0.36 0.556Error 18 2.5000 0.1389Total 19 2.5500

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Appendix 5.33. ANOVA table for flower abscission from C. uncinatum ‘Purple Pride’ sprigs onbunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L for 3 hours at 2oC in buckets of water orin cartons against a forced-air cooler. Half of the sprigs from each of these treatments sampledfrom 4 positions within cartons or on bunches were then exposed on day 0 to 10 µL ethylene/L for12 hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 20.71325 20.71325 2858.98 0.000Ethylene (B) 1 21.27670 21.27670 2936.75 0.000Position (C) 3 0.40014 0.13338 18.41 0.000A x B 1 18.27129 18.27129 2521.93 0.000A x C 3 0.19607 0.06536 9.02 0.000B x C 3 0.06526 0.02175 3.00 0.030A x B x C 3 0.05030 0.01677 2.31 0.075Rep (A B C) 32 2.00833 0.06276 8.66 0.000Day (D) 9 7.15053 0.79450 109.66 0.000A x D 9 5.11952 0.56884 78.51 0.000B x D 9 5.23844 0.58205 80.34 0.000C x D 27 0.15053 0.00558 0.77 0.794A x B x D 9 4.45400 0.49489 68.31 0.000A x C x D 27 0.11415 0.00423 0.58 0.956B x C x D 27 0.08063 0.00299 0.41 0.997A x B x C x D 27 0.07480 0.00277 0.38 0.998Error 768 5.56414 0.00724Total 959 90.92808

Appendix 5.34. ANOVA table for relative fresh weight of C. uncinatum ‘Purple Pride’ sprigs onbunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L for 3 hours at 2oC in buckets of water orin cartons against a forced-air cooler. Half of the sprigs from each of these treatments sampledfrom 4 positions within cartons or on bunches were then exposed on day 0 to 10 µL ethylene/L for12 hours at 20oC.


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Appendix 5.35. ANOVA table for vase solution uptake by C. uncinatum ‘Purple Pride’ sprigs onbunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L for 3 hours at 2oC in buckets of water orin cartons against a forced-air cooler. Half of the sprigs from each of these treatments sampledfrom 4 positions within cartons or on bunches were then exposed on day 0 to 10 µL ethylene/L for12 hours at 20oC.


Appendix 5.36. ANOVA table for vase life of C. uncinatum ‘Purple Pride’ sprigs on bunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L for 3 hours at 2oC in buckets of water or in cartonsagainst a forced-air cooler. Half of the sprigs from each of these treatments were then exposed onday 0 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 119.260 119.260 105.39 0.000Ethylene (B) 1 128.344 128.344 113.42 0.000Bucket/Carton (C) 1 7.594 7.594 6.71 0.011A x B 1 142.594 142.594 126.01 0.000A x C 1 0.010 0.010 0.01 0.924B x C 1 5.510 5.510 4.87 0.030A x B x C 1 0.260 0.260 0.23 0.633Error 88 99.583 1.132Total 95 503.156

Appendix 5.37. ANOVA table for vase life of C. uncinatum ‘Purple Pride’ sprigs on bunches pre-treated on day 0 with 0 or 200 nL 1-MCP/L for 3 hours at 2oC in buckets of water or in cartonsagainst a forced-air cooler. Half of the sprigs from each of these treatments sampled from 4positions within cartons or on bunches were then exposed on day 0 to 10 µL ethylene/L for 12 hoursat 20oC.

Source of variation DF SS MS F P1-MCP (A) 1 60.750 60.750 45.56 0.000Ethylene (B) 1 40.333 40.333 30.25 0.000Position (C) 3 3.417 1.139 0.85 0.475A x B 1 65.333 65.333 49.00 0.000A x C 3 1.750 0.583 0.44 0.728B x C 3 1.167 0.389 0.29 0.831A x B x C 3 7.833 2.611 1.96 0.140Error 32 42.667 1.333Total 47 223.250Appendix 5.38. ANOVA table for flower abscission from C. uncinatum ‘Alba’ sprigs on bunchespre-treated on day 0 in cartons with no 1-MCP (control), 1, 2 or 3 tubes of 1-MCP gas for 6 days at

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20oC. Half of the sprigs from each of these treatments sampled from 4 positions within cartonswere then exposed on day 6 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.39. ANOVA table for relative fresh weight of C. uncinatum ‘Alba’ sprigs on bunchespre-treated on day 0 in cartons with no 1-MCP (control), one tube, two tubes or three tubes of 1-MCP gas for 6 days at 20oC. Half of the sprigs from each of these treatments sampled from 4positions within cartons were then exposed on day 6 to 10 µL ethylene/L for 12 hours at 20oC.


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Appendix 5.40. ANOVA table for vase solution uptake by C. uncinatum ‘Alba’ sprigs on bunchespre-treated on day 0 in cartons with no 1-MCP (control), one tube, two tubes or three tubes of 1-MCP gas for 6 days at 20oC. Half of the sprigs from each of these treatments sampled from 4positions within cartons were then exposed on day 6 to 10 µL ethylene/L for 12 hours at 20oC.


Appendix 5.41. ANOVA table for vase life of C. uncinatum ‘Alba’ sprigs on bunches pre-treated onday 0 in cartons with no 1-MCP (control), one tube, two tubes or three tubes of 1-MCP gas for 6days at 20oC. Half of the sprigs from each of these treatments sampled from 4 positions withincartons were then exposed on day 6 to 10 µL ethylene/L for 12 hours at 20oC.

Source of variation DF SS MS F P1-MCP (A) 3 20.708 6.903 3.04 0.035Ethylene (B) 1 10.667 10.667 4.70 0.034Position (C) 3 11.542 3.847 1.69 0.177A x B 3 12.250 4.083 1.80 0.156A x C 9 19.375 2.153 0.95 0.491B x C 3 3.750 1.250 0.55 0.650A x B x C 9 46.333 5.148 2.27 0.028Error 64 145.333 2.271Total 95 269.958

Appendix 5.41. ANOVA table for weight loss from C. uncinatum ‘Alba’ bunches pre-treated onday 0 in cartons with no 1-MCP (control), one tube, two tubes or three tubes of 1-MCP gas for 6days at 20oC.

Source of variation DF SS MS F P1-MCP (A) 3 1146.22 382.07 22.18 0.000Carton (B) 2 319.15 159.57 9.26 0.000A x B 6 255.01 42.50 2.47 0.034Error 60 1033.59 17.23Total 71 2753.97

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Appendix 5.42. ANOVA table for abscised flowers and leaves from C. uncinatum ‘Alba’ bunchespre-treated on day 0 in cartons with no 1-MCP (control), one tube, two tubes or three tubes of 1-MCP gas for 6 days at 20oC.

Source of variation DF SS MS F P1-MCP (A) 3 27.0195 9.0065 22.14 0.000Error 8 3.2548 0.4069Total 11 30.2743

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APPENDIX C SUMMARY TABLE OF PROJECT ACHIEVEMENTS

Milestone Achievement indicator

1. Review literature Review of relevant 1-MCP and ethylene papers(Appendix A).

2. Manufacture and quantification of 1-MCP Gas chromatograms showing 1-MCP (Appendices2.1 and 2.2).

3. Testing 1-MCP on native cut flowers (conductdosage experiments)

Data presented in Chapter 2 showing 1-MCPdosage (concentration, duration and temperature)effects on Grevillea ‘Sylvia’ inflorescences.Additional data on the effect of temperature on theduration of efficacy of 1-MCP treatment onGrevillea ‘Sylvia’ and Chamelaucium uncinatum(Chapter 4).

4. Testing 1-MCP on native cut flowers (conductscreening experiments on a range of native cutflowers)

Data presented in Chapter 3 showing 1-MCP andethylene treatment effects on a variety of native cutflowers.

5. Design and test commercial application systemfor 1-MCP treatment

Data presented in Chapter 5 showing efficacy ofcommercial scale application of 1-MCP treatmentto Chamelaucium uncinatum flowers.

6. Prepare thesis and publications Presentation and/or preparation of materialintended to update research and industry personnelof 1-MCP effects on native cut flowers (seeCommunications Strategy)

native cut flowers · iii foreword postharvest flower fall from various native australian cut...

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