Reciprocal soil trials to test the presence or absence of edaphic constraints on the range of the narrow

endemic Monarda fruticulosa

Krista Lueth and Alan PratherMSU Department of Plant Biology

With special thanks to the graduate students of the Prather lab

What are edaphic effects?

• Edaphic effects are soil characteristics that modify growth and development of plant species:– Organic matter– Inorganic minerals– Heavy metals– Water holding capacity– Soil salinity

What is a narrow endemic?

• Narrow endemic taxa are species that occur in one or a few small populations

• The genus Monarda contains 4 narrow endemics that grow in South Central Texas

» M. fruticulosa» M. maritima» M. stanfieldii» M. viridissima

Why study endemism?

• To understand biodiversity• To understand speciation in plants• To understand rarity as a means of

facilitating conservation• To understand edaphic effects on growth

and development of plant species• Endemics are often restricted by edaphic

constraints

Species Descriptions•Monarda fruticulosa is a narrowly endemic species found only on the sand plains of central southern Texas

•Monarda punctata is a widespread species that is found across Southern, Central, and Eastern North America

•Phylogenetic analysis reveals that these two species are very closely related

Monarda punctata and Monarda fruticulosa

growth habits

Monarda punctata distribution in the USAhttp://plants.usda.gov/cgi_bin/plant_profile.cgi?symbol=MOPUP

Monarda fruticulosa range

Hypotheses

• Monarda fruticulosa performs better on M. fruticulosa soils than on M. punctata soils in general

• Monarda fruticulosa performs better on native soil from it’s home site than on any other soil

• Monarda fruticulosa is a perennial species and as such will have a higher root/shoot ratio than M. punctata

Collection• In May of 2002, Dr. Alan Prather collected soil and mature inflorescences

from native plants growing on the coastal plains of southern Texas

• 10 inflorescences each from 3 different populations of M. punctata• 10 inflorescences each from 3 different populations of M. fruticulosa• 60 inflorescences and 6 soil samples were brought back to MSU

Materials and Methods

•A reciprocal soil trial was performed using three populations each of Monarda puncata and Monarda fruticulosa along with the soils upon which they were collected

•We selected 60 seeds from each population and planted them on each of the six soils upon which the plants grew

Experimental Design

Watering and Light Application

• Plants were put under 12 hours light and 12 hours dark in the lab

• Plants were top watered daily with distilled, deionized water

• Plants were bottom watered on the weekends to prevent the soil from drying out

• Lab temperature was approximately 72 degrees Fahrenheit

Experimental conditions

Monarda punctata Monarda fruticulosa

Data Collection

• Germination date recorded for each seed

• If applicable, date of natural seedling death recorded

• 10 day intervals of growth recorded for each seedling

• At 40 days of growth, each seedling was harvested and weighed

Data Analysis

• 4 measures of fitness were considered for data analysis:– Germination– Height– Survivorship – Biomass

Statistical Test for the Difference between Two Population Proportions(Binomial Data)

π = Probability of Successn = sample size

Z= ( π – π )

1 2 2

1

1 ππ π π )( (1 1– – )+n n 2

1 2

Germination ResultsM. punctata on M. fruticulosa Soil (n=91) 85.70%

M. punctata on M. punctata Soils (n=90) 70%

Results from Germination Analysis

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

M. punctata on M.punctata Soils (n=90)

M. punctata on M.fruticulosa Soil (n=91)

M. fruticulosa on M.fruticulosa Soil (n=89)

M. fruticulosa on M.punctata Soil (n=90)

Species and Soil Type

Ger

min

atio

n (%

)

Survivorship ResultsM. fruticulosa on M. fruticulosa Soils (n=58) 82.80%M. fruticulosa on M. punctata Soil (n=58) 61.80%

Results from Survivorship Analysis

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

M. punctata on M. punctata Soils (n=63) M. punctata on M. fruticulosa Soils(n=78)

M. fruticulosa on M. fruticulosa Soils(n=58)

M. fruticulosa on M. punctata Soil (n=58)

Species and Soil Type

Surv

ivor

ship

(%)

Height and Biomass Results

• There were no significant data supporting nor opposing our hypotheses

• M. fruticulosa did perform better on M. fruticulosa soil in terms of height

• M. punctata performed better overall in both respects

Height ResultsM. Fruticulosa on M. Fruticulosa Soils (n=89) 27.49 mm

M. Fruticulosa on M. Punctata Soil (n=90) 25.32 mm Analysis of variance by Anova

22

23

24

25

26

27

28

29

30

31

Punctata on Punctata Soils (n=90) Punctata on Fruticulosa Soils (n=92) Fruticulosa on Fruticulosa Soils (n=89) Fruticulosa on Punctata Soil (n=90)

Population and Soil Type

Heig

ht (m

m)

Biomass Results Analysis of variance by Anova

0

0.005

0.01

0.015

0.02

0.025

Punctata on Punctata Soils (n=54) Punctata on Fruticulosa Soils (n=68) Fruticulosa on Fruticulosa Soils(n=47)

Fruticulosa on Punctata Soil (n=41)

Population and Soil Type

Aver

age

Bio

mas

s (g

)

Root to Shoot Ratio TestResults show that M. punctata has a higher root/shoot ratio

than M. fruticulosa

0

0.2

0.4

0.6

0.8

1

1.2

Species

Root

/ Sh

oot R

atio

Monarda punctata

Monarda fruticulosa

Overall Fitness AnalysisOverall Germination

0

10

20

30

40

50

60

70

80

90

Monarda punctata Monarda fruticulosa

Species

Ger

min

atio

n (%

)

Overall Survivorship

72

74

76

78

80

82

84

86

Monarda punctata Monarda fruticulosa

Species

Surv

ivor

ship

(%)

Overall Average Height

25.5

26

26.5

27

27.5

28

Monarda punctata Monarda fruticulosa

Species

Ave

rage

Hei

ght (

mm

)

Overall Average Biomass

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0.02

Monarda punctata Monarda fruticulosa

Species

Ave

rage

Bio

mas

s (g

)

Hypotheses Analysis • Hypothesis supported:

– Monarda fruticulosa performs better on M. fruticulosa soils than on M. punctata soils

• Supported significantly in terms of survivorship• Trends support this hypothesis in terms of germination and

height• Monarda fruticulosa did germinate better on its own native soil

than on soil from any other site, but not significantly

• Hypotheses not supported:– Monarda fruticulosa performs better on native soil from

it’s home site than on any other soil– Monarda fruticulosa is perennial and therefore will have

a higher root/shoot ratio than Monarda punctata

Conclusions

• Survivorship data supports the hypothesis that M. fruticulosa performs better on M. fruticulosa soil than on M. punctata soil.

• M. punctata is a better performer overall, out performing M. fruticulosa in terms of germination, survivorship, biomass, and root/shoot ratio

– This may have to do with the fact that M. punctata is an annual and genetically programmed to complete it’s lifecycle within a season, requiring rapid growth

• Whether or not the narrow endemic, Monarda fruticulosa, is edaphically constrained to it’s habitat, requires more research

Future Research

• Soil analysis– Organic matter– Heavy metals– Salts

• Water availability tests• Large scale reciprocal trials in nature• Survival to reproduction• Hybrid studies

Special Thanks To:• Jan Szyren

– Greenhouse and moral support• Victor Bato

– Mapping• Tao Sang

– Analytical balance• Uwe Rossbach

– Computer lab use and consulting• Deb Trock and Alan Fryday

– Moral support

Dr. Alan Prather and graduate students Jessie Keith, Orlando Alvarez, Rachel Williams, and Nate Sammons