reproductive response of two morphologically different pea cultivars to drought

European Journal of Agronomy 10 (1999) 119–128

Reproductive response of two morphologically differentpea cultivars to drought

H. Baigorri, M.C. Antolın, M. Sanchez-Dıaz *Departamento de Fisiologıa Vegetal, Universidad de Navarra, c/ Irunlarrea s/n, E-31008 Pamplona, Spain

Accepted 7 December 1998

Abstract

Water use by semi-leafless peas (Pisum sativum L.) is usually less than that of conventional peas because of theirreduced surface leaf area, suggesting that semi-leafless peas would be less sensitive to drought because droughtdevelops later. This work aimed to study the reproductive response of peas cv. Solara (semi-leafless) and cv. Frilene(conventional ) subjected to similar controlled soil drought during the critical period occurring between flowering andinitial seed filling. Plants were subjected to drought by watering with a fraction of water used in the evapotranspirationof control plants. Soil, pod and seed water contents, leaf water status parameters, dry matter (DM ) partitioning, seedyield, yield components and water use efficiency (WUE) were measured. Although soil water content decreased in asimilar way in both cultivars, leaf Yw and RWC only decreased significantly in Solara. Well-watered Frilene plantsproduced higher shoot and pod DM, but lower seed DM. Well-watered Solara plants produced lower pod DM andhigher seed DM than Frilene. Under drought, Frilene increased partitioning of total plant DM to vegetative organs,particularly roots, and decreased DM allocation to pods and seeds increasing flower abortion. By contrast, droughtedSolara interrupted vegetative growth and increased leaf senescence but maintained similar partitioning of total plantDM to pods and seeds as in well-watered conditions. For both cultivars there was a close relationship between thepercentage of total DM partitioned into seeds and WUEy (water use efficiency on seed yield basis). Results demonstratethat when plants suffered the same level of drought in the soil, the reproductive response of the two cultivars waslinked to differences in their WUE. © 1999 Elsevier Science B.V. All rights reserved.

Keywords: Dry matter partitioning; Leaf morphology; Pisum sativum L.; Water use efficiency; Yield

1. Introduction ticularly at flowering and pod filling, but also ondifferences in leaf morphology among cultivars

Pea (Pisum sativum L.) yield depends strongly (Silim et al., 1992; Martin et al., 1994).on environmental conditions such as drought, par- Conventional leafy pea cultivars have normal

leaflet and stipule sizes, being represented by thegenetic constitution AFAF STST. They usually* Corresponding author. Tel.: +34-948-425600;

fax: +34-948-425649; e-mail: [email protected] exhibit the highest yield potential, but also thelargest yield reduction under environmental limita-

Abbreviations: DM, dry matter; ET, evapotranspiration; PI, plas- tions (Stelling, 1994). Other types of pea aretochron index; RWC, relative water content; WC, water content;leafless (afaf stst), with reduced stipule size due toWS, water supplied; WUEy, WUE calculated on a seed yield basis;

WUEDM, WUE calculated on a total DM basis; Yw, water potential the gene st. They have lower growth rate, reduced

1161-0301/99/$ – see front matter © 1999 Elsevier Science B.V. All rights reserved.PII S1161-0301 ( 99 ) 00002-7

120 H. Baigorri et al. / European Journal of Agronomy 10 (1999) 119–128

leaf area and lower light interception than the vermiculite (2:1 v/v) (four plants/pot). Plants wereirrigated with Hoagland’s nutrient solutionconventional and semi-leafless types (Heath and(Hoagland and Snyder, 1933). The pots wereHebblethwaite, 1985), which affects seed yieldmaintained adequately irrigated until floweringstrongly. Semi-leafless peas (afaf STST ), that have(the soil WC was approximately 0.35–leaflets transformed into tendrils by the gene af0.40 cm3 cm−3).and conventional stipules (ST ), counterbalance

Plants were grown from April to June in athese disadvantages due to the presence of devel-greenhouse at 25/15°C, 50/70% RH (day/night)oped stipules.and illuminated during 14 h with natural daylightIt has been reported that water use by leaflesssupplemented with fluorescent lamps (Sylvaniaand semi-leafless peas was less than that of conven-DECOR 183, Professional-58W, Germany), pro-tional peas because of the reduced surface leafviding a minimum photosynthetic photon fluxarea of the leafless and semi-leafless types (Harvey,density of 300–400 mmol photons m−2 s−1.1980). This reduced water use could suggest that

these cultivars would be less sensitive to drought2.2. Treatmentsbecause it develops later than in the conventional

types. Some authors reported that semi-leaflessDrought treatments were imposed when floralpeas had greater water use efficiency ( WUE) (Silim

bud appearance took place in each cultivaret al., 1992; Martin et al., 1994), but other authors(30 day-old in Solara and 40 day-old in Frilene).indicated that conventional genotypes have betterPlants were divided in two groups: (1) controlWUE than the semi-leafless genotypes (Armstrongwell-watered plants that were replenished everyet al., 1994). These results led us to propose thatday with the water lost by evapotranspiration; andit is necessary to design experiments where both(2) plants subjected to water stress for 18 dayscultivars suffered the same level of drought in the(between flowering and initial seed filling period)soil to compare both types of plant.that were supplied with a fraction of water usedTherefore, the objective of this work was toby controls (Fig. 1).investigate the reproductive response of two mor-

The water supplied ( WS) was calculated on thephologically different peas (semi-leafless and con- basis of the average water lost by evapotranspira-ventional ) subjected to controlled drought tion in irrigated control plants (ETc), the waterconditions during the critical period occurring evaporated from each droughted plant (ETd) andbetween flowering and initial seed filling. The a drought factor (F ) (Medrano et al., 1992):experiments were carried out using pot-grown WS=(2F×ETc)−ETd. Evapotranspiration (ET)plants in a greenhouse and comparing the was measured by weighing the pots every day atresponses of both genotypes to similar soil the beginning of the photoperiod. The droughtdrought severity. factor (F ) corresponds to the desired equilibrium

ratio of ETd/ETc, and was fixed in a preliminaryexperiment as 1/2 in Frilene and 1/3 in Solara in

2. Materials and methods order to achieve similar soil water contents inthe pots.

2.1. Plant material and culture conditions Soil water content was calculated as (freshweight−dry weight)/fresh weight of the soil

Seeds of pea (Pisum sativum L.) of two cultivars samples. Soil dry weight was obtained after dryingwith differences in foliage type, Frilene (conven- at 70°C for five days and water was expressed pertional with normal leaflet and stipule size) and volume of pot.Solara (semi-leafless with leaflets converted intotendrils but normal stipule size) were surface disin- 2.3. Plant determinationsfected and germinated on wet filter paper in Petridishes. Seedlings were planted in 25×10 cm2 pots Predawn leaf water potential (Yw) was measured

with a pressure chamber (Scholander et al., 1965).(1600 cm3 volume) containing a mixture of perlite:

121H. Baigorri et al. / European Journal of Agronomy 10 (1999) 119–128

Michelini, 1957). Younger leaves of peas areenclosed inside the stipules of the unfolding leaf,forming the apical bud. Linear measurements ofemerged leaves were recorded regularly on plantsof all treatments. We have considered that a leafemerged only when it was visible. The plastochronindex (PI ) was estimated as:

PI=n+( log Ln−log R)/( log L

n−log L

n+1) (2)

where n is the serial number of the youngest leafthe length of which exceeds a reference value R(in our case, R=20 mm), and L

nand L

n+1 are thelengths of leaves n and n+1.

Plants were harvested at two moments: (1) atthe beginning of drought treatment; and (2) at theend of 18 days of treatment. Plants were separatedinto root, stems (including petioles), leaves, flow-ers, pods and seeds. Green and senescent leaveswere collected separately, and the percentage of

Fig. 1. Daily evapotranspiration in Solara (semi-leafless) andsenescence calculated as:Frilene (conventional ) peas under well-watered (control ) and

droughted (stressed) conditions. Stressed plants received a frac- Senescence=(senescent leaf DM/tion of the water used by controls, which was calculated as afunction of the factor F fixed as 1/2 in Frilene and 1/3 in Solara. total leaf DM)×100 (3)Drought treatments were imposed when floral bud appearancetook place in each cultivar (30 day-old in Solara and 40 day- From these data, DM production and partition-old in Frilene). Each point is the mean of 16 plants. The bars ing during drought period were determined. DMindicate standard error (S.E.) of the mean. S.E. values lower partitioning was calculated as a percentage of thethan 10% were not represented. FI indicates the time of floral

DM of the whole plant (Marcelis, 1996). DM wasinitiation.determined after drying at 70°C for two days.Plants were also analyzed for stem number, nodenumber per stem, pods per node, total pod number,Leaves (including leaflets, stipules and tendrils)

were inserted in plastic bags before excision to seeds per pod, total seed number and individualseed weight.avoid water losses, then excised and immediately

put into the pressure chamber. The predawn leaf Floral bud number was counted at harvest andwas considered as the sum of initiated floral buds,relative water content (RWC ) was measured on

the youngest fully mature leaves and determined fully opened flowers and pods. Open flowernumber was counted as the sum of open flowersas described by Wheatherley (1970):and pods, and the percentage of flower abortion

RWC=(fresh weight−dry weight)/was calculated as:

(turgid weight−dry weight)×100 (1) % abortion=[1−(open flower number/Pods were dissected into pod wall and seeds.

floral bud number)]×100 (4)Fresh weight and dry weight were measured ineach part and their water content ( WC) calculated The water use efficiency for dry matter

(WUEDM) was calculated as the total DM pro-as (fresh weight−dry weight)/fresh weight (LeDeunff and Rachidian, 1988). Dry weight was duced during drought period divided by the total

amount of water used in evapotranspiration (ET )determined after drying at 70°C for two days.The plastochron index is a continuous develop- during the same period. Similarly, the water use

efficiency for seed yield ( WUEy) was calculated asmental scale based on leaf number (Erickson and


seed DM divided by ET (Loomis and Connor, presented significantly lower WC than stressed1992). Solara pods.

Drought affected the rate of leaf appearance as2.4. Statistical analysis indicated by the plastochron index (PI ) (Fig. 3).

Well-watered Frilene plants produced leaves moreAnalysis of variance (ANOVA) was performed rapidly between days six to ten than stressed

to partition the variance into the main effects and plants, but at the end of treatment both plantsthe interaction between genotype and water level produced a similar leaf number on the main stem.(Sokal and Rohlf, 1979). Means±S.E. (n=16) In Solara, decreases in water supply slowed downwere calculated, and when the F ratio was signifi- the rate of leaf production and PI increased morecant, least significant differences LSD were eval- slowly than in well-watered plants. At the end ofuated by the Student’s t-test. treatment, Solara controls had approximately 18

leaves on the main stem, whereas stressed plantsproduced 16 leaves.

3. Results DM production was always smaller in Solaracompared with Frilene until the beginning of

The evapotranspiration rate decreased in both drought treatment (Table 2). During drought,pea types under drought (Fig. 1), but the decrease shoot DM production decreased significantly inin Frilene was greater than in Solara. However, both genotypes, but especially in Solara (Table 3).the soil water content was similar during drought By contrast, Frilene exhibited a strong increase intreatments in both genotypes (Fig. 2). Leaf water root DM production under water stress. Thestatus parameters (Yw and RWC) decreased sig- root/shoot ratio increased in both cultivars whennificantly in stressed Solara peas, whereas Frilene subjected to drought, especially in Frilenepeas exhibited no significant changes in their leaf (Table 3). There was a significant interactionwater status (Table 1). There were significant inter-

between cultivars and water level in the case ofactions between cultivars and water level in these

root DM. Leaf senescence only increased signifi-parameters, because cultivars responded in acantly in Solara. Frilene produced more pod DMdifferent way. Seed WC were similar in all treat-under well-watered conditions than did Solara, butments after 18 days of treatment and there werethe seed yield was greater in the latter (Table 3).no differences between cultivars. By contrast, inDrought produced significant decreases in pod andthe case of pod wall WC, stressed Frilene podsseed DM in both plant types, and there was asignificant interaction between cultivars and waterlevel in the case of pod DM.

Flower production was also greater in Frilene,although they exhibited about 24% flower abortionunder well-watered conditions. Under drought,abortion percentage increased to 47% (Table 4).In contrast, although Solara plants produced halfas many flowers, flower abortion was nil evenduring drought. Results also showed that Frileneincreased considerably the amount of delayedflowers that did not become pods at the time ofharvest, causing significant decrease in pod

Fig. 2. Change in soil water content for Solara (semi-leafless) number. In contrast, Solara produced similar aand Frilene (conventional ) peas during drought treatment. Soil number of flowers and pods under drought as inwater content of well-watered (control ) plants was similar in

well-watered conditions (Table 4). There was aboth types of pea (ca. 0.35 cm3 cm−3). For other details seeFig. 1. significant genotype×water level interaction for


Table 1Predawn leaf water potential (Yw), predawn leaf relative water content (RWC), pod wall and seed water content of Solara (semi-leafless) and Frilene (conventional ) peas under well-watered (control ) and droughted (stressed) conditions. Data were collected atthe end of 18 days of drought. Values are means (n=16)

Treatment Leaf Yw (MPa) Leaf RWC (%) Pod wall WC (%) Seed WC (%)

Solara Control −0.72a 87.6a 83.3ab 77.8aStressed −0.97b 74.1b 84.1a 80.6a

Frilene Control −0.73a 86.4a 82.0ab 81.7aStressed −0.88ab 82.1a 81.2b 76.9a

Cultivar NS NS * NSDrought ** *** NS NSInteraction * * NS NS

Comparison between means was made with the Student’s t-test. Within each column, means followed by the same letter are notsignificantly different (P>0.05).NS, *, ** and *** indicate non-significant or significant at 5%, 1% and 0.1% probability levels, respectively.

abortion percentage, remaining flowers at harvest ponents. Drought caused significant decreases inmost yield components of Frilene, but not in Solaraand number of pods per plant.

Individual seed weight in controls of Solara was (Table 5). The decreases in seed number per plantunder drought were greater in Frilene than inlarger than those of Frilene, but during drought

seed size decreased in Solara and increased in Solara. Reduced pod number in Frilene duringdrought was entirely due to fewer pods per node.Frilene (Table 5). Interactions between cultivars

and water level were significant in most yield com- The number of stems per plant and nodes per stemwas less variable than the number of pods andseeds per plant.

Under drought, Solara maintained similar parti-tioning of total plant DM to pods and seeds as inwell-watered conditions [Fig. 4(A)]. By contrast,Frilene increased partitioning of total plant DMto leaves, roots and flowers, but decreased stronglypercentage allocation to pods and seeds[Fig. 4(B)]. There was a significant genotype×water level interaction0 for most components ofplant DM partitioning (Tables 6 and 7).

WUE for seed yield ( WUEy) in Solara wasgreater than in Frilene [Fig. 5(A)]. However,

Table 2Dry matter (DM) production of Solara (semi-leafless) andFrilene (conventional ) peas from planting until the beginningof the drought treatment. Values are means (n=16). Levels ofsignificance as for Table 1

Treatment Leaf DM Stem DM Root DM Total DMFig. 3. Plastochron index in Solara (semi-leafless) and Frilene (g plant−1) (g plant−1) (g plant−1) (g plant−1)(conventional ) peas under well-watered (control ) anddroughted (stressed) conditions. The asterisks indicate signifi- Solara 0.84b 0.22b 0.39b 1.45bcant differences between treatments (P<0.05). For other details Frilene 2.40a 0.79a 1.27a 4.45asee Fig. 1.


Table 3Dry matter (DM) production, root/shoot ratio and percentage of leaf senescence (senescent leaf DW/total leaf DW×100) betweenthe beginning of the drought treatment and harvest of Solara (semi-leafless) and Frilene (conventional ) peas under well-watered(control ) and droughted (stressed) conditions. Data were collected at the end of 18 days of drought. Values are means (n=16)

Treatment Shoot DM Root DM Pod DM Seed DM Root/shoot Leaf senescence(g plant−1) (g plant−1) (g plant−1) (g plant−1) (g g−1) (%)

Solara Control 0.85b 0.55b 0.65b 0.55a 0.65b 6.0cStressed 0.18c 0.26c 0.25c 0.21c 1.33a 15.5ab

Frilene Control 1.34a 0.20c 1.06a 0.37b 0.16c 10.1acStressed 0.87b 0.83a 0.24c 0.16c 0.83ab 16.5ab

Cultivar *** * *** * ** NSDrought *** ** *** *** ** **Interaction NS *** *** NS NS NS

Levels of significance as for Table 1.

Table 4Flowers produced per plant, flower abortion, number of remaining flowers at harvest and pods produced per plant of Solara (semi-leafless) and Frilene (conventional ) peas under well-watered (control ) and droughted (stressed) conditions. Data were collected atthe end of 18 days of drought. Values are means (n=16)

Treatment No. flowers produced per plant Abortion (%) No. remaining flowers at harvest No. pods/plant

Floral buds Open flowers

Solara Control 2.9b 2.9c 0.0c 0.0b 2.9bStressed 2.4b 2.4c 0.0c 0.2b 2.2bc

Frilene Control 7.8a 5.7a 23.6b 0.1b 5.6aStressed 9.1a 4.6b 46.9a 3.1a 1.4c

Cultivar *** *** *** *** *Drought NS ** *** *** ***Interaction NS NS *** *** ***


Table 5Yield components and individual seed weight of Solara (semi-leafless) and Frilene (conventional ) peas under well-watered (control )and droughted (stressed) conditions. Data were collected at the end of 18 days of drought. Values are means (n=16)

Treatment Seeds/plant Seeds/pod Stems/plant Nodes/stem Pods/node Seed weight (mg seed−1)Solara Control 7.7b 2.6ab 2.0c 1.5b 1.0a 71.4a

Stressed 5.1bc 2.4bc 1.8c 1.4b 0.9a 41.4bFrilene Control 17.3a 3.1a 3.0b 2.3a 0.8a 20.9c

Stressed 4.4c 1.9c 3.9a 1.8ab 0.3b 42.1b

Cultivar ** NS *** * *** ***Drought *** ** NS NS *** NSInteraction ** * * NS ** ***



Fig. 5. WUE for seed yield (WUEy) (A) and WUE for totalFig. 4. Dry matter partitioning into different organs expressedas a percentage of total plant dry matter in Solara (semi-leafless) DM ( WUEDM) (B) for Solara (semi-leafless) and Frilene (con-

ventional ) peas. Values with a different letter differ significantlyand Frilene (conventional ) peas. Comparisons were made foreach organ between both cultivars and treatments. Within each at the 0.05 probability level. For other details see Fig. 1.organ means followed by the same letter are not significantlydifferent (P>0.05). For other details see Fig. 1.

Table 6Significance of ANOVA showing effects of cultivar and water level on dry matter partitioning into different organs expressed as apercentage of total plant dry matter in Solara (semi-leafless) and Frilene (conventional ) peas. Levels of significance as for Table 1

Treatment Leaves Stems (% total DM) Roots Flowers Pods Seeds

Cultivar *** NS NS * NS ***Drought NS * *** * ** NSInteraction ** NS *** * *** *

Table 7 a function of WUEDM [Fig. 6(B)] (r2=0.001)Significance of ANOVA showing effects of cultivar and water (P>0.05).level on WUE for seed yield (WUEy) and WUE for total DM(WUEDM) of Solara (semi-leafless) and Frilene (conventional )peas. Levels of significance as for Table 1

4. DiscussionTreatment WUEy WUEDM(mg seeds cm−3) (mg total DM cm−3)

The greater water use for evapotranspiration inCultivar *** NS conventional pea cultivars may cause the soil waterDrought NS NS

content to decrease more rapidly compared withInteraction NS NSsemi-leafless ( Wilson et al., 1981) and leafless peas(Harvey, 1980; Silim et al., 1992) (Fig. 1). Instudies carried out with different cultivars sub-expressed on a DM basis WUEDM was similar in

controls of both genotypes and only increased in jected to drought, it is difficult to compare treat-ments if plants do not have similar soil WC becausestressed Frilene [Fig. 5(B)]. There was a significant

correlation between WUEy and the percentage of unequal soil WC will induce a different environ-mental stress. This was not the case in our worktotal DM partitioned to seeds [Fig. 6(A)]

(r2=0.58) (P<0.001) but not when represented as because the soil WC under drought was very


lation during seed filling (Le Deunff andRachidian, 1988). Seed WC of 85% correspondsto beginning of seed filling (Dumoulin et al., 1994),and then seed WC decreases until physiologicalmaturity, considered to be reached when WC is55% (Le Deunff and Rachidian, 1988). In ourexperiments seed WC varied between 77% and82%, that could indicate approximately the firstphases of seed filling period (Table 1).

Solara reduced both shoot and root DM pro-duction under drought (Table 3). Vegetative DMproduction in Frilene was less affected by droughtthan in Solara, especially due to a strong increasein root DM production (Table 3). Diminishedwater availability in Solara also affected the rateof leaf appearance, as indicated by the PI (Fig. 3).The PI in Frilene agrees with results obtained infield-grown plants in which the rate of leaf appear-ance decreased only slightly under drought(Lecoeur and Sinclair, 1996).

Drought stressed Frilene decreased partitioningFig. 6. Relationship between the percentage of total DM parti-tioned to seeds and WUE for seed yield (WUEy) (A) and WUE of total plant DM to reproductive organs (flowers,for total DM (WUEDM) (B) for Solara (semi-leafless) and pods and seeds) [Fig. 4(B)]. This may causeFrilene (conventional ) peas. Straight line (———) corresponds increased flower abortion and lower pod numberto the regression lines fitted for the joint data of Solara and

(Table 4). Results also indicated that drought pro-Frilene. The corresponding equations were: (A) y=longed flowering period in Frilene because a sig-0.087+0.02x (r2=0.58) and (B) y=15.166+0.35x

(r2=0.001). nificant number of flowers remained at harvest(Table 4).

Well-watered Solara peas produced lower podsimilar in both genotypes (ca. 0.15–0.18 cm3 cm−3) (Fig. 2), so both cultivars ulti- DM but higher seed DM than Frilene due to the

greater seed size of the former (Table 5). Seed DMmately experienced the same degree of soil waterdeficit. is a function of the seed growth rate and the

duration of seed filling, and Solara is a plant typePredawn leaf Yw of controls was lower thanexpected values but other authors working with with a short period of seed set (Dumoulin et al.,

1994). Drought decreased pod, and seed DM andcultivar Solara also observed similarly low pre-dawn leaf Yw under well-watered conditions (Ney seed filling rate (as indicated by the individual seed

DM). Since decreases in PI coordinate with leafet al., 1994). Under drought, Yw and RWC inSolara leaves decreased whereas Frilene exhibited expansion in peas (Turc and Lecoeur, 1997), a

limited leaf area development and a reduction inno statistically significant changes in its leaf waterparameters. The WC of reproductive organs (pods photosynthetic efficiency during the reproductive

phase would cause seed yield reduction (Martinand seeds) was quite constant and independent ofboth the leaf Yw and soil water conditions et al., 1994). In spite of this, droughted Solara

maintained a similar percentage allocation of total(Bradford, 1994) (Table 1). Seed WC is the mostcommonly used parameter for evaluating seed plant DM into pods and seeds as in well-watered

conditions [Fig. 4(A)]. Ney et al. (1994) suggestedmaturity (Ney et al., 1993; Dumoulin et al., 1994).However, it is a poor indicator of the physiological that Solara responded to short-term water stress

(six days) by mobilizing its reserves to maintain awater status in developing seeds under drought,since it changes continuously due to DM accumu- constant seed growth rate. Our data also indicate


that Solara maintained the supply of photo- For that reason we only obtained a significantrelationship between the percentage of DM parti-synthates or increased the remobilization of C and

N from leaves and stems towards reproductive tioned to seeds and WUEy [Fig. 6(A) and (B)].structures during drought.

Dry matter partitioning is the result of the flowof assimilates from source organs via a transport 5. Conclusionspath to the sink organs and is primarily regulatedby the sink strengths (competitive ability to attract The stressed semi-leafless cultivar maintained aassimilates) of the sink organs (Marcelis, 1996). similar percentage of DM partitioning into repro-Because pea is an indeterminate plant, vegetative ductive organs as in well-watered conditions anddevelopment continues during formation of repro- had a higher WUEy than the conventional type.ductive structures. The presence of two sinks may By contrast, the stressed conventional cultivarresult in a greater competition for assimilates, allocated a higher proportion of DM to roots andespecially at the beginning of pod filling (Jeuffroy exhibited a greater reduction in seed and podand Warembourg, 1991), and may have a crucial yields due to increased flower abortion and reducedimportance under drought. This competition may number of pods. For both cultivars there was acause the abortion of flowers, pods and seeds close relationship between the percentage of DM(Duthion and Pigeaire, 1991; Guilioni et al., 1997) partitioned to seeds and WUEy. Results demon-because seed filling has priority over other sinks strate that when plants suffered the same level of(e.g. flowers) as observed in non-stressed condi- drought in the soil, the reproductive response oftions (Jeuffroy and Warembourg, 1991) and under semi-leafless and conventional pea types was linkeddrought (Ney et al., 1994). Our data demonstrate to differences in their WUE.that the competition between vegetative and repro-ductive organs (flowers, pods and seeds) was moreimportant in Frilene than in Solara under drought.

AcknowledgmentsFrilene diverted higher DM to roots and this mightproduce a lack of assimilates that promoted the

We thank Dr. Luis Ayerbe (CRF-INIA Madrid,greater abortion of reproductive organs observedSpain) and LYRA S.L. (Madrid, Spain) for pro-(Table 4).viding seeds. H. Baigorri was the recipient of aData of water use reported in field-grown con-grant from Asociacion de Amigos de laventional and leafless (Silim et al., 1992) and semi-Universidad de Navarra. We also thank Mr. I. Deleafless peas (Martin et al., 1994) have suggestedLuis for his help and support during theno clear differences in WUE among cultivars.experiments.Other workers have reported that conventional

genotypes showed greater WUE than the semi-leafless genotypes when grown in a glasshouse

References(Armstrong et al., 1994). Our results contrast withthe findings of these authors, and show that

Alvino, A., Leone, A., 1993. Response to low soil water poten-WUEy of Solara was greater than in Frilenetial in pea genotypes (Pisum sativum L.) with different leaf[Fig. 5(A)]. Similar findings were also reported bymorphology. Scientia Hort. 53, 21–34.

Alvino and Leone (1993). Usually, the crop WUE Armstrong, E.L., Pate, J.S., Tennant, D., 1994. The field peacan be expressed as the amount of total DM crop in South Western Australia. Patterns of water use and

root growth in genotypes of contrasting morphology andproduced per unit of water used ( WUEDM), or asgrowth habit. Aust. J. Plant Physiol. 21, 517–532.seed DM produced per unit of water used

Bradford, K.J., 1994. Water stress and the water relations of( WUEy) (Loomis and Connor, 1992). In ourseed development: a critical review. Crop Sci. 34, 1–11.

work, WUEDM masked the different responses of Dumoulin, V., Ney, B., Eteve, G., 1994. Variability of seed andvegetative and reproductive growth obtained in plant development in pea. Crop Sci. 34, 992–998.

Duthion, C., Pigeaire, A., 1991. Seed lengths corresponding toeach cultivar under drought [Table 3, Fig. 5(B)].


the final stage in seed abortion of three grain legumes. Crop matter partitioning in the whole plant. J. Exp. Bot. 47,1281–1291.Sci. 31, 1579–1583.

Erickson, R.O., Michelini, F.J., 1957. The plastochron index. Martin, I., Tenorio, J.L., Ayerbe, L., 1994. Yield, growth, andwater use of conventional and semi-leafless peas in semi-aridAm. J. Bot. 44, 297–305.

Guilioni, L., Wery, J., Tardieu, F., 1997. Heat stress-induced environments. Crop Sci. 34, 1576–1583.Medrano, H., Aguilo, F., Socias, X., 1992. Leaf water relationsabortion of buds and flowers in pea: is sensitivity linked to

organ age or to relations between reproductive organs? Ann. of subterranean clover plants subjected to rapid or slowly-induced drought. Photosynthetica 27, 413–419.Bot. 80, 159–168.

Harvey, D.M., 1980. Seed production in leafless and conven- Ney, B., Duthion, C., Fontaine, E., 1993. Timing of repro-ductive abortions in relation to cell division, water contenttional phenotypes of Pisum sativum L. in relation to water

availability within a controlled environment. Ann. Bot. 45, and growth of pea seeds. Crop Sci. 33, 267–270.Ney, B., Duthion, C., Turc, O., 1994. Phenological response of673–680.

Heath, M.C., Hebblethwaite, P.D., 1985. Solar radiation inter- pea to water stress during reproductive development. CropSci. 34, 141–146.ception by leafless, semi-leafless and leafed peas (Pisum sati-

vum) under contrasting field conditions. Ann. Appl. Biol. Scholander, P.F., Hammel, H.T., Bradstreet, E.D.,Hemmingsen, E.A., 1965. Sap pressure in vascular plants.107, 309–318.

Hoagland, D.R., Snyder, W.C., 1933. Nutrition of strawberry Science 148, 339–346.Silim, S.N., Hebblethwaite, P.D., Jones, C., 1992. Irrigationplant under controlled conditions. Proc. Am. Soc. Hort. Sci.

30, 288–296. and water use in leafless peas (Pisum sativum). J. Agric. Sci.119, 211–222.Jeuffroy, M.H., Warembourg, F.R., 1991. Carbon transfer and

partitioning between vegetative and reproductive organs in Sokal, R.R., Rohlf, F.J., 1979. Biometrıa. H. Blume, Madrid,832 pp.Pisum sativum L. Plant Physiol. 97, 440–448.

Lecoeur, J., Sinclair, T.R., 1996. Field pea transpiration and Stelling, D., 1994. Performance of morphologically divergentplant types in dried peas (Pisum sativum). J. Agric. Sci. 123,leaf growth in response to soil water deficits. Crop Sci. 36,

331–335. 357–361.Turc, O., Lecoeur, J., 1997. Leaf primordium initiation andLe Deunff, Y., Rachidian, Z., 1988. Interruption of water deliv-

ery at physiological maturity is essential for seed development expanded leaf production are co-ordinated through similarresponse to air temperature in pea (Pisum sativum L.). Ann.germination and seedling growth in pea (Pisum sativum L.).

J. Exp. Bot. 39, 1221–1230. Bot. 80, 265–273.Wheatherley, P.E., 1970. Some aspects of water relations. Adv.Loomis, R.S., Connor, D.J., 1992. Water relations. In: Loomis,

R.S., Connor, D.J. (Eds.), Crop Ecology: Productivity and Bot. Res. 3, 171–206.Wilson, D.R., Hanson, R., Jermyn, W.A., 1981. Growth andManagement in Agricultural Systems. Cambridge University

Press, Melksham, Wiltshire, pp. 224–256. water use of conventional and semi-leafless peas. Proc.Agron. Soc. New Zeal. 11, 35–39.Marcelis, L.F.M., 1996. Sink strength as a determinant of dry

reproductive response of two morphologically different pea cultivars to drought

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