Effect of Defoliation on Gender Expression and Fruit Set in Passiflora incarnata

Spears, E. Eugene; May, Peter G.

doi:10.2307/2444738

Cited by 9 publications

(7 citation statements)

References 9 publications

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“…Failure to set fruit in every leaf axil was due to a combination of flower and fruit abortion and a change in flower type from hermaphrodite to staminate. Similar observations have also been reported for papaya (Awada, 1967) and other hermaphroditic species (Spears and May, 1988;Wilson, 1983).…”

Section: Discussionsupporting

confidence: 85%

Defoliation and Fruit Removal Effects on Papaya Fruit Production, Sugar Accumulation, and Sucrose Metabolism

Zhou¹,

Christopher²,

Paull³

2000

jashs

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Papaya (Carica papaya L.) source size and sink strength were modified by a single defoliation or continual defoliation and fruit thinning. Fruit set, development, weight, total sugar (sum of sucrose, fructose, and glucose), sucrose phosphate synthase (SPS), sucrose synthase (SS), and acid invertase (AI) enzyme activities in response to defoliation and fruit thinning were determined. The effects of defoliation and fruit thinning varied with weather conditions, plant growth conditions, and cultivar. Removal of 75% of the leaves significantly reduced new flower production and fruit set, and decreased ripe fruit total soluble solids (TSS), while 50% defoliation did not reduce new fruit set or ripe fruit TSS. When every third leaf from the oldest leaf was not removed, the number of new flowers was reduced by 47% more than when the same number of leaves was removed from the oldest to younger leaves. Continual removal of old leaves reduced new fruit set, fruit weight, and TSS in the 168 day experimental period. Fruit thinning increased new fruit set and ripe fruit TSS. Larger fruit size, faster fruit development, lower respiration rate, and higher sugar contents and AI activity were observed in immature (young) fruit when old fruit were removed. AI activity was reduced during early fruit development and increased again in mature fruit in plants subjected to defoliation, and suggested a role for AI in mature fruit sugar accumulation, while SS activity declined significantly in fruit 154 and 175 days after anthesis and in mature fruit when plants were subjected to continual defoliation. SPS activity was not affected significantly by defoliation or fruit thinning. Source-sink balance was critical for papaya fruit set, development, and sugar accumulation and each mature leaf was able to provide photoassimilate for about three fruit.

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Section: Discussionsupporting

confidence: 85%

Defoliation and Fruit Removal Effects on Papaya Fruit Production, Sugar Accumulation, and Sucrose Metabolism

Zhou¹,

Christopher²,

Paull³

2000

jashs

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“…1980; Solomon 1985; Korpelainen 1998). While herbivory might also be expected to cause plants to concentrate on male function, empirical evidence of such a response is very limited (Spears & May 1988).…”

Section: Discussionmentioning

confidence: 99%

Strategies of Solanum carolinense for regulating maternal investment in response to foliar and floral herbivory

Wise

Cummins

2006

Journal of Ecology

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Summary 1The series of steps used to regulate a plant's investment in reproduction in response to environmental stresses is a life-history strategy critical to maximizing fitness. We investigated how the andromonoecious herb Solanum carolinense regulates its maternal investment in response to stress from foliar and floral herbivory. 2 Most of the variation among S. carolinense individuals (ramets) in maternal investment occurred during the initiation of flower-bud primordia, with ramets initiating between 9 and 167 flower buds. 3 In response to simulated floral herbivory, S. carolinense regulated maternal investment by decreasing the abortion rate of flower buds, increasing the ratio of perfect to male flowers and decreasing the rate of fruit abortion. 4 In response to foliar herbivory, the plants increased the rate of fruit abortion and decreased allocation to perennial root growth. 5 Some individuals specialized at regulating during early phenological stages, others specialized at later regulation, and there appeared to be trade-offs between these strategies. 6 Because most plants must cope with multiple stresses that occur at different times in their phenology, such trade-offs suggest the presence of adaptive constraints. In particular, a plant's ability to tolerate damage by one species of herbivore may be constrained by the cost of lower tolerance of the damage caused by the other herbivores that feed on the plant.

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“…However, the assumption that flowering occurs in a single, short flush, given this effect, allows R to be con sidered fixed for purposes of the model. Leaf-removal ex periments indicate that floral investment and fruiting invest ment often come from a plant's photosynthetic income as much as from a pool of remobilized assimilates (Janzen 1976;Spears and May 1988;Lubbers and Lechowicz 1989;McKone 1989;Tuomi et al 1989). Let each ovule cost Cq units of the resource, and all other floral parts together cost units.…”

Section: Resource Constraintmentioning

confidence: 99%

Ovule Packaging in Stochastic Pollination and Fertilization Environments

Burd

1995

Evolution

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Abstract.-The modular morphology of plants has important consequences for reproductive strategies. Ovules are packaged in discrete structures (flowers) that usually vary stochastically in pollen capture and ovule fertilization, because of the vagaries of pollen transfer by external agents. Different ovule packaging schemes may use limited reproductive resources more or less effectively, so that some number of ovules per flower may be optimal, given the prevailing probabilities of ovule fertilization. I derive a phenotypic model for ovule number per flower that maximizes the expected total ovule fertilizations on a plant when pollination and fertilization vary randomly among individual flowers. This model predicts that, except for small or inexpensive flowers, ovules should be "oversupplied" relative to the mean receipt of pollen tubes, so that pollen limitation of seed set should be common. Published data are congruent with this prediction. Additional hypotheses on the relation of ovule packaging to floral cost, plant size, and variance in pollen receipt are suggested by the model, but few data exist to evaluate these hypotheses.

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Effect of Defoliation on Gender Expression and Fruit Set in Passiflora incarnata

Cited by 9 publications

References 9 publications

Defoliation and Fruit Removal Effects on Papaya Fruit Production, Sugar Accumulation, and Sucrose Metabolism

Defoliation and Fruit Removal Effects on Papaya Fruit Production, Sugar Accumulation, and Sucrose Metabolism

Strategies of Solanum carolinense for regulating maternal investment in response to foliar and floral herbivory

Ovule Packaging in Stochastic Pollination and Fertilization Environments

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