scholarly journals Size-dependent sex allocation in Solanum lycocarpum St. Hil. (Solanaceae)

2022 ◽  
Vol 82 ◽  
Author(s):  
F. F. Coelho ◽  
A. G. Damasceno ◽  
A. Fávaro ◽  
G. S. Teodoro ◽  
L. P. Langsdorff
Keyword(s):  
Resource Allocation ◽  
Sex Allocation ◽  
Plant Size ◽  
Male And Female ◽  
Size Dependent ◽  
Female Function ◽  
Plant Group ◽  
Optimal Resource ◽  
Sex Allocation Theory ◽  
Male Flowers

Abstract Resource allocation to reproduction can change depending on size, as predicted by the size-dependent sex allocation. This theory is based on the fact that small individuals will invest in the allocation of sex with lower cost of production, usually male gender. In plants, there are some andromonoecy species, presence of hermaphrodite and male flowers in the same individual. Andromonoecy provides a strategy to optimally allocate resources to male and female function, evolving a reproductive energy-saving strategy. Thus, our objective was to investigate the size-dependent sex allocation in Solanum lycocarpum St. Hil. We tested the hypothesis that plants with larger size will invest in the production of hermaphrodite flowers, because higher individuals have greater availability of resources to invest in more complex structures involving greater energy expenditure. The studied species was S. lycocarpum, an andromonoecious species. From June 2016 to March 2017 the data were collected in 38 individuals, divided in two groups: the larger plant group (n=18; height=3-5 m) and the smaller plant group (n=20; height=1-2 m).Our data show that there was effect of plant size on the flower production and the sexual gender allocation. The larger plants showed more flowers and higher production of hermaphrodite flowers. Furthermore, in the flower scale, we observed allometric relationship among the flower’s traits with proportional investments in biomass, anther size and gynoecium size. Our results are in agreement with size-dependent sex allocation theory and andromonoecy hypothesis related to mechanisms for optimal resource allocation to male and female function.

scholarly journals The Patterns of Male and Female Flowers in Flowering Stage May Not Be Optimal Resource Allocation for Fruit and Seed Growth

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2819
Author(s):  
Lei Gao ◽  
Guozhu Yu ◽  
Fangyu Hu ◽  
Zhiqi Li ◽  
Weihua Li ◽  
...  
Keyword(s):  
Resource Allocation ◽  
Sex Differentiation ◽  
Nutrient Supply ◽  
Fruit Weight ◽  
Flowering Stage ◽  
Optimal Resource Allocation ◽  
Male And Female ◽  
Optimal Resource ◽  
Male Flowers ◽  
Female Flowers

Changes in the proportions of male and female flowers in monoecious plants in response to external environmental conditions are directly related to the reproductive fitness of plants. The monoecious cucumber (Cucumber sativus) plant was used in this study to assess the responses of sex differentiation and the breeding process to nutrient supply and the degree of artificial pollination using pollen solutions of different concentrations. We found that the nutrient supply significantly improved the number of female flowers, while pollination treatments did not obviously increase the number of male flowers. Continuous pollination changed the number of female flowers especially in the later stage of the pollination experiment. Therefore, pollination changed the ratio of male and female flowers in the flowering stage of cucumber. Pollination treatment affected the fruit growth, seed set, and fruit yield. The number of fruit, fruit set percentage, and total seeds per plant did not increase with the pollination level, but individual fruit weight and seed number in one fruit did increase. The differentiation of male and female flowers in the flowering stage of cucumber is a response to nutrient and pollination resources, but this response is not the optimal resource allocation for subsequent fruit development and seed maturity, which suggests that the response of plants to external environment resources is short-term and direct.

scholarly journals When to be a male? Role of resource-limitation and pollinators in determining floral sex in an andromonoecious spiderwort

2020 ◽  
Author(s):  
Asawari Albal ◽  
G Azad ◽  
Saket Shrotri ◽  
Vinita Gowda
Keyword(s):  
Resource Allocation ◽  
Resource Constraints ◽  
Apis Cerana ◽  
Resource Limitation ◽  
Sex Expression ◽  
Sexual Systems ◽  
Pollinator Preference ◽  
Optimal Resource ◽  
Male Flowers ◽  
Nutrient Resources

AbstractThe evolution and maintenance of sexual systems in plants is often driven by resource allocation and pollinator preferences, and very little is known about their role in determining floral sex expression in plants. In annual, entomophilous plants three major constraints can be identified towards optimal reproduction: 1) nutrient resources available from the environment, 2) nutrient resources allocated towards reproduction, i.e., fruits vs. flowers, and 3) pollinator visitations.Andromonoecy is a sexual system where plants bear both staminate and hermaphrodite flowers on the same inflorescence. The optimal resource allocation hypothesis suggests that under nutrient constraints, plants will produce more male flowers since they are energetically cheaper to produce over the more expensive hermaphrodite flowers. We test this hypothesis in the andromonoecious Murdannia simplex (Commelinaceae) by quantifying male and hermaphrodite flowers in a natural population and contrasting the distribution of the two sexes in plants from two resource conditions (stream population vs. plateau population). We next carried out choice experiments to test pollinator preference towards a specific sex.We found that in M. simplex, production of hermaphrodite flowers is resource-dependent and under resource constraints fewer numbers of flowers were produced and most of them were males. We failed to observe pollinator preference towards either sex but Amegilla spp. and Apis cerana showed higher visitation towards the most abundant sex within a trial, suggesting frequency-dependent visitation. Thus, we conclude that environmentally driven resource constraints play a bigger role in driving floral sex expression in Murdannia over direct pollinator-driven constraints.

Neighbour effects on gender variation in Ambrosia artemisiifolia

1994 ◽  
Vol 72 (6) ◽  
pp. 794-800 ◽  
Author(s):  
J. T. Lundholm ◽  
L. W. Aarssen
Keyword(s):  
Plant Height ◽  
Pollen Dispersal ◽  
Natural Populations ◽  
Plant Size ◽  
Ambrosia Artemisiifolia ◽  
Gender Variation ◽  
Female Function ◽  
Phytochrome System ◽  
Male Flowers ◽  
And Gender

In this study we tested the prediction that male gender allocation in natural populations of common ragweed (Ambrosia artemisiifolia L.) depends more on relative plant height within the neighbouring canopy than on absolute plant height. This is consistent with the assumption that success as a pollen donor for an anemophilous plant within a crowded population will be greater when neighbours are shorter than when neighbours are taller. Data on height and proximity of neighbours, irradiance, and target plant height, biomass, and gender allocation were collected from two natural populations. In one population, these data were also recorded for a group of target plants that had local neighbours artificially removed when the target plants were seedlings. Allocation to male flowers was most strongly positively correlated with height relative to that of close neighbours and with percent irradiance in natural populations. Numerous all-female plants were recorded among the smallest individuals that were suppressed by a dense overhead canopy of neighbours. No relationships were found between plant size and gender when plants were taller than their neighbours or when neighbours were artificially removed. Hence, previously reported size-dependent gender variation in this species may depend on the presence of neighbours. It is postulated that ragweed individuals may sense the presence of neighbours through the phytochrome system, and that effects of neighbours on light quantity and quality cues a shift to increased female function. However, plants that grew from the seedling stage without neighbours were heavier and more female but were not taller than plants with neighbours left intact. The interpretation of this effect is unclear but may reflect a change in plant architecture corresponding with the removal of neighbours. Key words: gender, plant height, plasticity, pollen dispersal, phytochrome, shading.

Floral sex ratios in scrub oak (Quercus ilicifolia) vary with microtopography and stem height

1990 ◽  
Vol 68 (6) ◽  
pp. 1364-1368 ◽  
Author(s):  
Marcelo A. Aizen ◽  
Alejandra Kenigsten
Keyword(s):  
Sex Ratios ◽  
Scrub Oak ◽  
Size Dependent ◽  
Female Function ◽  
Dependent Relationship ◽  
Quercus Ilicifolia ◽  
Allocation Patterns ◽  
Male Flowers ◽  
Short Stems ◽  
Female Flowers

We measured floral sex ratios (number of male inflorescences:number of female flowers) and height of stems (= ramets) of monoecious scrub oak (Quercus ilicifolia) growing along a topographic gradient on the slope of a 20 m deep depression. Stems lower in the gradient experienced increasingly severe conditions in terms of a shorter growing season and a higher incidence of killing frosts. At the top of the gradient, floral sex ratios of tall stems were male biased; however, sex allocation patterns at the bottom showed no such size-dependent relationship. With decreasing elevation (greater stress), the production of male flowers declined more rapidly than that of female flowers. Tall stems reduced overall resource allocation to flower production proportionately more with decreasing elevation than did short stems, but this reduction was again more marked in the male flowering function than in the female. These differential patterns of sex investment explain, at least in part, the variation in size-related gender relationships along this gradient. The more stressful environmental conditions prevailing at the bottom of the depression and the relative costs of the male and prezygotic female function may combine to produce these flowering patterns.

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