Sexual allocation in single-flowered hermaphroditic individuals in relation to plant and flower size

Gender expression in hermaphroditic plant species usually departs from strict equisexuality. Study of those departures can aid understanding of non hermaphroditic breeding systems and prevalence of hermaphroditism within angiosperms. Plant size is one of the most studied factors in relation to gender modification. We studied variation in gender expression in the hermaphroditic, mostly single-flowered Paeonia cambessedesii. We separately studied gender modification with increasing plant and flower size using a variety of currencies: number of ovules and stamens, dry mass, N and P. Flower size and number of floral structures (petals, stamens, carpels, and ovules) increased with plant size. Number of ovules increased more rapidly with increasing plant size than number of stamens, indicating a bias towards femaleness with increasing plant size. A similar pattern was found when regressing number of stamens and number of seeds against plant size. Number of floral structures increased with increasing flower mass, but no significant difference was found between stamens and ovules in their rate of increase. Thus, gender modification at plant level was not consistent with patterns at flower level. No differential allocation to stamens vs gynoecium, or sexual structures vs petals was found when using dry mass, N or P as currencies. However, a disproportionate increase in female allocation was found when number of structures was utilised as currency. Study of size-dependent gender expression will benefit from contrast of results obtained using several analysis levels and allocation currencies.     

Correlation between male and female reproduction in the subdioecious herb Astilbe biternata (Saxifragaceae)

Genotypic trade-offs between male and female reproduction are commonly assumed in theoretical studies of the evolution of gender specialization. Although these trade-offs are supported by higher seed production of females than hermaphrodites in natural populations of gynodioecious species, comparisons between male and female reproductive allocation among hermaphrodite individuals under controlled conditions are rare. We assessed phenotypic and genotypic correlations between stamen and fruit production in fruiting males of the near-dioecious herb Astilbe biternata. In the field, we found a significant negative phenotypic correlation between stamen production and fruit production within individuals that produced both stamens and fruit as well as higher fruit set in females than fruiting males. The negative correlation between fruit and stamen production that was observed in the field was also apparent across clonally propagated genotypes. These results suggest that negative genetic correlations between male and female reproduction may limit the independent evolution of fruit and stamen production in A. biternata.     

Sex allocation in an hermaphroditic plant: the case of gynodioecy in Thymus vulgaris L.

Resource allocation to male and female functions was investigated in Thymus vulgaris L. (thyme), a gynodioecious species, in which females produce twice as many seeds as hermaphrodites. Negative correlations were found between male and female fertility of hermaphrodites, providing evidence of a trade-off. There was a high variability in sexual investment, some of the hermaphrodites functioning almost as males, and others almost as females. Estimation of the relative cost of male and female gametes showed that the female advantage in seed production was mainly due to reallocation of the resources not allocated to male function into female function. The determination of sex allocation was shown to have a genetic component, and there were some evidence that an interaction between nuclear and cytoplasmic genomes was involved.     

Sex-allocation trade-offs in Nigella sativa (Ranunculaceae) examined with flower manipulation experiments

Sex-allocation trade-offs have long been invoked as a primary factor underlying the evolution of separate sexes and the reduction of pollen production accompanying the evolution of selfing. In the present study, I conducted stamen and style removal experiments to explore the existence of such trade-offs in Nigella sativa, a hermaphroditic plant species whose flower structure allows early manipulation of both male and female function. Plants on which all stamens were removed at the bud stage had a higher rate of flower initiation and produced significantly heavier seeds than did plants whose flowers remained intact, apparently by using resources that were released when the stamens were removed. However, there was no effect of stamen removal on the number of flowers that reached anthesis, the total biomass allocated to seed production, or the vigour of plants in the progeny generation. In contrast, prevention of fruit production (style removal) increased the amount of biomass invested in stamen by 57% relative to plants whose flowers were allowed to set fruit. These observations verify the existence of a sexual trade-off in N. sativa but also raise the possibility that stamen-suppressing mutations sometimes lack the pleiotropic consequences of increasing female function, at least in species with large, expensive fruits.     

Reproductive allocation and costs in gynodioecious Leucopogon melaleucoides (Ericaceae): implications for the evolution of gender dimorphism

In dioecious species, females typically allocate more resources to reproduction and incur greater costs of reproduction than males. In gynodioecious species, sex-based differences in reproductive allocation (RA) and costs have been less studied. Such knowledge, however, is relevant to address how females establish and increase in frequency in populations. We examine RA and reproductive costs by comparing fruit set, the proportion of biomass allocated to reproduction, and the responses of fruit set and vegetative growth to shoot defoliation in females and hermaphrodites in gynodioecious Leucopogon melaleucoides. Relative to hermaphrodites, females exhibited a two-fold fruit set advantage. Female fruit set increased proportionately with flower number, but hermaphrodite fruit set was reduced on plants with more flowers. Sex-based differences in allocation to other traits were small. Thus, female RA at flowering was similar to hermaphrodite RA, but was 1.4-fold greater at fruiting. Relative to controls, defoliation reduced fruit set and the percentage of shoots that produced new vegetative growth similarly in both sexes. However, females had a lower proportion of shoots with new growth overall. Further, defoliation on females reduced the dry mass of new growth by 44% compared with controls, whereas hermaphrodites were not affected. These results indicate a trade-off between reproduction and vegetative growth, and greater female costs of reproduction, particularly under resource-limiting conditions. In the absence of compensatory traits to offset higher female reproductive costs, such trade-offs have the potential to retard the spread of females in gynodioecious populations.     

GENETIC CONSTRAINTS ON THE INDEPENDENT EVOLUTION OF MALE AND FEMALE REPRODUCTIVE CHARACTERS IN THE TRISTYLOUS PLANT LYTHRUM SALICARIA

Here we test whether the potential exists for the independent evolution of allocation to male, female, and attractive functions within a flower. We employed half-sib and parent-offspring regression methods in the tristylous plant Lythrum salicaria to determine whether there is additive genetic variation for characters important to male and female reproductive success and whether genetic correlations could constrain the independent evolution of male and female function. Although significance levels were not consistent among morph types or between populations, there were significant narrow-sense heritabilities for several traits including stamen mass, pistil mass, perianth mass, petal length, and calyx length. Traits that might be under strong stabilizing selection to promote specific pollen transfer, such as stamen and style lengths, had little heritable variation. In the majority of cases in which heritable variation was present, there were positive genetic correlations among floral traits. A strong positive genetic correlation appeared between stamen and pistil mass in the short-styled morph from one of the populations studied. This suggests that selection might not be able to act independently on biomass allocation to male and female flower parts. No evidence of negative genetic correlations appeared that would suggest trade-offs and that could augment a selection response towards sexual specialization. The observed positive correlations could be explained if we consider the “functional architecture” that underlies the covariance structure. If there is more covariance generated by pleiotropic loci controlling overall flower size than at loci controlling male versus female allocation, it could result in the observed positive covariance. At the phenotypic level, we did find significant negative partial correlations between male and female traits when flower size was controlled, but these trade-offs were among rather than within morphs.     

Patterns of biomass allocation to male and female functions in plants with different mating systems

Summary Using dry weight biomass we examined the patterns of investment in male and female functions (prezygotic cost) in plants with different mating systems. All the flower parts of both xenogamous and facultatively xenogamous species were heavier, i.e., larger, than those of facultatively autogamous species. Likewise, the dry weights of all the flower parts of xenogamous species exceeded those of facultatively xenogamous species. On a relative basis, xenogamous species invested less in calyces and more in corollas compared to species with the other mating systems. Facultatively autogamous species invested relatively more in pistils. Xenogamous species invested relatively more in stamens than do facultatively autogamous species. The ratios of dry weight stamens to dry weight pistils were equivalent in xenogamous and facultatively xenogamous species.The available data from xenogamous species suggest a pattern of resource allocation that is independent of sexual system (perfect-flowered, monoecious, or dioecious) and pollen vector. The cost of mating (prezygotic cost) was male biased and frequently exceeded by parental investment (postzygotic cost). These results are not consistent with models that predict equal allocation of resources to male and female sexual function but are consistent with those that predict unequal allocation of resources to those functions in outbreeding hermaphroditic angiosperms. Two additional lines of evidence are inconsistent with the expectations of sex allocation theory. First, resource allocation to sexual function was not equal in wind-pollinated species. Second, relative amounts of the resources allocated to male vis-à-vis female function did not decrease between xenogamy and facultative xenogamy i.e., with an increase in the selfing rate.     

Invasion of unisexuals in hermaphrodite populations of animal-pollinated plants: effects of pollination ecology and floral size-number trade-offs

Abstract.— The most common sexual system in animal-pollinated plants is hermaphroditism, while some species are dioecious or gynodioecious and a very few are androdioecious. In this paper, I attempt to explain this pattern by extending previous models for the evolution of sexual systems to incorporate two main features: (1) a portion of investment in pollinator attraction contributes to only female or male function, because one sexual function of a flower is saturated with pollinator visitation earlier than the other sexual function; and (2) there are trade-offs between the size and number of flowers. The analysis was conducted to determine the conditions when females and males can increase in frequency in a hermaphroditic population, assuming either concave or convex pollinator gain curves (relation between investment to attractive structures of a flower and frequency of pollinator visits to the flower). The results suggest that both of the main factors play important roles in the evolution of plant sexual systems: uneven contribution of pollinator-attractive structures and nonlinear trade-offs between flower size and number can destabilize hermaph-roditism. When a convex pollinator gain curve was assumed, the effect of nonlinear trade-offs can produce accelerating compensation from the elimination of one sexual function, allowing males to increase for large regions of parameter space, where females could not increase. The last prediction obviously conflicts with the observed rarity of androdioecy in nature, indicating the necessity of exploring pollinator gain curves in more detail.     

Variation in inflorescence size in a dioecious fig tree and its consequences for the plant and its pollinator fig wasp

The host-specific relationship between fig trees (Ficus) and their pollinator wasps (Agaonidae) is a classic case of obligate mutualism. Pollinators reproduce within highly specialised inflorescences (figs) of fig trees that depend on the pollinator offspring for the dispersal of their pollen. About half of all fig trees are functionally dioecious, with separate male and female plants responsible for separate sexual functions. Pollen and the fig wasps that disperse it are produced within male figs, whereas female figs produce only seeds. Figs vary greatly in size between different species, with female flower numbers varying from tens to many thousands. Within species, the number of female flowers present in each fig is potentially a major determinant of the numbers of pollinator offspring and seeds produced. We recorded variation in female flower numbers within male and female figs of the dioecious Ficus montana growing under controlled conditions, and assessed the sources and consequences of inflorescence size variation for the reproductive success of the plants and their pollinator (Kradibia tentacularis). Female flower numbers varied greatly within and between plants, as did the reproductive success of the plants, and their pollinators. The numbers of pollinator offspring in male figs and seeds in female figs were positively correlated with female flower numbers, but the numbers of male flowers and a parasitoid of the pollinator were not. The significant variation in flower number among figs produced by different individuals growing under uniform conditions indicates that there is a genetic influence on inflorescence size and that this character may be subject to selection.     

花柱卷曲性的维持及功能性别特化

花柱多态型的型比通过选型交配形成的负频率依赖的选择来维持。种群空间格局对于频率依赖选择所维持的花柱多态型是至关重要的。该研究使用摆放实验构建不同型比的马来良姜(Alpinia mutica)人工种群, 以评价花柱卷曲性促进选型交配的功能。使用邻域模型调查了云南草蔻(Alpinia blepharaocalyx)种群中的目标植株的坐果数、结籽数及其邻域中花序的数量和型偏以探讨在局域尺度上目标植株的雌性适合度是否受负频率依赖的选择。通过比较云南草蔻上举型和下垂型各繁殖性状的差异以及两型的功能性别的计算以评估两型功能性别可能存在的特化趋势。摆放实验结果说明花柱卷曲性形成的二型种群可以促进型间花粉传递。在局域尺度上, 云南草蔻两型倾向于同型聚集分布, 这一分布特点反映出其克隆生长特性。统计结果说明: 邻域中异型花粉供体相对丰富度对两型目标植株都无影响; 目标植株雌性适合度在邻域中不受负频率依赖选择的影响。这一结果并不支持负频率依赖的选择在该研究尺度上是影响种群型比结构的主要机制。云南草蔻两型个体在花期和果期的繁殖指标上不存在显著差异; 功能性别计算结果显示选型交配是种群内唯一的交配模式时, 下垂型功能性别偏雌性而上举型功能性别偏雄性。这一功能性别特化的趋势可能是通过对上举型的雄性功能的选择而造成的, 并可能与种群型结构相关。当功能性别计算只考虑自交而忽略近交衰退时, 种群功能性别偏向雌性。     

Variation in restorer genes and primary sexual investment in gynodioecious Plantago coronopus: the trade-off between male and female function

In many gynodioecious species the nuclear inheritance of male fertility is complex and involves multiple (restorer) genes. In addition to restoring plants from the female (male sterile) to the hermaphrodite (male fertile) state, these genes are also thought to play a role in the determination of the quantity of pollen produced by hermaphrodites. The more restorer alleles a hermaphroditic plant possesses, the higher the pollen production. To test this hypothesis I combined the results of crossing studies of the genetics of male sterility with phenotypic data on investment in stamens and ovules among the progeny of plants involved in these studies. The sex ratio (i.e. the frequency of hermaphrodites among the progeny), being a measure of the number of restorer alleles of the maternal plant, was positively related to the investment in pollen (male function), but negatively related to the investment in ovules (female function), in both field and greenhouse experiments. Consequently, a negative correlation between male and female function was observed (trade-off) and it is suggested that antagonistic pleiotropic effects of restorer genes might be the cause. Phenotypic gender, a measure combining investment in both pollen and ovules, was highly repeatable between field and greenhouse, indicating genetic determination of a more male- or female-biased allocation pattern among the studied plants.     

Trade-offs between clonal and sexual reproduction in Sagittaria latifolia (Alismataceae) scale up to affect the fitness of entire clones

? Many plants combine sexual reproduction with vegetative propagation, but how trade-offs between these reproductive modes affect fitness is poorly understood. Although such trade-offs have been demonstrated at the level of individual shoots (ramets), there is little evidence that they scale up to affect genet fitness. For hermaphrodites, reproductive investment is further divided between female and male sexual functions. Female function should generally incur greater carbon costs than male function, which might involve greater nitrogen (N) costs. ? Using a common garden experiment with diclinous, clonal Sagittaria latifolia we manipulated investment in reproduction through female and male sex functions of 412 plants from monoecious and dioecious populations. ? We detected a 1?:?1 trade-off between biomass investment in female function and clonal reproduction. For male function, there was no apparent trade-off between clonal and sexual reproduction in terms of biomass investment. Instead, male function incurred a substantially higher N cost. ? Our results indicate that: trade-offs between investment in clonal propagation and sexual reproduction occur at the genet level in S.?latifolia; and sexual reproduction interferes with clonal expansion, with investment in female function limiting the quantity of clonal propagules produced, and investment in male function limiting the nutrient content of clonal propagules.     

Determinants of sex allocation in a gynodioecious wild strawberry: implications for the evolution of dioecy and sexual dimorphism

One evolutionary pathway from plants with combined male and female functions (hermaphroditism) to those with separate sexes (dioecy) involves females coexisting with hermaphrodites (gynodioecy). The research presented here explores sex allocation in Fragaria virginiana (a gynodioecious wild strawberry), within the context of theory on the gynodioecy–dioecy transition. By growing clonally replicated plants in the greenhouse and surveying six populations in situ, I evaluated the effects of plant size, genotype, sexual identity, population of origin and female frequency on sex allocation. I found significant positive effects of plant size on most sex allocation traits studied. In addition to strong sex-specific allocation patterns, I found significant broad-sense heritabilities for all traits, suggesting that plants could respond to selection. Moreover, there was a negative genetic correlation between pollen production and fruit set per flower within hermaphrodites, lending support to a basic assumption of sex allocation theory. On the other hand, several sex allocation traits, namely pollen and ovules per flower in hermaphrodites, were positively genetically correlated, suggesting that they may act to constrain the evolution of sexual dimorphism. Populations differed in the frequency of females, and females were more prevalent on sites with lower soil moisture and where hermaphrodites were least likely to produce fruit, suggesting that females’ seed fitness relative to that of hermaphrodites may be strongly environment-dependent in this species.     

The functional ecology of gynodioecy in Eritrichum aretioides (Boraginaceae), the alpine forget-me-not

Eritrichum aretioides is a gynodioecious species with female and hermaphrodite individuals. In populations on Pennsylvania Mountain in central Colorado (USA), the frequency of females ranges from 22 to 41%. Flower number and the number of seeds produced per flower were similar in hermaphrodites and females. However, hermaphrodites produced larger flowers, while females produced larger seeds (P < 0.05 for both). In the field, seed germination was higher for seeds from females than for seeds from hermaphrodites (20 vs. 9% germination; P < 0.05). Unvisited flowers and open-pollinated flowers of hermaphrodites had similar pollen receipt (approx 20 pollen grains per stigma), but seed set following autogamous pollination was significantly lower than seed set following natural pollination. This finding indicates that hermaphrodites have a barrier to selfing and implies that the larger seed size and greater establishment advantage of offspring from females is unlikely to have resulted from female outcrossing advantage. Rather, differences in the quality of seed progeny between morphs probably reflect a trade-off in sexual allocation or pleiotropic effects of the sex-determining genes.     

Genetics of sex allocation in Mimulus (Scrophulariaceae)

Theoretical models of the evolution of resource allocation patterns to male and female function make the assumption that there are inherent trade-offs between the two. Here we use a quantitative genetic approach to quantify trade-offs between male and female function and to determine whether plant populations could readily respond to natural selection by quantifying the amount of genetic variation for pollen and ovule production. Both intra- and interspecific crossing designs were applied to two populations of the predominantly outcrossing Mimulus guttatus and two populations of the highly selfing congener, M. micranthus. The only significant correlations observed among pollen number, pollen size and ovule number were positive. Positive genetic correlations among the traits were sometimes reduced after removing the effect of flower size but still no significant negative correlations were detected. These results suggest that positive correlations between pollen and ovule production may be due to the joint positive correlation of these characters with the resource pool available for pollen and ovule production, as reflected by flower size. Heritabilities were moderate to high for ovule production but low for pollen number and pollen size and suggest that responses to selection would differ between the two traits. Crosses between the species revealed that there are additional genetic factors contributing to differences between the two species for corolla width, vs. pollen:ovule ratio. This is consistent with the hypothesis that genetic variation for resource acquisition may in part be responsible for the overall lack of a negative correlation between pollen and ovule production and provides a genetic explanation for little evidence of trade-offs between sexual functions in Mimulus.     

Wind pollination, sexual dimorphism, and changes in floral traits of Schiedea (Caryophyllaceae)

Both changes in sex allocation and pollination mode may promote the separation of sexes in plant populations. Simultaneous evolution of wind pollination and dimorphism has occurred in Schiedea, where species with different female frequencies provide an opportunity to observe the effect of wind pollination on sex allocation and floral morphology. Differences among species in the ratio of anther to ovary volume were not the result of sex allocation trade-offs, but instead resulted from production of vestigial stamens in females; there were no changes in ovary volume in males and hermaphrodites (MH) of dimorphic species. Relative to hermaphroditic species, dimorphic species had more condensed inflorescences, a pattern often associated with wind pollination. Within dimorphic species, MH had longer filament lengths than females, and females had longer stigmas than MHs. These traits are characteristic of wind pollination, but there was no relationship between the degree of sexual dimorphism and female frequency. Ovary volume and ovule number and size had positive phenotypic correlations between females and MH of dimorphic species, making sex specialization more difficult. In dimorphic Schiedea species, selection for wind pollination may have a greater effect on floral traits than trade-offs in allocation between male and female function.     

Intraspecific variation in sex allocation in hermaphroditic Plantago coronopus (L.)

Models for sex allocation assume that increased expenditure of resources on male function decreases the resources available for female function. Under some circumstances, a negative genetic correlation between investment in stamens and investment in ovules or seeds is expected. Moreover, if fitness returns for investment in male and female function are different with respect to size, sex allocation theory predicts size‐specific gender changes. We studied sex allocation and genetic variation for investment in stamens, ovules and seeds at both the flower and the plant level in a Dutch population of the wind‐pollinated and predominantly outcrossing Plantago coronopus. Data on biomass of floral structures, stamens, ovules, seedset and seedweight were used to calculate the average proportion of reproductive allocation invested in male function. Genetic variation and (genetic) correlations were estimated from the greenhouse‐grown progeny of maternal families, raised at two nutrient levels. The proportion of reproductive biomass invested in male function was high at flowering (0.86 at both nutrient levels) and much lower at fruiting (0.30 and 0.40 for the high and low nutrient treatment, respectively). Androecium and gynoecium mass exhibited moderately high levels of genetic variance, with broad‐sense heritabilities varying from 0.35 to 0.56. For seedweight no genetic variation was detected. Significant among‐family variation was also detected for the proportion of resources invested in male function at flowering, but not at fruiting. Phenotypic and broad‐sense genetic correlations between androecium and gynoecium mass were positive. Even after adjusting for plant size, as a measure of resource acquisition, maternal families that invested more biomass in the androecium also invested more in the gynoecium. This is consistent with the hypothesis that genetic variation for resource acquisition may in part be responsible for the overall lack of a negative correlation between male and female function. Larger plants had a more female‐biased allocation pattern, brought about by an increase in seedset and seedweight, whereas stamen biomass did not differ between small and large plants. These results are discussed in relation to size‐dependent sex allocation theory (SDS). Our results indicate that the studied population harboured substantial genetic variation for reproductive characters.     

VARIATION IN SEX ALLOCATION AND FLORAL MORPHOLOGY IN IPOMOPSIS AGGREGATA (POLEMONIACEAE)

Intrapopulational variation in biomass allocation to male vs. female function was quantified for the hermaphroditic plant Ipomopsis aggregata in terms applicable to sex allocation models. The proportions of flower biomass put into the corolla and calyx averaged 0.59 and 0.20 and were relatively constant across plants. The proportions in the stamens and pistil averaged 0.13 and 0.08, with considerable variation among plants. Phenotypic gender at the time of flowering ranged from 0.34 to 0.77 female. Pistil dry weight was correlated with stigma exsertion. Stamen weight was correlated with corolla width, which influences male pollination success, and was also correlated with anther position and pollen production. Female reproductive success as estimated by seeds per flower showed no detectable relationship with initial allocation of biomass at the time of flowering, but decreased in accelerating fashion with the proportion of final biomass including seeds that was allocated to male function.     

Selfing and resource allocation in Schiedea salicaria (Caryophyllaceae), a gynodioecious species

Abstract Levels of selfing and resource allocation patterns were investigated in Schiedea salicaria (Caryophyllaceae), a gynodioecious species with high levels of inbreeding depression and nuclear control of male sterility. Selfing levels were higher in hermaphrodites than females, especially when adjusted for early acting inbreeding depression. The sexes of S. salicaria were similar in most allocation patterns including number of flowers and capsules per inflorescence, seeds per flower, and seed mass. Seeds produced by females had higher levels of germination than seeds of hermaphrodites, a likely result of high selfing levels and the expression of inbreeding depression in the progeny of hermaphrodites. Invasion of females in populations of S. salicaria is probably related to the expression of inbreeding depression at germination and in later life history stages. Comparisons with related species of Schiedea that also have nuclear control of male sterility suggest that reallocation of resources in hermaphrodites to male function occurs as females increase in frequency, but that resource reallocation is not important for the success of females when they first invade populations.     

湿地植物大花百合种群的性系统特征

开花植物性系统特征是植物在长期适应进化过程中逐渐形成的繁殖策略, 它在一定程度上影响了物种的种群结构及其在生境中的分布格局, 因此性系统特征一直是植物进化与生态学领域的研究热点。本研究于2012年和2020年在吉林省金川泥炭沼泽湿地, 通过样地调查取样的方法, 研究了湿地植物大花百合(Lilium concolor var. megalanthum)的性系统特征以及不同性别表型植株的比例、密度及空间分布格局, 并探究了大花百合植株个体大小和其性别表达的联系, 比较了不同性别表型的花粉实际可育性和来源不同的花粉授粉处理结实后的种子活力。结果显示, 个体水平上, 大花百合具有雄花植株、两性花植株和雄花两性花同株(即雄全同株) 3种性表型; 种群水平上, 具有雄花的个体充当父本, 通过花粉向下一代传递基因, 而具有两性花的个体主要充当母本, 通过胚珠实现基因的传递。2020年大花百合雄花植株占种群内开花植株的39.14%, 相比2012年雄花植株比例增加了22.80%; 大花百合种群分布密度为0.06株/m², 较2012年下降了0.09株/m²。从2012年到2020年, 总体表现为种群密度降低, 雄花植株相对比例增加的趋势。两性花植株和雄花植株在小尺度范围主要呈聚集分布, 随着尺度增大, 趋于随机分布。雄花植株显著小于两性花植株, 但鳞茎资源分配显著高于两性花植株。大花百合植株的性表达遵循大小依赖的性分配假说: 个体较小的植株表达为雄花植株, 而个体较大的植株则为两性花植株或雄全同株。在不同授粉处理下的结籽率和种子萌发结果表明, 大花百合自花授粉结籽率和坐果率显著低于异花授粉, 雄花植株和两性花植株花粉可育性以及对两性花植株授粉后所获得种子活力无显著差异。大花百合雄花植株的出现可能是对有限环境资源条件适应的结果, 反映了湿地条件下该植物在生长和繁殖资源之间的权衡策略, 在长期的湿地演变过程中, 这种性系统特征的出现具有一定的适应性意义。