Sex-allocation plasticity in hermaphrodites of sexually dimorphic Fragaria virginiana (Rosaceae)

Botany ◽  
2010 ◽  
Vol 88 (3) ◽  
pp. 231-240 ◽  
Author(s):  
Eric J. Bishop ◽  
Rachel B. Spigler ◽  
Tia-Lynn Ashman
Keyword(s):  
Sex Allocation ◽  
Seed Set ◽  
Reproductive Traits ◽  
Plant Size ◽  
Sexually Dimorphic ◽  
Flower Number ◽  
Fragaria Virginiana ◽  
Ovule Number ◽  
Indirect Consequence ◽  
Resource Gradient

Sex-allocation plasticity is thought to play an important role in the evolution of separate sexes in plants. Accordingly, much attention has been paid to environmentally induced variation in fruit and seed production in sexually dimorphic species, but we know little about whether this variation arises as a direct response to environmental variation or is instead an indirect consequence of changes in plant size. In this study, we characterize sex-allocation plasticity across a resource gradient for several reproductive traits in hermaphrodites of gyno(sub)dioecious Fragaria virginiana Duch. We find significant plasticity, on average, for flower number, proportion fruit set, ovule number, proportion seed set, and runner number in response to resource variation. Plasticity of most traits examined tended to be at least partially independent of variation in plant size, suggesting that it is not simply an indirect consequence of plant allometry. Moreover, we find genetic variation for plasticity of key reproductive traits. Comparisons of relative plasticities among traits reveal that F. virginiana hermaphrodites are more likely to adjust female investment via changes in fruit and seed set than ovule number, and most likely to adjust male investment via flower number rather than anther number or pollen per anther, although there is genotypic variation for plasticity in pollen per anther. Evidence of within-population variation can logically be extended to suggest that variation in hermaphrodite sex-expression seen among natural populations of F. virginiana may be due, at least in part, to sex-allocation plasticity.

Seasonal variation in reproductive traits in Ipomopsis longiflora (Polemoniaceae), a desert annual

2004 ◽  
Vol 82 (3) ◽  
pp. 401-408
Author(s):  
Gretchen LeBuhn
Keyword(s):  
Seasonal Variation ◽  
Chihuahuan Desert ◽  
Reproductive Traits ◽  
Allocation Of Resources ◽  
Flower Number ◽  
Evolutionary Forces ◽  
Ovule Number ◽  
Desert Annual ◽  
Evolution By Natural Selection ◽  
Efficiency Of Reproduction

Seasonal variation in reproductive traits is commonly documented in flowering plants. This variation is critical because it is the material for evolution by natural selection. Understanding the mechanisms that maintain that variation is important, because it can tell us about the ecological and evolutionary forces acting on populations. Using Ipomopsis longiflora (Torr.) V. Grant subsp. australis, a Chihuahuan desert annual that has two discrete flowering seasons, I studied the relative influence of seasonality, variation in the individuals present in the population, and prior reproduction on reproductive traits. I found that traits that represent the allocation of resources within a plant (ovule number, flower number, and flower size) were influenced by seasonality and the individuals present in the population, whereas traits that represent the efficiency of reproduction (seeds/ovule, fruits/flower, and seeds/fruit) were influenced only by seasonality.Key words: iteroparity, semelparity, efficiency, phenology.

Male biased sex allocation with plant size in gynomonoecious Aster ageratoides

2013 ◽  
Vol 20 (3) ◽  
pp. 386-390
Author(s):  
Ge Xingyue ◽  
Zhu Biru ◽  
Liao Wanjin
Keyword(s):  
Sex Allocation ◽  
Plant Size

scholarly journals Effects of fragmentation on plant adaptation to urban environments

2017 ◽  
Vol 372 (1712) ◽  
pp. 20160038 ◽  
Author(s):  
Jonathan Dubois ◽  
Pierre-Olivier Cheptou
Keyword(s):  
Reproductive Traits ◽  
Urban Ecosystems ◽  
Terrestrial Ecosystems ◽  
Plant Size ◽  
Urban Environments ◽  
Trait Variation ◽  
Fragmented Habitats ◽  
Dispersal Traits ◽  
Neutral Markers

Urban ecosystems are relatively recent and heavily human-altered terrestrial ecosystems with a surprisingly high diversity of animals, plants and other organisms. Urban habitats are also strongly fragmented and subject to higher temperatures, providing a compelling model for studying adaptation to global change. Crepis sancta (Asteraceae), an annual Mediterranean wasteland weed, occupies fragmented urban environments as well as certain unfragmented landscapes in southern France. We tested for shifts in dispersal, reproductive traits and size across a rural–urban gradient to learn whether and how selection may be driving changes in life history in urban and fragmented habitats. We specifically compared the structure of quantitative genetic variation and of neutral markers (microsatellites) between urban and rural and between fragmented and unfragmented habitats. We showed that fragmentation provides a better descriptor of trait variation than urbanization per se for dispersal traits. Fragmentation also affected reproductive traits and plant size though one rural population did conform to this scheme. Our study shows the role of fragmentation for dispersal traits shift in urban environments and a more complex pattern for other traits. We discuss the role of pollinator scarcity and an inhospitable matrix as drivers of adaptation. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’.

scholarly journals The defensive benefit and flower number cost of selenium accumulation in Brassica juncea

AoB Plants ◽  
2019 ◽  
Vol 11 (5) ◽  
Author(s):  
Janet C Steven ◽  
Alexander Culver
Keyword(s):  
Brassica Juncea ◽  
Pieris Rapae ◽  
Leaf Tissue ◽  
Plant Size ◽  
Sodium Selenate ◽  
Negative Effects ◽  
Flower Number ◽  
Specialist Herbivore ◽  
Selenium Accumulation ◽  
The Cost

Abstract Some plant species accumulate selenium in their tissues in quantities far above soil concentrations, and experiments demonstrate that selenium can serve as a defence against herbivores and pathogens. However, selenium may also cause oxidative stress and reduce growth in plants. We measured growth, selenium accumulation and herbivory in four varieties of the selenium accumulator Brassica juncea to investigate the cost of accumulation as well as its benefit in reducing herbivory. We measured selenium levels, plant size and flower number in four varieties of B. juncea watered with sodium selenate or treated as controls. We also conducted no-choice herbivory trials on leaves from both treatments with the specialist herbivore Pieris rapae. The selenate treatment slightly increased leaf number over the control, but tissue concentrations of selenium and flower number were negatively correlated in some varieties. In herbivory trials, leaves from the plants in the selenate treatment lost less leaf tissue, and the majority of larvae given leaves from selenate-treated plants ate very little leaf tissue at all. In the variety with the highest selenium accumulation, leaves from selenate-treated plants that showed reduced flower production also experienced less herbivory in feeding trials. The protective advantage of greater selenium accumulation may be offset by negative effects on reproduction, and the relatively low level of selenium accumulation in this species as compared to more extreme hyperaccumulators could reflect the minimum level necessary to enhance protection from herbivory.

On the function of flowers

1985 ◽  
Vol 224 (1235) ◽  
pp. 223-265 ◽  
Keyword(s):  
Seed Set ◽  
Large Fraction ◽  
Natural Populations ◽  
Sexually Dimorphic ◽  
Male Organ ◽  
Total Pollen ◽  
Comparative Survey ◽  
Male Flowers ◽  
Almost All ◽  
Single Insect

Most flowers are bisexual in function, but counting secondary allocation to attractive structures such as the corolla as equally male and female leads to the paradoxical conclusion that plants bearing perfect flowers invariably allocate much more to female than to male function. A method of calculating the gender of secondary floral allocation is described, and it is speculated that this allocation is predominantly male. Observations and experiments with natural populations of herbs, designed to test this hypothesis gave the following major results, (i) Insects visit larger flowers more frequently ( Fragaria ), and removal of floral biomass causes a reduction in the frequency of insect visits proportional to the fraction of biomass removed ( Impatiens ). (ii) Removal of attractive structures may cause a decline in the probability that a fruit will be formed but has no effect on the number of seeds set per fruit; thus, mutilation of essentially solitary flowers has no effect on seed-set per fruit ( Impatiens ), while removal of flowers from inflorescences in a species that forms several many-seeded fruits per inflorescence reduces fruit-set per inflorescence but has no effect on seed-set per fruit ( Asclepias ), and removal of sterile flowers from an inflorescence in which the fertile flowers yield one-seeded fruits is effective in reducing seed-set per inflorescence ( Viburnum ), (iii) Larger flowers may disperse a greater fraction of their pollen in unit time ( Impatiens ) and the removal of flowers from inflorescences causes a steep reduction in total pollen exported and a weak decline in the quantity of pollen exported per flower ( Asclepias ). These results are consistent with the hypothesis that a single insect visit (or a very few visits) suffices to fertilize almost all available ovules and is procured by a very small allocation to attractive structures, while much greater allocation is necessary to procure the numerous visits required to disperse a large fraction of the pollen. This inference is supported by a comparative survey of sexually dimorphic plants, in which male flowers are generally larger than female flowers, male inflorescences bear more flowers, and male plants bear more inflorescences. It is concluded that the flower is primarily a male organ, in the sense that the bulk of allocation to secondary floral structures is designed to procure the export of pollen rather than the fertilization of ovules. This conclusion may be sensitive to whether it is the flower or the inflorescence as a whole that represents the primary unit of attraction to insects. It was found that the performance of a given flower was substantially affected by other flowers in the same compact inflorescence ( Asclepias ), though not by other inflorescences on the same plant nor by those borne by nearby plants ( Fragaria, Impatiens ). A general quantitative theory of flower and inflorescence design is outlined, and used to organize the extensive experimental results for Asclepias .

VARIABILITY OF SEED-SET IN ALFALFA AND CORRELATIONS WITH SOME POLLEN AND OVULE CHARACTERISTICS

1981 ◽  
Vol 61 (2) ◽  
pp. 319-323 ◽  
Author(s):  
R. Y. GURGIS ◽  
D. E. ROWE
Keyword(s):  
Seed Set ◽  
Pollen Viability ◽  
Genetic Material ◽  
Tube Length ◽  
Paternal Effects ◽  
Ovule Number ◽  
High Heritability ◽  
Paternal Parent ◽  
The Difference ◽  
Germinated Pollen

A random sample of 30 named alfalfa (Medicago sativa L.) cultivars representing diverse genetic material was investigated for relationships among the following traits: frequency of seed-set (seeds per flower) after self-pollination, frequency of seed-set after cross-pollination, abundance of pollen, viability of pollen, germinated pollen tube length, ovule number, and ovule size. In each cultivar, 100 reciprocal crosses and selfs were made by hand in the greenhouse, with emasculation when appropriate. A second experiment re-used the plants of 11 cultivars for specific inter- and intra-cultivar crosses to estimate the relative importance of maternal and paternal effects on seed-set. In the first experiment, seed-set of crosses did not correlate with any other factors, and the seed-set of selfs was only slightly correlated with pollen viability. An analysis of broad sense heritabilities indicated a very low heritability for seed-set of selfs (H = 0.11), and relatively high heritability for seed-set of crosses (H = 0.74). The difference in rates of seed-set for crosses and selfs on the same plant also had high heritability (H = 0.66). The mechanisms controlling seed-set with selfing and with crossing appeared to be different. In the second experiment, correlation analysis indicated that the maternal parent had over five times the influence of the paternal parent on the frequency of seed-set.

scholarly journals The maleness of larger angiosperm flowers

2020 ◽  
Vol 117 (20) ◽  
pp. 10921-10926 ◽  
Author(s):  
Gustavo Brant Paterno ◽  
Carina Lima Silveira ◽  
Johannes Kollmann ◽  
Mark Westoby ◽  
Carlos Roberto Fonseca
Keyword(s):  
Sex Allocation ◽  
Seed Set ◽  
Limited Resource ◽  
Male And Female ◽  
Allocation Patterns ◽  
Biomass Components ◽  
Flower Evolution ◽  
Primary Male ◽  
Shed Light ◽  
Allocation Strategies

Flower biomass varies widely across the angiosperms. Each plant species invests a given amount of biomass to construct its sex organs. A comparative understanding of how this limited resource is partitioned among primary (male and female structures) and secondary (petals and sepals) sexual organs on hermaphrodite species can shed light on general evolutionary processes behind flower evolution. Here, we use allometries relating different flower biomass components across species to test the existence of broad allocation patterns across the angiosperms. Based on a global dataset with flower biomass spanning five orders of magnitude, we show that heavier angiosperm flowers tend to be male-biased and invest strongly in petals to promote pollen export, while lighter flowers tend to be female-biased and invest more in sepals to insure their own seed set. This result demonstrates that larger flowers are not simple carbon copies of small ones, indicating that sexual selection via male–male competition is an important driver of flower biomass evolution and sex allocation strategies across angiosperms.

scholarly journals Costly induction of defense reduces plant growth and alters reproductive traits in mixed-mating Datura stramonium

2020 ◽  
Author(s):  
Deidra J. Jacobsen
Keyword(s):  
Reproductive Traits ◽  
Datura Stramonium ◽  
Floral Biology ◽  
Plant Size ◽  
Mixed Mating ◽  
Chemical Induction ◽  
Plant Trait ◽  
Cost Of Defense ◽  
Trade Offs ◽  
Defense Induction

AbstractHerbivory shapes plant trait evolution by altering allocation to growth and defense in ways that affect plant reproduction and fitness. Initiation of these trade-offs may be particularly strong in juvenile plants with high phenotypic plasticity. Herbivory costs are often measured in terms of plant size or flower numbers, but other herbivore-induced floral changes can alter interactions with pollinators and have important implications for mating systems. In mixed-mating plants that can both self-fertilize and outcross, herbivory can maintain mating system variation if herbivore damage and defensive induction change a plant’s likelihood of selfing versus outcrossing. Here, I use mixed-mating Datura stramonium to evaluate how early defensive induction and herbivory result in trade-offs among plant defense, growth and reproduction. I used a 2×2 factorial manipulation of early chemical defense induction and season-long insecticide in the field. Growth costs of chemical induction were seen even before plants received damage, indicating an inherent cost of defense. Induction and herbivory changed multiple aspects of floral biology associated with a plant’s selfing or outcrossing rate. This including reduced floral allocation, earlier flowering, and reduced anther-stigma separation (herkogamy). Although these floral changes are associated with decreased attractiveness to pollinators, plants exposed to natural herbivory did not have decreased seed set. This is likely because their floral morphologies became more conducive to selfing (via reduced herkogamy). These vegetative and floral changes following damage and defensive induction can impact interactions among plants (by altering mating environment) and interactions with pollinators (via changes in floral allocation and floral phenology).

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