scholarly journals Effects of sexual dimorphism on pollinator behaviour in a dioecious species

2021 ◽  
Author(s):  
Laura Moquet ◽  
Anne-Laure Jacquemart ◽  
Mathilde Dufay ◽  
Isabelle De Cauwer
Keyword(s):  
Sexual Dimorphism ◽  
Bombus Terrestris ◽  
Male Flower ◽  
Pollen Grains ◽  
Flower Size ◽  
Pollination Efficiency ◽  
Flower Number ◽  
Pollinator Behaviour ◽  
Number Of Visits ◽  
Female Flowers

Floral traits often display sexual dimorphism in insect-pollinated dioecious plant species, with male individuals typically being showier than females. While this strategy is theorized to be optimal when pollinators are abundant, it might represent a risk when they become scarce, because the disproportionately high number of visits on the most attractive sex, males, might preclude efficient pollen transfer from males to females. Here, the effect of sexual dimorphism on pollination efficiency was assessed in experimental arrays of dioecious Silene dioica that were exposed to one frequent visitor of the species, Bombus terrestris, and that differed in the magnitude of sexual dimorphism for either flower number or flower size. While flower size dimorphism did not impact pollination efficiency, we found that flower number dimorphism negatively affected the number of visits on female plants, on female flowers and on the number of female flowers visited after a male flower. However, flower number dimorphism had no effect on the number of pollen grains deposited per stigma, presumably because the decrease in the number of visits to female flowers was compensated by a higher number of pollen grains deposited per visit.

scholarly journals Temporal dynamics of sexual dimorphism in a dioecious species

2020 ◽  
Vol 126 (3) ◽  
pp. 471-480
Author(s):  
L Moquet ◽  
L Lateur ◽  
A-L Jacquemart ◽  
I De Cauwer ◽  
M Dufay
Keyword(s):  
Sexual Dimorphism ◽  
Plant Species ◽  
Temporal Dynamics ◽  
Flower Size ◽  
Flowering Plant ◽  
Floral Traits ◽  
Flower Number ◽  
Pollinator Behaviour ◽  
Flower Production ◽  
Flowering Season

Abstract Background and Aims Sexual dimorphism for floral traits is common in dioecious plant species. Beyond its significance for understanding how selection acts on plant traits through male vs. female reproductive function, sexual dimorphism has also been proposed as a possible risky characteristic for insect-pollinated plants, as it could drive pollinators to forage mostly on male plants. However, even though most flowering plant species spread their flowering across several weeks or months, the temporal variation of floral phenotypes and sexual dimorphism have rarely been investigated. Methods We performed a survey of male and female plants from the dioecious generalist-pollinated Silene dioica (Caryophyllaceae) in a common garden experiment, over two consecutive flowering seasons. Flower number and floral size were measured each week, as well as pollen quantity and viability in male plants. Key Results Sexual dimorphism was found for all investigated floral traits, with males showing an overall higher investment in flower production and flower size. Males and females showed a similar temporal decline in flower size. The temporal dynamics of daily flower number differed between sexes, with males showing a peak in the middle of their flowering season, whereas flower production by females was quite stable over time. At the scale of the experimental population, both individual and floral sex ratios appeared to vary across the flowering season. Moreover, because the onset of flowering varied among plants, the magnitude of sexual dimorphism in floral size also fluctuated strongly through time. Conclusions Capturing male/female differences with only one temporal measurement per population may not be informative. This opens stimulating questions about how pollinator behaviour and resulting pollination efficiency may vary across the flowering season.

Sexual dimorphism in floral traits of gynodioecious Lobelia siphilitica (Lobeliaceae) is consistent across populations

Botany ◽  
2012 ◽  
Vol 90 (12) ◽  
pp. 1245-1251 ◽  
Author(s):  
Christina M. Caruso
Keyword(s):  
Sexual Dimorphism ◽  
Genetic Correlations ◽  
Species Range ◽  
Flower Size ◽  
Floral Traits ◽  
Flower Number ◽  
Gender Dimorphism

In angiosperms, the evolution of gender dimorphism is often correlated with the evolution of sexual dimorphism in floral traits. The magnitude of sexual dimorphism will reflect both sex-specific selection and constraints on evolution in response to this selection. If the evolution of sexual dimorphism is constrained by genetic correlations, then trait means are predicted to evolve more quickly than the magnitude of sexual dimorphism in the same traits. To test whether mean floral traits evolve more quickly than sexual dimorphism in these traits, I measured flower size and flower number of gynodioecious Lobelia siphilitica L. from 10–14 populations across the species’ range. Females produced more flowers than hermaphrodites, but neither mean flower number nor the magnitude of dimorphism in flower number varied among populations. Pistillate flowers were smaller than perfect flowers, and mean flower size varied among populations. However, the magnitude of dimorphism in flower size did not vary. My results suggest that the evolution of sexual dimorphism in flower size, but not necessarily flower number, could be constrained by within- or between-sex genetic correlations in L. siphilitica.

The effects of date pollinizer variety and pollination time on fruit set and yield of Medjhol date palm

2014 ◽  
Vol 2 (2) ◽  
pp. 67-71 ◽  
Author(s):  
Abdoul Amir Rahnama ◽  
Esmaeil Rahkhodaei
Keyword(s):  
Date Palm ◽  
Fruit Set ◽  
Block Design ◽  
Male Flower ◽  
Fruit Weight ◽  
Palm Fruit ◽  
Tropical Fruit ◽  
Male And Female ◽  
Time Interaction ◽  
Female Flowers

Date palm is unisexual, being either male or female. Male and female flowers grow on buds called Spathe, which opens naturally when fully mature. It is easy to identify the male and female flowers. Under the method of manual pollination, pollen from a male flower is smeared over female flowers. The pollen variety and pollination time have important effects on date palm fruit set, yield and quality. This experiment was carried out to study the effect of date pollinizer variety and pollination time on fruit set, growth and development of Medjhol date palm variety, in date palm garden of date palm and tropical fruit research institute of Iran during three years from 2009 to 2011. The trail was randomized complete block design in factorial manner with three pollen variety as Ghaname, Vardy, and Samesmave, two pollination time as 1-3 days before or after spathe opening and four replication. The results showed that the Vardy pollen had significant effects and increased the fertility percent and fruit yield, rather than two other pollen varieties. The pollen variety had no significant effects on fruit quality as total sugar, acidity, and bricx. The pollination time before spathe opening significantly increased fertility percent, decreased fruit weight and date palm yield. Finally the pollen variety and pollination time interaction effects showed that, application of Vardy pollen from 1-3 days after spathe opening with the most production date palm yield, equal 19.9 kilogram per any date palm trees, so this treatment is the best and are recommended.

Differential nectar production between male and female flowers in a wild cucurbit: Cucurbita maxima ssp. andreana (Cucurbitaceae)

2002 ◽  
Vol 80 (11) ◽  
pp. 1203-1208 ◽  
Author(s):  
Lorena Ashworth ◽  
Leonardo Galetto
Keyword(s):  
Reproductive Output ◽  
Male Flower ◽  
Female Flower ◽  
Cucurbita Maxima ◽  
Nectar Production ◽  
Male And Female ◽  
Nectar Sugar Composition ◽  
Nectar Sugar ◽  
Male Flowers ◽  
Female Flowers

In dioecious and monoecious plants that depend on animal vectors for reproduction, pollinators have to be attracted to male and female flowers for pollination to be effective. In the monoecious Cucurbita maxima ssp. andreana, male flowers are produced in greater quantity, are spatially more exposed to pollinators and offer pollen in addition to nectar as floral rewards. Nectar traits were compared between male and female flowers to determine any differences in the characteristics of the main reward offered to pollinators. Nectar chemical composition and sugar proportions were similar between flower types. Total nectar sugar production per female flower was threefold higher than per male flower, and nectar removal did not have any effect on total nectar production in both flower morphs. Pollinators reduced nectar standing crops to similar and very scarce amounts in both flower types. Results indicate indirectly that pollinators are consuming more nectar from female flowers, suggesting that the higher nectar production in female flowers may be a reward-based strategy to achieve the high female reproductive output observed in this species.Key words: Cucurbitaceae, Cucurbita maxima ssp. andreana, nectar production, nectar sugar composition, removal effects, standing crop.

scholarly journals The Effects of Silver Nitrate Applications on the Flower Quantity of Cucumbers (Cucumis sativus L.)

2011 ◽  
Vol 39 (1) ◽  
pp. 139 ◽  
Author(s):  
Deniz KARAKAYA ◽  
Hüseyin PADEM
Keyword(s):  
Silver Nitrate ◽  
Cucumis Sativus ◽  
Male Flower ◽  
Flower Formation ◽  
Cucumis Sativus L ◽  
Male Flowers ◽  
Female Flowers

This study was conducted to investigate the effects of silver nitrate (AgNO3) on the flower quantity of cucumbers. The seeds used in this study, which was carried out in a plastic greenhouse, in the Gazi village of Antalya Province (Turkey) the during spring and autumn 2005 breeding periods, were ‘Mostar F1’ (designated as ‘GND1’) and ‘Vesco Seeds Beith Alpha F1 (26.50 F1)’, designated as ‘GND2’ and those are the types having common production. The silver nitrate application was performed by the method of spraying on the growth tips of plants and 0, 250, 500, 750, and 1000 ppm silver nitrate doses were administered. The research was conducted with 4 repetitions having 5 plants in each repetition according to the Random Parcel Trial Pattern. In order to determine the effects of the applications, the effects of a number of female flowers and male flowers on generative characteristics of planting periods (spring and fall) were identified and the results were statistically evaluated. According to the results obtained in this research, AgNO3 has led to the formation of male flowers (no male flower formation in control), has increased the number of male flowers, and has led to a decrease in the number of female flowers. The increase in the number of male flowers varied according to the periods (in ‘GND2’).

scholarly journals Studies on the Structure of Flowers and Inflorescences of Cornelian Cherry (Cornus mas L.)

2012 ◽  
Vol 40 (2) ◽  
pp. 53 ◽  
Author(s):  
Cevriye MERT
Keyword(s):  
Pollen Grains ◽  
Flower Morphology ◽  
Flower Number ◽  
Flower Buds ◽  
Cornelian Cherry ◽  
Cornus Mas ◽  
Conducting Tissue ◽  
Stereo Microscope ◽  
The Mean ◽  
Scanning Electron

This study reports on the arrangement of flower buds and structure of floral organs of cornelian cherry (Cornus mas L.) cultivars local to Turkey. The local cultivars were investigated under stereo microscope, light microscope, and scanning electron microscope (SEM). The results indicate that each node has two oppositely positioned buds on 1-year-old shoot. Inflorescences resembled the umbel structure that enclosed four (two sets of oppositely oriented) bud scales. The mean flower number varied between 16.3 and 19.9 per cluster among the cultivars. The flowers resembled the hermaphrodite type and one flower was found to have four rudimentary sepals, four petals, four stamens, and one pistil. The stamens were noted to be arranged around the base of the ovary. Each normal anther was observed to have two pollen-producing theca, and each theca was found to have two locules. The number of pollen grains per anther varied between 1380 and 4240 among the genotypes. The pistil was noted to have a deeply hollowed papillate stigmatic surface, and the central part of the style had conducting tissue. The ovarium part of the pistil was found to be surrounded by the nectary tissue, inferior type, and had two atropous ovules. The fruit resembled single-seeded, stone fruit type. This study is the first detailed study on the flower morphology and inflorescences of the cornelian cherry cultivars in Turkey.

scholarly journals Pollination effectiveness of European honeybee, Apis mellifera (Hymenoptera: Apidae), in an Oriental persimmon, Diospyros kaki (Ericales: Ebenaceae), orchard

2020 ◽  
Vol 55 (4) ◽  
pp. 405-412
Author(s):  
Shoko Nakamura ◽  
Shunsuke Yamamoto ◽  
Nobuo Sawamura ◽  
Aoi Nikkeshi ◽  
Shigeki Kishi ◽  
...  
Keyword(s):  
Apis Mellifera ◽  
Trifolium Pratense ◽  
Pollen Grains ◽  
Red Clover ◽  
Diospyros Kaki ◽  
Japanese Persimmon ◽  
Pollination Effectiveness ◽  
Mature Seeds ◽  
European Honeybee ◽  
Female Flowers

Abstract Most common cultivars of Oriental (or Japanese) persimmon, Diospyros kaki Thunb. (Ericales: Ebenaceae), set mostly female flowers and require pollen from male flowers of other cultivars for pollination. Growers often introduce the European honeybee, Apis mellifera L. (Hymenoptera: Apidae), into their orchards to promote pollination. Here, we investigated the pollination effectiveness of A. mellifera for D. kaki ‘Saijo,’ by monitoring flower visitors, analyzing pollen grains on bees’ body surfaces, and comparing the number of mature seeds in fruits among years with different pollinator availabilities. Apis mellifera and the bumblebee Bombus ardens ardens Smith (Hymenoptera: Apidae) were the major visitors for 3 years, although their dominance varied among years. The number of mature seeds was positively correlated with the number of B. ardens ​ardens visiting D. kaki flowers, but not with that of A. mellifera. Apis mellifera might be less efficient because visitors to female flowers carried significantly fewer pollen grains on their body surfaces than those of B. ardens ​ardens. Analysis of pollen loads of honeybees captured at their nest entrance suggested their preference for red clover, Trifolium pratense L. (Fabales: Fabaceae), and Toxicodendron spp. (Sapindales: Anacardiaceae), over D. kaki as a pollen source in our study site. The effectiveness of A. mellifera on D. kaki pollination should be carefully evaluated considering the effects of coexisting floral and pollinator species.

scholarly journals Lisianthus Growth and Flowering Responses to Uniconazole

HortScience ◽  
1991 ◽  
Vol 26 (2) ◽  
pp. 150-152 ◽  
Author(s):  
Terri Woods Starman
Keyword(s):  
Plant Height ◽  
Foliar Spray ◽  
Flower Size ◽  
Flower Number ◽  
Eustoma Grandiflorum ◽  
Height Control ◽  
Foliar Sprays ◽  
Potted Plant ◽  
Butanedioic Acid ◽  
Time Of Harvest

One and two foliar spray and single-drench applications of uniconazole were applied to Eustoma grandiflorum (Raf.) Shinn (lisianthus) `Yodel Blue' to determine optimal concentrations for potted plant height control. A single uniconazole spray at 10.0 mg·liter-1 applied 2 weeks after pinching, two uniconazole applications at 5.0 mg·liter -1 applied 2 and 3 weeks after pinching, or a drench at 1.60 mg a.i. per pot applied 2 weeks after pinching gave equally good height control. At these concentrations, uniconazole was similar in its effect on plant height to daminozide foliar sprays at 7500 and 2500 mg·liter-l applied once and twice, respectively. Drenching with uniconazole at 1.60 mg a.i. per pot did not increase days to flower (DTF), whereas foliar spray applications did. Drenching did not reduce flower size, but increased flower number at time of harvest. Chemical names used: α-cyclopropyl-α-(4-methoxyphenyl)-5-pyrimidinemethanol (ancymidol); butanedioic acid mono(2,2-dimethylhydrazide) (daminozide);(E)-(S)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-1-yl)-pent-1-ene-3-01 (uniconazole).

scholarly journals The Study of Pollen Development in Nine Cultivars of Hazelnut (Corylusavellana)

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1117A-1117
Author(s):  
Chantalak Tiyayon ◽  
Anita Nina Azarenko
Keyword(s):  
Pollen Development ◽  
Developmental Stages ◽  
Male Gametophyte ◽  
Male Flower ◽  
Pollen Grains ◽  
Corylus Avellana ◽  
Tissue Sections ◽  
Development And Differentiation ◽  
Mother Cells ◽  
Pollen Shed

Pollen development is an important event in plant reproduction. Hazelnut (Corylus avellana) male flower differentiation starts in summer and pollen shed is in the winter. Hazelnut pollen shed can vary up to 3 months between early to late flowering genotypes. Microsporogenesis and microgametogenesis of hazelnut is not well understood. Pollen development and differentiation of nine genotypes, representing early to late blooming cultivars from the National Clonal Germplasm Repository in Corvallis, Ore., were studied. Catkins were collected weekly from Aug. to Nov. 2002. Tissue sections were examined under the light microscope. Microsporogenesis was divided into five stages: archesporial cells, sporogenous cells and parietal layers, pollen mother cells (PMC), tetrads, and microspores. Microgametogenesis was distinguished between young pollen grains (uninucleate) and mature pollen grains (binucleate). On 4 Aug., cultivars were at different developmental stages of microsporogenesis. Early blooming cultivars had PMCs present. Later-blooming cultivars only contained archesporial cells. PMCs were present in all cultivars by 22 Aug. Microspores were observed on 26 Sept. in all cultivars. This study contributes to a better understanding of male gametophyte development in hazelnut, which has increased our ability to correlate hazelnut pollen development with bloom phenology.

scholarly journals Aspects of pollination and floral development in Ficus capensis Thunb. (Moraceae)

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 883-888 ◽  
Author(s):  
H. Baijnath ◽  
S. Ramcharun
Keyword(s):  
Sexual Dimorphism ◽  
Floral Development ◽  
Second Primary ◽  
Female Flowers

A unique obligatory symbiosis exists between Ficus capensis Thunb., and its pollinator, Ceratosolen capensis Grandi. Flowers from both aerial and geocarpic syconia may be pollinated and produce seeds. Females of C. capensis possess specialized mesothoracic pockets in which pollen is transferred from ripening syconia to receptive ones. A second primary sycophile, Sycophaga cyclostigma Waterston, appears to be ineffective in pollination.Several secondary sycophiles oviposit through the syconial wall. Strong sexual dimorphism exists in most sycophilous wasps. All female flowers have the potential to produce either seeds or galls and variation is merely one of gross morphology. Flowering is distinctly asynchronous. Seeds are dispersed by various fruit predators and germinate very easily under warm humid conditions.

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