Evolution of Sexual Systems in Flowering Plants

Bawa, Kamaljit S.; Beach, James H.

doi:10.2307/2398798

Cited by 294 publications

(184 citation statements)

References 69 publications

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“…Visitantes florais e polinização -A polinização de J. mutabilis e J. mollissima é estritamente biótica. Embora muitos autores relacionem monoicia com polinização pelo vento (Faegri & Pijl 1979, Primack 1985, em florestas tropicais a maioria das espécies monóicas é zoófila (Bawa & Beach 1981), sendo polinizadas por insetos ou beija-flores. Dentro da família Euphorbiaceae, algumas espécies de Croton são anemófilas (Tejada & Bullock 1988, Dominguez & Bullock 1989, Passos 1995, enquanto outras, como Croton bonplandianum e Phyllanthus pinnatus, são polinizadas tanto pelo vento como por insetos, sendo a polinização anemófila mais significativa (Reddi & Reddi 1985).…”

Section: Discussionunclassified

Biologia reprodutiva de duas espécies de Jatropha L. (Euphorbiaceae) em caatinga, Nordeste do Brasil

Santos¹,

Machado²,

Lopes³

2005

Rev. bras. Bot.

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-(Reproductive biology of two species of Jatropha L. (Euphorbiaceae) in "Caatinga", northeastern Brazil). The phenology, pollination and breeding system of Jatropha mutabilis (Pohl) Baill. and J. mollissima (Pohl) Baill. were studied in the municipalities of Buíque (8°67' S and 37°01' W) and Arcoverde (8°25' S and 37°02' W), both in the Caatinga, Pernambuco state. Twenty individuals of each species were tagged for phenological observations, and the study of floral biology, reproductive system, as well as the frequency and behaviour of floral visitors. The species are monoecious, with diurnal dish flowers, the male ones more ephemeral (12 h) than the female (36 h). The sugar concentration in the nectar of J. mutabilis and J. mollissima varied between 26%-32% and 20%-28%, respectively. Volume was usually greater (16 µL) in female flowers of both species. Pollen viability was high (> 97%). Both species are self-compatible. The percentage of fruit set under natural conditions was c. 75% in J. mutabilis and of 85% in J. mollissima, indicating high reproductive success. The flowers are pollinated by bees and wasps, and also by hummingbirds in J. mutabilis and butterflies in J. mollissima. The species have flowers along the whole year, thus they are important resources for the maintenance of the local communities of animals that visit them. Also, the presence and effectiveness of these groups of pollinators are fundamental for both plant species, since they are responsible for the pollen flow among male and female flowers in these monoecious shrubs.Key words -Caatinga, Jatropha, monoecy, pollination, reproductive phenology RESUMO -(Biologia reprodutiva de duas espécies de Jatropha L. (Euphorbiaceae) em Caatinga, Nordeste do Brasil). A polinização, o sistema reprodutivo e a fenologia de floração e de frutificação de Jatropha mutabilis (Pohl) Baill. e J. mollissima (Pohl) Baill. foram estudados no Estado de Pernambuco, nos Municípios de Buíque (8°67' S e 37°01' W) e Arcoverde (8°25' S e 37°02' W), ambos em Caatinga. Foram marcados 20 indivíduos de cada espécie para registro dos dados fenológicos, aspectos da biologia floral, sistema reprodutivo, bem como freqüência e comportamento dos visitantes florais. As duas espécies são monóicas, apresentam flores do tipo disco, com antese floral diurna, havendo variação em relação à longevidade das flores nos dois sexos, sendo as flores masculinas mais efêmeras (12 h), e as femininas mais duradouras (36 h). Ambos os tipos florais são nectaríferos e a concentração de açúcares no néctar variou entre 26% e 32% em J. mutabilis e 20% a 28% em J. mollissima. A viabilidade do pólen foi alta (> 97%) em ambas as espécies. As espécies são autocompatíveis, formando frutos tanto nos tratamentos de geitonogamia como nos de xenogamia. O percentual de formação de frutos em condições naturais foi ca. 75% em J. mutabilis e de 85% em J. mollissima, indicando alto sucesso reprodutivo. As flores de ambas as espécies são polinizadas por abelhas e vespas, além de beija-flores em J. mutabilis e ...

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Section: Discussionunclassified

Biologia reprodutiva de duas espécies de Jatropha L. (Euphorbiaceae) em caatinga, Nordeste do Brasil

Santos¹,

Machado²,

Lopes³

2005

Rev. bras. Bot.

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“…At least in theory, this can produce phenological patterns that seem maladaptive at the population level (Forrest & Thomson 2009). In addition, males and females within a population may differ in the optimal timing of emergence or reproduction, because precedence is often favoured in mate competition between males but is less strongly selected in females (Wiklund & Fagerströ m 1977;Bawa & Beach 1981;Morbey & Ydenberg 2001). This could, in principle, drive sexual conflict over timing (Møller et al 2009), something that could again produce apparently maladaptive features in the population as a whole.…”

Section: Evolution Of Phenologymentioning

confidence: 99%

Toward a synthetic understanding of the role of phenology in ecology and evolution

Forrest

Miller‐Rushing

2010

Phil. Trans. R. Soc. B

567

512

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Phenology affects nearly all aspects of ecology and evolution. Virtually all biological phenomenafrom individual physiology to interspecific relationships to global nutrient fluxes-have annual cycles and are influenced by the timing of abiotic events. Recent years have seen a surge of interest in this topic, as an increasing number of studies document phenological responses to climate change. Much recent research has addressed the genetic controls on phenology, modelling techniques and ecosystem-level and evolutionary consequences of phenological change. To date, however, these efforts have tended to proceed independently. Here, we bring together some of these disparate lines of inquiry to clarify vocabulary, facilitate comparisons among habitat types and promote the integration of ideas and methodologies across different disciplines and scales. We discuss the relationship between phenology and life history, the distinction between organismal-and population-level perspectives on phenology and the influence of phenology on evolutionary processes, communities and ecosystems. Future work should focus on linking ecological and physiological aspects of phenology, understanding the demographic effects of phenological change and explicitly accounting for seasonality and phenology in forecasts of ecological and evolutionary responses to climate change.

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“…The occurrence of androdioecy (cosexuals and males in a single population), and its potential significance for the evolution of dioecy (females and males in a single population) has long been of interest (Darwin, 1877 ;Lloyd, 1975 ;Charlesworth & Charlesworth, 1978 ;Bawa & Beach, 1981 ;Ross, 1982 ;Charlesworth, 1984). Despite several reports of androdioecy, close analysis has revealed that nearly all those species reported to be androdioecious are in fact functionally dioecious (Charlesworth, 1984 ;Anderson & Symon, 1989).…”

Section: mentioning

confidence: 99%

Androdioecy in the entomophilous tree Fraxinus ornus (Oleaceae)

et al. 1999

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Androdioecy (the coexistence of two genders, cosexuals and males, in a single population) is a rare breeding system. In terms of functional gamete production, androdioecy has been reported in a small number of windpollinated and insect-pollinated species. In this study we examine the floral biology, stability of gender, and fruit and seed production after self-pollination and outcrossing pollination in a potentially androdioecious tree, Fraxinus ornus, in southern France. Individual trees have either hermaphrodite flowers or male flowers, the latter lacking a well-developed gynoecium. The two genders produce morphologically similar pollen and were present in 1 : 1 or slightly male-biased ratios. Only hermaphrodites set fruit during 2-4 yr of observation at four different sites in southern France. Experimental pollinations of eight trees in two different sites showed that hermaphrodites produce viable pollen in dehiscent anthers and viable seeds. Thus, in terms of functional gamete production, F. ornus is a new case of functional androdioecy. Seven hermaphrodites were self-compatible, and such self-compatibility of hermaphrodites might improve the colonizing ability of F. ornus in a region where this species is actively expanding its range.

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Evolution of Sexual Systems in Flowering Plants

Cited by 294 publications

References 69 publications

Biologia reprodutiva de duas espécies de Jatropha L. (Euphorbiaceae) em caatinga, Nordeste do Brasil

Biologia reprodutiva de duas espécies de Jatropha L. (Euphorbiaceae) em caatinga, Nordeste do Brasil

Toward a synthetic understanding of the role of phenology in ecology and evolution

Androdioecy in the entomophilous tree Fraxinus ornus (Oleaceae)

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