Como duas espécies de Chamaecrista lidam com o dilema do pólen? diferença no tamanho floral e estratégia reprodutiva mediada pelas abelhas
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Data
2019-02-26
Autores
Lima, Tamiris Daiane Delgado de
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Universidade Estadual Paulista (Unesp)
Resumo
A variação no tamanho floral entre espécies vegetais interfere diretamente no grau de heteranteria e grau hercogamia dentro da flor, e pode favorecer a divisão de trabalho entre as anteras, diminuindo o conflito por pólen entre planta e polinizador. Neste trabalho, nosso objetivo principal é investigar como o tamanho floral modifica o processo de polinização e estratégia reprodutiva em duas espécies com tamanhos florais contrastantes: Chamaecrista desvauxii var. latistipula e Chamaecrista nictitans. Nossa hipótese é de que a morfologia das flores maiores de C. desvauxii var. latistipula com androceu evidentemente heteromórfico favoreça a divisão de trabalho, e a segurança reprodutiva nessas flores ocorra via anteras de polinização; enquanto que a morfologia das flores menores de Chamaecrista nictitans não favorece a divisão de trabalho entre as anteras e que a segurança reprodutiva e o conflito por pólen sejam superados pelo predomínio da autopolinização. Nossos resultados indicam que não ocorre divisão de trabalho entre os conjuntos das anteras em ambas as espécies, embora o heteranteria seja visível em C. desvauxii. Independente do tamanho das flores os diferentes conjuntos de anteras não diferem em atração visual para as abelhas. Já em flores menores de C. nictitans nossos resultados indicam a quebra da heteranteria e da hercogamia em um sistema mais generalista quando comparado a flores maiores de C. desvauxii var. latistipula. As flores pequenas de C. nictitans dependem do auto pólen para alcançar o sucesso reprodutivo, o mesmo não ocorre com as flores grandes de C. desvauxii. A preponderância da autopolinização mediada pelas abelhas ou por autopolinização espontânea é evidente nas flores menores, diferente das flores de C. desvauxii muito mais dependente da visita das abelhas.
The variation in floral size between plant species directly interferes with the degree of heteranthery and degree of hercogamy within the flower and may favor the division of labor between the anthers, reducing the conflict between plant pollen and pollinator. In this work, our primary objective is to investigate how the floral size modifies the pollination process and reproductive strategy in two species with contrasting floral sizes: Chamaecrista desvauxii var. latistipula and Chamaecrista nictitans. We hypothesize that the morphology of the larger flowers of C. desvauxii with evident anther dimorphism favors the division of labor, and reproductive security in these flowers occurs via pollination anthers. Alternatively, the morphology of the smaller flowers of C. nictitans does not favor the division of labor between the anthers and that reproductive security and pollen conflict are overcome by the predominance of self-pollination. Our results indicate that there is no division of labor between the anther sets in both species, although heteranthery is visible in C. desvauxii. Regardless of the size of the flowers, the different anther sets do not differ in visual attraction for the bees. In smaller flowers of C. nictitans, our results indicate the breakage of heteranthery and hercogamy into a more general system when compared to larger flowers of C. desvauxii. The small flowers of C. nictitans depend on auto pollen to achieve reproductive success, the same does not occur with the large flowers of C. desvauxii. The preponderance of self-pollination by bees or spontaneous self-pollination is evident in the smaller flowers, different from the flowers of C. desvauxii, which is much more dependent on the visit of the bees.
The variation in floral size between plant species directly interferes with the degree of heteranthery and degree of hercogamy within the flower and may favor the division of labor between the anthers, reducing the conflict between plant pollen and pollinator. In this work, our primary objective is to investigate how the floral size modifies the pollination process and reproductive strategy in two species with contrasting floral sizes: Chamaecrista desvauxii var. latistipula and Chamaecrista nictitans. We hypothesize that the morphology of the larger flowers of C. desvauxii with evident anther dimorphism favors the division of labor, and reproductive security in these flowers occurs via pollination anthers. Alternatively, the morphology of the smaller flowers of C. nictitans does not favor the division of labor between the anthers and that reproductive security and pollen conflict are overcome by the predominance of self-pollination. Our results indicate that there is no division of labor between the anther sets in both species, although heteranthery is visible in C. desvauxii. Regardless of the size of the flowers, the different anther sets do not differ in visual attraction for the bees. In smaller flowers of C. nictitans, our results indicate the breakage of heteranthery and hercogamy into a more general system when compared to larger flowers of C. desvauxii. The small flowers of C. nictitans depend on auto pollen to achieve reproductive success, the same does not occur with the large flowers of C. desvauxii. The preponderance of self-pollination by bees or spontaneous self-pollination is evident in the smaller flowers, different from the flowers of C. desvauxii, which is much more dependent on the visit of the bees.
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Palavras-chave
Divisão de trabalho, Heteranteria, Hercogamia, Autopolinização, Dilema do pólen, Tamanho floral, Polinização por vibração, Division of labor, heteranthery, hercogamy, self-pollination, pollen dilemma, floral size, vibration pollination