Programa de Pós-Graduação em Botânica.
Ann Bot. 2013 Oct;112(6):1117-23. doi: 10.1093/aob/mct188. Epub 2013 Sep 11.
Reciprocal herkogamy, including enantiostyly and heterostyly, involves reciprocity in the relative positions of the sexual elements within the flower. Such systems result in morphologically and, since pollen is deposited on and captured from different parts of the pollinator, functionally distinct floral forms. Deviations from the basic pattern may modify the functionality of these mechanisms. For heterostylous species, such deviations are generally related to environmental disturbances, pollination services and/or reduced numbers of one floral morph. Deviations for enantiostylous species have not yet been reported. This study aims to investigate enantiostyly in Chamaecrista flexuosa, in particular the presence of deviations from the standard form, in an area of coastal vegetation in north-east Brazil.
Observations and investigations of floral biology, the reproductive system, pollinator behaviour, floral morphology and morphometry were performed.
In C. flexuosa flowers, anthers of different size but similar function are grouped. The flowers were self-compatible and set fruits after every treatment, except in the spontaneous self-pollination experiment, thereby indicating their dependence on pollen vectors. The flowers were pollinated by bees, especially Xylocopa cearensis and X. grisencens. Pollen is deposited and captured from the ventral portion of the pollinator's body. Variations in the spatial arrangement of floral elements allowed for the identification of floral morphs based on both morphological and functional criteria. Using morphological criteria, morphologically right (MR) and morphologically left (ML) floral morphs were identified. Three floral morphs were identified using functional criteria: functionally right (FR), functionally central (FC) and functionally left (FL). Combinations of morphologically and functionally defined morphs did not occur in equal proportions. There was a reduced frequency of the MR-FR combination.
The results indicate the occurrence of an atypical enantiostyly in C. flexuosa. This seems to improve reproductive success by increasing the efficiency of pollen deposition and capture.
雌雄异位现象，包括对生花柱和异型花柱，涉及花内生殖器官相对位置的相互关系。这些系统导致花具有形态和功能上的差异，因为花粉是在不同的传粉者部位上沉积和捕获的。偏离基本模式可能会改变这些机制的功能。对于异型花柱物种，这种偏离通常与环境干扰、传粉服务和/或一种花形态数量减少有关。尚未报道过对生花柱物种的偏离。本研究旨在调查巴西东北部沿海植被区 Chamaecrista flexuosa 的对生花柱现象，特别是偏离标准形式的情况。
进行了花朵生物学、生殖系统、传粉者行为、花朵形态和形态测量学的观察和研究。
在 C. flexuosa 的花朵中，大小不同但功能相似的花药被组合在一起。这些花朵是自交亲和的，除了在自发自交实验中，在所有处理后都能结出果实，这表明它们依赖于花粉载体。花朵由蜜蜂授粉，特别是 Xylocopa cearensis 和 X. grisencens。花粉从传粉者身体的腹面沉积和捕获。花部元素空间排列的变化使得根据形态和功能标准来识别花形态成为可能。使用形态学标准，识别出形态上正确（MR）和形态上错误（ML）的花形态。使用功能标准，识别出功能上正确（FR）、功能上中央（FC）和功能上错误（FL）的三种花形态。形态和功能定义的花形态组合没有以相等的比例出现。MR-FR 组合的频率降低。
研究结果表明 C. flexuosa 中存在一种非典型的对生花柱现象。这似乎通过提高花粉沉积和捕获的效率来提高繁殖成功率。
