Floral Development of Monoecious Pseuduvaria Trimera (Annonaceae) and Comparative Morphology and Structure of Its Stamens and Indehiscent Staminodes
Floral Development of Monoecious Pseuduvaria Trimera (Annonaceae) and Comparative Morphology and Structure of Its Stamens and Indehiscent Staminodes
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DOI：
10.1086/688710
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发表时间：
2016-09
影响因子：
2.3
通讯作者：
Gui-Fang Yang;Fengxia Xu
中科院分区：
文献类型：
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作者：
Gui-Fang Yang;Fengxia Xu
研究的优先权。首次对番荔枝雌雄蕊花的发育进行了比较研究，以了解其性别分化和发育过程。同时比较了成熟雄蕊和退化雄蕊的形态和解剖特征，以阐明花药开裂和退化雄蕊不育的机制。方法论利用扫描电镜和光镜对不同发育时期的花及成熟雄蕊和退化雄蕊进行了观察。初步结果。与其它番荔枝科植物相似，三瓣假番荔枝的花具有复杂的轮生叶序。它们在生殖器官的最外圈有两个位置，每轮雄蕊和心皮的数量可变。每个囊的气孔区由隔和气孔组成。雄蕊的隔膜和气孔细胞退化，有利于花药的开放，而退化雄蕊的隔膜和气孔细胞保持完整，形成不裂的花药。结论.这些数据表明，雄花是单性的，从他们的成立，而雌花形态雌雄同体，但功能雌花。花药不裂，三聚体的结构雄核单胞体实际上起着单胞体的作用。不裂退化雄蕊的不育性和外层雄蕊的延迟开裂的机制可能促进了异花受精。退化雄蕊的存在与假牡丹属功能单性花的进化密切相关。
Premise of research. The comparative development of staminate and pistillate flowers in Pseuduvaria trimera (Annonaceae) was investigated for the first time to understand its sexual differentiation and developmental processes. The morphological and anatomical features of mature stamens and staminodes were also compared to clarify anther dehiscence and to understand the mechanism underlying staminode sterility. Methodology. Flowers at different developmental stages as well as mature stamens and staminodes were examined using SEM and LM. Pivotal results. Similar to other Annonaceae, the flowers of Pseuduvaria trimera have a complex whorled phyllotaxis. They have double positions in the outermost whorl of reproductive organs and variable numbers of stamens and carpels per whorl. The stomium region of each theca is composed of the septum and the stomium. The septum and stomium cells of stamens degenerate and facilitate anther opening, whereas those of staminodes remain intact and form indehiscent anthers. Conclusions. The data suggest that staminate flowers are unisexual from their inception while pistillate flowers are morphologically hermaphroditic but nevertheless functionally pistillate. The anthers are indehiscent, and the structural andromonoecy of P. trimera actually functions as monoecy. The mechanism underlying the sterility of the indehiscent staminodes and the delayed dehiscence of the outer stamens might promote xenogamy. The presence of the staminodes is closely correlated with the evolution of functional unisexual flowers in the genus Pseuduvaria.