棕榈花发育形态和解剖结构

Morphological and anatomical structure of Chinese windmill palm(Trachycarpus fortunei)flowers during development

为揭示棕榈(Trachycarpus fortunei)花的发育特点,使用常规石蜡切片法、超薄切片法和扫描电镜法对棕榈不同时期的雌花和雄花进行观察。结果表明棕榈花在发育初期为两性,随后由于雌、雄蕊选择性败育出现单性化。棕榈雌花的雌蕊具有干性柱头、中空花柱、基生胎座、倒生胚珠、双珠被等结构特征;雄花的雄蕊具有二细胞型花粉,在药室内壁内侧边缘区域发现乌氏体。棕榈雌花具退化雄蕊6枚,在花丝花药分化不久就停止发育,随后干瘪萎缩,失去细胞活性,没有产生花药壁层结构和小孢子。雄花具退化雌蕊3枚,在花发育后期还有一定分化,逐步停滞发育,没有萎缩,仍具细胞活性;胚珠内部发育不完善,仅具双珠被,无胚囊及大孢子。本研究探明了棕榈花的发育过程为I型,补充了雌、雄蕊的结构特征,明确了败育性器官的停滞时间与败育程度,为进一步深入研究棕榈花发育过程中的机制提供研究基础。

In order to reveal the developmental characteristics of Chinese windmill palm(Trachycarpus fortunei)flowers,the female and male flowers of T.fortunei at different stages were observed by conventional paraffin section,ultrathin section and scanning electron microscope methods.The results show that T.fortunei flowers are bisexual in the early stage of development,and then unisexual due to the selective abortion of pistil and stamen.The pistil of T.fortunei female flower has the structural characteristics of dry stigma,hollow style,basal placenta,anatropous ovule and double integument.The stamen of male flower has bicellular pollen,and ubisch body is found in the inner edge area of the endothecium.T.fortunei female flower has six staminodes.The stamen stops developing shortly after the differentiation of filaments and anthers,then shrivelled and atrophied,loses cell activity,and does not produce anther wall structure and microspore.The male flower has three pistillodes.The pistil has certain differentiation in the late stage of flower development,and then gradually stagnant development.The pistil without atrophy still has cell activity.The internal development of ovule is imperfect,only with double integument,no embryo sac and megaspore.This study proves the development process of T.fortunei flower was type I,supplements the structural characteristics of pistils and stamens,and clarifies the stagnation time and degree of abortion of the abortive sex organs,laying a solid foundation for further in-depth study of the developmental mechanism in the development of T.fortunei flower.