毛竹的花药发育研究

Observation on anther development of Phyllostachys edulis

关键词:  毛竹, 花药, 花药壁, 小孢子, 花序, 发育

Key words:   Phyllostachys edulis, anther, anther wall, microspore, inflorescence, development

摘要:

竹类植物因有着较长的开花周期,其生殖生物学研究的报道相对较少。该研究采用石蜡切片与野外观察的方法,对毛竹花药的发育以及花药发育与花序的关系进行了研究。结果表明:毛竹的花药壁结构包括4层细胞:表皮细胞、药室内壁细胞、中层细胞和绒毡层细胞。药室内壁和中层都只有一层细胞,而且细胞形状较扁,花药发育后期药室内壁会逐渐降解,而中层则会完全解体消失。花药壁的发育为单子叶型,绒毡层为腺质型,而且只有一层,细胞径向较长,最后也会消失。小孢子母细胞减数分裂时,胞质分裂方式为连续型。形成的小孢子经一次有丝分裂后逐渐形成成熟花粉粒,大多为二细胞型,很少产生三细胞型。此外,还发现毛竹花药的发育与花序形态变化存在着相对应的关系。野外连续观察和切片发现,随着花序形态的不断发育变化,首先花药开始形成并不断分化,药壁各层也逐渐形成; 接着小孢子逐渐成熟,各层也慢慢随之解体、消失; 最后花药逐渐开裂并开始散粉。该研究结果不仅丰富了毛竹和竹类生殖生物学的研究内容,而且对毛竹种质的研究也具有重要意义。

Abstract:

Because of the long flowering stage, studies about the reproductive biology of bamboos were rarely fewer. In this research, the anther development of Phyllostachys edulis was studied by paraffin section, and the process of anther development of P. edulis was also analysed, including the development process of the anther, anther wall and microspore. The results showed that the anther wall of P. edulis contains four layer of cells, which were epidermal cells, endothecium cells, middle layer cells and tapetum cells. There was only a layer of cells with flat shape in endothecium cells and middle layer cells. At the end of the anther development when microspore goes to pull over, endothecium cells would degrade gradually and the middle layer cells would break up and disappeared. The development of anther wall was monocotyledonous type, and the tapetum belonged to secretory type with a layer of cells growing in radial direction, the final development of tapetum disappeared by themselves. The type of cytokinesis of microsporocyte meioticdivision was successive, and the generated microspore from which then fomated mature pollen by one mitosis process. Mature pollen grains were mostly two-celled, rarely three-celled. In addition, we found that there was a corresponding relationship between the development of anther and continuous morphology change of the inflorescence. Based on the results of continuous observation on the inflorescence and paraffin section assays, we also found that unceasing development and division of anther occurred with the continuous development of inflorescence, and anther wall layers of cells were gradually formed. Then microspore became mature gradually and the layers of the anther degraded and disappeared during the process, and then mature pollen spilled out from the dehiscenced anther. Our research would enrich the studies on the reproductive biology of bamboos and also was of great significance to the study on the germplasm of moso bamboo.