水稻小孢子形成和发育过程中胼胝质的动态变化

摘要

Callose plays an important role in microsporogenesis and pollen development. However, few studies with the emphasis on callose changes have been carried out in rice. Taichung 65 was employed to investigate the dynamic changes of callose in microsporogenesis and microgametogenesis of rice by using techniques of intact fresh anther epifluorescence microscopy, PEG section epifluorescence microscopy, semi-thin section light microscopy, and TEM. It was found that callose appears in microsporangium at the microspore mother cell formation stage. During meiosis, callose deposition in microspore mother cell firstly occurs on the primary cell wall in the central region of the anther locule, and the intact callose wall appears at the meiotic diakenesis I. In microgametogenesis, callose deposits in tapetal cells and begins to accumulate around microspore nucleus at the early microspore stage, callose deposition around microspore nucleus continues through uninucleate microspore stage. At the late microspore stage, the degeneration of the tapetal cell begins, and the thickening of the endothecium cell wall by callose happens. At the early bicellular pollen stage, accumulation of callose in the cytoplasm of the vegetative cell occurs, and the callose wall of the generative cell is formed and then degraded before the third nuclear migration. At the mature pollen stage, certain amount of callose accumulates in cytoplasm of the vegetative cell. These results indicate that callose metabolism is active and very important not only in microsporogenesis but also in microgametogenesis in rice.%利用活体荧光显微术,PEG切片荧光显微术,半薄切片光学显微术和透射电镜观察了粳稻台中65小孢子形成和发育过程中胼胝质的动态变化.结果发现,胼胝质最早于小孢子母细胞形成期出现于花粉囊中.进入小孢子母细胞减数分裂期,胼胝质首先在小孢子母细胞靠近药室中央的初生细胞壁上沉积,并于减数分裂Ⅰ终变期形成完整的胼胝质壁;随后胼胝质在小孢子母细胞中央开始沉积,并向四周扩展形成第1个赤道板,随后形成第2个赤道板;减数分裂后,四分体周围的胼胝质解体释放出小孢子.小孢子早期,绒毡层细胞中积累胼胝质类物质,小孢子核周围也开始沉积胼胝质,逐渐形成完整胼胝质壁;小胞子晚期,绒毡层细胞开始解体,药室内壁细胞开始加厚,其加厚的物质为胼胝质类物质.二胞花粉早期,小孢子进行不均等分裂,形成营养细胞和具有胼胝质壁的生殖细胞,随后营养细胞的细胞质中积累胼胝质,生殖细胞的胼胝质壁开始解体;二胞花粉晚期,药室内壁加厚完成,营养细胞的细胞质中继续积累胼胝质,花粉成熟期,营养细胞的细胞质中积累了大量胼胝质.对胼胝质在小孢子形成和发育过程中的功能进行了讨论.