烟草花药发育过程中钙动态分布的初步观察

在烟草花药发育过程中,用焦锑酸钾沉淀的松弛结合钙显示出了一个与花药发育事态有关的动态:在孢原细胞时期的花药中几乎看不到钙颗粒.但到小孢子母细胞时期,花药中开始有钙颗粒沉淀,而且显示出向花药室中流动的迹象.当花粉母细胞进行减数分裂时,花药绒毡层细胞和花粉母细胞中出现了许多的细小钙颗粒.在小孢子发育时期,在绒毡层细胞解体之前,细胞中的钙被集中到小液泡中.在小孢子细胞质中仍有较多的钙颗粒,同时在花粉壁上也有钙颗粒沉积在外壁的基部.到小孢子分裂形成二胞花粉后,细胞质中的钙明显减少.当二胞花粉中的大液泡消失,细胞质中积累淀粉粒以后,花粉中可看到的钙颗粒很少.同时,在花药维管束周围的薄壁细胞中,又出现了较多的钙颗粒,表明花粉对钙离子的需求可能已降低.烟草花药发育过程中钙的动态分布特征暗示着钙参与了调控花粉发育过程,尤其是与小孢子转变过程中的重要事态有密切关系.

The Primary Observation of Calcium Distribution During the Anther Development of Tobacco

The feature of calcium distribution during anther development of tobacco was investigated by using potassium antimonate to precipitate "exchangeable cellular Ca~(2 )".Before microspore mother cell,no calcium-induced precipitates were found in sporogenous cells and the cells of anther wall.When microspore mother cell preparing meiosis,abundant calcium precipitates appeared in cytoplasm of tapetal cells and microspore mother cells,and in callus wall surrounding the cells.After the meiosis of microspore mother cell,some calcium grains were first deposited on the surface of early microspores,and many calcium precipitates still located in the tapetum and microspore cells.During the late microspore stage,a big vacuole forms and the nucleus was forced to move to peripheral region.Numerous calcium precipitates were still in cytoplasm and the exine of microspores,but calcium grains in tapetal cells decreased and concentrated in some small vacuoles following tapetum degenerating.After microspore mitosis,bicellular pollen contained a large vegetative cell and a small generative cell,and then the big vacuole disappeared.The precipitates of calcium in cytoplasm of pollen decreased with the cytoplasm becoming densel and the storage materials accumulating.When pollen accumulated starches,only some calcium precipitates were still located on the pollen wall,but a few in cytoplasm.In the meanwhile,some precipitates were accumulated in parenchymatous cells outside the vascular.The feature of calcium distribution during anther development of Nicotiana tabacum meaned that played some biological significance during microspore development.