华北落叶松花粉发育过程中的钙动态分布

运用焦锑酸钾沉淀法研究了华北落叶松(Larix principis-rupprechtii Mayr)小孢子发育过程中不同阶段Ca2 的分布情况.减数分裂时期,小孢子囊壁表皮和中层细胞的细胞壁及细胞间隙Ca2 分布较多,绒毡层只有外切向面的细胞膜有Ca2 分布,小孢子母细胞的各部位则很少有Ca2 ;四分体时期,包围四分小孢子的胼胝质壁上有大量的Ca2 分布,在四分孢子壁上也有较多沉淀;游离小孢子时期,钙离子在小孢子壁的分布较四分体时期有所减少,而到花粉成熟时又逐渐增多;从四分体到花粉成熟,乌氏体周围的Ca2 有增多的趋势.对四分体外壁Ca2 的大量分布与花粉壁的形成及信号物质在花粉表面贮存的关系,以及小孢子囊的外壁、绒毡层和乌氏体在Ca2 向花粉运输中所起的作用进行了讨论.

Calcium Distribution During Pollen Development of Larix principis-rupprechtii

Potassium pyroantimonate precipitation method was used for ultracytochemical localization of calcium in microsporangia of Prince Rupprecht Larch (Larix principis-rupprechtii Mayr) at different developmental stages. During meiosis, calcium precipitates were abundant on the cell wall and intercellular space among cells of the epidermis and middle layers of the microsporangium wall. Calcium precipitates were only found on the cell wall of the outer tangential membrane of the tapetal cells, but few was found in microspore mother cells. At tetrad stage, a large amount of calcium precipitates were observed on the callose wall of each tetraspore as well as the wall surrounding the whole tetrad. The quantity of calcium precipitates decreased at free microspore stage and then gradually increased till pollen maturation. Calcium around the Ubisch bodies increased from the tetrad stage till pollen maturation. This study also discusses the relation between the distribution of calcium precipitates on the tetrad walls and the formation of pollen wall, as well as the possible function of epidermis, middle cells, tapetum and Ubisch bodies in transportation of Ca²⁺ to the pollen.