Calcium Distribution During Pollen Development of Larix principis-rupprechtii

摘要

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 Ca~(2+) to the pollen.