Studies On Pollen-Ovule Reaction Before Fertilization Of Larix Principis-rupprechtii Mayr.

Self-pollination was brought as the essential reason for causing emptied seeds by former researchers. Based on those studies, potassium antimonate and electron microscopy were used to study the calcium distribution of pollens in the micropylar canal of self-pollinated and cross-pollinated ovules and morphological changes in certain cells undergoing programmed cell death from pollination to fertilization, and observation of histo-chemical changes during microgametopyte development was performed by paraffin section. The relationship among calcium signal transduction, pollen-ovule interaction, and Programmed cell death (PCD) was discussed from these studies, and the results are as follows: (1) Great difference was observed in the calcium distribution of pollens in the micropylar canal of self-pollinated and cross-pollinated ovules: a large quantity of calcium precipitates was located on the intine of self-pollinated pollen, while none on cross-pollinated pollen. (2) At the same time, there was remarkable difference in the calcium distribution on the wall of micropylar canal between self-pollinated and cross-pollinated ovules: abundant calcium precipitates were found on the wall of self-pollinated ovules, whereas none on cross-pollinated pollen. (3) Certain cells were undergoing programmed cell death during microgametopyte development, and that was be related to calcium signal transduction. (4) Starch mostly distributed in tissue which cell divide frequently and develop actively, at the same time, the distribution of protein changed from pollination to fertilization stage.