关键词: 杏, 花粉, 花药壁, 胚胎学

Abstract: In order to understand the embryological features of the pollen and anther wall of apricot，anthers of different ages were examined by means of light microscopy. The cell layers of anther wall were established in early November，including epidermis，endothecium，middle layers，and tapetum. The tapetum belonged to secretory type. The process of microsporogenesis lasted about 3 months. Microspore mother cells were formed in early November，and underwent meiosis during the period from late January to early February the next year. The microspore mother cell accumulated a large number of lipid droplets as meiosis began. The 4 meiotic nuclei were separated by simultaneous cytokinesis to form four microspores that were joined together in a tetrad. The four microspores in the tetrad were in a tetrahedral arrangement. The microspore was present for about one month before it underwent mitotic division to a 2-celled pollen grain. The 2-celled pollen stage lasted 2–3 weeks till anthesis. The mature pollen belonged to lipidic type，for it accumulated lipid droplets rather than starch. As the structure of anther walls was established，the scaly buds started winter dormancy，i.e.，they stopped elongation temporarily. When the meiosis of the microspore mother cell was completed，the winter dormancy was broken，i.e.，the scaly buds resumed elongation. Apparently，there was a coincidence between the mcirosporogenesis in the anther and the winter dormancy of the scaly buds. The microspore underwent mitotic division at the time when the flower bud reached the length of the scale. In summary，the process of apricot pollen development lasted 4.5 months，and the exclusive features included the coincidence between the microsporogenesis and the winter dormancy of the scaly buds，the accumulation of lipid droplets in the microspore mother cell，and that the first mitotic division of male gametophyte was marked by the growth of the flower bud to the length of the scale.

Key words: apricot, pollen, anther wall, embryology