| Abstract: | (1) Pathways A-V, A-G, A-GV, and B existed in androgenesis of rice. Usually B pathway was predominant. Degeneration could happen on androgenic grains via each pathway during the early stage of androgenesis. (2) Statistics suggested that the multinucleate grains might be converted to multicellular grains by a later formation of cell walls and were consequently one of the sources of callus. (3) Androgenic grains was usually of medium size (35–40 μm) with dense protoplasm. In isolated pollen culture, the diameter of androgenic grains increased 2.5–5μm per day. Before the breakdown of exine, the cell walls seemed to be thickened and the grains would contract abruptly. (4) Small, slowly-moving starch granules were usually contained within multicellular grains cultured isolately. They were speculated to participate actively in the metabolism of androgenic grains. |
