Cytoplasmic genetic male sterility in cultivated rice oryza sativa 3. histological investigation on pollen sterility of cultivar taichung 65 having oryza rufipogon cytoplasm
Cheng, Y.K.; Huang, C.S.; Lai, K.L.
Journal of the Agricultural Association of China 114: 15-37
To examine the cause of pollen abortion in a cytogenetic male sterile rice, 'Taichung 65' (TC65) having O. rufipogon cytoplasm, cytohistological observations on the male sterile anthers were carried and compared with those of the fertile maintainer. Most of degeneration and disintegration of microspores in the CMS [cytoplasmic male sterile] plants occurred after meiosis. The main characteristics associated with these abnormalities were degeneration of cytoplasm, nucleus lacking wall-thickening, and swelling of cell. After release from tetrads, some microspores developed, normally up to the late uninucleate stage, but microspore mitosis did not take place and the nuclei subsequently lost their spherical shape and stainability. The pollen wall later folded inward, giving a deformed, often sickle-shaped or broken wall appearance of abortive pollen grains. Tapetal cells of sterile plant anthers were significantly different from those of fertile ones. The abnormalities of tapetum in relation to pollen abortion were classified into the following types: tapetal hypertrophy; hill and balloon types; vacuolation of tapetal cells; formation of intratapetal syncytium or tapetal periplasmodium; persistence of inner primary tapetal wall; formation of abnormal tapetal inclusions; early separation of radial cell walls between tapetum cells. The abnormal behavior of tapetum was associated with male sterility. The sequence of events in the CMS anther suggested that the failure of the tapetum was a cause of pollen abortion of this CMS line.