Cytohistology of cytoplasmic male sterile lines in hybrid rice

摘要

By 1985, 36 male sterile lines from 14 cytoplasmic sources and 6 male sterile materials from pollen-free types had been cytologically studied in China. Based on pollen abortion pattern, male sterile rice can be classified into four types; pollen-free, uninucleate abortive, binucleate abortive, and trinucleate abortive. Pollen-free types abort before the uninucleate stage and have no pollen. In uninucleate and binucleate abortion types, nuclei and cytoplasms dissolve, forming wrinkled irregular or spherical empty pollen.The trinucleate abortion types have normal shaped pollen, but form abnormal sperm during reproductive division. In some male sterile species, a special pattern of pollen abortion occurs:sterility for all factors from sporogenesis through germination of pollen grains. This results in few mature pollen grains, low percentage of split anthers, and low pollen germination. Among the variant types, the vascular bundles of filaments and connectives develop abnormally, and are not identical. The vascular system of a wild abortive male sterile line was more poorly developed and differentiated than other male sterile lines. The abnormal dehiscent structure in the anther of male sterile are shown mainly at the splitter in the fracture cavity and by irregularly developed anther "springs."