The Microstructural and Ultrastruc-tural Study on Microsporogenesis of Cytoplasmic Male-sterile Cotton Line Jin A

This study was conducted on the male sterile cotton line Jin A in mo rphological characters.The results showed that: (1) The auxocyte abortion of Ji n A took place at the stage of sporogenous cell division. In most cases,the spor ogenous tissues collapsed and coalesced during the premiotic stage of developmen t,while occasionally a few microspore mother cells formed and meiosis progressed in some locules. However, these cells degenerated during the early stages of pr ophase Ⅰ.The collapse of the tapetum was responsible for the abortion of micros por mother cells. (2) The abnormal mitochondrium in microspore mother cells and tapetume cells had directly effects on abortion of MMCs.The abnormal characteris tics of mitochondrium are inflation and splitting of mitochondrium, melt and dis appearance of cristae.