The Possible Mechanism Of Wheat Male Sterility Induced By Chemical Hybridizing Agents

This work focus on isozyme analysis and cytological studies on the effect of two chemical hybridizing agents-BAU9403 and Genesis, both could induce male sterility in wheat successfully.In the course of pollen abortion, the changes of peroxidase(POD) and esterase(EST) were assayed. The research result showed:(l) the tendency of peroxidase changes induced by two CHAs were similar. The POD activity in anther of treatments was lower than control, which indicated that wheat male sterility induced by CHA was correlated with the decrease of POD activity.(2) there were obvious different isozyme bands between BAU9403 and Genesis inducing male sterility, which indicated that different CHAs had different mechanism to induce male sterility. The zymograms of POD showed that when treated by Genesis, from the 2nd day, the expression of POD began to decrease, but for wheat used with BAU94Q3,from the 1^st day ,activity of isozyme decreased. Two kinds of CHA influenced different isozyme bands. (3) the two CHAs had not evident effect on EST activity, which showed that different isozymes had different response to CHA.At the same time, we designed another experiment-adding CHA in vitro. We added Genesis into enzyme liquid directly, and found that the CHA can inhibit POD's activity, but had little influence on EST's activity. This new discovery help us to understand further the mechanism of male sterility induced by CHA.Employing optical and electronic microscope, the morphological and cytological feature of wheat anther induced by CHA-BAU9403 and Genesis for different dosages.The morphological feature was as follow: the sterile plant was low and light green in color. The spike expanded and the anther was not open.The cytological studies showed:(l) The abortive degree of the pollen from BAU9403 induced male sterile wheat was related closely with CHA's dosage. There exist higher sterile degree in plant under high dosage than under low dosage.(2) The functional abnormality of tapetum and vascular in anther induced by CHA was responsible for male sterility.(3) Abortive process began from tetrad stage, and continue until to the end of thinucleate stage. Although abortion occurred at all developmental stages, pollen abortive feature was most obviously during uninucleate stage.(4)The abortive indication was that tapetum degenerated abnormally, the development of vascular was bad, cell-organelles disorganized earlier than normal pollen, pollen wall was thinner and not arrayed compactly, pollen was wizened and the action of vacuole was abnormal.(5) The cell-orgenelles and cytoplasm degenerated firstly, then nucleate structure disorganized, at last, nucleolus disappeared.