The Abortive Characteristics And Physiological Metabolism Responses Of Five Kinds Of Cytoplasmic Male Sterile Wheats

Cytoplasmic male sterility（CMS） is a kind of common natural phenomenon in higher plants. At present, CMS has been found in various plants. Wheat cytoplasmic male sterility plays an important role in heterosis utilization. So, 5 heterologous cytoplasmic male sterile lines U116A、Ju116A、Va116A、C6116A、K116A and the maintainer line 116 B were employed for finding the possible mechanism of CMS in wheat, by observing the plant, anther and cell morphology change, determination reactive oxygen species, antioxidant enzymes and non-enzymatic antioxidants in the process of anther development, analyzing antioxidase-associated genes expression pattern with RT-PCR. The results were as follows:1. In this paper, there was no difference between sterile lines and maintainer line in meiosis stage and early uninucleate stage, all the lines developed normally. In later uninucleate stage, microspores of CMS began to appear irregular shape, the maintainer line developed normally. In binucleate and trinucleate stage, the cytoplasm of U116 A, Ju116 A and C6116 A was degraded into empty shell. Only a small number of microspores of Va116 A and K116 A could develop into three nuclei, but they couldn’t form two normal fusiform nuclei, causing pollen abortion. In trinucleate stage, the vast majority of microspores of 116 B developed into normal pollen grains with a vegetative nucleus and two fusiform nuclei, only a few were abnormal. This showed that the abortion stage of 5 kinds of CMS lines was probably in later uninucleate stage. So, Pollen mother cells structural abnormalities were important cytological characteristics of microspore abortion in wheat CMS.2. During the whole pollen development, the generation rate of O₂^- and H₂O₂ contents of all the CMS lines reached the peak in later uninucleate stage, were higher than that of maintainer line 116 B. The MDA contents of 5 kinds of sterile lines were higher than 116 B since the later uninucleate stage. SOD activities of all the sterile lines were always higher than that of maintainer line, compared with 116 B, the CMS lines reached significant difference in the later uninucleate stage. CAT activities of sterile lines were significantly higher than 116 B in the later uninucleate stage, but since this stage, CAT activities of 5 kinds of sterile lines were in a downward trend, while the maintainer line 116 B showed a rise trend. There was significant difference between POD activities of K116 A and 116 B since binucleate stage, whereas POD activities of other sterile lines were significantly higher than that of 116 B since the later uninucleate stage. APX, GPX enzyme activities of all sterile lines were obviously lower than 116 B respectively in the binucleate and later uninucleate stage. As A and GSH contents of CMS lines sharply reduced, the contents were extremely significantly lower than the maintainer lines in the later uninucleate stage. It concluded that critical pollen abortion period of 5 heterologous CMS lines was the later uninucleate stage to binucleate stage. Wheat cytoplasmic male sterility had a close relationship with antioxidant enzymes and non-enzymatic antioxidants content.3. SOD, APX enzyme genes expression level was in accordance with SOD, APX enzyme relative size and enzyme activity change in sterile line and maintainer line at different development stages. However, CAT gene expression quantity of 116 B was significantly higher than all the sterile lines since the later uninucleate stage, there was great difference between the gene expression level and the enzyme activity change. The possible reason for this difference was that CAT was multiple-gene encoding gene, CAT expression level was different with CAT enzyme activity, and maybe the gene expression was covered by other genes expression of CAT family.