Cytological Observation And Molecular Mechanism Research Of Cytoplasmic Male Sterility In Onion(Allium Cepa L.)

Onion (Allium cepa. L) is one of the main cultivation of vegetables in the world. The production area and output of onion in our country is in the front rank of the world. However the growth cycle of onion is very long, using conventional methods to breed new varieties will be time-consuming, and the character is not stable, In recent years, the rapid development of molecular biotechnology speeded up the breeding process, especially breeding new varieties by using cytoplasmic male sterile lines.So on studying the male sterility mechanism of onion cytoplasmic male sterile lines has important significance on onion breeding.The research results of male sterility mechanism on onion cytoplasmic male sterile lines are as follows:1. Cytology observation of onion cytoplasmic male sterile line and maintainerWith onion cytoplasmic male sterile lines 8A and maintainer line 8B as experimental material, the microspore was observed by paraffin sectioning of cytology, the results showed that the microspores' growth had no obvious difference spore group period of onion cytoplasmic male sterile lines 8A and maintainer line 8B; The anther tapetum completely separates in pollen mother cell stage and middle of Onion sterile lines 8 A, and gradually expands extrusion pollen mother cells, and then finally degradation.The residue after degradating invasived medicine room, and mixed together with microspore adhesion and took part of medicine room space, and can't supply the nutrients that are necessary for the development of the microspore, eventually microspore degraded, anthers aborted.Test has been clear that the anthers aborried in pollen mother cells of onion cytoplasmic male sterile lines of 8 A.2. Onion cytoplasmic male sterility and ATP contentWith onion cytoplasmic male sterile lines 8A, maintainer line 8B and restorer lines 8F as the experimental material, the ATP content were determined by using the fluorescein-fluorescein enzymatic in bud development periods of onion cytoplasmic male sterile lines, maintainer lines and restorer lines, the results show that the ATP content is obviously different in different development period of flower buds of onion cytoplasmic male sterile lines, maintainer lines and restorer lines.Especially from mononuclear pollen period to early mature pollen grains.We also found that ATP content are significantly lower than the maintainer lines and restorer lines in various development periods of male sterility, especially in the mature pollen grains early, ATP content in bud of sterile lines is rapidly dropping, almost close to zero, and the ATP content in bud of maintainer lines and restorer lines is rapidly rising, in the process of the whole anther development, the change of ATP content in the different periods of maintainer line buds is consistent with the change of ATP content in the different periods of restorer line buds, the ATP content in bud of maintainer lines and restorer lines had no significant difference.3. The expression of gene which related with onion cytoplasmic male sterile linesWith onion cytoplasmic male sterile lines 8A, maintainer line 8B and restorer lines 8F as the experimental material, through the real-time fluorescent quantitative PCR technique to detect the coxl recombinant gene expression and its copy number in the mitochondriaonion which related to cytoplasmic male sterility of onion. The results show that the coxl recombinant gene were expressed in various periods of bud, and as the constitutive expression. But the expression of coxl recombinant gene in the "three lines" have a big difference, the expressions of coxl recombinant gene in different development period of maintainer lines and restorer are similar and increase in turn,the expressing quantity is the highest in the mature pollen grains early. And the expressions of coxl recombinant gene in different development periods of cytoplasmic male sterile lines were significantly lower than the amount of maintainer lines and restorer lines.Then determined the copy number of coxl recombinant gene in the mitochondria, I found that the relative copy number in three series respecttively were 0.98,1.02,0.96, after Duncan significant test showed that the difference of coxl gene copy number in three series was not significant, namely the three series have the same copy number.The results excluded the possibility that the difference of coxl recombinant gene expression level in RNA amount is because of three different department copy number.