Relationship Of Phytohormones And Correlative Enzymes With Cotton Cytoplasmic Male Sterility

Effects of phytohormones and relative enzymes on cotton cytoplasmic male sterility (CMS) were studied by using cytoplasmic male sterile cotton and its maintainer, restorer and hybrid F₁. The results were shown as follows.During the development stage of anther, It is observed that changes of contents of IAA, ZR ,GA₃ and ABA were obviously abnormal in CMS anther comparing with in its maintainer anther, but they were normal in CMS leaf and ovule. Especially at the pollen mother cell meiosis stage, the contents of IAA, GA₃ and ZR and the value of (IAA+GA3+ZR) /ABA in CMS anther were remarkably lower, and the contents of ABA were significantly higher than that in its maintainer anther. According to anther abortion characteristics and hormone functions, it was suggested that IAA, GA3 and ZR deficiency might be associated respectively with the inhibition of starch grain accumulation, pollen mother cell and tapetal cell expansion and tetrad formtion, and that abortion and even death of pollen mother cells and tapetal cells in sterile anther might be accelerated by high ABA accumulation.Changes of the activity of IAA oxidase, tryptophan synthetase and cytokinin oxidase in sterile anther, leaf and ovule were similar to those of phytohormones. The activity of IAA oxidase and cytokinin oxidase was significantly higher in CMS anther, but the activity of tryptophan synthetase was lower than in fertile anther. Since the metabolism of phytohormones was regulated by many kinds of enzymes, the decrease of tryptophan synthetase activity and the rise of IAA oxidase activity might cause the reduction of IAA content, and affect the balance of IAA and the development of pollen in sterile anther. The rise in activity of cytokinin oxidase might resulte in the deficiency of CK and affect cell division.