Abscisic acid as the final product of antioxidative metabolism of xanthophylls influenced by diquat

摘要

We have studied the effect of diquat on the content of abscisic acid (ABA), #beta#-carotene, zeaxanthin and violaxanthin in the green winter rye seedlings. It is found that diquat caused the increasing in ABA, and decreasing in #beta#-carotene levels. It is concluded that increasing in the ABA level to diquat action is a defense reaction of antioxidative systems in response to the increasing of oxidative agents in tissues. The general scheme of ABA formation from #beta#-carotene is described. In accordance to this scheme (+), S-ABA and (-), R-ABA are prooxidants but their restored forms 1,4-diol ABA are antioxidants Because of the zeaxanthin and violaxanthin decreasing was less than #beta#-carotene it is supposed that ABA could be formed preferably from #beta#-carotene after the breaking of an unsaturated chain of carbons.