| The effect of exogenous methyl jasmonate(MeJA) on photosynthetic characteristics in wheat under simulated drought stress after anthesis was investigated by potting and water control.Zhoumai 18,a broad cultivation wheat variety,was used as the test material. The results showed that,the contents of chlorophyll a,chlorophyll b,xanthophyll as well as Gs and Tr were significantly decreased by drought stress; on the contrary,the levels of Fo,NPQ,(V+A+Z) and(A +Z)/(V+A+Z) were increased. Pn,Fv/Fo,Fv/Fm and ΦPSⅡ were significantly inhibited,eventually leading to a significant decrease of WUE and LUE. Xanthophyll,β-carotene,(V+A+Z) and(A+Z)/(V+A+Z) were significantly elevated by exogenous MeJA under drought stress,so that Fo and NPQ were significantly increased,which alleviated the oxidation damage of chlorophyll under drought stress. Moreover,the lower ratio of chlorophyll a/b increased the utilization efficiency of weak light. Furthermore,appropriate stomatal closure induced by exogenous MeJA reduced the further loss of water. Therefore,the improvement of Pn,Fv/Fo,Fv/Fm and ΦPSⅡwere promoted in the middle-late stages of grain filling,further alleviated the inhibiting of WUE and LUE induced by drought stress. The results suggested that exogenous MeJA could improve stability of photosystem and reduce transpiration of wheat leaves,which resulted in improvement of photosynthesis in wheat under drought stress after anthesis. |
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