Abstract

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Title:: Effects of High Temperature Stress on Leaf Structures and Physiological Metabolism of Potentilla fruticosa L.

Author(s):: Potentilla fruticosa L.；high temperature stress；ultrastructure；chlorophyll fluorescence；antioxidant enzyme activity; (1.College of Landscape，Beijing University of Agriculture/Beijing Collaborative Innovation Center For Eco-environmental Improvement With Forestry and Fruit Trees，Beijing 102206；2.Forestry Bureau of Chongli District，Zhangjiakou，Hebei 076350)

Keywords:: Potentilla fruticosa L.; high temperature stress; ultrastructure; chlorophyll fluorescence; antioxidant enzyme activity

Abstract:: 3-year-old Potentilla fruticosa L.was taken as material and treated at 42 ℃for 3 days.The effects of high temperature on chloroplast ultra-structures of leaf，chlorophyll fluorescence parameters，the membrane permetability，osmotic regulation substances and antioxidant enzyme activities of Potentilla fruticosa L.were studied.The results showed that with the extension of high temperature stress time,the chloroplast showed severe degradation and the maximal photochemical efficiency Fv/Fm reduced significantly，while the non-photochemical quenching(qN)and the photochemical quenching(qP) first rose then declined.The membrane permetability，the contents of MDA，free proline and soluble sugar increased gradually，and all the indicators were significantly higher than those of control（no high temperature stress）.While the activity of SOD showed no obvious change，and the activity of CAT first rose and then declined.The leaves of P.fruticosa suffered seriously damaged with the high temperature stress，but the plant could relieve heat damage through osmotic regulation substances and antioxidant enzyme.