遮光对Pb胁迫下白花泡桐叶片生理响应的影响

目的]研究光环境变化条件下，白花泡桐叶片对Pb胁迫的生理响应。方法]在全光照、50％、20％光照条件下，对不同Pb处理下白花泡桐叶片生理特性进行研究。结果]Pb处理下，SOD、CAT、APX均在20％光照处有最小活性，而POD在该条件下有最大活性。在Pb处理时，白桦泡桐叶片光合色素含量在20％光照条件下达最小值。丙二醛和脯氨酸随光照强度减弱呈现先减后增的趋势，而膜透性在处理组中呈现逐渐下降的趋势。Pb处理下，超氧阴离子自由基和过氧化氢含量随光照强度减弱呈现先减少后增加的趋势。结论]适当的遮光处理缓解了Ph胁迫对白花泡桐叶片的氧化损害。

The Physiological Responses of Paulownia fortunei Leaves to the Change of Light Irradiances when Exposed to Pb Stress

Objective ] The physiological responses of P. fortunei leaves to Pb stress was investigated under different light conditions. Method] The P. fortunei plants were exposed to different Pb contents, and were repeatedly conducted under natural light, 50% , 20% light conditions. Result]The SOD, CAT and APX activities were the least at 20% light under Pb treatment, activity of POD in the condition was the largest. Under the Pb processing, photosynthetic pigment content of Paulowniafortunei leaves in 20% light condition got the minimum value. With light intensity decreased, the content of MDA and Proline at first decreased and then increased, membrane permeability showed a trend of gradual decline in the treatment group. Under Pb treatment, the contents of superoxide anion free radical and hydrogen peroxide showed an increasing trend after the first decrease with reduced light intensity. Conclusion] Light shading relieved the oxidative damage of Pb to P. fortunei leaves.