强光胁迫下外源NO对霍山石斛叶绿素荧光和抗氧化系统的影响

 以兼性景天酸代谢(CAM)植物霍山石斛为材料，研究强光胁迫条件下，外源NO对其叶绿素荧光和抗氧化系统的影响。结果表明： 0. 1 mmol·L^-1硝普钠(SNP)处理提高了石斛光合系统Ⅱ(PSⅡ)的光能转换效率和潜在活性，增加了过剩光能的非光化学耗散，缓解了光抑制的发生，同时通过增强抗氧化系统的活性氧清除能力，有效保护了光合机构免受强光胁迫的伤害，PSⅡ反应中心得以较快恢复。而经0.5 mmol·L^-1SNP处理后，霍山石斛的光能转换系统未能通过有效的光能转换和非光化学反应耗散过剩的光能，降低了抗氧化系统中SOD、POD和CAT的活性，加剧了PSⅡ反应中心光抑制的发生。

Effects of Exogenous Nitric Oxide on The Chlorophyll Fluorescence and Antioxidant System of Dendrobium huoshanense Under High Light Stress

In this paper, the effects of NO donor sodium nitroprusside (SNP) on the chlorophyll fluorescence and antioxidant system of Dendrobium huoshanense under high light stress were studied. The result showed that the efficiency of light energy conversion and nonphotochemical dissipation of excess light energy for photosystemⅡ were inproved, and the capacity of scavenging active oxygen for antioxidant system was increased as well by presoaking with 0.1 mmol·L^-1SNP , which alleviated the photoinhibition on leaves of Dendrobium huoshanense significantly. Therefore the PSⅡ was protected efficiently and the recovery was faster. On the contrary, the leaves presoaked in 0.5 mmol·L^-1SNP were severely inhibited by the high light and the enzyme activities of SOD, POD and CAT were decreased.