强光胁迫下SOD对姜叶片光抑制破坏的防御作用

晴天条件下，田间姜叶片的光化学效率（Ｆｖ／Ｆｍ）和表观量子效率（ＡＱＹ）上午随ＰＦＤ升高而降低，１２￣１４时后随ＰＦＤ的降低而升高，中午前后丙二醛（ＭＤＡ）含量达到最高，而光全速率（Ｐｎ）出现低谷，表明午间强光使光合作用发生光抑制，甚至光氧化。超氧物岐化酶（ＳＯＤ）１４时以前呈增加趋势，之后逐渐降低。苗期遮荫６０％，Ｆｖ／Ｆｍ与ＡＱＹ明显提高ＭＤＡ含量降低，ＳＯＤ活性减弱，Ｐｎ降低且日变化曲线变为

The Role of SOD in Protecting Ginger Leaves from Photoinhibition Damage under High Light Stress

On sunny day,the photochemical efficiency of PSII(Fv/Fm)and apparent quantum yield(AQY)of ginger leaves declined gradually in the morning,but raised progressly after 12:00.The MDA content in ginger leaves increased,but the photosynthetic rate(Pn)declined under mid-day high light stress.SOD activity in ginger leaves increased gradually before 14:00,then decreased.Shaded 60% in seedling stage,Fv/Fm and AQY of ginger leaves increased,but MDA content,SOD activity and Pn decreased.Pn,AQY and Fv/Fm of ginger leaves treated with DDTC decreased whether shading or not,but the effect of DDTC on shaded plants was less than that on unshaded plants.It is clear that mid-day high light stress caused photoinhibition and lipid peroxidation of ginger leaves.SOD and shading play an important role in protecting the photosynthetic apparantus of ginger leaves against high light stress.