彩叶杨树叶片中花色素苷的光保护作用

Photoprotective Effects of Anthocyanins in Leaves of Color-leaved Poplar

【目的】以全红杨、中红杨、金红杨、红霞杨和翡翠杨5个彩叶杨树品种为试材,以探究不同光照所产生的过剩光能对不同品种的彩叶杨树叶片光保护能力影响的差异。【方法】采用高光胁迫(温度为25/15℃,光照强度为500μmol·m^-2·s^-1为对照,连续处理3 d,每天取样对色素含量,DPPH清除能力等多个生理指标进行测定,3 d后将受胁迫后的样本置于智能温室内进行适当遮阴处理恢复光照,在恢复的2 d后进行再次取样测定,进行对比。【结果】高光胁迫下花色素苷含量高的品种能激发叶片产生更强的光保护作用。在进行高光胁迫期间,全红杨的最大光化学效率(Fv/Fm)变化幅度、花色素苷含量及增加幅度和非酶抗氧化剂活性(DPPH的自由基清除能力)均显著高于其余4个品种。5个品种的彩叶杨树的花色素苷含量随胁迫时间延长的增加均十分显著,但叶绿素含量及组成比例随光照时间延长没有显著差异,即5个品种的光捕获能力并未表现出显著差异。高光胁迫同时造成全红杨的O-2产生速率的增加幅度较低,叶黄素库容量(V+A+Z)在整个实验阶段未表现出显著变化、过氧化氢酶(CAT)、脱氢抗坏血酸还原酶(DHAR)和抗坏血酸过氧化物酶(APX)活性均低于其余4个品种。【结论】在高光胁迫及恢复状态下,花色素苷含量与DPPH活性关联密切,花色素苷在彩叶杨树叶片中的光保护作用主要来自于对叶片中非酶抗氧化能力的贡献。

【Objective】Five varieties of Populus euphratica,including Populus×euramericana‘quanhong’,Populus×euramericana‘zhonghong’,Populus×euramericana‘jinhong’,Populus×euramericana‘hongxia’,Populus×euramericana‘feicui’,were used as materials to study the difference of the effect of excess light energy caused by different illumination on the photoprotective ability of Populus euphratica leaves.【Method】With high light stress(temperature 25/15℃,light intensity 500μmol·m^-2·s^-1)as the control condition,the samples were continuously treated for 3 days,the pigment and content DPPH removal ability were measured daily.After 3 days,the stressed samples were placed in a smart greenhouse for proper shading treatment to restore light,and after 2 days of recovery,samples were taken again for measurement and comparison.【Result】Varieties with high anthocyanin content under high light stress could enhance the photoprotection of the leaves.During the high light stress period,the maximum photochemical efficiency(F v/F m)increase,anthocyanin content and increase range and non-enzymatic antioxidant activity(DPPH free radical scavenging ability)of Populus×euramericana‘quanhong’were significantly higher than the other four varieties.The anthocyanin content of the five varieties of Populus euphratica increased significantly with the increase of stress time,however the chlorophyll content and composition ratio did not change significantly with the extension of illumination time,that is,the light capture ability of the five varieties did not show significant difference.High light stress also caused the O-2 production rate of Populus×euramericana‘quanhong’to be low,and the lutein library capacity(V+A+Z)showed no significant changes throughout the experimental period,and the activities of catalase(CAT),dehydroascorbate reductase(DHAR)and ascorbate peroxidase(APX)activity were lower than the other four varieties.【Conclusion】Content of anthocyanin is closely related to DPPH ac-tivity under high light stress and recovery state,and its photoprotective effect in the leaves of Populus euphratica mainly due to the contribution of non-enzymatic antioxidant capacity in leaves.