麻花艽叶片光合色素含量及厚度对UV-B辐射的响应

Response of Gentiana straminea to UV-B Radiation by Analysis of Photosynthetic Pigment Contents and Leaf Thickness

以中国科学院海北高寒草甸生态系统定位站自然生长的麻花艽(Gentiana straminea Maxim.)为材料,进行了不同月份和草盛期不同天数的短期增补和过滤UV-B辐射试验,比较分析叶片光合色素含量和叶片厚度等的变化。结果表明:(1)生长季内麻花艽叶片叶绿素a+b含量呈波动变化的趋势,7月份含量均较高;草盛期不同天数处理时,UV-B辐射对麻花艽叶片叶绿素a+b含量的影响不大。(2)生长季内麻花艽叶片类胡萝卜素含量也是7月份较高,短期增补UV-B辐射有降低其含量的趋势。(3)增加UV-B辐射能够降低Chl a/b值;自然UV-B辐射下Car/Chl比值能维持一个较高水平,是对强辐射的适应。(4)随处理时间延长,麻花艽叶片厚度有降低趋势,其叶缘出现一些发黄、变黑、变透明等受害症状,叶片能通过增加叶片厚度来适应增强的UV-B辐射。可见,生长于高海拔地区的植物麻花艽虽然对UV-B辐射表现出诸多的生理适应特性,但依然不可避免地受到其损伤。

The photosynthetic pigment contents were mainly analyzed in Gentiana straminea Maxim.after UV-B-exclusive and UV-B-supplementation treatment.Field experiments were conducted at the Haibei Alpine Meadow Ecosystem Research Station,the Chinese Academy of Sciences.The result indicated that：（1）Chlorophyll contents varied among different months with a high value appeared in July,and there were no seriously influence of UV-B radiation during 15 days of treatment.（2）Carotenoids contents also high in July,and there was a decreased tendency during short-terms of increased UV-B radiation.（3）Chl a/b ration were decreased under high UV-B radiation treatment,and Car /Chl seems a little high in ambient UV-B radiation when compared with no UV-B treatment.（4）Increasing of leaf thickness was the one adaptation way to enhanced UV-B radiation;with prolongation of treatment,leaves became thinner than early due to the accumulation of UV-B damage,as a results leaf color turned to yellow,the apex turned to purple and finally leaf margin got brown.It was obvious that alpine plants had some of physiological adaptation characters,but they still suffered a certain inevitable injury.