青藏高原不同海拔地区唐古特山莨菪叶片光合色素含量和抗氧化酶活性的比较研究

以青藏高原东北隅的西宁和海北(海拔分别为2 300 m和3 200 m)人工栽培唐古特山莨菪为材料,对两不同海拔地区间各叶层叶片光合色素含量和抗氧化酶活性等生理指标进行比较分析.结果显示:(1)生长在海北的唐古特山莨菪叶片厚度极显著高于西宁(P<0.01),且两地区植物的叶片厚度从第1层到第4层均呈显著增加趋势;海北唐古特山莨菪叶片的叶绿素a、叶绿素b、总叶绿素、类胡萝卜素含量以及紫外吸收物质的含量均显著高于西宁地区(P<0.05),从第1层到第4层,两地植株叶片的光合色素和紫外吸收物质的含量都呈降低的趋势,且两地区让差异显著;叶绿素a/b的层间差异显著(P<0.05),但两海拔地区间差异不显著;类胡萝卜素/叶绿素比值海北高于西宁,从第1层到第4层叶片呈降低趋势.(2)生长于海北的唐古特山良菪叶片组织中的SOD、CAT活性和MDA含量比西宁的高,POD、APX则相反;从第1层叶片到第4层,西宁和海北唐古特山莨菪叶片中的SOD活性显著增高(P<0.05),但两地区各层间的CAT、POD、APX活性和MDA含量无明显的变化.研究表明,不同海拔对唐占特山莨菪叶片的生理特性有影响,同一海拔不同叶层叶片之间差异也较为明显;生长在高海拔地区的植物尽管表现出诸多生理适应特征,但膜系统依然有一定受损.

Comparison of Photosynthetic Pigment Contents and Antioxidase Activity of Anisodus tanguticus from Different Leaf Layers Grown at Two Altitudes Level in Qinghai-Tibet Plateau

The four-year-old Anisodus tanguticus from two different altitudes(Xining and Haibei,altitude is 2 300 m and 3 200 m,respectively) was used to compare the physiological difference among different leaf layers.The results showed that leaf thickness was significantly thicker from Haibei than those from Xining(P<0.01),and it continuously increased from top canopy leaf determined as the first layer to the lower leaf of the fourth layer.The contents of Chl a,Chl b,total chlorophyll,carotenoids and UV-absorbing compounds were higher in the leaves from Haibei than those from Xining(P<0.05),and the contents of photosynthetic pigment and UV-absorbing compounds in the leaves showed a decreasing trend from the first layer to the fourth layer in Xining and Haibei.The ratio of Chl a/Chl b showed a decreasing trend from the first layer to the fourth layer(P<0.05),but there was no significant difference between Xining and Haibei.The ratio of Car/Chl in Haibei was higher than that in Xining and there was a decreasing trend from the first layer to the fourth layer.The activities of SOD and CAT and the content of MDA in the leaves from Haibei were higher than those from Xining.Contrariwise,the activities of POD and APX were lower.The activity of SOD increased from the first layer to the fourth layer,but there was no significant difference in the activities of CAT,POD,APX and MDA contents among four layers.It was obvious that there was difference in the physiological activity of A.tanguticus leaves not only at different altitudes but also among different leaf layers at the same altitude.Although the plants in the high-altitude area had lots of physiological adaptation,the membrane system suffered a certain injury.