以生长在青藏高原不同海拔地区的多年生高山植物美丽风毛菊（Saussureapulchra）为研究材料，分析比较了不同海拔叶片光合色素和抗氧化酶活性等生理生化指标，以探讨高山植物对于寒冷、高紫外辐射环境的适应机理。结果表明：随着海拔的升高，叶绿素a（Chla）、叶绿素b（Chlb）含量有下降的趋势，而胡萝卜素（Car）含量则呈增加的趋势，Car/Chl与Chla/Chlb增大，美丽风毛菊叶片的紫外吸收物质、丙二醛（MDA）含量明显增加；抗氧化酶的活性也受到明显影响，其中叶片中超氧化物歧化酶（SOD）、过氧化物酶（POD）活性和过氧化氢酶（CAT）活性随海拔升高呈增强的趋势，膜脂过氧化与抗氧化物酶的变化具有不一致性，表明抗氧化系统之间存在一定的协同作用，可能在高山植物适应高寒环境的胁迫方面具有重要的作用。%Environmental change is likely to act as a multiple stressor ,leading to cumulative and /or synergis-tic impacts on alpine plants .The phytochemical and physiological processes have been conducted to assess the potential impacts of different altitudes in Tibet plateau .This study shows that the antioxidant enzymes activities of Saussureapulchrafrom Haibeiwere are higher than those from Xining .The level of UV -screen-ing compounds ,the concentration of malondialdehyde (MDA ) .Furthermore ,Compared with Xining ,the Chla ,Chlb and total chlorophyll contents from Haibei ,they decrease w hile Chla/Chlb and Car/Chla+ b in-crease .Therefore ,the physiological and biochemical characteristics of Saussureapulchra ,play an important role in adapting the plateau environmental stresses .
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