不同海拔珠芽蓼抗氧化系统的研究

对生长在青藏高原不同海拔地区的多年生高山植物珠芽蓼(Polygonum viviparum L.)的抗氧化系统进行了测试，以探讨高山植物对于高寒环境的适应机理。结果表明：随着海拔的升高，叶绿素a(chla)、叶绿素b(chlb)含量明显下降，chla／chlb增大，珠芽蓼叶和根细胞的膜脂过氧化均加剧，丙二醛(MDA)含量明显增加。3种抗氧化酶的活性受到明显影响，其中叶片中过氧化物酶(POD)和超氧化物歧化酶(SOD)活性，随海拔升高而活性降低，而均与根中的变化趋势相反，过氧化氢酶(CAT)活性随海拔升高呈增强的趋势，且叶片中活性较根中变化明显，抗坏血酸(AsA)随海拔的升高，含量呈明显增加，膜脂过氧化与抗氧化物酶的变化具有不一致性，这可能表明两种抗氧化系统之间存在一定的协同作用，特别是高含量的抗坏血酸，可能在高山植物适应高寒环境的胁迫方面具有更加重要的作用。图5表1参22。

ANTIOXIDATIVE COMPOUNDS OF POLYGONUM VIVIPARUM L. FROM DIFFERENT ALTITUDES

In order to reveal the adaptation mechanism of alpine plant species to the Qinghai-Tibet Plateau environment, compared in this study are mainly antioxidative compounds of Polygonum viviparum L. from different altitudes. At the higher altitude, the amount of both chla and chlb decreased, but chla/chlb increased. With the increase of altitude, the memberane lipid peroxidation also became stronger in both leaves and roots, and the MDA accumulated more. Both the activity and amount of three detected antioxidant enzymes varied also with altitude. At the higher altitude. the activity of both SOD and POD declined in leaves, but increased in roots, while that of CAT increased in both leaves and roots, and this trend more distinct in the former organs. The amount of AsA accumulated more with the increase of altitudes. Although the amount and activity of three antioxidative enzymes were not accurately correlated with each other, their variations with altitude, especially the higher amount of AsA at the higher altitude, inferred a similar role of this alpine species in adapting to the plateau surrounding. Fig 5, Tab 1, Ref 22