青藏高原几种高寒植物的抗寒生理特性

研究了青藏高原高寒地区3种多年生植物在生长过程中植物叶组织的可溶性糖、脯氨酸和丙二醛（MDA）含量、超氧化物歧化酶（SOD）和过氧化物酶（POD）活性的变化及其生理特性。结果表明；矮嵩草（Kobresia humilis）、垂穗披碱草（Elymus nutans）和黑褐苔草（Carex atro-fusca）叶中的可溶性糖含量随着生长期的进程而增加；脯氨酸含量的变化因植物种类的不同而表现各异，其中在各生长期．垂穗披碱草的脯氨酸含量均高于矮嵩草和黑褐苔草，并在草盛中期表现出明显的差异；3种高寒植物叶片中的丙二醛（MDA）含量随着生长季和气温的变化而呈现不断增加的趋势；3种植物中的超氧化物歧化酶（SOD）和过氧化物酶（POD）活性表现出随生长期和气温变化而改变的趋势，但黑褐苔草的2种膜保护酶活性最高，垂穗披碱草的次之．矮嵩草最低。可见，在不同生长季，这3种高寒植物的抗寒生理反应或低温适应方式可能是多途径的．其中在抗寒物质代谢、膜脂过氧化能力和抗氧化酶系统等方面，有生理反应的共同规律和各自特有的生理抗寒特性．其适应性与抗逆性有所不同，这种差异和生理特性可能与高寒植物的遗传特性和极端高寒低温环境胁迫有关。

Physiological Characteristics in Cold Resistance of Several Alpine Plants in Qinghai-Tibet Plateau

The soluble sugar and proline contents,and the MDA ,SOD,POD activities in the leaves of several perennial alpine plants ,and the physiological characteristics of the plants during their growth were studied. The results showed that Kobresia humilis,Elymus nutans and Carex atro-fusca presented an increased soluble sugar content as they grew;their proline contents differed depending on the kinds of the plants and the proline content of Elymus nutans was highter than those of Kobresia humilis and Kobresia humilis at various growth stages, which appeared remarkable at the middle stage of quick and vigorous growth;the three plants presented a gradually increasing tendency in MDA content with the seasons and air temperature for their growth;the three plants presented a varying tendency in SOD and POD activity with the sea- sons and temperature for their growth,Carex atro-fusca appearing to have the highest SOD and POD activities ,Elymus nutans taking the second position in the activities of the two enzyme and Kobresia humilis appearing to have the lowest SOD and POD activities. It is obvious that in different growing seasons, the three plants probably have many ways in physiological reactions of their cold resistances or their adaptation to low temperature ,sharing common physiological reaction patterns and possessing their own physiological cold-resisting characteristics in the metabolisms of cold-resisting substances, the capacities of membrane lipid peroxidation and the system of anti-oxidative enzymes which result in their differences in adaptability and resistance ;the differences probably relate to their genetic characteristics and extremely high and cold environments of alpine plants.