Abstract: In order to explore the adaptability of wild grasses in Tibet to low temperature stress,this study analyzed the malondialdehyde content,soluble sugar content,free proline content and the activity of Peroxidase and Superoxide dismutase of the wild Elymus nutans Griseb,Leymus secalinus Tzvel,Stipa purpurea and Lolium perenne in response to cold temperature at -10℃～5℃. The results showed that with the intensification of low temperature stress,the MDA content of all tested materials showed an upward trend,SS content,Pro content,POD activity and SOD activity showed an increase and then a decrease trend,of which the ryegrass Pro content reached a peak at 0℃ The other three indicators peaked at -5℃,and the indicators of the three wild grasses all peaked at -5℃. Using the membership function method to comprehensively evaluate and classify the materials,the results showed that Elymus nutans Griseb and Stipa purpurea had the strongest cold resistance and were classified as grade Ⅰ,Leymus secalinus Tzvel was moderately cold resistant,and classified as grade Ⅱ. The cold resistance of Lolium perenne was the weakest,and it was classified as grade Ⅲ.

Key words: Wild grass, Low temperature stress, Physiology and biochemistry, Cold tolerance evaluation

摘要： 为了探究西藏野生禾本科牧草对低温胁迫的适应性，本研究以西藏野生垂穗披碱草（Elymus nutans Griseb）、赖草（Leymus secalinus Tzvel）、紫花针茅（Stipa purpurea）和栽培品种黑麦草（Lolium perenne）为试验材料，比较分析其幼苗在—10℃～5℃低温条件下叶片丙二醛（Malondialdehyde，MDA）含量、可溶性糖（Soluble sugar，SS）含量、游离脯氨酸（Free proline，Pro）含量、过氧化物酶（Peroxidase，POD）活性和超氧化物歧化酶（Superoxide dismutase，SOD）活性的变化。结果表明：随着低温胁迫的加剧，所有供试材料叶片MDA含量呈上升趋势，SS含量、Pro含量、POD活性和SOD活性呈先升高后降低趋势，其中黑麦草Pro含量在0℃达到峰值，其他3种指标在—5℃达到峰值，3种野生禾草的各指标均在—5℃达到峰值。采用隶属函数法对各材料进行综合评价并分级，结果表明垂穗披碱草和紫花针茅抗寒性最强，划分为Ⅰ级，赖草抗寒性中等，划分为Ⅱ级，黑麦草抗寒性最弱，划分为Ⅲ级。

关键词: 野生禾草, 低温胁迫, 生理生化, 抗寒性评价