Abstract: In order to selected the cold resistance germplasm of Poa, the physiological, biochemical responses and resistances of nine wild Poa germplasms in Gangsu province were investigated under different low temperature treatments (5, 0, -5, -10℃). The results showed that the relative membrane permeability in the leaves, the contents of free proline (Pro), soluble sugar (SS), soluble protein (SP) and malondialdehyde (MDA), superoxide dismutase (SOD)and peroxidase (POD)activities of nine wild Poa seedlings gradually increased with the temperature decreasing. Membership function analyses showed that P. annua had the strongest cold resistance, followed by P. micrandra, P. pratensis (Tianzhu) and P. pratensis (Gannan). P. poophagorum, P. sphondylodes, P. pratensis (Sunan), P. pratensis (Weiyuan) and P. pratensis (Xinglongshan) had the weakest cold resistance. Correlation analyses demonstrated that integrated assessment value of cold resistance had significant positive correlation with the content of soluble protein (P<0.01) and POD activity (P<0.05), had positive correlation with the contents of soluble sugar and free proline, SOD activity and altitude, while had significant negative correlation with relative membrane permeability and MDA. Thus, these measuring indexes can be used as the evaluation indexes of cold resistance of wild Poa.

Key words: Wild Poa L., Cold stress, Physiological characteristics, Assessment of cold-tolerance

摘要： 以甘肃省境内采集的9个野生早熟禾（Poa）为试验材料，设5，0，-5，-10℃共4个温度处理，探讨其对低温胁迫的生理响应和抗寒性，为抗寒早熟禾种质材料筛选和新品种选育提供依据。结果表明：随着温度下降，各材料的叶片相对膜透性逐渐增大，游离脯氨酸（Pro）、可溶性糖（SS）、可溶性蛋白（SP）、丙二醛（MDA）含量逐渐增加，超氧化物歧化酶（SOD）和过氧化物酶（POD）活性逐渐增强。运用隶属函数法综合评价9个材料苗期抗寒性发现，一年生早熟禾（P. annua）抗寒性最强，小药早熟禾（P. micrandra）、草地早熟禾（天祝）（P. pratensis）和草地早熟禾（甘南）抗寒性中等；硬质早熟禾（P. sphondylodes）、波伐早熟禾（P. poophagorum）、草地早熟禾（肃南）、草地早熟禾 （渭源）、草地早熟禾（兴隆山）抗寒性弱。相关性分析表明，SP含量与抗寒综合评价值极显著正相关（P<0.01），POD活性与抗寒综合评价值显著正相关 （P<0.05），Pro含量、SS含量、SOD活性、海拔与抗寒综合评价值成正相关，相对膜透性、MDA含量和年均温与抗寒综合评价值成负相关。

关键词: 野生早熟禾, 低温胁迫, 生理特性, 抗寒性评价