高寒地区6种禾本科牧草对低温胁迫的生理响应及耐寒性评价

Effect of low-temperature stress on the physiological responses of six gramineous forages in alpine regions and evaluation of their cold resistance

为筛选出耐寒性强的禾本科牧草品种,研究了青牧一号老芒麦(Elymus sibiricus‘Qingmu No.1’)、同德老芒麦(E.sibiricus‘Tongde’)、同德短芒披碱草(E.breviaristatus‘Tongde’)、青海冷地早熟禾(Poa crymophila‘Qinghai’)、青海扁茎早熟禾(P.pratensis var.anceps Gaud‘Qinghai’)和青海中华羊茅(Festuca sinensis‘Qinghai’)幼苗生理特性对低温胁迫的响应,并通过隶属函数法对其耐寒性进行了综合评价。结果表明:1)低温胁迫对6种禾本科牧草的生长产生不同程度的抑制,其中,青海冷地早熟禾鲜重降幅最小,青牧一号老芒麦的干重降幅最小。2)低温胁迫下,6种禾本科牧草叶绿素含量较对照有不同程度的下降,而超氧化物歧化酶(superoxide dismutase,SOD)活性、丙二醛(malondialdehydem,MDA)含量、可溶性糖含量和脯氨酸含量均呈现不同程度的增加趋势。3)运用隶属函数法的综合评价表明,6种禾本科牧草耐寒性强弱依次为青牧一号老芒麦>青海中华羊茅>青海冷地早熟禾>青海扁茎早熟禾>同德短芒披碱草>同德老芒麦。综上可见,青牧一号老芒麦为上述六种禾本科牧草中耐寒性最强的牧草。

To screen gramineous forage varieties with strong cold resistance,the physiological responses of Elymus sibiricus‘Qingmu No.1’,E.sibiricus‘Tongde’,E.breviaristatus‘Tongde’,Poa crymophila‘Qinghai’,P.pratensis var.anceps Gaud‘Qinghai’,and Festuca sinensis‘Qinghai’seedlings to low-temperature stress were studied,and a comprehensive evaluation of the cold resistance of the six grasses was conducted based on subordinate function values analysis.The results showed that low-temperature stress inhibited the growth of the six grasses to different extents.The decrease rate in the fresh weight of P.crymophila‘Qinghai’was the lowest,whereas the rate of decrease in the dry weight of E.sibiricus‘Qingmu No.1’was the lowest.Under low-temperature stress,the chlorophyll content of the six grasses decreased to different degrees,whereas the malondialdehyde content,superoxide dismutase activity,soluble sugar content,and proline content increased to different extents.Based on the comprehensive evaluation using subordinate function values analysis,the order of cold resistance of the six grasses was as follows:E.sibiricus‘Qingmu No.1’>F.sinensis‘Qinghai’>P.crymophila‘Qinghai’>P.pratensis var.anceps Gaud‘Qinghai’>E.breviaristatus‘Tongde’>E.sibiricus‘Tongde’.Therefore,E.sibiricus‘Qingmu No.1’has the strongest cold resistance among the six gramineous forages.