野生赖草和垂穗披碱草抗旱能力比较

Comparison of drought resistance of wild Leymus secalinus and Elymus nutans in Tibet

干旱是制约西藏牧草生长发育的一个重要因素,为此,本研究以西藏野生赖草(Leymus secalinus)和披碱草(Elymus nutans)作为试验材料,探究两种野生牧草抗旱能力的强弱,以期为西藏干旱半干旱区域生态恢复和栽培草地建植时草种的选择提供参考依据。结果表明,两种野生牧草的株高增长速率、植株含水量和叶绿素含量均随干旱时间的增加而降低(P<0.05);丙二醛和游离脯氨酸含量随着干旱胁迫时间的增加而增加(P<0.05)。赖草可溶性糖含量呈先减后增的变化趋势,而垂穗披碱草可溶性糖含量则呈减-增-减的变化趋势;可溶性蛋白含量均表现出先减后增的变化趋势。利用隶属函数{正相关函数模型F_1=(X_i-X_(min))/(X_(max)-X_(min))和负相关函数模型F_2=[1-(X_i-X_(min)]/(X_(max)-X_(min))}法对两种野生牧草的两个生物学特性指标(植株含水量和株高)和5个生理特性指标(叶绿素、游离脯氨酸、丙二醛、可溶性糖和可溶性蛋白)进行综合评价,得出赖草的抗旱能力大于垂穗披碱草。

Drought is one of the most important factors restricting the growth and development of grasslands in Tibet. To counter these effects, we studied drought resistance ability in two species of wild forage plant, by collecting seeds of Leymus secalinus and Elymus nutans in Tibet, in order to provide reference for the ecological restoration of arid and semi-arid areas, and selection of grass species in artificial grassland. The results showed that the growth rate, plant water content, and chlorophyll content of two wild forage species decreased with the increase of drought time, and the difference was significant （P〈0.05）. The contents of malondialdehyde and free proline increased with increase in drought time, and the difference was significant （P〈0.05）. Soluble sugar content of L. massoniana decreased first and then increased, while the soluble sugar content of E. nutans decreased first and then increased, and finally decreased. The soluble protein content decreased first and then increased. The two biological characteristics and the five physiological characteristic indexes of the two wild forage species were comprehensively evaluated by the membership function method, and the drought resistance of L. secalinus was greater than that of E. nutans.