披碱草属4个牧草品种苗期抗旱性综合评价

Comprehensive Evaluation of Drought Resistance of Four Elymus Varieties at Seedling Stage

以披碱草属的同德短芒披碱草、同德老芒麦、天水肥披碱草和甘南垂穗披碱草为材料,研究5 d持续干旱对其抗氧化酶活性、渗透调节物质积累量、光合作用和生物量等的影响,并通过隶属函数综合评价4个品种的抗旱性。结果显示:与对照组相比,干旱胁迫下4个供试材料的抗氧化酶活性、丙二醛含量呈上升趋势,净光合速率、株高呈下降趋势。干旱条件下,同德短芒披碱草可溶性糖和丙二醛积累量较对照组增幅最大,分别为180.55%和36.46%;相对电导率较对照组上升53.69%,增幅最小。同德老芒麦POD和CAT活性较对照组增幅最大,分别为202.78%和48.83%;净光合速率下降1.01%,降幅最小。干旱胁迫下,天水肥披碱草蒸腾速率和PSⅡ最大光化学效率降幅最小,分别为12.99%和8.47%;气孔导度降低了42.86%,降幅最大;游离脯氨酸含量较对照组上升76.72%,增幅最大。甘南垂穗披碱草地上部分鲜重和叶绿素含量较对照组分别下降3.62%和35.77%,降幅最小;PSⅡ潜在活性和PSⅡ光合电子传递效率降幅最大,分别为5.55%和30.44%。隶属函数综合评价结果表明,4个品种抗旱性表现为同德短芒披碱草>甘南垂穗披碱草=同德老芒麦>天水肥披碱草。

In order to investigate the response of different forage varieties of Elymus to drought stress,Elymus breviaristatus Keng cv.Tongde,Elymus sibiricus L.cv.Tongde,Elymus excelsus Turcz.cv.Tianshui and Elymus nutans Griseb.cv.Gannan were used as materials in this experiment,the effects of continuous drought stress for 5 days on antioxidant enzyme activity,osmotic adjustment substance accumulation,photosynthesis and biomass were studied,and the drought resistance of the four varieties was comprehensively evaluated by the membership function.The results showed that the antioxidant enzyme activities and malonaldehyde(MDA) content of the four species in the experimental group showed an upward trend compared with the control group,while the net photosynthetic rate and plant height showed a downward trend.Under drought conditions,the accumulation of soluble sugar and MDA in Elymus breviaristatus Keng cv.Tongde increased by 180.55% and 36.46%,respectively,while the relative conductivity increased by 53.69% and the least compared with the control group.The activities of POD and CAT in Elymus sibiricus L.cv.Tongde increased by 202.78% and 48.83%,respectively,net photosynthesis rate decreased by 1.01%,with the slowest decline.The transpiration rate and maximal efficiency of PSⅡ of Elymus excelsus Turcz.cv.Tianshui decreased by 12.99% and 8.47%,respectively,with the lowest decrease,and the stomatal conductance decreased by 42.86%,with the highest decrease,and the content of free proline increased by 76.72%,with the largest increase.Compared with the control group,the fresh weight of aboveground and chlorophyll content of Elymus nutans Griseb.cv.Gannan decreased by 3.62% and 35.77%,respectively,with the lowest decrease.The potential activity of PSⅡ and the photosynthetic electron transfer rate of PSⅡ decreased by 5.55% and 30.44%,respectively.The evaluation results of membership function showed that the drought resistance of the four varieties was E.breviaristatus Keng cv.Tongde > E.nutans Griseb.cv.Gannan = E.sibiricus L.cv.Tongde > E.excelsus Turcz.cv.Tianshui.