西藏3份垂穗披碱草耐旱性评价

Evaluation of Drought Tolerance of Three Elymus nutans in Tibet

探索野生垂穗披碱草(Elymus nutans Griseb.)种子萌发与幼苗生长对干旱胁迫的生理响应,为西藏乡土植物耐旱性鉴定和育种提供依据。以西藏那曲市班戈县和索县2个地区的2份野生垂穗披碱草(Ⅰ号和Ⅱ号)为试验材料,以驯化品种巴青垂穗披碱草(E. nutans G. cv. Baqing)为对照材料,使用聚乙二醇(PEG-6000)溶液和盆栽后自然干旱法分别模拟垂穗披碱草在萌发期和幼苗期的干旱胁迫环境,并测定相关生理指标。结果表明,PEG-6000抑制了Ⅰ号和Ⅱ号种子萌发,低浓度(-0.10MPa)的PEG-6000处理有利于巴青垂穗披碱草种子萌发;PEG-6000抑制了垂穗披碱草根和芽的生长,其中对于芽的抑制作用尤为明显。干旱胁迫下,幼苗叶片相对电导率值和丙二醛含量不断上升,超氧化物歧化酶、过氧化氢酶和过氧化物酶活性呈先升后降的趋势。经隶属函数分析,供试的3份垂穗披碱草在种子萌发期和幼苗期生理耐旱性较强,均属于Ⅱ级(较抗),其耐旱性为巴青垂穗披碱草>垂穗披碱草Ⅰ号>垂穗披碱草Ⅱ号。

This paper aimed to provide basis for drought resistance identification and breeding of native plants in Tibet, by exploring the physiological response to drought stress of wild Elymus nutans at seed germination stage and seedling stage. Two wild E. nutans seeds came from Baingoin county and Sog county in Naqu city of Tibet were used as experimental materials No. Ⅰ and No. Ⅱ, and the domesticated variety E.nutans G. cv. Baqing was used as reference material. The solution of polyethylene glycol(PEG-6000) and natural drought after potted plants to simulate drought stress environment at germination and seedling stages and determined the physiological indexes. The results were as followos: PEG-6000 inhibited the germination of No. I and No. Ⅱ seeds, but the low concentration of PEG-6000(-0.10 MPa) was beneficial to the germination of E.nutans. PEG-6000 inhibited the growth of roots and buds of E. nutans, especially the buds. Under drought stress, the relative electrical conductivity and malondialdehyde content of E. nutans seedlings increased continuously, while the activities of superoxide dismutase, catalase and peroxide increased at first and then decreased. Through the analysis of average value of subordinate function. The three E.nutans tested materials had strong physiological drought tolerance at seed germination and seedling stages, and all of them belonged to grade Ⅱ resistance. The order of drought tolerance was as follows: E.nutans G. cv. Baqing > E.nutans No. Ⅰ > E.nutans No. Ⅱ.