中文摘要：

测定高寒牧草垂穗披碱草（Elymus nutans）和老芒麦（Elymus sibiricus）幼苗在4个不同浓度的Na Cl溶液（0、50、150、250 mmol·L^–1）与6—15℃和15—25℃两种温度处理条件下的生理生化反馈机制。结果表明：①垂穗披碱草随着盐浓度的提高,可溶性糖含量呈现先低后高的趋势;在盐浓度为Na50时,可溶性糖含量最低,且不同温度处理对垂穗披碱草可溶性糖含量影响不大;但在高盐浓度（Na150、Na250）处理下,温度对幼苗可溶性糖含量影响极显著,6—15℃处理显著提高垂穗披碱草幼苗的可溶性糖含量。②随着盐浓度增加,两种牧草游离脯氨酸含量均迅速积累,且15—25℃处理下脯氨酸含量显著高于6—15℃处理。③除垂穗披碱草在Na250下SOD酶活性达到最高外,垂穗披碱草CAT活性和老芒麦SOD、CAT活性均随着盐浓度的增加呈现先增加后降低的趋势。表明在一定盐浓度下,牧草借助抗氧化酶来清除胁迫产生的活性氧,但高盐浓度在一定程度上抑制了牧草抗氧化酶活性,而6—15℃温度处理可诱导牧草抗氧化酶活性的提高,尤其是老芒麦。④盐胁迫导致两种牧草根尖过氧化氢含量和细胞死亡率的增加,而6—15℃温度处理可以降低根尖过氧化氢的积累。两种牧草随盐浓度增加根尖细胞死亡率均有增加的趋势,但6—15℃低温可以有效减轻盐胁迫对根细胞的损伤。

英文摘要：

This research studied physiological and biochemical indexes and feedback mechanism of alpine plant Elymus nutans and Elymus sibiricus under the four NaC1 concentrations （0, 50, 150, 250 mmol·L^-1） and two temperature gradient （6- 15 ℃/15-25 ℃）. The results showed that soluble sugar content of E. Nutans decreased and then increased with the increase of the salt concentration. Soluble sugar content was the lowest in Na50 salt concentration and different temperature treatment had not significant influence on soluble sugar in Na50 salt concentration. But under high salt concentration treatment, temperature was a very important factor for soluble sugar content of seedling. For E. nutans, 6-15 ℃ treatment could significantly increase soluble sugar content of seedling. The free proline content of two plants accumulated rapidly with increased salt concentration, and that under 15-25 ℃ was remarkable higher than that under 6-15℃. Except that SOD enzyme of E. Nutans was the highest under high salt concentrate, CAT ofE. Nutans and SOD, CAT ofE. Sibiricus were quadratic curve with the increased salt concentration. It showed that under the low-middle salt stress, the alpine plant could produce antioxidant enzyme to remove reactive oxygen species produced by the salt stress, but the activity of antioxidant would decrease under high salt stress. Temperature could influence the activity of antioxidant enzyme under salt environment. The 6-15 ℃ treatment could induce to increase of the SOD and CAT activity, especially E.Sibiricus. Salt stress led to H202 accumulation and root tip cell death of two alpine plants, and 6-15 ℃ treatment could bring down the H202 accumulate of root tip. The mortality of root tip cell raised with increased of salt concentration, but the 6-15 ℃ treatment could alleviate the root tip cell damage which produced by salt stress.