Abstract: In this study,22 Elymus dahuricus Turcz. germplasms were used as experimental materials,and two nitrogen concentrations of total N (1 mmol·L^-1,TN) and 1/100 N (0.01 mmol·L^-1,LN) were set to treat for 28 d. Morphological and physiological indexes of the lanceolate were measured after the treatments,and the values of the measurements were subjected to the analysis of the affiliation function. The morphological and physiological indexes of lanceolate were measured after treatment,and the values were compared with each other in an affiliation function analysis to investigate the low nitrogen tolerance characteristics of 22 lanceolate germplasm under long-term low nitrogen stress. The results showed that the plant phenotypes of 22 Elymus dahuricus Turcz. were affected to different degrees under low nitrogen stress,as evidenced by reduced plant height and shortened root length. For physiological indicators:low nitrogen significantly reduced nitrate nitrogen content,net photosynthetic rate,transpiration rate,intercellular carbon dioxide concentration,stomatal conductance,nitrate reductase and glutamate synthetase activities,and soluble sugar content in Elymus dahuricus Turcz. seedlings. Low nitrogen significantly increased glutamine synthetase and glutamate dehydrogenase activities,along with significant increases in superoxide anion,hydrogen peroxide,and soluble protein content. After correlation analysis,principal component analysis and affiliation function analysis,seven principal components were extracted as comprehensive indexes for the evaluation of low-nitrogen tolerance of Elymus dahuricus Turcz,and the germplasm with stronger low-nitrogen tolerance were calculated to be E17 and E19,and low-nitrogen-sensitive germplasm were E12 and E16. The results of the study provide theoretical support for the selection and breeding of low-nitrogen-tolerant varieties of Elymus dahuricus Turcz.

Key words: Elymus dahuricus, Low nitrogen stress, Morphological characteristics, Physiological characteristics, Low nitrogen resistance, Comprehensive evaluation

摘要： 本研究以22份披碱草(Elymus dahuricus Turcz.)种质为试验材料，设置全氮(1 mmol·L^-1，TN)和1/100氮(0.01 mmol·L^-1，LN)两个氮浓度处理28 d，对处理后披碱草的形态指标和生理指标进行测定，并对各测定值进行隶属函数分析比较，探究22份披碱草种质在长期低氮胁迫下的耐低氮特性。结果表明：在低氮胁迫下，22份披碱草的植株表型均受到不同程度影响，表现为株高降低，根长缩短；生理指标方面：低氮显著降低了披碱草幼苗的硝态氮含量、净光合速率、蒸腾速率、胞间二氧化碳浓度、气孔导度、硝酸还原酶和谷氨酸合成酶活性以及可溶性糖含量；低氮显著提高了谷氨酰胺合成酶和谷氨酸脱氢酶活性，同时显著增加了超氧阴离子、过氧化氢以及可溶性蛋白的含量。经过相关性分析、主成分分析和隶属函数分析，提取7个主成分作为披碱草耐低氮性评价的综合指标，经过计算得出耐低氮性较强的种质是E17，E19，低氮敏感型种质是E12，E16。研究结果为披碱草耐低氮品种选育工作提供理论支持。

关键词: 披碱草, 低氮胁迫, 形态特征, 生理特性, 耐低氮性, 综合评价