Abstract: This study was aimed to clarify the effects of drought,salt,and drought-salt stress on the photosynthesis and physiology of Agropyron mongolicum, in this study,a new species of Agropyron mongolicum ‘Yanchi’ is used as the material,and a pot experiment was conducted with a control CK (normal water supply,75% maximum field water holding capacity),drought D (35% maximum field water holding capacity),salt S (75% maximum field water holding capacity and 0.4% soil salt content) and the combined drought and salt stress DS (35% maximum field water holding capacity and 0.4% soil salt content) four treatments were set to determine its growth,photosynthetic reaction and physiological characteristics. The results showed that:The plant height,leaf area,and root diameter of A. mongolicum were significantly higher than of CK under S stress (P<0.05),under the stress of D and DS,the root surface area,leaf area,and root diameter were significantly different from CK,but the damage of DS stress was less than that of D stress;The photosynthetic characteristics of A. mongolicum increased after S stress,and showed a downward trend under D and DS stress,while the damage of DS stress was less than D stress;The peroxidase (POD),Na⁺/K⁺ ratio,malondialdehyde (MDA) and free proline of A. mongolicum showed an increasing trend under D,S,DS stress,and the POD and free proline under the DS stress were between the single stress,and the MDA content was significantly higher than the single stress. The results showed that A. mongolicum had a certain salt tolerance and showed a certain cross-adaptability under DS stress.

Key words: Agropyron mongolicum, Drought stress, Salt stress, Combined drought and salt stress, Photosynthetic and physiological characteristics

摘要： 为明确干旱、盐及旱盐复合胁迫对沙芦草（Agropyron mongolicum）光合和生理的影响，本研究以‘盐池’沙芦草新品种为材料，采用盆栽试验，设置对照CK（正常供水，75%田间最大持水量）、干旱D（35%田间最大持水量）、盐S（75%田间最大持水量，土壤含盐量0.4%）和旱盐复合DS（35%田间最大持水量，土壤含盐量0.4%）4个处理，测定其生长、光合响应和生理特性等指标。结果显示：沙芦草株高、叶面积和根直径在S胁迫下比CK显著升高（P<0.05），D与DS胁迫下，根表面积、叶面积和根直径与CK均存在显著差异，但DS胁迫造成的伤害小于D胁迫；沙芦草的光合特性指标在S胁迫后升高，D和DS胁迫下呈现下降趋势，DS胁迫降低幅度小于D胁迫；D，S，DS胁迫下沙芦草的过氧化物酶（Peroxidase，POD）、Na⁺/K⁺比、丙二醛（Malondialdehyde，MDA）、游离脯氨酸呈现升高趋势，且DS胁迫下的POD、游离脯氨酸介于单一胁迫之间，MDA含量高于单一胁迫。结果表明，沙芦草具有一定的耐盐性，并且在DS胁迫下表现出一定交叉适应性。

关键词: 沙芦草, 干旱胁迫, 盐胁迫, 旱盐复合胁迫, 光合与生理特性