Abstract: Drought stress is the dominant environmental factor limiting plant growth in arid and semi-arid areas. The effects of 15 d drought stress and 6 d re-watering on physiological indices relating drought tolerance and enzyme activities of crested wheatgrass (Agropyron cristatum) were analyzed. Results showed that the leaves of crested wheatgrass could keep relatively high water content under drought stress and relative water content (RWC) recovered rapidly in leaves during re-watering. There was no severe drought damage on photochemical system. Photochemical efficiency (F_v/F_m) only decreased 6.62% after 10 days drought stress. Electrolyte leakage (EL) of leaves had no significant difference after 5 or 10 days drought stress compared with well-water control. With extended drought stress, EL increased significantly. Under drought stress, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities gradually decreased. CAT was the most sensitive enzyme to drought stress and POD activities decreased the slowest. The activities of three antioxidant enzymes increased after re-watering and did not show any significant differences 6 days later compared with well-water control. These results suggest that drought tolerance of crested wheatgrass could be related with water retaining capacity during short-time drought stress and rapid recovery of physiological functions after re-watering.

Key words: Agropyron cristatum, Drought, Re-watering, Superoxide dismutase (SOD), Peroxidase (POD), Catalase (CAT), Malondialdehyde (MDA)

摘要： 干旱胁迫是干旱与半干旱地区限制植物生长的一个最主要的环境因子。本文研究了15 d的干旱胁迫和6 d的复水对冰草(Agropyron cristatum)叶片抗旱相关生理指标及抗氧化酶活性的影响。结果表明:在干旱胁迫下冰草叶片具有较强的水分保持能力,并且在复水过程中叶片相对含水量快速恢复;干旱胁迫对冰草光化学系统的影响较小,10 d的干旱胁迫下,F_v/F_m仅下降了6.62%;5 d和10 d的干旱胁迫对冰草叶片电解质外渗的影响与对照差异不显著,而随着干旱胁迫时间的延长,叶片电解质外渗显著升高。在水分胁迫下, 冰草超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性逐渐降低,CAT对干旱胁迫最敏感,而POD活性下降最慢;复水后3种酶的活性升高,复水6 d后都恢复到干旱处理前的水平。由此表明,冰草的抗旱性可能和短期干旱胁迫下叶片的保水能力以及复水后叶片生理功能的快速恢复有关。

关键词: 冰草, 干旱, 复水, 超氧化物歧化酶, 过氧化物酶, 过氧化氢酶, 丙二醛