Abstract: Reproduction and renewal of Leymus chinensis seeds under natural conditions are usually affected by various abiotic stresses, such as unstable rainfall, so seeds generally undergo repeating hydration-dehydration. Based on this, the study investigated the effects of different hydration-dehydration treatments on the stress resistance of L. chinensis seed germination. Results showed that germination rates and indices of seed, and root and plant length of seedlings decreased under drought stress and salt stress. The seeds of L. chinensis were more sensitive to salt stress than drought stress. All tested hydration-dehydration treatments significantly decreased the stress resistance of L. chinensis seeds and induced secondary dormancy. Seed germination rates were 11%, 20% and 18% (CK 44%), dormant rates were 65%, 54% and 53% (CK 40%) under drought stress, while seed germination rates were 18%, 23% and 19% (CK 39%), dormant rates were 69%, 54% and 68% (CK 52%) under salt stress, respectively. These results indicated that different hydration-dehydration treatments caused lower seed germination rates and more difficult planting. However, it induced secondary dormancy that could be beneficial for conserving germplasm resources.

Key words: Drought stress, Salt stress, Secondary dormancy

摘要： 羊草(Leymus chinensis)种子在自然条件下的繁殖更新通常受各种非生物逆境的影响,如干旱及盐胁迫的影响,并且由于降雨不稳定,种子在土壤中常经历反复的"吸湿-回干"。基于此,以蒸馏水、氯化钠(NaCl)和聚乙二醇(PEG-6000)对羊草种子进行吸湿-回干处理,再以不同浓度的PEG-6000和NaCl溶液模拟干旱胁迫和盐胁迫,探讨干旱、盐胁迫下羊草种子萌发成苗状况及不同吸湿-回干处理对其萌发抗逆性的影响。结果表明:干旱胁迫和盐胁迫降低了羊草种子的萌发率、萌发指数及幼苗的根长和苗长,诱导休眠形成,相比干旱胁迫,羊草种子萌发对盐胁迫更为敏感。不同吸湿-回干处理降低了羊草种子的萌发抗逆性,诱导种子形成次生休眠。如在-0.8 MPa 干旱胁迫条件下,经水、NaCl和PEG-6000预处理的种子萌发率分别为11%,20%和18%(CK 44%),休眠率为65%,54%和53%(CK 40%)。这一结果表明不同吸湿-回干处理一方面造成羊草种子野外萌发率低、建植难;另一方面诱导次生休眠,从而有利于羊草种子在土壤种子库中的保存。

关键词: 干旱胁迫, 盐胁迫, 次生休眠