Abstract: To compare the tolerance to salt and drought of different Desmodium species seeds during germination,the seed germination rate,germination potential,germination index,radical length and plumule length of 8 Desmodium species seeds were measured by the method of paper germination in petri dishes under treatments with NaCl and PEG stress. The results showed that the Desmodium seeds were sensitive to salt during germination. The germination index of all 8 Desmodium species seeds was inhibited by NaCl solution at the concentration of 50 mmol·L^-1,and the radical and plumule of them was inhibited at 100 mmol·L^-1. When the concentration of NaCl ≥ 150 mmol·L^-1,all 8 Desmodium species didn’t grow normally or even decay. PEG solution with low concentrations have no effect on germination of Desmodium seeds,but it could promote the growth of radical and plumule. When the concentration of PEG≤15%,all 8 Desmodium species seeds germinated and grow normally. The seed germination and growth of all 8 Desmodium species were inhibited by PEG solution with the concentration of 20%. Except D. strigillosum with 86.00% germination rate,all other Desmodium species didn’t germinate when the concentration of PEG=25%. Among 8 Desmodium species,D. racemosum and D. heterocarpum have stronger salt tolerance ability,D. strigillosum and D.heterophyllum had stronger drought tolerance ability,and D. tortuosum was most sensitive to salt and drought during germination.

Key words: Desmodium, Drought stress, NaCl stress, Seed germination, Radical length, Plumule length

摘要： 为比较不同山蚂蝗（Desmodium Desv.）种子萌发期耐盐耐旱性差异，本研究选用8种山蚂蝗种子为材料，采用培养皿纸上发芽法观测了NaCl和聚乙二醇（Polyethylene glycol，PEG）处理对其发芽率、发芽势、发芽指数、胚根和胚芽的影响，并探讨了8种山蚂蝗种子在萌发期耐盐耐旱性能差异。结果表明山蚂蝗种子对NaCl胁迫较敏感。当NaCl浓度为50 mmol·L^-1时，发芽指数均明显下降；当NaCl浓度为100 mmol·L^-1时，胚根和胚芽生长均受到明显抑制；当NaCl浓度≥150 mmol·L^-1时，胚根胚芽均不能正常生长，甚至出现腐烂。低浓度的PEG胁迫对山蚂蝗种子发芽无显著影响，但可促进胚根和胚芽生长。在PEG浓度≤15%时，山蚂蝗种子均能正常萌发且生长良好；当PEG浓度为20%时，种子萌发和生长均显著受到抑制；当PEG浓度为25%时，仅糙伏山蚂蝗发芽率为86.00%，其它种子不能萌发。在8种山蚂蝗种子中，山蚂蝗、赤山绿豆和异果山绿豆耐盐性较好，糙伏山蚂蝗和异叶山蚂蝗抗旱能力较强，南美山蚂蝗耐盐性和抗旱均较差。

关键词: 山蚂蝗, 干旱胁迫, NaCl胁迫, 种子萌发, 胚根长, 胚芽长