松嫩草地主要豆科牧草种子萌发期耐旱性差异研究

Study on the Difference of Drought Resistance of Main Legumes in Songnen Grassland at Germinating Stage

采用8个PEG渗透势梯度模拟干旱胁迫,探讨了松嫩草地8种豆科牧草种子萌发期抗旱性的差异。结果表明:紫花苜蓿、扁蓿豆、兴安胡枝子、细叶胡枝子和黄花草木樨5种小粒种子的发芽率、发芽势和活力指数等指标,在溶液渗透势下降到-0.6 M Pa后迅速下降,当渗透势下降到-0.8 M Pa时,各项指标为0;而五脉山黧豆、多茎野豌豆和山野豌豆3种大粒种子则在溶液渗透势下降到-0.3M Pa时指标显著下降,下降到-0.6M Pa时下降到0。小粒种子的抗旱性明显好于大粒种子。在较低的溶液渗透势范围内,PEG有提高种子活力指数和促进幼苗生长的现象,是因为PEG对种子有引发作用,增强了种子的活性所致;PEG处理抑制胚芽生长,是幼苗调节营养分配以适应不良环境的结果。

The drought resistance of eight legume species in Songnen grassland at seeds germination stage with eight osmotic potential treatments of PEG was studied. The results indicated that the germination percentage,germination energy and vigour index of Medicago sativa ,Mealie＇ago ruthenica , Lespedeza hedusaroides,L, dahurica and Melilotus officinalis with small seeds were decreased sharply below-0.6M Pa and were zero when treated under-0.8M Pa. The indexes of Lathyrus sativus, Vicia vracca and V. amoena with big seeds decreased sharply under-0.3M Pa and decreased to zero under-0.6M Pa. The drought resistance of the small seeds were higher than the big seeds. Polyethylene glycol （PEG） could improve the vigour indexes and seedling growth under low osmotic potential treatments because polyethylene glycol （PEG） could improve the seeds vigour.