Abstract: In order to screen salt resistant varieties, the seeds of eight wild Poa L. varieties were treated with NaCl and Na₂SO₄ solutions and the effects of salt stress on the seed germination characteristics of this plant were investigated. Results indicated that the seed germination of P. poophaqorum and the coleoptile growth of P. pratensis (Xinglongshan), P. pratensis (Tianzhu) and P. sphodylodes varieties were improved by 50 mmol稬^-1 NaCl, while the seed germination of P. pratensis (Xinglongshan), P. pratensis (Tianzhu), P. pratensis (Gannan), P. sphodylodes, P. poophaqorum and P. micrandra and the coleoptile growth of P. micrandra were improved by 25 mmol稬^-1 Na₂SO₄. Both salt stresses inhibited the root growth more than the seedling growth of tested varieties. The effect of NaCl was more robust than Na₂SO₄ on seed germination. Among all six investigated indices, the average critical value and the ultimate values of salt resistance were minimum, thus both parameters can be used to evaluate the salt resistance of these wild Poa L. varieties. Salt resistances of these varieties were ranked as P. micrandra>P. poophagorum>P. sphondylodes>P. pratensis (Xinglongshan)>P. pratensis (Sunan)>P. pratensis (Tianzhu)>P. pratensis (Gannan)>P. pratensis (Weiyuan).

Key words: Salt stress, Wild Poa L., Germination characteristics, Critical value, Limit value

摘要： 用不同浓度的NaCl和Na₂SO₄这2种单盐溶液处理8个野生早熟禾(Poa L.)种子,通过种子萌发特性的变化,研究其萌发时的耐盐能力,以期为耐盐早熟禾种质材料的筛选提供依据。结果表明:50 mmol·L^-1 NaCl促进波伐早熟禾(P. poophagorum)种子的萌发和草地早熟禾(兴隆山)(P. pratensis)、草地早熟禾(天祝)、硬质早熟禾(P. sphondylodes)胚芽的生长;25 mmol·L^-1 Na₂SO₄ 促进草地早熟禾(兴隆山)、草地早熟禾(天祝)、小药早熟禾(Poa micrandra)、硬质早熟禾、波伐早熟禾、草地早熟禾(甘南)种子的萌发,及小药早熟禾胚芽的生长。2种盐胁迫均抑制胚根的生长,且对胚根生长的影响大于胚芽;NaCl对种子萌发的影响大于Na₂SO₄。6个指标中,胚根长的平均耐盐临界值和耐盐极限值最小,作为8个野生早熟禾种子萌发期耐盐临界值和耐盐极限值比较可靠。种子萌发期耐盐性强弱依次为:小药早熟禾>波伐早熟禾>硬质早熟禾>草地早熟禾(兴隆山>草地早熟禾(肃南)>草地早熟禾(天祝)>草地早熟禾(甘南)>草地早熟禾(渭源)。

关键词: 盐胁迫, 野生早熟禾, 种子萌发, 耐盐临界值, 耐盐极限值