Abstract: Switchgrass seeds were irrigated by two of salt solution treatments(sodium chloride mixture,sodium sulfate mixture) with 6 saline concentration levels(control,0.4%,0.8%,1.2%,1.6%,2.0%).Effects of salt stress on switchgrass seed germination and seedling growth are reported.Results indicate that the seeds’ germination rate reduces with an increase in salt concentration.Germination is restrained under all the concentration levels during early development;however,under lower salt concentrations this negative effect is reduced with further germination.After 11 days,the germination rate has no significant difference between control and low concentration treatments(sodium sulfate mixture 0.4%,0.8% and 1.2%,sodium chloride mixture 0.4 %).Results indicate that switchgrass has some salt tolerance.Seed germination rate and index of switchgrass seeds irrigated by both 0.4% sodium sulfate mixture and 0.4% Sodium chloride mixture are significantly higher than controls.Therefore,the low salt treatment improves germination of switchgrass seeds.Under the same salt concentration level,both seedling vigor index and relative seedling vigor index of the switchgrass seeds are lower in sodium chloride solution than in sodium sulfate solution.Sodium chloride solution is more harmful on switchgrass seedling than sodium sulfate solution.

Key words: Switchgrass, Salt stress, Salt resistance, Germination rate, Seed germination

摘要： 选用NaCl混合盐和Na₂SO₄混合盐2类盐溶液处理柳枝稷(Panicumvirgatum)种子,研究盐胁迫对柳枝稷种子萌发和幼苗生长的影响,以期为柳枝稷耐盐性研究提供科学依据。NaCl混合盐和Na₂SO₄混合盐浓度均分别设0(CK),0.4%,0.8%,1.2%,1.6%,2.0%。结果表明:种子发芽率随着盐浓度的增加逐渐降低,在萌发初期,各浓度的盐溶液都具有抑制作用,随着发芽天数延长,低浓度盐溶液(Na₂SO₄混合盐0.4%,0.8%和1.2%,NaCl混合盐0.4%)抑制作用缓解,处理11 d后,柳枝稷种子的发芽率与对照相比没有显著性差异,表明柳枝稷具有一定的耐盐性。0.4%的Na₂SO₄混合盐和NaCl混合盐处理的柳枝稷种子的发芽率和发芽指数均显著高于对照,有促进柳枝稷发芽的作用。同时,相同盐浓度处理下,NaCl混合盐溶液处理的发芽率和幼苗活力指数、相对幼苗活力指数低于Na₂SO₄混合盐,NaCl混合盐溶液对柳枝稷种子萌发的胁迫高于Na₂SO₄混合液。

关键词: 柳枝稷, 盐胁迫, 耐盐性, 发芽率, 种子萌发