不同盐胁迫对斜茎黄芪种子萌发及幼苗生长的影响

[目的]明晰斜茎黄芪种子萌发及幼苗生长对不同盐胁迫的适应性。[方法]分别采用NaCl溶液、Na₂SO₄溶液和Na₂CO₃溶液对斜茎黄芪种子进行盐胁迫处理,每种溶液均设置0（CK）、10、20、30、40 mmol/L 5个浓度梯度,每种溶液每个处理浓度设置3次重复。计算不同盐溶液处理下斜茎黄芪种子的发芽率、发芽势、发芽指数、活力指数和相对盐害率,测定幼苗株高、根长。[结果]随着盐溶液浓度逐渐升高,斜茎黄芪种子萌发及幼苗生长指标均呈下降趋势。与CK组相比,NaCl、Na₂SO₄、Na₂CO₃处理组在盐溶液浓度为40 mmol/L时,斜茎黄芪种子的发芽率、发芽势、发芽指数、活力指数显著（P<0.05）降低,幼苗株高及根长显著（P<0.05）降低。Na₂SO₄处理组在盐溶液浓度为10 mmol/L时,幼苗根部较CK组长5.5%,低浓度Na₂SO₄溶液促进了幼苗根部生长;Na₂CO₃溶液处理对斜茎黄芪种子造成严重的盐害,各浓度处理组的种子萌发及幼苗生长指标均显著（P<0.05）低于CK组,且各处理浓度之间差异较大。[结论]斜茎黄芪种子对3种盐胁迫的耐受程度为Na₂SO₄>NaCl>Na₂CO₃。低浓度Na₂SO₄溶液对斜茎黄芪种子的萌发和幼苗生长表现出一定的促进作用,Na₂CO₃溶液则表现出较强的抑制作用。

Effects of Different Salt Stresses on Seed Germination and Seedling Growth of Astragalus laxmannii

[Objective] This study was conducted to clarify the adaptability of seed germination and seedling growth of Astragalus laxmannii to different salt stresses. [Method] Astragalus laxmannii seeds were exposed to five gradient concentrations of NaCl, Na₂SO₄, and Na₂CO₃ solutions respectively at 0 （CK）, 10, 20, 30, and 40 mmol/L. Three replicates were set for each treatment concentration of each salt solution. Under the treatments of different salt solutions, the germination rate, germination potential, germination index, vigour index, and relative salt damage rate of Astragalus laxmannii seeds were calculated, and the seedlings′ height and root length were measured. [Result] The indexes associated with seed germination and seedling growth of Astragalus laxmannii declined as salt solution concentrations increased. Compared with CK group, the germination rate, germination potential, germination index, and vigour index of Astragalus laxmannii seeds decreased significantly （P<0.05） when the concentration of NaCl, Na₂SO₄, and Na₂CO₃ solutions was 40 mmol/L, and the seedlings′ height and root length decreased significantly （P<0.05） as well. The Astragalus laxmannii seedlings′ root length in 10 mmol/L Na₂SO₄ solution treatment group was 5.5% longer than that in CK group, indicating the promoting effect of Na₂SO₄ solution on the seedlings′ root growth at low concentrations. Na₂CO₃ solution treatments resulted in severe salt damage to Astragalus laxmannii seeds. The indexes associated with seed germination and seedling growth of Astragalus laxmannii in Na₂CO₃ solution treatment groups were all significantly （P<0.05） lower than those in CK group, and the differences among varied treatment concentrations were large. [Conclusion] Astragalus laxmannii seeds were most tolerant to Na₂SO₄ salt stress, followed by NaCl and Na₂CO₃ salt stresses. While low concentrations of Na₂SO₄ solution had certain promoting effect on seed germination and seedling growth of Astragalus laxmannii, Na₂CO₃ solution had strong inhibitory effect.