模拟盐胁迫对勿忘草种子萌发及幼苗生长的影响

Effects of Salt Stress on Seed Germination and Seedling Growth of Myosotis silvatica Ehrh. ex Hoffm.

采用NaCl,Na_2SO_4,MgCl_2这3种单盐溶液及NaCl+Na_2SO_4(2∶1)复合盐溶液,并且每溶液设置5个浓度梯度进行模拟盐胁迫,探究盐胁迫下,勿忘草种子萌发和幼苗生长的各指标的改变,旨在研究勿忘草在干旱半干旱的盐碱地区存活及生长的潜力。结果表明,在1.5%浓度下,MgCl_2,Na_2SO_4及复合盐胁迫处理组种子发芽率高于50.0%,大于NaCl盐胁迫;0.3%~0.9%的MgCl_2盐胁迫发芽指数显著低于对照,但对种子发芽率无显著影响,种子表现出对Mg2+盐有更强的耐受性;除MgCl_2盐溶液处理外,其他盐溶液处理组种子发芽率及发芽指数整体随盐浓度的升高而降低;MgCl_2盐胁迫下,幼苗胚根长与盐浓度呈负相关;NaCl,Na_2SO_4及复合盐胁迫处理,胚根长呈先升后降的趋势,在0~0.3%浓度范围升高,0.3%~1.5%浓度降低;各盐胁迫下,胚芽长均随浓度的升高而降低;NaCl及Na_2SO_4盐胁迫下,幼苗叶面积与浓度呈负相关;0.3%~1.2%浓度下,MgCl_2盐溶液处理叶面积与对照差异不显著,复合盐则显著高于对照。勿忘草种子及幼苗均表现出较强的耐盐潜力,在盐胁迫下仍能保持高的发芽率,并且幼苗通过形态的调整应对盐胁迫的影响。

The paper used the seed of Myosotis silvatica Ehrh. ex Hoffm. as experimental material to study the salt stress on seed germination and seedling growth. The aim of this study was to discuss the potential of Myosotis silvatica Ehrh. ex Hoffm. to survive and grow in arid and semi-arid saline areas. Four kinds of salt were used and five different concentration gradients were set up to simulate seed germination under salt stress. The results showed that at the concentration of 1.5%, seed germination rate of Mg Cl2, Na2SO4 and compound salt stress treatment group was higher than 50.0%, and higher than that of Na Cl salt stress. The germination index of 0.3%-0.9% Mg Cl2 salt stress was significantly lower than that of the CK, but it had no significant influence on the germination rate of seeds,showing that seeds were more tolerant to Mg2＋salt. Except for the treatment of Mg Cl2 salt solution, the germination rate and germination index of seeds in other salt solution treatment groups decreased with the increase of concentration. Under the stress of Mg Cl2 salt, seedling radicle length and concentration were negatively correlated. Under the stress of Na Cl, Na2SO4 and compound salt, the endoderm length showed a trend of first rising and then falling, which increased in the range of 0-0.3% concentration and decreased in the range of 0.3%-1.5% concentration. Under various salt stress, the length of germ decreased with the increase of concentration. Under Na Cl and Na2SO4 salt stress, leaf area and concentration of seedlings were negatively correlated. At the concentration of 0.3%-1.2%, the leaf area of Mg Cl2 salt solution was not significantly different from that of the control group, while the compound salt was significantly higher than that of the control group. In the study, Myosotis silvatica Ehrh. ex Hoffm. seeds and seedlings all showed strong salt tolerance potential, maintained high germination rate under salt stress, and the seedlings responded to salt stress by morphological adjustment.