盐胁迫对丹参种子萌发及幼苗生长的影响

Effect of Na Cl stress on seed germination and seedling growth of Salvia miltiorrhiza Bunge

为探讨盐胁迫对丹参种子萌发及幼苗生长过程中生理指标的影响,采用Na Cl模拟不同程度的盐胁迫,共设置0、20、50、75、100和150 mmol·L-1共6个浓度梯度,研究不同程度盐胁迫下丹参种子萌发及幼苗生长的相关生理特性。结果表明,20 mmol·L-1的Na Cl可促进丹参种子萌发,但随着盐胁迫浓度的增加,丹参种子发芽率和发芽指数、发芽势均呈下降趋势;丹参幼苗苗高和根长生长则在75 mmol·L-1 Na Cl溶液处理下达到最大值,且此时显著增加了丹参幼苗叶片中SOD、POD、CAT酶的活性;在100 mmol·L-1 Na Cl溶液处理下可溶性糖,可溶性蛋白含量最高,MDA的含量则随着Na Cl胁迫浓度的升高而增加,说明丹参幼苗叶片通过自身协调物质来抵抗盐胁迫的同时细胞膜随着盐浓度的升高而受到严重的破坏;同时,与对照相比,各处理均显著降低了丹参幼苗的叶绿素与类胡萝卜素的含量,抑制了叶片产生光合色素的能力。综上所述,低浓度的Na Cl胁迫下,有利于丹参种子的萌发,丹参幼苗也可通过提升自身的生理机制来缓解一定浓度盐胁迫造成的伤害,但是随着Na Cl胁迫浓度的升高,丹参幼苗耐盐能力明显下降。

In order to investigate the effect of salt stress on seed germination and seedling growth of Salvia miltiorrhiza, the different levels of salt stress were simulated using NaCl at concentrations of 0, 20, 50, 75, 100 and 150 mmol·L-1. The results showed that 20 mmol·L-1 NaCl promoted Salvia miltiorrhiza seed germination, but with increasing salt concentration, the seed germination percentage, germination index and the germination potential of Salvia miltiorrhiza declined. The seedling height, root length and seedling growth reached the maximum value and the activities of SOD, POD and CAT in the seedling leaf significantly increased at 75 mmol·L-1 NaCl level.The soluble sugar and soluble protein contents were the highest at 100 mmol·L-1 NaCl and the content of MDA increased with an increase of NaCl concentration.This suggested that the seedling leaf should resist salt-stress through coordinating cellular materials by itself. However, with the increase of salt concentration, the cell membrane was under severe damage. Meanwhile, the salt treatment could significantly reduce the chlorophyll and carotenoid contents and inhibit the synthetic ability of leaf photosynthetic pigment. To sum up, a low concentration of NaCl stress is advantageous to the seed germination. The seedling itself can alleviate the harm of salt stress to a certain concentration through its physiological mechanism, but with increasing NaCl concentration, salt tolerance of Salvia miltiorrhiza seedlings significantly decreased.