外源ALA、SNP和Spd对NaCl胁迫下桔梗种子萌发特性的影响

Effect of exogenous ALA、SNP and Spd on seed germination characteristics of Platycodon grandiflorum under NaCl stress

关键词:  桔梗  ALA  SNP  Spd  盐胁迫  种子萌发  萌发特性

Key words:  Platycodon grandiflorum  ALA  SNP  Spd  NaCl stress  seed germination  germination characteristics

摘要:

以药用植物桔梗为研究对象，通过测定不同浓度的ALA、SNP和Spd对NaCl胁迫下桔梗种子发芽势、发芽率、萌发指数和平均根长等萌发指标的影响，寻找提高桔梗种子及幼苗在盐胁迫条件下抗性能力的途径。实验结果表明，75 mmol•L 1 NaCl胁迫下的桔梗种子萌发受到显著抑制，但是用不同浓度的ALA、SNP和Spd对桔梗种子进行恢复处理后各萌发指标均显著升高。Spd（2.5 mmol•L 1）、ALA（5 mg•L 1）、SNP（0.1 mmol•L 1）处理能有效缓解盐对种子的胁迫伤害。其中，经Spd（2.5 mmol•L 1）处理下发芽势、发芽率、发芽指数和平均根长均达到最大值，发芽势为40.0%，发芽率为49.5%，发芽指数为9.28、平均根长为280 cm。由此可以得出，适宜浓度的ALA、SNP、Spd可以缓解NaCl对桔梗种子的胁迫伤害，提高种子的抗盐能力，其中Spd效果最好，SNP次之，再者是ALA。

Abstract:

In order to get the method to improve the salt resistance of seeds and seedlings for Platycodon grandiflorum under NaCl stress，the different concentration of 5 aminolevulinic acid（ALA），sodium nitroprusside（SNP），spermidine（Spd）effect on P.grandiflorum seed germination，seed germination rate，seed germination index，and the average length of root were studied under different concentrations of NaCl stress. The results showed that the seed germination was inhibited under 75 mmol•L 1 concentrations of NaCl stress，but with different concentrations of ALA，SNP and Spd on the P. grandiflorum seeds，all germination index were significantly higher. Spd(2.5 mmol•L 1），ALA （5 mg•L 1）and SNP（0.1 mmol•L 1）could obviously alleviate the damage of salt stress to the seeds of P. grandiflorum. Spd(2.5 mmol•L 1)significantly increased all indexes. The germination vigor was 40.3%，the germination rate was 49.5%，the germination index was 9.28 and the average length of root was 2.80 cm. So we conclude that，ALA，SNP and Spd with appropriate concentration could significantly alleviate the damages to the P.grandiflorum seeds under NaCl stress and promote the salt resistance of the seeds，the best of them was Spd，the second was SNP，furthermore was the ALA.