干旱胁迫下水杨酸对桔梗种子萌发及植物激素的影响

为提高干旱胁迫下桔梗种子萌发,研究了不同浓度水杨酸(10 mg/L、20 mg/L和30 mg/L)对干旱胁迫(5%、10%和20%PEG)下桔梗种子萌发和植物激素(脱落酸、赤霉素和吲哚乙酸)的影响。结果表明:20%PEG胁迫处理抑制桔梗种子萌发,外源添加水杨酸后,发芽率、发芽势、发芽指数、根长、苗长和鲜重均显著高于对照组,其中水杨酸浓度为10 mg/L时,各检测指标值最大; PEG胁迫处理下,10 mg/L和20 mg/L水杨酸处理后3种植物激素含量均显著低于对照组。在干旱胁迫下施加水杨酸处理可提高桔梗种子的抗干旱胁迫能力,并且对植物激素含量具有一定的调控作用。水杨酸浓度为10 mg/L时缓解干旱胁迫效果较好。

Influence of Salicylic Acid on Seed Germination and Plant Hormones of Platycodon grandiflorum under Drought Stress

In order to improve Platycodon grandiflorum seed germination under drought stress, this paper studied the effects of different salicylic acid concentrations（10 mg/L, 20 mg/L and 30 mg/L）on seed germination and 3 plant hormones under drought stress （5%, 10% and 20% PEG）. The results showed that 20% PEG could inhibite seed germination of Platycodon grandiflorum. After adding salicylic acid to exogenous, the germination percentage, germination potential, germination index, root length, seedling length and fresh weight were all significantly higher than those of control group, when salicylic acid concentration were 10 mg/L, the targeted value of each detection were the largest. Under PEG stress and after 10 mg/L and 20 mg/L salicylic acid treatment, 3 plant hormone contents were all significantly lower than those of control group. Under drought stress, applying salicylic acid treatment could improve drought resistant ability of Platycodon grandiflorum seeds, and also had certain regulatory effect on plant hormones contents. In this study, 10 mg/L salicylic acid concentration had better effect to alleviate drought stress.