外源水杨酸对盐胁迫下广藿香种子萌发和幼苗生长的影响

目的研究外源水杨酸(SA)对盐(NaCl)胁迫下广藿香Pogostemon cablin种子萌发和幼苗生长的影响,并筛选缓解盐胁迫的SA最适浓度。方法用50 mmol/L NaCl溶液模拟盐胁迫,采用纸上发芽,研究不同浓度梯度外源SA处理对盐胁迫下广藿香种子的发芽势(GE)、发芽率(GR)、发芽指数(GI)、活力指数(VI)、苗长(SL)、根长(RL)、苗鲜质量(SFW)、苗干质量(SDW)、叶绿素量(SPAD值)、可溶性蛋白质(SP)量和丙二醛(MDA)量的变化,并对各指标进行相对盐害率分析。结果盐胁迫显著抑制了广藿香种子萌发和幼苗生长。0.10和0.25 mmol/L SA处理均可有效缓解广藿香盐害程度,而0.50 mmol/L SA处理却加剧了盐害程度。综合考虑各项指标,0.25 mmol/L SA处理的盐害缓解效果最好,与盐对照相比,GE、GR、GI、VI、SL、RL、SFW、SDW、SPAD值和SP量分别显著提高46.02%、27.45%、30.16%、92.63%、39.80%、47.94%、26.48%、18.85%、15.94%和14.70%,且叶片MDA量显著降低18.35%。结论一定浓度范围的SA可明显缓解盐胁迫对广藿香种子萌发和幼苗生长的抑制作用,提高广藿香种子的萌发能力和幼苗对环境的适应能力,以0.25mmol/L SA效果最佳,但过高质量浓度SA处理会加剧盐胁迫对广藿香的不利影响。

Effects of exogenous salicylic acid on seed germination and seedling growth of Pogostemon cablin under salt stress

Objective To study the effects of exogenous salicylic acid (SA) on the seed germination and seedling growth of Pogostemon cablin under salt stress and the optimal concentration of SA for alleviating the salt stress. Methods Under salt stress simulated by 50 mmol/L NaCl solution, P. cablin was used to investigate the effects of exogenous SA on the seed germination and seedling growth with paper media. The germination energy (GE), germination rate (GR), germination index (GI), vigor index (VI), seedling length (SL), root length (RL), seedling fresh weight (SFW), seedling dry weight (SDW), and contents of soluble protein (SP) and chlorophyll in the leaves were determined, and the relative salt-damage rate of these indexes was analyzed. Results The seed germination and seedling growth of P. cablin were significantly inhibited under 50 mmol/L NaCl stress. Compared with NaCl stress, the seed germination and seedling growth were improved when SA were 0.10 and 0.25 mmol/L, while reduced when SA was 0.50 mmol/L. GE, GR, GI, VI, SL, RL, SFW, SDW, and contents of SP and chlorophyll were significantly improved by 46.02%, 27.45%, 30.16%, 92.63%, 39.80%, 47.94%, 26.48%, 18.85%, 15.94%, and 14.70% with 0.25 mmol/L SA, as well as MDA content was significantly reduced by 18.35%. Conclusion SA could improve the ability of the seed germination and seedling growth of P. cablin to adapt the environment and alleviate the inhibitory effects of salt stress. Among all the treatments, the optimal concentration of SA is 0.25 mmol/L.