[目的]为研究γ-氨基丁酸(GABA)种子引发处理对盐胁迫下辣椒种子萌发和幼苗生长的效果及其可能机制.[方法]以茂蔬360朝天椒为材料,通过不同浓度γ-氨基丁酸(0、1.0、2.0、4.0、6.0、8.0 µmol/L)种子引发处理,分析了100 mM NaCl模拟盐胁迫下的辣椒种子萌发及幼苗生长的形态、生理和生化指标,[结果]浓度为6.0 µmol/L 的GABA引发处理显著增加了辣椒种子的可溶性糖、可溶性蛋白含量,降低了O2-·和MDA的积累,提高了CAT酶活性、ASA及DHA含量;GABA引发处理提高了辣椒种子盐胁迫下发芽率22.6%、发芽势9.91倍、发芽指数56.3%及活力指数70.6%;GABA引发处理增加了盐胁迫下辣椒幼苗的地上部鲜质量、根系鲜质量、干质量及株高,降低了幼苗MDA含量、可溶性糖和脯氨酸含量,增加了SOD、CAT和APX活性.[结论]GABA通过提前启动种子贮藏物质的代谢及调控抗氧化防御能力增强辣椒种子萌发能力及耐盐性,并且在幼苗阶段再遇盐碱胁迫下,调控渗透调节物质含量和增强抗氧化酶活性,增加幼苗对盐胁迫的耐受性.
Effect of seed priming with γ-aminobutyric acid(GABA)on seed germination and seedling growth of pepper under salt stress
[Objective]The objective of this study was to investigate the effect of gamma-aminobutyric acid(GABA)on seed priming and its potential mechanism in regulating salt tolerance in pepper(Capsicum annuum L.).[Method]With Maoshu 360 Chaotian Pepper as the experimental material,the influence of seed priming with different concentrations of GABA(0,1.0,2.0,4.0,6.0,8.0 µmol/L)on seed germina-tion and physiological and biochemical characteristics of pepper seedlings under 100 mmol/L NaCl stress was examined.[Result]The findings demonstrated that GABA priming at 6.0 µmol/L significantly in-creased the contents of soluble sugars and soluble proteins in pepper seeds.It also decreased the accumula-tion of O2-·and malondialdehyde(MDA),while increasing the activities of catalase(CAT)and the contents of ascorbic acid(ASA)and dehydroascorbic acid(DHA).GABA priming improved the germination percent-age,germination energy,germination index,and vigor index of pepper seeds by 22.6%,9.91 times,56.3%,and 70.6%,respectively.Additionally,GABA priming resulted in higher shoot fresh weight,root fresh weight,dry weight,and plant height,while reducing MDA,soluble sugar,and proline concentrations.Fur-thermore,it enhanced the activities of superoxide dismutase(SOD),CAT,and ascorbate peroxidase(APX).[Conclusion]In conclusion,GABA seed priming enhanced pepper seed germination and salt tolerance by modulating the metabolism of seed storage materials and regulating antioxidant defense capacity.At the seedling stage under salt-alkali stress,it regulated osmotic adjustment substance content and enhanced anti-oxidant enzyme activity,thereby increasing seedling tolerance to salt stress.
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