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为探讨外源5-氨基乙酰丙酸(ALA)对盐胁迫下植物生长的缓解作用,以夏枯草为试验材料,研究1.25~10.00 mg·L~(-1)ALA对70 mmol·L~(-1)盐胁迫下夏枯草幼苗叶片和根系的抗氧化酶活性、叶片的叶绿素含量与光合特性的影响。结果表明,1.25~5.00 mg·L~(-1)ALA处理均可不同程度地提高盐胁迫下夏枯草幼苗叶片和根系过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的活性及可溶性糖含量;增加夏枯草叶片的叶绿素a(Chl a)、叶绿素b(Chl b)、总叶绿素(Chl a+b)及类胡萝卜素(Car)含量;提高净光合速率(Pn)、气孔导度(Gs)与蒸腾速率(Tr),降低胞间CO2浓度(Ci)。外源ALA可以通过提高抗氧化酶活性和渗透调节物质的含量,增强叶片的光合作用,进而缓解盐胁迫对夏枯草幼苗产生的伤害,从而提高夏枯草幼苗的抗盐能力,ALA浓度以5.00 mg·L~(-1)最佳。本研究结果为探明ALA缓解夏枯草盐胁迫危害的作用机理提供了理论依据。
In order to investigate the alleviating effect of exogenous 5-aminolevulinic acid (ALA) on plant growth under salt stress, Prunella vulgaris as experimental material was used to study the effects of 1.25 ~ 10.00 mg · L -1 ALA on the growth of 70 mmol·L ~ -1) on the activities of antioxidant enzymes, chlorophyll content and photosynthetic characteristics of leaves and roots of Prunella vulgaris under salt stress. The results showed that 1.25 ~ 5.00 mg · L -1 ALA could increase the contents of peroxidase (POD), catalase (CAT), ascorbate peroxidation (APX) activity and soluble sugar content, increased the contents of Chl a, Chl b, Chl a + b and Car in Prunella vulgaris leaves; Photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) and intercellular CO2 concentration (Ci). Exogenous ALA could enhance the photosynthesis of leaves by increasing the content of antioxidant enzymes and osmotic adjustment substances, and then alleviate the damage caused by salt stress on Prunella vulgaris seedlings, thus increasing the salt-tolerance ability of ALA to 5.00 mg · L ~ (-1) is the best. The results of this study provide a theoretical basis for exploring the mechanism by which ALA alleviates the damage caused by salt stress of Prunella vulgaris.