ALA对低温胁迫下辣椒植株叶片中AsA-GSH循环的影响

Effect of 5-aminolevulinic acid on the ascorbate-glutathione system of pepper leaves under low temperature stress

以超越五号辣椒品种为试材,探讨低温胁迫期间及随后的常温恢复过程中5-氨基乙酰丙酸(ALA 25mg/L)处理对始花期辣椒植株叶片中超氧阴离子(O.2-)的产生速率、抗坏血酸-谷胱甘肽(AsA-GSH)循环中抗氧化酶活性及抗氧化剂含量的影响。结果表明,叶面喷施25mg/L的ALA能有效降低低温胁迫下植株叶片中O.2-的产生速率和脱氢抗坏血酸还原酶(DHAR)活性,显著提高植株叶片中抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)、单脱氢抗坏血酸还原酶(MDHAR)的活性和谷胱甘肽(GSH)、抗坏血酸(AsA)等抗氧化物质的含量及AsA/DHA和GSH/GSSG的比值;常温恢复后,APX、GR和DHAR酶活性均相对有所降低。说明低温胁迫下,辣椒叶面喷施ALA能通过提高AsA-GSH循环中抗氧化酶活性和抗氧化剂的含量,降低辣椒叶片中O.2-的产生速率,从而增强其抗氧化能力,有效缓解低温胁迫对辣椒植株的伤害。

Effect of 5-aminolevulinic acid（ALA,25 mg/L） on the production rate of active oxygen（O2 ·-）,the activities of antioxidant enzymes and the content of antioxidants in AsA-GSH cycle was investigated with pepper variety Chaoyue No.5 in flowering stage under low temperature stress.Results showed that 25 mg/L ALA significantly decreased the production rate of O2 ·-and the activities of DHAR,increased the activities of APX,GR,MDHAR and the content of AsA,GSH,as well as the ratio of AsA/DHA and GSH/GSSG under low temperature stress.The activites of APX,GR and DHAR were slightly decreased after restoration under normal conditions.It indicates that exogenous ALA treatment could allieviate the injuries caused by active oxygen through increasing the content of antioxidants and the activities of antioxidant enzymes in the cycle of AsA-GSH and decreasing the production rate of O2 ·-in pepper leaves under low temperature stress.