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以一年生‘福客’盆栽葡萄苗为试材,研究不同浓度(0、100、300、500和700 nmol·L~(-1))外源褪黑素对碱胁迫(85mmol·L~(-1)NaHCO_3)下葡萄生理生化指标的影响。测定葡萄叶片叶绿素含量、叶绿素荧光和叶片电导率及丙二醛、根系活力和活性氧代谢指标。结果表明,100、300和500 nmol·L~(-1)外源褪黑素处理均缓解了NaHCO_3胁迫对葡萄叶片叶绿素的降解和光系统(PSII)活性的抑制,显著降低了根系O_2~-产生速率和H_2O_2含量,提高了植株根系活力,以300 nmol·L~(-1)外源褪黑素处理效果最明显。外源褪黑素处理能够清除NaHCO_3胁迫下葡萄根中过量活性氧的累积,维持膜系统的完整性,提高根系活力,缓解NaHCO_3胁迫对葡萄叶片叶绿素的降解以及PSII活性的抑制。
A pot experiment was conducted to study the effects of different concentrations (0, 100, 300, 500 and 700 nmol·L -1) of exogenous melatonin on alkali stress (85 mmol·L ~ (- 1) NaHCO_3) grape physiological and biochemical indicators. The contents of chlorophyll, chlorophyll fluorescence and leaf conductivity, MDA content, root activity and reactive oxygen species metabolism in grape leaves were measured. The results showed that exogenous melatonin treatment at 100, 300 and 500 nmol·L -1 all alleviated the inhibition of chlorophyll degradation and PSII activity of grape leaves under NaHCO 3 stress, and significantly reduced the root O 2 - production H 2 O 2 and H 2 O 2 increased the root activity of the plants. The treatment with exogenous melatonin at 300 nmol·L -1 was the most effective. Exogenous melatonin treatment could eliminate excessive accumulation of reactive oxygen species (ROS) in grape roots under NaHCO 3 stress, maintain the integrity of membrane system, increase root activity and alleviate the degradation of chlorophyll and PSII activity of grape leaves under NaHCO 3 stress.