外源NO对核桃幼苗叶多酚及其抗氧化活性的影响

NO作为氧化还原信号分子在植物抵抗干旱、寒冷胁迫中扮演着重要角色。为探究外源NO对核桃叶多酚积累及其相关抗氧化酶活性影响，揭示外源NO的施用对核桃潜在抗逆功能的影响，以1年生‘香玲’核桃幼树为材料，采用不同浓度硝普钠（SNP）对其进行处理，测定核桃叶总多酚含量及其抗氧化活性以及核桃抗氧化酶（SOD、POD等）活性。结果表明，通过外源NO供体SNP处理后，核桃叶总多酚含量及其抗氧化活性均有一定提升，在SNP浓度为150 μmol/L时，核桃叶总多酚含量达最高值，DPPH·和ABTS·的清除率达最高值，核桃抗氧化酶（SOD、POD等）的活性同时增强，变化趋势与多酚积累一致。可见适宜浓度SNP能正向调节核桃叶片多酚积累，提高植株抗氧化能力，为今后施用外源NO在核桃抗逆生产中的广泛应用提供理论依据。

Effect of Exogenous Nitric Oxide on Polyphenols and Antioxidant Activity of Walnut Seedling Leaves

Nitric oxide (NO),as a redox signal molecule,plays an important role in the resistance of plants to drought and cold stress.In order to explore the effect of exogenous NO on walnut leaf polyphenol accumulation and related antioxidant enzyme activities,and reveal the influence of exogenous NO on walnut’s potential stress resistance,in the current study,the annual walnut saplings of a walnut cultivar ’Xiangling’ were treated with different concentrations of sodium nitroprusside (SNP),and the total polyphenol content and antioxidant enzyme (SOD,POD,etc.) activities in walnut leaves were determined.The results showed that the total polyphenol content of walnut leaves and its antioxidant activity increased to a certain extent after SNP treatment.When the SNP concentration was 150 μmol/L,the total polyphenol content of walnut leaves reached the highest value,the clearance rate to DPPH· and ABTS· reached the maximum values,and the activity of walnut antioxidant enzymes (SOD,POD,etc.) increased at the same time,the change trend was consistent with the accumulation of polyphenols.These results suggested that the appropriate concentration of SNP could positively regulate the accumulation of polyphenols in walnut leaves and improve the plant’s antioxidant capacity.This study will provide a theoretical basis for the extensive application of exogenous NO in walnut resistance production in the future.