外源磷酸钠对枣果实活性氧和苯丙烷代谢关键酶活性及酚类物质积累的影响

以三星枣果实为材料，采后用0.5 mg/mL磷酸钠溶液浸泡处理10 min，研究其对室温贮藏期间枣果实活性氧和苯丙烷代谢关键酶活性和酚类物质积累的影响。结果表明，磷酸钠处理提高了整个贮藏期间枣果实过氧化氢含量，并且在贮藏第4 d和第10 d出现高峰，同时显著提高了贮藏第4~12 d和4~8 d果实抗坏血酸过氧化物酶和谷胱甘肽还原酶活性（P<0.05）。此外，磷酸钠显著提高了贮藏中后期果实苯丙氨酸解氨酶、4-香豆酰CoA连接酶和过氧化物酶活性，分别在贮藏第6、8和8 d出现高峰，是对照果实的1.18、1.16和1.40倍（P<0.05）。这些酶活性的升高显著促进了贮藏第6~12 d果实中总酚和类黄酮的积累，并且分别在贮藏第8 d和10 d达到高峰，是对照果实的1.38和1.29倍（P<0.05）。由此表明，采后外源磷酸钠处理能够激活枣果实活性氧清除酶的活性，增强苯丙烷代谢关键酶活性和酚类物质的积累，从而保持果实的抗病能力。

Effects of Exogenous Trisodium Phosphate on Activities of Key Enzymes of Reactive Oxygen Species and Phenylpropane Metabolism and Accumulation of Phenolic Compounds in Jujube Fruits

Jujube fruit (cv. Sanxing) were soaked in 0.5 mg/mL trisodium phosphate solution for 10 min after harvest to study its effects on key enzymes activities and phenolic compounds accumulation in reactive oxygen species metabolism and phenylpropanoid pathway during storage at room temperature. Results showed that trisodium phosphate promoted hydrogen peroxide content during the entire storage time and peaked at 4 d and 10 d. Additionally, trisodium phosphate treatment distinctly increased the activities of ascorbate peroxidase and glutathione reductase on days 4~12 d and 4~8 d of storage (P<0.05). Moreover, trisodium phosphate treatment increased the activities of phenylalanine ammonilyase, 4-coumarate/coenzyme A ligase and peroxidase in the middle and late storage period. A ligase and peroxidase activities in jujube fruit and peaked at 6, 8 and 8 d, respectively, which was 1.18, 1.16 and 1.40 times of those in control (P<0.05). The increase of these enzymes activities significantly accelerated total phenols and flavonoids accumulation in jujube fruit on 6~12 d and peaked on 8 d and 10 d, which was 1.38 and 1.29 times of those in control, respectively (P<0.05). These findings suggest that postharvest trisodium phosphate treatment can activate the activities of enzymes to eliminate reactive oxygen species, and enhance the activities of key enzymes and phenolic compounds accumulation in phenylpropanoid metabolism, thus enhancing disease resistance.