水杨酸诱导枣树抗缩果病研究

Induction of systemic resistance against jujube fruit shrinking disease with salicylic acid

为明确水杨酸(SA)对枣树缩果病抗性的诱导作用,应用水杨酸(SA)及其添加KH2PO4和微量元素的溶液(SA+),采用喷施和输液方式处理感染缩果病枣树,开展了SA诱导枣树抗缩果病及抗病相关酶活性的研究。结果表明:SA处理对于枣缩果病有防效,1mmol/L喷雾处理时防效不明显,3mmol/L、5mmol/L的防效均与对照有显著性差异,SA+喷雾施用无防效;SA输液处理对枣缩果病的防效明显,SA+输液处理无防效。对不同处理枣果实中苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)、过氧化物酶(POD)活性进行测定,发现各处理样品PAL活性均未出现显著性差异;SA和SA+2种药剂不同浓度经过喷施处理,枣果样品PPO活性均未出现显著性差异,而通过输液处理枣果样品的PPO活性显著增强;采用3mmol/L SA输液,以及喷施1、3和5mmol/L均使枣果样品的POD活性显著增加,而SA+处理与对照相比均未出现差异显著性。可见,SA通过输液比喷雾更能促进枣树吸收,并提高枣树抗缩果病的能力,POD酶活性增强是枣树抗病性提高的重要指标。

To understand the roles of salicylic acid （SA） in induction of systemic resistance against jujube fruit shrinking disease （JFS）, SA and SA plus KH2PO4 and half micronutrients from MS medium （SA＋） were investigated to test their inducing abilities by spraying and infusion, and the changes of enzymatic activities related to plant disease resistances, i.e. peroxidase （POD）, poiyphenoloxidase （PPO） and phenyanine ammonialyase （PAL） were determined as well. The results showed that SA at 3--5 mmol/L could effectively induce systemic resistance against JFS and significantly reduce the percentage of diseased jujube fruits through spraying, but 1 mmol SA treatment showed no significant effect. It was observed that SA at optimal concentration had better inducing effects when it was infiltrated into the xylem tissue of jujube stem compared with spraying. Neither spraying nor infusion of SA＋ was capable of inducing systemic resistance against JFS. There was no significant difference among all the samples, collected after application of SA, for the change of PAL activities, but PPO activities in jujube showed significant difference when SA was infused into jujube stem. The activity of POD was significantly higher than that of control both by infusion with 3 mmol/L SA and by spraying SA at 1, 3 and 5 mmol/L, but no significance was detected with the application of SA＋. It can be concluded that stem infusion could improve the absorption of SA solution, SA application could significantly increase its resistance against jujube fruit shrinking disease, and POD activity is an important indicator for jujube disease resistance.