中文摘要：

【目的】探讨壳聚糖处理对脐橙果实抗病性的诱导效果，以及对果实内源水杨酸（SA）含量和活性氧代谢的影响。【方法】以脐橙果实为试材，采收后不同时间用2％壳聚糖溶液浸泡处理1min，测定壳聚糖处理对果实青霉病抗病性、水杨酸含量和活性氧代谢的影响。【结果】壳聚糖处理显著降低脐橙果实接种发病率的升高和病斑直径的扩展（P〈0．01），诱导2d时抗病效果最显著。2％壳聚糖处理果实果皮内游离态sA和过氧化氢（H2O2）含量明显高于对照果实；壳聚糖处理提高脐橙果实过氧化物酶（POD）、谷胱甘肽还原酶（GR）活性，抑制过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）活性，延缓果实还原型抗坏血酸（Ash）含量的下降，引起诱导初期还原型谷胱甘肽（GSI）的积累。【结论】2％壳聚糖处理可以诱导脐橙果实对青霉病的抗病性，其诱导的脐橙果实抗病反应涉及果皮内SA含量和活性氧水平的调节以及抗氧化酶活性的变化。

英文摘要：

[Objective] The effects of chitosan treatment on the disease resistance, the content of salicylic acid （SA） and the active oxygen metabolism of navel orange fruit （Citrus sinensis L. Osbeck） cv. Newhall were investigated [Method] After harvest, navel orange fruits were treated with 2% chitosan solution for 1 rain in different days. The influences of chitosan treatment on the disease resistance of navel orange to Penicillium italicum, the content of SA content and materials related to active oxygen metabolism in navel orange＇s peel were detected. [Result] The inoculated disease incidence and the expansion of lesion diameter of navel orange were significantly reduced by 2% in chitosan treatment （P〈0.01）, and fruits dipped into 2% chitosan 2 days before inoculation shown the most significant effect. Two percent treatment effectively enhanced the activities of peroxidase （POD）, glutathione reductase （GR） and the levels of free SA and hydrogen peroxide （H2O2）, while inhibited the activities of catalase （CAT）, ascorbate peroxidase （APX） and the decreased the ascorbate （AsA） content. Besides, the accumulation of glutathione （GSH） was sharply induced in the early time after treatment. [Conclusion] Two percent chitosan treatment could induce the disease resistance of Navel orange to the infection of Penicillium italicum, and these resistance reactions relate to the regulation of the content of SA, the levels of active oxygen metabolism and the changes of antioxidant enzymes.