外源H2O2处理对马铃薯块茎干腐病的控制及其机理

【目的】研究外源过氧化氢（H2O2）处理对采后马铃薯块茎干腐病的控制效果及作用机理。【方法】在离体条件下通过扫描电镜、透射电镜等方法观察分析外源H2O2对马铃薯干腐病菌(Fusarium sulphureum)生长、菌落形态及其超微结构的影响，并以陇薯3号马铃薯为试材，分别在处理前后接种F. sulphureum，研究外源H2O2对病害的治愈和预防作用。【结果】外源H2O2处理强烈抑制了F. sulphureum的菌丝生长和孢子萌发且表现出明显的浓度效应，显著增大了F. sulphureum的细胞膜透性；扫描电镜观察发现H2O2处理过的F. sulphureum菌落分布不均匀，菌丝缠绕、扭曲在一起，部分菌丝出现断裂、塌陷等现象；透射电镜进一步观察到H2O2处理过的菌丝细胞壁加厚且内部出现空腔。体内试验结果表明，外源H2O2处理对处理前后接种F. sulphureum的马铃薯块茎干腐病均具有一定控制作用。【结论】H2O2不仅对病原物具有直接的抑制作用，还能有效提高马铃薯块茎组织的抗病性，因此H2O2可以作为一种具有潜力的天然防腐剂应用于马铃薯采后病害的控制。

Control of Exogenous H2O2 on Dry Rot of Potato Tuber and Possible Mechanism of Action

【Objective】The inhibitory effect of exogenous H2O2 against dry rot of potato and its mechanism of action were studied in this paper. 【Method】Mycelium growth, colonial morphology and hyphae ultrastructure of Fusarium sulphureum after treated with H2O2 were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in vitro test, and the curative and preventative effect of exogenous H2O2 on dry rot of potato tuber (Longshu No.3) inoculated with F. sulphureum pre- and post-etreatment were also evaluated.【Result】Spore germination and mycelium growth of F. sulphureum were strongly inhibited by exogenous H2O2 in a concentration-dependent manner. Besides, exogenous H2O2 could dramatically increase the membrane permability of F. sulphureum. Morphological changes such as asymmetrical, distorted, broken and wizened hyphae were observed by scanning electron microscopy (SEM) observation. Transmission electron microscopy (TEM) observation further documented these changes, irregularly thickened hypha cell walls and cavity could be observed. Results of in vivo test showed that exogenous H2O2 was effective in the control of dry rot of potato tuber inoculated with F. sulphureum pre- and post-etreatment.【Conclusion】 H2O2 can directly suppress the pathogen, and effectively increase the disease resistance of potato tuber tissue, thus it represent a potential fungicides for the integrated control of postharvest diseases in potato tuber.