马蹄莲软腐病自然抗性机制研究

Resistance mechanism of Zantedeschia aethiopica to soft rot

【目的】探索自然抗软腐病白花马蹄莲的抗性机制,为彩色马蹄莲软腐病防治及抗性品种培育提供技术支持。【方法】以高抗软腐病的白花马蹄莲为材料,感病的彩色马蹄莲为对照,利用透射电镜观察比较白花马蹄莲和彩色马蹄莲细胞壁的厚度;软腐病菌侵染后,比色法测定马蹄莲细胞壁降解酶果胶酶和纤维素酶活性,分光光度法测定抗性相关酶多酚氧化酶和过氧化物酶活性。【结果】白花马蹄莲细胞壁厚度是彩色马蹄莲的2~3倍;接种软腐病菌后,在白花马蹄莲组织中检测到果胶酶、纤维素酶两种酶活性均降低,而在感病彩色马蹄莲组织中酶活性升高;多酚氧化酶、过氧化物酶活性在不同抗性马蹄莲中均有升高,但白花马蹄莲比彩色马蹄莲升高更明显。【结论】白花马蹄莲通过厚实的细胞壁机械屏障、抑制软腐病菌分泌的纤维素酶和果胶酶活性防止细胞壁降解,以及迅速产生大量的酚类、醌类化合物杀死或抑制病菌等方式抵抗软腐细菌侵染。

[Objective]The resistance mechanism of Zantedeschia aethiopica born with resistance to soft rot were in- vestigated, in order to provide technological supports for controlling soft rot of colorful Zante^deschia hybdda and breeding new varieties. [Method]Z. aethiopica with resistance to soft rot was used as tested materials, colorful Z. hybrida suffering soft rot was used as control materials. The thicknesses of their cell walls were measured with transmission electron micro- scope. After materials were infected with soft rot pathogenic bacteria （Pectobacterium carotovora subsp. Carotovora）, the activities of cellulase and pectinase were determined by colorimetry, the activities of polyphenol oxidase and peroxidase were determined by spectrophotometry. [Result]The results showed that, the cell wall of Z. aethiopica was 2-3 times as thick as colorful Z. hybrida. After being inoculated with P. carotovora subsp. Carotovora, Z. aethiopica decreased in activi- ties of cellulase and pectinase, but colorful Z. hybdda increased in activities of cellulase and pectinase. The activities of polyphenol oxidase and peroxidase in both Z. aethiopica and colorful Z. hybrida were increased, but Z. aethiopica in- creased more obviously. [Conclusion]Z. aethiopica is resistant to soft rot, because it has thick cell wall and prevent cell wall from degrading via inhibiting activities of cellulase and peetinase, and produce quickly much phenols, quinones com- pounds to kill or inhibit P. carotovora subsp. Carotovora.