小麦抗白粉病菌侵染乳突反应的超微结构研究

ULTRASTRUCTURAL STUDIES ON PAPILLA RESPONSE OF WHEAT AGAINST ATTACK BY ERYSIPHE GRAMINIS F.SP.TRITICI

本文利用透射电镜对小麦白粉病菌与不同抗性寄主相互作用中乳交反应的超微结构进行了系统研究。结果表明：在超微结构上乳突反应是所有侵染位点的共有特征；大量线粒体、多聚核糖体、高尔基体及各种小囊泡参与了小麦乳突的形成；进入乳突沉积区的小囊泡首先形成一个个结构致密的小颗粒，然后堆积起来形成乳突的内部主体和核心，其外围是细胞器解体后沉积的一层染色淡而均匀的无定形物质；乳突沉积开始的早晚、沉积速度及持续时间决定着乳突最终的形态结构特征及其抗性强弱；乳突抗性取决于乳突沉积的早晚与速度，而不是最终沉积量即乳突的大小。乳突抗性强的材料如KhaplixCc8总是在入侵栓进入前已形成较完整的半圆形乳突。而高感寄主如高加索，绝大部分乳突物质是在病菌入侵栓进入后沉积的，所形成的多是沿吸器颈部周围沉积的筒状元抗性乳突。病菌侵染点附近寄主细胞壁上过氧化物酶活性的增强是所有寄主的一种普遍反应，且无明显的抗侵入作用。

The ultrastructural studies on the papilla responses of wheat cultivars to the infection of Erysiphe graminis f. sp. tritci were conducted. The results showed that papilla response is a general defence reaction in all infection sites; Mitochondria, polyribosomes,endoplasmic reticulum,Golgi bodies and vesicules were involved in the papilla formation; After moving into the papilla formation zone,some vesicules changed into dense granulae and then piled up into the main and central part of papilla; While these organelle broke down,another thin layer of amorphous materials with light staining was produced around the central part of papilla;The presence of a performed papilla when penetration peg invaded was the key for papi1la-associated resistance (PAR),rather than the matural papilla size. The cultivars with high PAR usually produced semispherical papilla,and the low PAR ones had cylindrical or T-shaped papillae without resistance. The enhanced activity of peroxidases in host cell wall had no contribution to papillaassociated resistance.