中文摘要：

用不同浓度的毒素处理抗感不同的大豆品种的根部，研究毒素对大豆细胞根部超微结构的影响。结果表明，较高浓度大豆疫霉根腐病菌毒素（稀释50倍，浓度为0．1794mg·mL^-1）处理抗感不同大豆品种的根部后，抗病品种和感病品种根部细胞内部结构均遭到了明显的破坏。适宜浓度的毒素（稀释100倍，浓度为0．0897mg·mL^-1）处理抗感品种根部后，抗病品种细胞内部结构基本上比较完整，而感病品种细胞内部结构已经发生了较大的变化，线粒体绝大多数都出现了空泡化。这说明只有在适宜浓度毒素处理下，才能在细胞超微结构上区分出抗感品种在抗性上的差异。本研究为揭示毒素在细胞水平的致病机理及寄主抗毒素的机理奠定了一定的理论基础。

英文摘要：

The roots of different soybean varieties with different concentration pathotoxin were treated to study the effect of pathotoxin on the cell ultrastructure of soybean root. The results showed that the inner structure of the root cells of both resistant and susceptible varieties were destroyed apparently when they were treated with high concentration （0.1794 mg·mL^-1） pathotoxin. However, when they were treated with the optimum concentration （0.0897 mg·mL^-1）, the inner structures of resistant varieties were mainly complete, but the susceptible varieties were changed largely and their mitochondria were mainly destroyed. It was concluded that only treated with the optimum concentration of pathotoxin could distinguish soybean varieties between resistant and susceptible to Phytophthora sojae. The research lays a fundation for revealing the pathologic and antitoxin mechanism on the cell level.