Abstract: The effects of nematode infection on reactive oxygen metabolism and the activities of related enzymes were investigated and compared between the seedling roots of nematode-resistant eggplant variety Solanum torvum and susceptible Solanum intergriflium in this study. The results showed that the production rate of superoxide anion radical (O₂^-·), the content of hydrogen peroxide (H₂O₂) as well as the activities of superoxide dismutase (SOD), catalase (CAT), chitinase (CHT) and β-1,3-glucanase (GLU) were rather higher in the resistant variety than susceptible one, while peroxidase (POD) activity acted contrarily in resistant and susceptible varieties. At the early stage of first infection, O₂^-·production rate, H₂O₂ content and the activities of CHT and GLU were increased rapidly in both varieties with the increasing rate higher in S. torvum than S. intergriflium. At the late stage of first infection, however, all above four indexes decreased. Interestingly, those indexes enhanced again at the late stage of second infection with a smaller increment than the first infection, especially in susceptible variety S. intergriflium. In addition, the activities of SOD and CAT in roots infected with M. incognita was remarkably decreased with the decreasing rate higher in S .torvum than S. intergriflium at the early stage of infection circle, while their activities were increased in both varieties at the later stage of infection circle. The changes of POD activity were contrary to that of SOD and CAT during the whole infection circle. Infection by M. incognita also led to a persistent increase in malondialdehyde content in roots with S. intergriflium being higher than S. torvum, suggesting that nematode infection aggravated the extent of membrane lipid peroxidation in roots, especially in susceptible variety.

Key words: Eggplant, Rootstock, Meloidogyne incognita, Reactive oxygen metabolism, Chitinase, β-1, 3-glucanase