Abstract:To understand the relationship between phenylpropanes metabolism in tomato rootstock seedlings and their resistance to Meloidogyne incognita, highly susceptible rootstock ‘Ls-89’ and highly resistant rootstock ‘Banzhen No. 2’ were selected as materials, planted in pots and inoculated with second instar larvae. The effect of M. incognita infection on the phenylpropanes metabolism in roots and leaves of tomato rootstock seedlings was studied. The results showed that the phenylalanine ammonia lyase (PAL) activity in ‘Banzhen No. 2’ and ‘Ls-89’ roots had not significant difference without inoculation, but polyphenol oxidase (PPO) activities in ‘Banzhen No. 2’ roots, PAL and PPO activities, total phenolic, flavonoid and lignin contents in ‘Banzhen No. 2’ leaves were significantly greater than those in ‘Ls-89’. After inoculated by M. incognita, PAL and PPO activities, total phenolic and flavonoid contents in roots and leaves of two rootstocks increased cyclically, while the lignin contents gradually increased, and their increases in ‘Banzhen No. 2’ were significantly greater than those in ‘Ls-89’. In an infection cycle, the peak values of PAL and PPO activities, total phenolic and flavonoid contents in ‘Banzhen No. 2’ roots were greater than those in ‘Ls-89’ for 28.45%, 71.47%, 54.24%, 91.71%, respectively, while those in ‘Banzhen No. 2’ leaves were higher than those in ‘Ls-89’ for 47.29%, 64.00%, 23.33%, 52.61%, respectively. Therefore, phenylpropanes metabolism activities were significantly enhanced infected by M. incognita, and those in ‘Banzhen No. 2’ were significantly higher than those in ‘Ls-89’, So, it was suggested that there were close relation between the phenylpropanes metabolism in tomato rootstock seedlings and resistance to M. incognita.