EFFECT OF GRAFTING ON COLD TOLERANCE IN EGGPLANT SEEDLINGS

Low temperature treatment inhibited eggplant growth. We have studied the difference of cold tolerance with two grafted seedlings, one grafted onto ‘Taibyo’ and the other onto ‘Hiranasu’, and own-rooted seedlings (control) under low temperature (4°C) conditions. The results showed that chilling injury index and electrolyte leakage rate were increased in both grafted and own-rooted eggplant seedlings, but the increase was lower in grafted seedlings than own-rooted seedlings, especially in highly-tolerant rootstocks, and photosynthesis parameters were also decreased. Antioxidant enzymatic activities increased with low temperature treatment during the initial period, and then subsequently decreased. After 3 d of subsequent growing at normal temperatures, chilling injury index and electrolyte leakage rate were reduced, while the antioxidant enzymatic activities and photosynthesis parameters increased. During the 3-day recovery period, T2 showed higher capability of recovery while T1 and control showed relatively low recovery rate, thus showing significant differences between them. Therefore we concluded that grafting onto highly-tolerant rootstock could improve cold tolerance of eggplant significantly.