| Eggplant is a crop in regions where the temperature is high, it always meets with low temperature stress in winter and spring greenhouse. Have already known now, vegetable grafting could enhance the ability to resist chilling, promote root absorption of nutrient and development and growth, which has been a lot of study in the melon. But there have been short of systemic research on relationship between the tolerance to chilling of eggplant and grafted eggplant. We had screened the chilling tolerance of eggplant rootstocks, they are Torvum, Hiranasu, Taibyo VF, Daidaro, and with 'Jinong 2000'as control. And we also studied relationship between the tolerance to chilling of eggplant and grafted eggplant. Additionaly, we carried through compared experiment of grafted eggplant planting in greenhouse. Our aims were to make clear the effect of different rootstocks on cold tolerance of scion and physiological mechanism on cold resistance of grafted seedlings, in order to offer theory thereunder for eggplant grafted planting in winter. The main results were as follows: 1. Through investigated and menstruated status of developing and growth of different rootstocks, we known that the main growth characteristic of different rootstocks. About Torvum and Taibyo VF, The roots were vigorous, the stem was straight and strong, the leaves were dark green, but the seed was hard to been collected. While Daidaro and Hiranasu were easy to collected seed, but their growth potentials were worse than Torvum's. 2. Via measured the changes of chilling injury index, electrolytic leakage, photosynthesis rate under low temperature stress (the temperature of day/night was 10℃/1 ℃) , we appraised cold tolerance of different eggplant rootstocks, and got a result of cold tolerance of test varieties by Subjection function comprehensive screening, the cold tolerance sequence was as follows: Hiranasu> Torvum> TaibyoVF> Daidaro> Jinong 2000. 3. Grafting could notably affect the chilling tolerance of eggplant in seedling stage. The results showed that indexes such as chilling injury index, electrolyte leakage rate, MDA content were all increased in grafted seedlings and 'Jinong 2000', but the above indexes increased slower in grafted seedlings, especially in 'Hiranasu', a high chilling resistant variety, they increased least. These indexes such as Chlorophyll fluorescence parameters and Photosynthesis parameters decreased, and the indexes such as SOD, POD, CAT activity increased in the primary period of treatment and then reduced. After three days recovery in normal temperature, chilling injury index, electrolyte leakage rate and MDA content fell, while SOD,POD, CAT activity, chlorophyll fluorescence parameters and photosynthesis parameters increased. Among the treated materials, the recovery capability of T2 (with Hiranasu as rootstock) was relatively better; and the recovery capability of T1 (with Taibyo as rootstock) and CK were relatively worse, and there was marked difference between them. So we could markedly improve cold tolerance of eggplant coins using stronger cold tolerance rootstocks. 4. The change of physiology and biochemistry, the relationship of the change and cold tolerance were studied in grafted eggplant seedlings root. The result showed that test materials are most sensitivity during treatment initial stages under the temperature 10℃/3℃(day/night). MDA content, Chilling injury index, POD activity, Pro content, and soluble protein content fast enhanced; but root activity, SOD activity, CAT activity rapidly decreased. With low temperature stress time delaying, Root respiration rate and osmotic adjustment were always reduced, while chilling injury index had increased...
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