Effect Of Cold Inducement On Chilling Tolerance And Leaf Ultrastructure In Cucumber Seedling

With the cucumber materials Shannong No.5(cold tolerance),Jinyou No.1(middle variety) and Jinchun No.4(cold sensitive),the effects of cold inducement on chilling tolerance of cucumber seedling in cold stress solution were studied. The inducement temperatures included 10℃/4℃(day/night),10℃/6℃(day/night) and 10℃/8℃(day/night),and major indexes comprised SOD activity, POD activity, CAT activity, content of Vc,root activity,electrolytical leakage, MDA content, soluble sugar content, proline content, soluble protein content, chlorophyll content, cholroplast ultrastructure and etc.. The main results were as follows:1. The lamina of cucumber seedling could maintain higher SOD, POD and CAT activity through cold acclimation with feasible temperature. Different treatment with different temperatures would lead to different results. In the mass, the impact of treatments, 10℃/6℃and 10℃/8℃,were better than the treatment 10℃/4℃.Different varieties, under the same inducement temperature, appeared similar change trend, however, in different extent. The cold-sensitive cucumber seedling had greater change.2. Through suitable cold inducement, the leaf of cucumber kept lower MDA content and electrolytic leakage. Such result would be appeared under the treatment with 10℃/6℃,2-3 days, and the treatment with 10℃/8℃,3-4days.3. Feasible cold inducement could increase the contents of soluble sugar, proline, soluble protein and Vc in cold stress. Contents of soluble sugar and proline appeared higher than CK in every treatment,including 10℃/4℃,10℃/6℃and 10℃/8℃,1-4days.For contents of soluble protein and Vc,it appeared the same trend under 10℃/6℃and 10℃/8℃.4 Through suitable cold inducement, the leaf of cucumber kept better cell membrane and chloroplast.5. In this study,for Shannong No.5,the best coldacclimation was 10℃/6℃for 3...