1College of Horticulture，Northeast Agricultural University，Harbin 150030，Heilongjiang，China；2Liaoyang City Academy of Agricultural and Forestry Science，Liaoyang 111000，Liaoning，China
Abstract：The effects of gradually decreasing temperature stress（decreasing temperature by 1 ℃ per hour）on the cold damage index and enzyme activity protection in cucumber （Cucumis sativus L.）seedlings were studied with‘Jinyou No.1’as experiment material．The result showed that the cold damage degree of cucumber seedlings was reduced by gradually decreasing temperature stress，compared with directly decreasing temperature stress and the cold damage degree index was remarkably decreased．The protective enzymes SOD，POD, and CAT activity in cucumber seedlings were significantly boosted, then descend along with low temperature stress．
