Variation of protective enzyme's activity in grafted and self-rooted cucumber seedlings under salt stress

The protective enzymes activities in grafted and self-root cucumber seedlings under 25,50,75 mmol/L NaCl stress were studied using Yunnan black seed pumpkin as the stock and Jinlu NO.4 cucumber cultivar as the scion.And the germinative ability of Yunan black seed pumpkin and cucumber seeds under stress was studied too.The result showed that Yunan black seed pumpkin maintained a higher germination rate,and that of cucumber dropped signifcantly.Both SOD and CAT activity enhanced along with NaCl concentration increasing.The activity of SOD and CAT in seedlings leaves of black seed pumpkin keeped the highest level all along and the two indexes of grafted cucumber were close to the corresponding levels in black seed pumpkin.Self-root cucumber had the lowest level.The SOD activity of each treatment presented a trend of decreasing.It showed that the grafted cucumber performed better than the self-root cucumber at seedlings stage.