Preliminary Study Of Waterlogging On Physiology Of Cucumber At Seedling Stage

Cucumber (Cucumis sativus L.) is one of the most widely cultivated fruit-vegetable, which plays an important role in the balanced anniversary supply and farmer income. In the middle and lower reaches of the Yangtze River, it often have raining sheets in spring and high temperature and rainy in summer. The hazards from waterlogging to cucumber cultivation in spring and summer are frequently. In fact, waterlogging has become a major environmental stress factor to cucumber open field cultivation. In this paper, Subordinate function value method (SFVM) was adopted to evaluate waterlogging tolerance of cucumber varieties at seedling stage and the effects of waterlogging stress and moving waterlogging stress, on the physiological index of leaves of two typical cucumber varieties at seedling stage were studied.The changes of related physiological characters during and after waterlogging of two cucumber varieties differed in the ability of waterlogging were investigated.Main results ars as follows:1.Responses of 31 cucumber cultivars to waterlogging were determined through pot culture experiment. Chlorophyll content, survival percentage and relative nodes treated with waterlogging for 7 days were introduced as the indexes of evaluation. The results of comprehensive evaluation by means of the subordinate degree comprehensive value of growth and physiological characters showed that the"Zao Er N"and"PW0832"had of the highest subordinate degree comprehensive value (∑( )X u) and the largest average value ( X ( u)) of these indexes among 31 cultivars under waterlogging, whereas"PW0801"had the lowest related indexes. It meant that"Zao Er N"and"PW0832" had stronger ability of waterlogging tolerance, whereas"PW0801"less ability.2.With two different cucumber varieties,"PW0801"used as susceptive and"PW0832"as tolenant, the effects of waterlogging stress on the physiological index of leaves at seedling stage were studied with pot culture experiment. The results showed that chlorophyll (chl) content, soluble sugar content, activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in cucumber leaves of"PW0801"decreased immediately , and declined rapidly after the third day under waterlogging stress. And in the early period (1-3) of waterlogging stress"PW0832"had not marked differences in contents of physiological characters between treatment and the control, and those contents of the characters above both in treatments and the control decreased rapidly after the third day. Malondiadehyde (MDA) content of"PW0801"increased rapidly after third day under waterlogging stress but no significant difference in the content of MDA was found in"PW0832"between traetment and the control in the stress.3.Also with two different cucumber varieties,"PW0801"used as susceptive and"PW0832"as tolenant cultivars, the effects of waterlogging stress on the physiological characters of leaves after having moved waterlogging at seedling stage were studied with pot culture experiment. The changes of waterlogging stress moved on the physiological characters of leaves, such as chlorophyll (chl) content, activity of POD, SOD and CAT, of"PW0832"got close very quickly to those of the control 3 days after the stress treatment. Very big differences of chlorophyll (chl) content, activity of POD, SOD and CAT in the leaves of"PW0801"were found between the stress and control during the whole restoring period. It suggest that marked differences in increasing of the contents of physiological characters after having moved waterlogging between two cultivars result in marked differences in the ability of resistantce to waterlogging stress.