Investigated of anti oxidant activity, chlorophyll fluorescence,amount of chlorophyll (a, b) and Carotenoids leaves Influenced by the flooding and diffrent levels of nutrition a soybean (Glycine max

er to investigated the effect of flooding, different nutrition levels an anti-oxidant characteristics, chlorophyll fluorescence, amount of chlorophyll (a, b) and Carotenoids leaves Soybean (Glycine max (L.) Merr), cultivar DPX research at the University of Agricultural Sciences and Natural Resources, Gorgan, in a completely randomized design to factorial arrangement with three replications was done in 2012. The experiment consists of three levels of nitrogen nutrition treatments factor (1 – non inoculation plus nitrogen fertilizer 2 - inoculated with bacteria (Bradyrhizobium japonicum) 3 - non inoculation without fertilizer) and flooding stress in four levels (0, 5, 10 and 15 days). Maximum enzyme activity of Ascorbate peroxidase was in first treatment (non inoculation plus nitrogen fertilizer) in flooded on day zero. Peroxidase and Catalase enzyme activity at all levels of the nutrition flooded up to 5 days at 10 and 15 days showed an increasing trend, but the flooding had reduced the activity of two enzymes. Flooding during the production of Ascorbic acid (from 0 to 15 days) was increased at all three levels of nitrogen nutrition. The amount of chlorophyll fluorescence, amount of chlorophyll (a, b) and Carotenoids showed a decreasing trend during flooding. Reduce the amount of chlorophyll a, was much more chlorophyll b. overall to intensity increases flooding increased activity of free radical resistance mechanism fall continues, the more damage will be flooded with increasing time.