Effect Of NO₃^- Stress On Physiological And Biochemical In Cucumber Seedlings Under Different Light Intensity

Under the condition of solar glasshouse vegetable production in winter-spring season, low temperature, poor light and salt stresses constitute the main adverse circumstances factor of influencing vegetable yield and quality,and usually occur simultaneously. Currently there are many studies about the influences of salt stresses and light in plants,but most of them regarded single factor, there are fewer investigations about the two factor of salt stresses and light, and most of the research regarded NaCl as means of researching, but secondary salinization soil in the protected farmland is greatly different from seaside or inland, the main cation and anion are Ca²+ and NO₃^-. In this research cucumber was selected as experimental material to study the physiological and biochemical of cucumber by the way of banding salt stresses and light together, in order to establish theory basis to cucumber production. The main results obtained were presented as follows:1 NO₃^- stress inhibited cucumber seedlings growth, increased photosynthesis pigment content, decreased net photosynthetic rate (Pn) and stomatal conductance (Gs). Compare to high light intensity, low light intensity alleviate cucumber seedlings growth inhibition and the decrease of net photosynthetic rate and stomatal conductance and promoted the increment of photosynthesis pigment content2 NO₃^- stress increased cucumber seedlings SOD, decreased POD,CAT,APX of leaves, but increased POD,APX of root, Compare to the acuity change of high light intensity, low light intensity was more calm, low light intensity reduce the difference between NO₃^- stress and comparison.3 NO₃^- stress decreased cucumber seedlings GS,GOGAT,GDH, compare to high light, low light intensity alleviate the harm affection of NO₃^- stress to the nitrogen metabolism in cucumber seedlings.