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At present, many countries are paying more attention to nitrate which accumulates in vegetable. A lot of experiments in animal have showed that the nitrate can be reduced into nitrite by bacteria, which is not only poisoning to the human body and causes to methemoglobin symptom hypoxia disease, can also lead to cancer, such as digestive system. Several studies have showed that nitrate intaken by body is 81.2% from vegetables. The nitrate is very easily enriched in vegetable, especially for the non-heading Chinese cabbage. So it’s of great significance for studying nitrate accumulate in non-heading Chinese cabbage.Three varieties were used as materials, which were Zaoshenghuaguan, Shuiyuepakchoi and Heiyexiang pakchoi, respectivly. In this study there were three sunlight levels (10%,50% and 100%) and three temperature levels (20℃/10℃, 5℃/15℃and 35℃/25℃). Effect of interaction temperature, light with fertilization and varieties on nitrite, NRA, root activity and yield of non-heading Chinese cabbage were studied.The result showed:As temperature and fertilization interaction, the nitrate content was no significant difference. The same as interaction among temperature, fertilization and varieties. This means that the nitrite accumulation was affected not only by varieties, but also by temperature. And when temperature increasing properly, the nitrite content could be decresed in leaf.The average yield of non-heading Chinese cabbage single plant significantly increased and the nitrite content decreased with light intensity increasing. Interaction of light and variety, different variety had differet action on nitrite content and yield. As light intensity rised from 50% to 100%, the nitrite content of Shuiyue pakchoi, Zaoshenghuaguan decreased by 14.39%,35.2%, respectivly.Studying on interaction temperature, light intensity with varieties and fertilization amount on accumulation of nitrate in non-heading Chinese cabbage, the date showed that temperature and light affected content of was different, effect of temperature on accumulation of nitrate in the non-heading Chinese cabbage mainly by altering root activity, growth potential and nitrate reductase activity,and the relevance were 0.456、0.695 and 0.468, respectively. meanwhile, light intensity by affecting nitrate reductase activity (r=0.729**) and growth potential (r=0.658**) to regulate nitrate of the non-heading Chinese cabbage. Interaction of three factors, different of fertilization levels on nitrate content and nitrate reductase activity of the non-heading Chinese cabbage were no significant difference but the yield was significant difference, indicated that fertilization can not directly affect accumulation of nitrate in non-heading Chinese cabbage.In production, many environmental factors are non-independent existence, by increasing light intensity can raise the ambient temperature, which i contributed to promote plants to use effectively nutrients and improve the photosynthetic efficiency.
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