| Enrichment of vegetables in the excess of NO3-potential factors become a danger tohuman health has been a consensus. It is generally believed that nitrate absorption isgreater than the reduction is the main cause of nitrate accumulation. Studies and productionat home and abroad, applying generally take the control of nitrogen content, the reasonableratio of NPK fertilizer, nitrification inhibitors to suppress the soil nitrification, and useother forms of nitrogen substitution method of phosphorus and nitrogen to reducevegetable nitrate accumulation in the body. Although blindly limit nitrogen fertilization cansignificantly reduce nitrate accumulation, slow the growth and decrease the nitratereduction of vegetables because of lack of nitrogen. Recently, we have explored somepositive measures for nitrate reduction, including exogenous carbon source, glutamic acidand salicylic acid to chinese chive, and we have been to reduce the nitrate accumulation getsignificant results. At present, the method of active reduces nitrate accumulation in plantsremains to be further explored.Modern plant physiological and biochemical studies have shown that N and Selements in physiological metabolism and protein synthesis in particular to show highlevels of collaborative relationship.Therefore, this study on nitrate accumulation in Chinese chive production and soilsulfur element missing problem, chinese chive, for testing materials, leeks spraying on theleaf in different growth periods and soil application of different types, differentconcentration or doses of inorganic sulfur (S, inhibition of nitrification) processing, testanalysis of plant growth dynamic change, the dynamic change of nitrate accumulation,screening effective reduce the Chinese chive nitrate accumulation types and application ofkey technologies of inorganic sulfur. On this basis, the test and analysis of nitrate reductionin the process of assimilation, the key enzyme activity and nutrient content, the mainresults are as follows:1. Inorganic sulfur in chinese chive lower nitrate accumulation effect to show, theeffect of nitrate accumulation of spraying on the leaf is more quick than soil application,unsaturated valence state better than saturated effect of valence state characteristic, also isassociated with the nitrogen levels. The most obvious to reduce nitrate accumulation is soil fertilization with4g·m-2sulfur and foliar spraying with10mmol·L-1NaHSO3.2. The most significant effect on reducing nitrate accumulation was found on the20thd when the4g·m-2sulfur was applicated of chinese chive grown in middle nitrogen level.The sulfur respectively made for urea in nitrogen source and organic fertilizer processingcompared with nitrate content was reduced by23.73%and23.73%. The most significanteffect on reducing nitrate accumulation was found on the10th d when the10mmol·L-1NaHSO3was sprayed on the leaves of chinese chive grown in middle nitrogen level.Nitrogen source urea and organic fertilizer processing for a drop of29.63%and31.38%respectively3. In the middle nitrogen level, key enzymes of nitrogen metabolism Nitrate reductase(Nitrate reductase, NR), Glutamine synthetase (Glutamine synthetase, GS), Glutamatesynthase (Glutamate synthetase, incorporated) and Glutamate pyruvate transaminase,Glutamic, pyruvic transaminase, GPT) activity were significantly enhanced in the20thdwith soil application of4g·m-2sulfur and in the10thd spraying on the leaf with10mmol·L-1NaHSO3. At the same time, Chinese chives and utilization rate of nitrogen andsoluble sugar, total nitrogen content of Vc, soluble protein, free amino acids and othernutrients content also increased significantly.4. The chlorophyll content of chinese chive is obviously increased in the20thd withsoil application of4g·m-2sulfur and in the10thd spraying on the leaf with10mmol·L-1NaHSO3, the increase of chlorophyll content could improve the chlorophyll of light energyabsorption. Photosynthesis improved for reduction of nitrate assimilation provide moreabundant energy.By the comprehensive analysis showed that inorganic sulfur may be through thetwo-way mutual adjustment leek nitrogen metabolism to reduce the nitrate accumulation.On the one hand, improve the activity of key enzymes of nitrogen metabolism, promote theefficiency of the nitrogen metabolism, contributed to the reduction of nitrate assimilationdirectly; on the other hand, the chlorophyll content was improved, which promot thephotosynthesis, thus promote the transformation of nitrate indirectly. |