Study Of Nitrogen And Sulfur On Growth And Physiological Characteristics Of Formation For Yield And Quality In Chinese Spring Onion

In order to make clear the effect of nitrogen and sulfur on yield and quality in Chinesespring onion and explore their action mechanism, the variety of “Tianguang” was taken asmaterial to determine the influence of nitrogen and sulfur on plant growth, absorptioncharacteristics of mineral nutrition, and to evaluate the responses of key enzyme activity forN-S assimilation and exchange characteristics of H2O and CO2to sulfur by the method ofsplit-plot design. The research clarified the sulfur requirement of Chinese spring onion, andoffered the scientific foundation for its high-yield and high-quality cultivation and efficientfertilization. The chief results are showed as follows:1. The growth of each organs increased significantly with the solution N increasing, andthe higher change of yield was shown in N16.00mmol·L^-1, which was higher50.09%and22.46%than N4.00mmol·L^-1, N8.00mmol·L^-1respectively. Meanwhile the growth of allorgans also increased with solution S increasing, but the response was less sensitive than theresponse to N. The yields was higher while sulfur concentration were1.68mmol·L^-1,3.35mmol·L^-1levels, but it began to decrease when the sulfer concentration increased to the6.69mmol·L^-1. Although the main inclusion reacted differently in response to N, S levels, theorgano-sulfur compounds （EPY） increased significantly as N, S levels increasing. Moreover,combined application of N, S could significantly improve the Chinese spring onioncomprehensive quality. The interaction effect of nitrogen and sulfur was significant on growth,yield and quality of Chinese spring onion. Comprehensive analysis of results showed that, thenutrient solution containing N16.00mmol·L^-1, S3.35mmol·L^-1is the optimal to improvingthe growth, yield and quality of Chinese spring onion.2. The different N and S concentration had significant influence on the N, P, K, Scontents of each organ. With increasing of the solution N, S level, the dry matter and theabsorption of N, P, K, S of plant were advanced significantly, then decreased under the6.69mmol·L^-1of sulfur level （S4）. Though higher significantly than those of0.01mmol·L^-1（S0）,the dry matter and absorption of N, P, K, S with S4were lower than those of1.68mmol·L^-1（S1） by7.97%,16.37%,10.24%,9.06%and5.77%respectively. The effects of the N, Slevels and their interaction were significant on the N, P, K, S distribution of about all organsof Chinese spring onion, while the response to S was less sensitive than N. In conclusion, it isoptimal to improve the mineral nutrition status and the dry matter of Chinese spring onionthat the nutrient solution containing N16.00mmol·L^-1, S1.68³.35mmol·L^-1.3. The growth, the N and S content, the yield and the quality were improved by appropriately increasing the content of sulfur, while the yield and quality were reduced whenthe content of S level was over S4. The activity of ATP sulfurylase （ATPS） of leaves reducedwith the S level increasing, while the activities of o-acetylserine thiollyase （OASS）, nitratereductase （NR） and glutamine synthetase （GS） responded differently at each growth stage. Inthe initial stage, the higher S level increased the activity of NR, while it had no significanteffect on the activities of GS and OASS. In the later stage, increasing the S level appropriatelyenhanced the activities of OASS and GS, and reduced the activity of NR. Comprehensiveanalysis of results showed that, the nutrient solution containing S2.01mmol·L^-1is the optimalto improving the yield and quality of Chinese spring onion, and the yield was19.13%higherthan the CK.4. With the increase of applying sulfur amount, light use efficiency of leaf in Chinesespring onion was improved. The light use efficiency at the S level of2.01mmol·L^-1was thebest, and net photosynthetic rate and water use efficiency were increased by20.53%and11.46%5. The distribution of Sulfur in leaf decreased, but increased in root of cauloid withgrowth of Chinese spring onion. Sulfur distribution was stable in each organ among thetreatments, whose in root was significantly higher than other treatments, and was lower in leaf.Considering for the whole product forming stage, the absorption rate of sulfur was higher, andrequirement amount of sulfur was more in cauloid forming stage, so the stage was the mostkey stage to applying sulfur in Chinese spring onion.