Characteristics Of Nitrogen Metabolic And Nitrogen Transformation In Rhizosphere Soil Of Different Wheat Cultivars

In order to improve the nitrogen use efficiency of different wheat cultivars, we use hydroponic experiments to study the content of free amino acids, soluble protein content and glutamate synthesize(GS) activity of the first leaf in different periods of wheat as well as the root activity of Yumai 34,Yumai 49 and Yumai 50.We also study the nitrogen losses characteristics of different wheat cultivars. At the same time we study the characteristics of nitrogen assimilation and activities of microorganisms and enzymes in rhizosphere soil by pot experiment.The hydroponic experiments results showed that:the nitrogen losses percentage of wheat cultured by deionized water is that Yumai49> Yumai34> Yumai50.This may be realated with the low GS activity of the first leaf in Yumai49. The nitrogen losses percentage of wheat cultured by nutrient solution showed that Yumai50 are the most,followed by Yumai 34 and Yumai 49 are the least.The root activities of Yumai50 is low compared with the other two, this may affect the absorb of nutrient elements, affect the assimilation of nitrogen. The soluble protein content and GS activity of wheat cultured in nutrient solution are higher than the wheat cultured by deionized water; the free amino acid content of wheat cultured in nutrient solution is lower than that cultured in deionized water.The pot experiment showed that:the GS activities of leaf first rised and then decreased with the plant growth, the GS activity of Yumai 34 achieved a maximum on flowering stage, but that of Yumai 49 and Yumai 50 achieved a maximum on the 14th day after anthesis; the content of free amino acids substantially decreased then rised, and all cultivars achieved a maximum on the 14th day after anthesis, the content of Yumai 50 is the highest; except the jointing stage, the soluble protein content showed that Yumai 34> Yumai 50> Yumai 49; The SPAD value of yumai49 is higher than Yumai34 and Yumai50.The denitrifying bacterial activity of rhizosphere soil was low on the flowering stage, in other periods it showed that Yumai 34> Yumai 49> Yumai 50. There were significant differences of nitrification activity among different cultivars on the jointing stage and the 28th day after anthesis; the nitrozation activity of Yumai 34 and Yumai 49 increased slightly on flowering stage, but Yumai 50 reached the lowest value. The activities of protease and urease were high in the late stage. The ammonium and nitrate nitrogen content of rhizosphere soil of different cultivars had significant differences only in the jointing stage.The soil moisture content in rhizosphere soil gradually delayed and achieve the lowest on the 28th day after anthesis.Different wheat cultivars have its own characteristics of nitrogen assimilation and activities of microorganisms in rhizosphere soil. The nitrogen metabolic of wheat have relationship with the transformation of nitrogen in soil. The next study is how to use right measures to make the microorganisms and enzymes in soil to improve the growth and development of wheat.