The Effects Of N Forms On Glutamine Synthetase And Soluble Protein Content In Different Genotypic Wheat

From 2006 to 2008,with the methods of pot experiment,the effects of N forms on GS activities,the soluble protein content and the expression of GS isoenzymes in different organs during different phase of different wheat cultivars were studied,the main results were as follows:By the hydroponic experiment with ddH₂O,the characteristics of GS expression and its activity in the first leaf of different genotypes wheat in the seeding stage were studied.The results showed that:the discrepancies on the expression of different genotypes were mainly in emergency stage and senescence stage.In 3 days after emergence of seedlings,the GS2 isozyme of strong-gluten yumai34 began to express, but there is no GS2 isozyme in medium-gluten yumai49 and weak-gluten yumai50;when the leaves has been senescenced,the discrepancy is remarkable on GS2 activity in different genotypes,it showed that yumai50＞yumai49＞yumai34.In the other stages,there are three types of GS isozymes,of them,GSx is not reported upto now,the discrepancy is not obvious in different genotypes.By the hydroponic experiment,the effects of N forms on the expression of GS isozymes and the GS activity in the first leaf of wheat in the seeding stage were studied,the result showed that the nitrate could induce the expression of GS2 isozyme in the early stage and restrain the expression in the later stage and both are regulated by genotypes,there were no expression of GS2 in wheat of strong-gluten and medium-gluten in the later stage,but the expression was obvious in the weak-gluten. The total GS activity had the similar tendency in different N forms and genotypes. Through the study on the total GS activity in the seedling stage,we got that urea could enhance the GS activity.By the pot experiment in field,simulating field,the effects of N forms on the expression of GS,GS activity and the soluble protein content in leaves,stems,kernels of special wheat were studied.The results indicated:the expression of GS isozymes in leaves of the seeding stage was little affected by N forms and genotypes,but affected greatly by different growth stages.There are three types of GS isozymes in all phases of seeding stage,but compared the other three phases,the GS activity was lower in the stage of one leave and one heart;the soluble protein content is higher in urea,and there are little differences in ammonium and nitrate.Compared to the expression of GS isozymes in the seeding stage,a new isozyme GSX2 was found in the leaves of anthesis,the ammonium has certain function in inducing the appearance of GSX2.It appears in anthesis and 7DAF only.There are also four types of isozymes expressed in the stem,the GS1 isozyme occupy the dominant position,the expression of other three kinds of isozymes is different in different stages and stems.Only GS1 isozyme expresses in the grain.From the florescence to 21DAF,GS activity in the same leaf and the same stem put up the same tendency which elevates first then reduces as a whole,and in 7 DAF or 14 DAF,the GS activity achieves to the highest.Through the comparison in soluble protein content to the leaves,stems and kernel,we get the conclusions that:adopted urea,the soluble protein content in kernel,stem and leaves of seeding stage in yumai 34 are the highest,but the middle in leaves after blossoming and the photosynthesis;For yumai49,the soluble protein content was little affected by N forms;adopted ammonium,the soluble protein content in kernel,stem and leaves of seeding stage in yumai50 are the lowest,but the middle in leaves after blossoming and the photosynthesis;i.e.for the wheat of the strong-gluten and the weak-gluten,the soluble protein content in kernel correspond to the soluble protein content in stem and leaves of seeding stage.