The invention relates to a special 
plant expression vector pH2-35S-PrbcS-GS1 which comprises an 
arabidopsis thaliana 
cytoplasm glutamine synthetase 
gene GS1 and can improve the 
utilization rate of a 
plant nitrogen element. A method of RT-PCR is used for 
cloning the GS1 
gene from the 
arabidopsis thaliana of a model 
plant, a photoinduction type promotor (the promotor of a a 
small subunit Rubisco) is used for controlling the excessive expression of the GS1 
gene in a plant leaf and a leaf disc 
conversion method is used for transferring the GS1 gene into a pPZP221-PrbcS-Dof1 type 
transgene tobacco. An experiment result shows that the GS1 gene can be normally transferred in the 
transgene tobacco; under the 
nutrition condition of 
low nitrogen and the growing conditions of indoor 
irradiation for 24 hours of 2000
LUX and 25 DEG C, the growing situation of the plant transferred with the 
single gene of Dof1 is (the expression of the gene is controlled by the photoinduction type promotor Prbcs) is a little better than that of a contrast tobacco (a 
wild type without 
transgene); after being transferred under the natural growing condition of a green house, the growing situation of the tobacco which is simultaneously transferred with the GS1 gene and the Dof1 gene shows remarkable growing advantages than that of the contrast plant; and therefore, simultaneously and excessively expressing the GS1 gene and the Dof1 gene, can improve the efficiency of the GS / GOGAT (
glutamine synthetase  / 
glutamic acid synthetase) approaches in the leaf more extensively, thereby improving the 
utilization rate of the plant 
nitrogen element. The vector can be broadly applied to the molecule breeding of crops, improving the 
utilization rate of the plant 
nitrogen element thereof and the durability to the 
nutrition condition of 
low nitrogen and being capable of obtaining a higher yield under the conditions of applying less fertilizers and even not applying the fertilizers.