Effect of nitrogen application levels on nitrogen assimilation and grain protein components accumulation in strong gluten wheat was studied on the condition of high-yield.Results showed that with nitrogen supply increasing from 0 to 195 kg/hm2

nitrate reductase(NR) and glutamine synthetase(GS) activities in flag leaf were enhanced

the content of nitrogen and the amount of nitrogen accumulated in every organs increased

the content of monomeric protein

soluble glutenin and insoluble glutenin increased

the content of total protein and the ratios of soluble glutenin and insoluble glutenin to total protein increased

grain quality was improved.With excessive nitrogen supplied

NR and GS activity in flag leaf and total protein content in grain were not affected significantly

but the ratios of soluble and insoluble glutenin to total protein

and grain quality decreased.Nitrogen supplied from 105 kg/hm2 to 195 kg/hm2 can realize high yield and high quality simultaneously.