Aims: To isolate aerobic denitrifying bacteria to enhance nitrate and nitrite removal from aquaculture system.

Change of nitrate reductase activity and nitrite content during jiangshui celeries fermentation;

Research progress on nitrate reductase of sugar beet;

Effect of different respiratory inhibitors on the nitrate reductase activity;

Changes of nitrate reductase activity of dark tobacco and tobacco-specific nitrosamines accumulation during air-curing;

Under high and low nitrogen fertilizer application level,eight wheat cultivated mainly in Henan were selected to study the relationship between nitrate reductase activity(NRA) in flag leaf and root and N efficiency after flowering.

A two years study indicated that nitrate reductase activity(NRA)in vivo sharply decreased after harvest.

The results were as the follows:comparing with the control,the activities of NR,POD,SOD in the leaves at green bud stage,as well as the contents of chlorophyll and soluble protein decreased with the rise of KT content;the flower diameter did not change obviously,stalk diameter was thicker and stalk height was high.

Studies were carried out on influences of replacement of 25% NO~-_3-N with NH~+_4-N in nutrient solution(enhanced ammonium nutrition) on tomato growth and activity of such key enzymes in N assimilation and organic acids as nitrate reductase(NR),glutamine synthetase(GS)and phosphoenolpyruvate carboxylase(PEPcase)in tomato leaves and fruits sampled at different developmental stages.

The result showed that all the treatments can improve the content of chlorophyll, solar sugar, enhance the activity of NR, and reduce the relative conductivity.