Effects of allelochemicals on activity of nitrate reductase

Study on the effects of allelochemicals such as trans \|ferulic acid ( t \|FA), benzoic acid (BA) and p \|hydroxybenzoic acid ( p \|HA), isolated from decomposed wheat straw on the activity of nitrate reductase at different concentrations of allelochemicals and different pH is described. t \|FA (0.26, 2.58 and 5.15 mmol/L) and BA (4.09, 8.19 mmol/L) showed a certain inhibition to the activity of nitrate reductase. The highest inhibition rate was 18.40%, but BA (0.41 mmol/L) and p \|HA (0.36, 1.81 and 3.62 mmol/L) showed stimulation, the more strong stimulation rate was 15.80%. At pH 6 condition, the activity of nitrate reductase was stronger inhibited than pH 7 and pH 8, but the mixture of 3 allelochemicals at pH 6 showed a stimulation. The mixture, however, at pH 7 and pH 8 showed some inhibition. It was found that there was a relationship between production of NO\+-\-2 and transformation of NO\+-\-3.