Abstract: In an incubation test of soil with glucose amendment,two kinds of nitrogenous fertilizer and three kinds of specific microbial biocides were applied,and the contents of soil NH₄⁺-N,NO₃^--N,glucosamine and muramic acid were measured to differentiate the relative contribution and timing characteristics of soil microbes in nitrogen immobilization.The results showed that penicillin and streptomycin decreased the transformation rate of NH₄⁺-N markedly,with more significant effects than actidione.The amount ratio of glucosamine to muramic acid after applying penicillin and streptomycin rapidly increased first,and tended to equilibrium then.With the application of actidione,the transformation rate of NO₃^--N decreased continuously,and the synthesis of glucosamine was inhibited,while penicillin and streptomycin had no significant effects on them.At the early stage of incubation,bacteria could rapidly immobilize both NH₄⁺-N and ,NO₃^--N with NH₄⁺-N preferred,while at the later stage of incubation,fungi were the dominant contributor to nitrogen transformation,and had much stronger ability of utilizing NO₃^--N than bacteria.

Key words: Nilaparvata lugens, Heat shock response, Endogenous enzymes of protective system, Lipid peroxides