[Effects of methyl bromide fumigation on community structure of denitrifying bacteria with nitrousoxide reductase gene (nosZ) in soil].

OBJECTIVE

We studied the effect of methyl bromide fumigation on soil edaphic denitrification.

METHODS

We adopted nosZ-PCR-RFLP (restriction fragment length polymorphism) method, nosZ-MPN-PCR (Most-Probable-Number- PCR) counting method and soil nitrate elimination rate method, to explore the effect of methyl bromide fumigation on community structure, quantity and activity of denitrifying bacteria in soil.

RESULT

After methyl bromide fumigating soil for 100 d, soil denitrification did not change obviously (P > 0. 05). Margalef index, Shannon-wiener index and Evenness index had no significant difference (P > 0.05) in nosZ denitrifying bacterial communities between fumigated soil and the control. There were Rhodopsendomonas, Pseudomonas fluorescens, Herbacspirillum, uncultured bacterium partial in both of them. However, Azospirillum, Rhizobium melibei, Nitrosospira multiformis were exclusively found in the control, and Uncultured Azospirillum sp, Mesorhizobium sp were in fumigated one. Moreover, the number of denitrifying bacteria in the control resolved by nosZ-MPN-PCR (Most-Probable-Number-PCR) was 1.4 times higher than that of the fumigated one.

CONCLUSION

After 100 d fumigating soil, the composition of nosZ denitrifying microbial community and the population of denitrifying bacteria changed. Furthermore, there was no difference in denitrification between the fumigated soil and the control.