The effects of some commercial herbicides and
N-heterocyclic compounds structurally related to corn root constituents on N
2O-emitting soil bacteria were examined. In the N
2O emission assay, two N
2O-emitting eubacteria, the incomplete denitrifier
Pseudomonas sp. 10CFM5-1B and
Pseudomonas sp. 10CFM5-2D (both isolated from Andisol corn farmland in Hokkaido), were used. We found that methyl viologen dichloride (Paraquat®) at 2 µM significantly repressed N
2O emission by the active denitrifying bacteria. A corn antifungal secondary metabolite, 6-methoxy-2-benzoxazolone (MBOA), also repressed pseudomonad denitrifiers at a concentration of 10 µM. Other herbicides such as simazine (6-chloro-
N,
N′-diethyl-1,3,5-triazine-2,4-diamine) and amitrole (3-amino-1,2,4-triazole) accelerated N
2O emission by
Pseudomonas sp. 10CFM5-1B at 2 or 10 µM. It was thus shown that methyl viologen dichloride may have somewhat contributed to the repression of global warming by suppressing N
2O production in farmland soils. Some herbicides, including amitrole and other triazole-type chemicals, may instead have the potential to activate soil N
2O emission.
抄録全体を表示