title: Denitrification in soil amended with thermophile-fermented compost suppresses nitrate accumulation in plants.
abstract: NO                   (3)                             (-)                  is a major nitrogen source for plant nutrition, and plant cells store NO                   (3)                             (-)                  in their vacuoles. Here, we report that a unique compost made from marine animal resources by thermophiles represses NO                   (3)                             (-)                  accumulation in plants. A decrease in the leaf NO                   (3)                             (-)                  content occurred in parallel with a decrease in the soil NO                   (3)                             (-)                  level, and the degree of the soil NO                   (3)                             (-)                  decrease was proportional to the compost concentration in the soil. The compost-induced reduction of the soil NO                   (3)                             (-)                  level was blocked by incubation with chloramphenicol, indicating that the soil NO                   (3)                             (-)                  was reduced by chloramphenicol-sensitive microbes. The compost-induced denitrification activity was assessed by the acetylene block method. To eliminate denitrification by the soil bacterial habitants, soil was sterilized with γ irradiation and then compost was amended. After the 24-h incubation, the N(2)O level in the compost soil with presence of acetylene was approximately fourfold higher than that in the compost soil with absence of acetylene. These results indicate that the low NO                   (3)                             (-)                  levels that are often found in the leaves of organic vegetables can be explained by compost-mediated denitrification in the soil.
authors.affiliation: Graduate School of Horticulture, Chiba University, 648 Matsudo, Chiba, 271-8501, Japan.
authors.forename: Kazuto
authors.initials: K
authors.lastname: Ishikawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Ohmori
authors.forename: Hirokuni
authors.initials: H
authors.lastname: Miyamoto
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ito
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Kumagai
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Sonoda
authors.forename: Jirou
authors.initials: J
authors.lastname: Matsumoto
authors.forename: Hisashi
authors.initials: H
authors.lastname: Miyamoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Kodama
mesh_terms: D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D058440:Denitrification; D008969:Molecular Sequence Data; D009566:Nitrates / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry; D010944:Plants / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D009566:Nitrates; D012987:Soil