title: Bleaching of leaf litter and associated microfungi in subboreal and subalpine forests.
abstract: Fungal decomposition of lignin leads to the whitening, or bleaching, of leaf litter, especially in temperate and tropical forests, but less is known about such bleaching in forests of cooler regions, such as boreal and subalpine forests. The purposes of the present study were to examine the extent of bleached area on the surface of leaf litter and its variation with environmental conditions in subboreal and subalpine forests in Japan and to examine the microfungi associated with the bleaching of leaf litter by isolating fungi from the bleached portions of the litter. Bleached area accounted for 21.7%-32.7% and 2.0%-10.0% of total leaf area of Quercus crispula and Betula ermanii, respectively, in subboreal forests, and for 6.3% and 18.6% of total leaf area of B. ermanii and Picea jezoensis var. hondoensis, respectively, in a subalpine forest. In subboreal forests, elevation, C/N ratio and pH of the FH layer, and slope aspect were selected as predictor variables for the bleached leaf area. Leaf mass per area and lignin content were consistently lower in the bleached area than in the nonbleached area of the same leaves, indicating that the selective decomposition of acid unhydrolyzable residue (recalcitrant compounds such as lignin, tannins, and cutins) enhanced the mass loss of leaf tissues in the bleached portions. Isolates of a total of 11 fungal species (6 species of Ascomycota and 5 of Basidiomycota) exhibited leaf-litter-bleaching activity under pure culture conditions. Two fungal species (Coccomyces sp. and Mycena sp.) occurred in both subboreal and subalpine forests, which were separated from each other by approximately 1100 km.
authors.affiliation: a Center for Ecological Research, Kyoto University, Otsu, Shiga 520-2113, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hagiwara
authors.affiliation: a Center for Ecological Research, Kyoto University, Otsu, Shiga 520-2113, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Matsuoka
authors.affiliation: b Department of Environmental Symbiotic Sciences, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Hobara
authors.affiliation: c Graduate School of Environment and Information Sciences, Yokohama National University, Yokohama, Kanagawa 204-8501, Japan.
authors.forename: Akira S
authors.initials: AS
authors.lastname: Mori
authors.affiliation: d College of Pharmacy, Nihon University, Funabashi, Chiba 274-8555, Japan.
authors.forename: Dai
authors.initials: D
authors.lastname: Hirose
authors.affiliation: a Center for Ecological Research, Kyoto University, Otsu, Shiga 520-2113, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Osono
mesh_terms: D001203:Ascomycota / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001483:Base Sequence; D001487:Basidiomycota / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D029662:Betula / Q000382:microbiology*; D003081:Cold Climate; D065928:Forests; D007564:Japan; D008031:Lignin / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D028222:Picea / Q000382:microbiology*; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D029963:Quercus / Q000382:microbiology*; D017422:Sequence Analysis, DNA
chemical_list: D008031:Lignin
keywords: champignons ligninolytiques; decomposition; diversité fongique; décomposition; elevational gradient; feuilles; fungal diversity; gradient altitudinal; leaves; lignin; lignine; ligninolytic fungi