title: How interacting fungal species and mineral nitrogen inputs affect transfer of nitrogen from litter via arbuscular mycorrhizal mycelium.
abstract: In the karst landscape, widespread in the world including southern China, soil nutrient supply is strongly constrained. In such environments, arbuscular mycorrhizal (AM) fungi may facilitate plant nutrient uptake. However, the possible role of different AM fungal species, and their interactions, especially in transferring nitrogen (N) from litter to plant, is poorly understood. We conducted two microcosm experiments to investigate the role that two karst soil AM fungi, Glomus etunicatum and Glomus mosseae, play in the transfer of N from decomposing litter to the host plant and to determine how N availability influences these processes. In experiment 1, Cinnamomum camphora tree seedlings were grown in compartments inoculated with G. etunicatum. Lolium perenne leaf litter labeled with δ15N was added to the soil in unplanted compartments. Compartments containing the δ15N labeled litter were either accessible to hyphae but not to seedling roots or were not accessible to hyphae or roots. The addition of mineral N to one of the host compartments at the start of the experiment significantly increased the biomass of the C. camphora seedlings, N content and N:P ratio, AM mycelium length, and soil microbial biomass carbon and N. However, significantly, more δ15N was acquired, from the leaf litter by the AM hyphae and transferred to the host when mineral N was not added to the soil. In experiment 2, in which C. camphora seedlings were inoculated with both G. etunicatum and G. mosseae rather than with G. mosseae alone, there was a significant increase in mycelial growth (50.21%), in soil microbial biomass carbon (417.73%) in the rhizosphere, and in the amount of δ15N that was transferred to the host. These findings suggest that maintaining AM fungal diversity in karst soils could be important for mediating N transfer from organic material to host plants in N-poor soils.
authors.affiliation: Forestry College, Research Center of Forest Resources and Environment of Guizhou Province, Guizhou University, Huaxi, Guiyang, People's Republic of China. hyj1358@163.com.|Laboratory of Quantitative Vegetation Ecology, Institute of Botany, The Chinese Academy of Sciences, Xiangshan Nanxincun, Beijing, People's Republic of China. hyj1358@163.com.
authors.forename: Yuejun
authors.initials: Y
authors.lastname: He
authors.affiliation: Systems Ecology Department of Ecological Science, Faculty of Earth and Life Sciences, VU University (Vrije Universiteit) Amsterdam, De Boelelaan 1085, Amsterdam, HV, 1081, The Netherlands.
authors.forename: J Hans C
authors.initials: JH
authors.lastname: Cornelissen
authors.affiliation: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education)/Life Science College, Southwest University, Beibei, Chongqing, People's Republic of China. zzhong@swu.edu.cn.
authors.forename: Zhangcheng
authors.initials: Z
authors.lastname: Zhong
authors.affiliation: Laboratory of Quantitative Vegetation Ecology, Institute of Botany, The Chinese Academy of Sciences, Xiangshan Nanxincun, Beijing, People's Republic of China.|College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Dong
authors.affiliation: Forestry College, Research Center of Forest Resources and Environment of Guizhou Province, Guizhou University, Huaxi, Guiyang, People's Republic of China.
authors.forename: Changhong
authors.initials: C
authors.lastname: Jiang
mesh_terms: D002681:China; D055137:Glomeromycota; D025282:Mycelium; D038821:Mycorrhizae; D009584:Nitrogen; D018517:Plant Roots / Q000382:microbiology
chemical_list: D009584:Nitrogen
keywords: Arbuscular mycorrhizae; Litter; Nitrogen; Transfer