Distributional optimum of sclerotia, resting bodies of Cenococcum geophilum in forest soils

• Main Author: Sakagami Nobuo
• Format: Report
• Language: English
• Published: Department of Geography, Tokyo Metropolitan University 2011
• Subjects: Cenococcum geophilum; Forest soil; Sclerotia; Soil organic component; Warmth Index; Arctic
• Online Access: https://tokyo-metro-u.repo.nii.ac.jp/?action=repository_uri&item_id=3089; http://hdl.handle.net/10748/4245; https://tokyo-metro-u.repo.nii.ac.jp/?action=repository_action_common_download&item_id=3089&item_no=1&attribute_id=18&file_no=1

Cenococcum geophilum (Cg) is known for its vast habitat range in temperate and arctic-alpine climatic zone. The resting bodies of Cg, which reveal their persistence for a long term as a structural organic component in soils, are studied from their geographical aspect in this paper. The objective of this study is to understand the distributional optimum of sclerotia as soil organic component by examinations along altitudinal gradient and its seasonal variance in central and northern Japan. Distributional properties of sclerotia were examined in soil in terms of weight density (mg g^<−1> soil), count density (no. g^<−1> soil), and mean weight per grain (mg no.^<−1> sclerotium). Density of sclerotia showed an optimum distribution in cool-temperate and subalpine vegetation zones with a distinct peak at the boundary of these two zones, while soil T-C did not show such apparent peaks. Furthermore, sclerotia content showed larger seasonal variance compared to T-C, presumably due to primary activities of micro-organisms. Altitudinal distribution and seasonal variance of sclerotia of Cg in Japanese forest soils, highlighted sclerotia as more biotic soil organic component compared to soil humus, supposedly caused not only by germination but also by still unknown biological implication of sclerotia remaining in soil. Regarding all samples studied in this study, C/N ratio of soil behaved as one of the regulating factors of formation size of sclerotia. Although the contribution of sclerotial carbon to total soil carbon is small (<0.96%), it was suggested that sclerotia may have an important role as sink and/or source of soil carbon in cool-alpine to alpine climatic zone, aside from seasonal turnover.