| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2004: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
To estimate quantitatively the role of ectomycorrhizal fungi in carbon cycling of forest ecosystem, symbiotic fungal biomass in ectomycorrhiza of several tree species with different ages were quantified by 3 different methods.
Six coniferous and 7 broad-leaved seedlings, and 2 coniferous and 2 broad-leaved adult trees were sampled in sub-arctic to warm-temperate forests in Hokkaido and Hiroshima prefectures. (1) For all sampled ectomycorrhizas, area ratios of fungal sheath (as index of symbiotic fungal biomass) in transverse section of ectomycorrhiza was measured under optical microscope. For adult Pinus densiflora - Suillus luteus ectomycorrhiza, area ratio of fungal sheath in transverse section of ectomycorrhiza was also measured. Then, (2) fungal sheath of ectomycorrhiza was peeled out, and weighed as index of symbiotic fungal biomass. (3) Fungal membrane specific ergosterol in ectomycorrhiza, fungal sheath and core plant tissue were determined, and their contents were converted to s
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ymbiotic fungal biomass.
(1) The averaged area ratios of fungal sheath of seedlings were 23.2 (converted value in weight basis, 34.6) for coniferous, and 26.4 (in weight basis, 39.3)% for broad-leaved trees, respectively, showing the value for broad-leaved trees was larger than that for coniferous trees. About the differences between seedlings and adult trees, in Pinus densiflora and Fagus crenata the values were not significantly different each other, but in Abies firma and Quercus serrata the values of adult trees were significantly larger than those of seedlings. (2) Symbiotic fungal biomass in weight basis of Pinus densiflora - Suillus luteus ectomycorrhiza was 41.9%. (3) Symbiotic fungal biomass in fungal sheath estimated from ergosterol content of Pinus densiflora - Suillus luteus ectomycorrhiza was 41.7%. Larger amount of fungal biomass, 28.8%, was found in core plant tissue of ectomycorrhiza.
(1) Symbiotic fungal biomass of ectomycorrhizas of 13 tree species of seedlings and adult trees were in the range of 35-40%, which were similar to 40% of Fagus sylvatica of Harley and McCready (1952). (2) It is very interesting that larger amount of fungal biomass, 28.8%, was found in core plant tissue of ectomycorrhiza. (3) Next step is the determination of the turnover time of symbiotic fungal biomass to clarify quantitatively the role of ectomycorrhizal fungi in carbon cycling of forest ecosystem. Less
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