Silicon’s organic pool and biological cycle in moso bamboo community of Wuyishan Biosphere Reserve

摘要

Biomineralization of Si by plants into phytolith formation and precipitation of Si into clays during weathering are two important processes of silicon’s biogeochemical cycle. As a silicon-accumulating plant, the widely distributed and woody Phyllostachys heterocycla var. pubescens (moso bamboo) contributes to storing silicon by biomineralization and, thus, prevents eutrophication of nearby waterbodies through silicon’s erosion of soil particles.A study on the organic pool and biological cycle of silicon (Si) of the moso bamboo community was conducted in Wuyishan Biosphere Reserve, China. The results showed that: (1) the standing crop of the moso bamboo community was 13355.4 g/m², of which 53.61%, 45.82% and 0.56% are represented by the aboveground and belowground parts of moso bamboos, and the understory plants, respectively; (2) the annual net primary production of the community was 2887.1 g/(m²·a), among which the aboveground part, belowground part, litterfalls, and other fractions, accounted for 55.86%, 35.30%, 4.50% and 4.34%, respectively; (3) silicon concentration in stem, branch, leaf, base of stem, root, whip of bamboos, and other plants was 0.15%, 0.79%, 3.10%, 4.40%, 7.32%, 1.52% and 1.01%, respectively; (4) the total Si accumulated in the standing crop of moso bamboo community was 448.91 g/m², with 99.83% of Si of the total community stored in moso bamboo populations; (5) within moso bamboo community, the annual uptake, retention, and return of Si were 95.75, 68.43, 27.32 g/(m²·a), respectively; (6) the turnover time of Si, which is the time an average atom of Si remains in the soil before it is recycled into the trees or shrubs, was 16.4 years; (7) the enrichment ratio of Si in the moso bamboo community, which is the ratio of the mean concentration of nutrients in the net primary production to the mean concentration of nutrients in the biomass of a community, was 0.64; and lastly, (8) moso bamboo plants stored about 1.26×10¹⁰ kg of silicon in the organic pool made up by the moso bamboo forests in the subtropical area of China.