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 wide...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 Phyl-lostachys heterocycla var. pubescens (moso bamboo) contributes to storing silicon by biomineralization and, thus, prevents eu-trophication 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 under-story 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%, respec-tively; (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 com-munity 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.展开更多
Soil samples for conventional management (CM) and intensive management (IM) practices were taken over a year at 2-month intervals to determine the effect of management practices on soil organic carbon (SOC) and to qua...Soil samples for conventional management (CM) and intensive management (IM) practices were taken over a year at 2-month intervals to determine the effect of management practices on soil organic carbon (SOC) and to quantify seasonal dynamics in SOC for bamboo (Phyllostachys pubescens Mazel ex H. de Lehaie) stands. The results with IM compared to CM showed large decreases in total organic carbon (TOC), microbial biomass carbon (MBC), water-soluble organic carbon (WSOC), and the MBC/TOC ratio in the soils. With all IM plots in the 0-20 cm depth across sampling periods, average decreases compared with CM were: TOC, 12.1%; MBC, 26.1%; WSOC, 29.3%; the MBC/TOC ratio, 16.1%; and the WSOC/TOC ratio, 20.0%. Due to seasonal changes of climate, seasonal variations were observed in MBC and WSOC. Soil MBC in the 0-20 cm depth in September compared to May were 122.9% greater for CM and 57.6% greater for IM. However, due primarily to soil temperature, soil MBC was higher during the July to November period, whereas because of soil moisture, WSOC was lower in July and January. This study revealed that intensive management in bamboo plantations depleted the soil C pool; therefore, soil quality with IM should be improved through application of organic manures.展开更多
Atomic force microscope(AFM) was used to investigate the arrangement of cellulose microfibrils (CMF) in Moso bamboo (Phyllostachys pubescens) fibers. Two methods of sample preparation were used here for different purp...Atomic force microscope(AFM) was used to investigate the arrangement of cellulose microfibrils (CMF) in Moso bamboo (Phyllostachys pubescens) fibers. Two methods of sample preparation were used here for different purposes. The first method was chemical maceration with a mixture of hydrogen peroxide and glacial acetic acid, through which the obtained fibers were suitable for observing the orientation of CMF in the primary wal1. The other method was to prepare tangential microtomed sections with a thickness of approximately 30 μm, which was used to investigate the arrangement of CMF in the inner wall of cell cavity of bamboo fibers. The results indicated that the CMF are randomly oriented in the primary wall while in the inner wall of cell cavity they are nearly vertical to the long axis of fibers , which is similar to the arrangement of CMF in the corresponding layer of wood fibers. Meanwhile, the highly oriented arrangement of CMF is also observed in a certain layer of bamboo fibers, though it is incapable of determining which layer it is in this study. The pilot investigation demonstrates that AFM is a powerful tool for the high-resolution observation of CMF in bamboo fibers, meanwhile it has the advantages of simple procedure of sample preparation and easy operation compared to the traditional transmission electron microscopy.展开更多
基金Project (No. 30370275) supported by the National Natural Science Foundation of China
文摘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 Phyl-lostachys heterocycla var. pubescens (moso bamboo) contributes to storing silicon by biomineralization and, thus, prevents eu-trophication 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 under-story 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%, respec-tively; (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 com-munity 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.
基金Project supported by the National Natural Science Foundation of China (No. 30271072) and the Zhejiang Provincial Natural Science Foundation of China (No. 301250).
文摘Soil samples for conventional management (CM) and intensive management (IM) practices were taken over a year at 2-month intervals to determine the effect of management practices on soil organic carbon (SOC) and to quantify seasonal dynamics in SOC for bamboo (Phyllostachys pubescens Mazel ex H. de Lehaie) stands. The results with IM compared to CM showed large decreases in total organic carbon (TOC), microbial biomass carbon (MBC), water-soluble organic carbon (WSOC), and the MBC/TOC ratio in the soils. With all IM plots in the 0-20 cm depth across sampling periods, average decreases compared with CM were: TOC, 12.1%; MBC, 26.1%; WSOC, 29.3%; the MBC/TOC ratio, 16.1%; and the WSOC/TOC ratio, 20.0%. Due to seasonal changes of climate, seasonal variations were observed in MBC and WSOC. Soil MBC in the 0-20 cm depth in September compared to May were 122.9% greater for CM and 57.6% greater for IM. However, due primarily to soil temperature, soil MBC was higher during the July to November period, whereas because of soil moisture, WSOC was lower in July and January. This study revealed that intensive management in bamboo plantations depleted the soil C pool; therefore, soil quality with IM should be improved through application of organic manures.
基金Supported by the "948" Project of the State Forestry Administration (2002-45)the National Natural Science Foundation Project(30400337)the Key Project of Science & Technology Supporting Programs Funded by China during the 11th Five-year Plan(2006BAD19B0402)
文摘Atomic force microscope(AFM) was used to investigate the arrangement of cellulose microfibrils (CMF) in Moso bamboo (Phyllostachys pubescens) fibers. Two methods of sample preparation were used here for different purposes. The first method was chemical maceration with a mixture of hydrogen peroxide and glacial acetic acid, through which the obtained fibers were suitable for observing the orientation of CMF in the primary wal1. The other method was to prepare tangential microtomed sections with a thickness of approximately 30 μm, which was used to investigate the arrangement of CMF in the inner wall of cell cavity of bamboo fibers. The results indicated that the CMF are randomly oriented in the primary wall while in the inner wall of cell cavity they are nearly vertical to the long axis of fibers , which is similar to the arrangement of CMF in the corresponding layer of wood fibers. Meanwhile, the highly oriented arrangement of CMF is also observed in a certain layer of bamboo fibers, though it is incapable of determining which layer it is in this study. The pilot investigation demonstrates that AFM is a powerful tool for the high-resolution observation of CMF in bamboo fibers, meanwhile it has the advantages of simple procedure of sample preparation and easy operation compared to the traditional transmission electron microscopy.
