Research Of Phytolith-occluded Carbon Sequestration Of Important Sympodial Bamboo Ecosystem In China

Phytolith is an amorphous silica body, which is filled with higher plant cell walls and lumen of Byophyta and Trachophyta. There is a small amount of organic carbon was sealed in Phytolith in this process named Phyt OC. Phytolith has a strong capacity of inoxidizability and decomposition. Due to the protection of Phytolith, Phyt OC can preserve and accumulate in the soil for thousands of years after the death of plants. It is in favour of forming stable soil organic carbon tank than the other forms of organic carbon in soil. The return-fixation form has a great important adjusting the ecosystem carbon balance and remitting the global climate change.As a important kind of bamboo resources, sympodial bamboo has the capacity of enriching the Phytolith, with prominent features of fast growth, large biomass, root system prosperous and prominent ecological functions. It is widely distributed in the region of south of the Yangtze river. Besides, sympodial bamboo ecosystem may be an important storage pool of Phyt OC, because of the cultivation of long history. Research on Phyt OC could explore the regulatory mechanism of carbon sink in the sympodial bamboo ecosystem. It is benefit to understand the potential of the bamboo with the Phyt OC sequestration and providing a foundation of estimating the Phyt OC sequestration potential for Chinese forest. In this study chose 8 important sympodial bamboos as the material which have the vast planting area in China. We collected plant and soil samples in the main sympodial bamboo producing area(Guangdong Province, Fujian Province, Zhejiang Province, Yunnan Province, Sichuan Province) of different bamboo species and measured their contents of Phytolith and Phyt OC. We estimate the Phyt OC stock of important sympodial bamboo ecosystem in China. The results are as follows:1. There was significant variation(P<0.05) in the phytolith and Phyt OC contents among different sympodial bamboo organs. The phytolith contents of different organs in sympodial bamboo species was in the order of leaves(31.55~156.10 g·kg-1)>branches(15.02~61.79 g·kg-1)> culms(1.57~10.38 g·kg-1). Besides,the phytolith contents in the leaves,branches and culms of the same specie as increased with the bamboo age from 1 to 3-year-old. The phytolith content of Dendrocalamus latiflorus Munro leaf and branch is significant higher than other species. The Phyt OC contents ranged IV from 0.14 to 6.30 g·kg, the content was highest in leaf of Bambusa textilis Mc Clure, and was about 45 times than in culm of Neosinocalamus affinis(Rendle) Keng f.. There was no obvious regularity in the Phyt OC contents in the same organs with the different bamboo ages. The Phyt OC contents of leaf in Bambusa textilis Mc Clure、branch in Bambusa chungii Mc Clure and culm in Dendrocalamus giganteus Munro were significant higher than others in same organ of different species There was significant variation(P<0.05) in the organic carbon contents in the phytolith in different organs and species, the contents ranged from 5.34 to 165.50 g·kg-1, the content was highest in branch of Bambusa chungii Mc Clure, and was about 31 times than in leaf of Dendrocalamus latiflorus Munro.2. There was significant different between the phytolith and Phyt OC contents in leaf litter of different sympodial bamboo species. The phytolith content of Neosinocalamus affinis(Rendle) Keng f. was significant higher than others species. The Phytolith content ranged from 106.92 to 373.57 g·kg-1 in leaf litter. The Phyt OC contents ranged from 3.16 to 7.55 g·kg-1. The content in Dendrocalamus membranceus Munro was significant higher than other bamboo species,but the difference of the Phyt OC contents among with the other bamboo species was less than 52.8%.3. The Phytolith contents in the sympodial bamboo soil deceased with soil depths under the same bamboo species. The phytolith contents ranged from 4.95 to106.91 g·kg-1 in different soil layer(0~10 cm、10~30 cm、30~60 cm) under the different bamboo species. The phytolith contents of 0~10 cm soil layer is significant higer than other bamboo species in Dendrocalamus membranceus Munro and Bambusa burmanica Mc Clure.There was no difference in the Phyt OC contents in different soil layer in same bamboo species, which was similar to the change of phytolith contents with soil depths. The Phyt OC contents ranged from 0.024 to 0.428 g·kg-1. The Phyt OC in soil of Bambusa burmanica Mc Clure was significant higher than other bamboo species. The Phyt OC accounted for the total organic carbon ranged from 0.26% to11.67%, which increased with soil depths.4. Phyt OC storage in different sympodial bamboo ecosystem ranged from 0.33 to 2.74 t·ha-1. Phyt OC storage in Bambusa burmanica Mc Clure was the highest, whereas the Dendrocalamus latiflorus Munro was the lowest. Besides, Phyt OC storage of soil in sympodial bamboo ecosystem was highest and ranged from 86.89% to 98.69%. Phyt OC storage in different components decreased in the order: soils(309.02~2705.17 kg·ha-1)>litters(7.49~47.09 kg·ha-1)>culms(1.96~31.89 kg·ha-1)>branches(1.69~25.97 kg·ha-1)>leaves(0.75~17.97 kg·ha-1). The total Phyt OC storage among 8 sympodial bamboo species in China was in the order of Neosinocalamus affinis(Rendle) Keng f.(4.00×105 t·C)> Dendrocalamus membranceus Munro(1.72×105 t·C)> Dendrocalamus giganteus Munro(1.52×105 t·C)> Bambusa textilis Mc Clure(7.41×104 t·C)> Bambusa chungii Mc Clure(4.46×104 t·C)> Dendrocalamus latiflorus Munro(3.61×104 t·C)> Bambusa burmanica Mc Clure(2.74×104 t·C)> Dendrocalamopsis oldhami(Munro) Keng f.(1.18×104 t·C). Through the calculation of the Phyt OC content and leaf litter biomass, the Phyt OC stock rate of different sympodial bamboo species were ranged from 0.0647 to 0.1949 t-e-CO2·ha-1·yr-1.