摘要
Rice is a well-known silicon accumulator. During its periods of growth, a great number of phytoliths are formed by taking up silica via the plant roots. Concurrently, carbon in those phytoliths is sequestrated by a mechanism of long-term biogeochemical processes within the plant. Phytolith occluded C （PhytOC） is very stable and can be retained in soil for longer than a millennium. In this study, we evaluated the carbon bio- sequestration within the phytoliths produced in rice seed husks of 35 rice cultivars, with the goal of finding rice cultivars with relatively higher phytolith carbon sequestra- tion efficiencies. The results showed that the phytolith contents ranged from 71.6 mg. g^-1 to 150.1 mg. g^-1, and the PhytOC contents ranged from 6.4 mg.g^-1 to 38.4 mg.g^-1, suggesting that there was no direct correlation between the PhytOC content and the content of rice seed husk phytoliths （R = 0.092, p 〉 0.05）. Of all rice cultivars, six showed a higher carbon sequestration efficiency in phytolith seed husks. Additionally, the carbon bio- sequestration within the rice seed husk phytoliths was approximately 0.45-3.46 kg-e-CO2-ha^-1. yr^-1. These rates indicate that rice cultivars are a potential source of carbon biosequestration which could contribute to the global carbon cycle and climate change.
Rice is a well-known silicon accumulator. During its periods of growth, a great number of phytoliths are formed by taking up silica via the plant roots. Concurrently, carbon in those phytoliths is sequestrated by a mechanism of long-term biogeochemical processes within the plant. Phytolith occluded C （PhytOC） is very stable and can be retained in soil for longer than a millennium. In this study, we evaluated the carbon bio- sequestration within the phytoliths produced in rice seed husks of 35 rice cultivars, with the goal of finding rice cultivars with relatively higher phytolith carbon sequestra- tion efficiencies. The results showed that the phytolith contents ranged from 71.6 mg. g^-1 to 150.1 mg. g^-1, and the PhytOC contents ranged from 6.4 mg.g^-1 to 38.4 mg.g^-1, suggesting that there was no direct correlation between the PhytOC content and the content of rice seed husk phytoliths （R = 0.092, p 〉 0.05）. Of all rice cultivars, six showed a higher carbon sequestration efficiency in phytolith seed husks. Additionally, the carbon bio- sequestration within the rice seed husk phytoliths was approximately 0.45-3.46 kg-e-CO2-ha^-1. yr^-1. These rates indicate that rice cultivars are a potential source of carbon biosequestration which could contribute to the global carbon cycle and climate change.
基金
Acknowledgements This work was partially supported by the National Natural Science Foundation of China （Grant No. 41271208）, the JiangsuPlanned Projects for Postdoctoral Research Funds （No. 1301061C）, the China Postdoctoral Science Foundation funded project （No. 2013M541744）, and the Key Projects in the National Science ＆ Technology Pillar Program during the Twelfth Five-year Plan Period （2013BADllB00）. We also express our sincere thanks to Ms. Yanan Zhang and Ms. Yilan Liu for their kind help with the sampling.
