在嘉兴杭嘉湖平原实验基地,以嘉花11、浙粳37、宁81、祥湖301、秀水09等5个品种水稻及其0—10cm表层土壤为研究对象,运用微波消解和Walkley-Black的方法,研究了稻田生态系统中植硅体的产生和积累通量,为了解植硅体在稻田生态系统硅和碳生物地球化学循环中的作用提供科学参考。结果表明:(1)植硅体含量在不同品种水稻中嘉花11、宁81和祥湖301高于浙粳37和秀水09,在各器官中鞘>叶>茎>根>穗;(2)水稻植株植硅体产生通量为1269.59 kg hm-2a-1,其中地上部分为1203.44 kg hm-2a-1,地下部分为66.15 kg hm-2a-1,在种植50a的稻田0—10cm土壤中的积累通量为40.38 kg hm-2a-1;(3)选择嘉花11等高植硅体含量品种进行推广种植,对提高水稻植硅体产生通量及其包裹大气中CO2通量有很大的作用。
Global warming as a result of rapid increase in atmospheric COa emission is significantly influencing world＇s economy and human activities. Carbon sequestra- tion in phytoliths is regarded as a highly stable carbon sink mechanism in terrestrial ecosystems to mitigate climate change. However, the response of plant phytolith-occluded carbon （PhytOC） to external silicon amendments remains unclear. In this study, we investigated the effects of basalt powder （BP） amendment on phytolith carbon sequestration in rice （Oryza sativa）, a high-PhytOC accumulator. The results showed that the contents of phytolith and PhytOC in rice increased with BP amendment. The PhytOC produc- tion flux in different rice plant parts varied considerably （0.005-0.041 Mg CO_2 ha^-1 a^-1）, with the highest flux in the sheath. BP amendment can significantly enhance flux of phytolith carbon sequestration in croplands by 150 %. If the global rice cultivation of 1.55 × 10^8 ha had a similar flux of PhytOC production in this study, 0.61× 10^7 to 1.54 × 10^7 Mg CO_2 would be occluded annually within global rice phytoliths. These findings highlight that exter- nal silicon amendment such as BP amendment represents an effective potential management tool to increase long- term biogeochemical carbon sequestration in crops such as rice and may also be an efficient way to mitigate the global warming indirectly.
As an important long-term terrestrial carbon sequestration mechanism, biogeochemical sequestration of carbon within phytoliths may play a significant role in the global carbon cycle and climate change. The aim of this study is to explore the potential of carbon bio-sequestration within phytoliths produced by wetland plants. The results show that the occluded carbon content of phytoliths in wetland plants ranges from 0.49% to 3.97%, with a CV (coefficient of variation) value of 810%. The data also indicate that the phytolith-occluded carbon (PhytOC) content of biomass for wetland plants depends not only on the phytolith content of biomass, but also the efficiency of carbon occlusion within phytoliths during plant growth in herb-dominated fens. The fluxes of carbon bio-sequestration within phytoliths of herb-dominated fen plants range from 0.003 to 0.077 t CO2 equivalents t-e-CO2ha-1a-1 . In China, 0.04×106 to 1.05×106t CO2 equivalents per year may be sequestrated in phytoliths of herbaceous-dominated fen plants. Globally, taking a fen area of 1.48×108 ha and the largest phytolith carbon biosequestration flux (0.077 t-e-CO 2 ha-1a-1 ) for herb-dominated fen plants, about 1.14×10 7 t CO 2 equivalents per year would have been sequestrated in phytoliths of fen plants. If other wetland plants have similar PhytOC production flux with herb-dominated fen plants (0.077 t-e-CO2ha-1a-1 ), about 4.39×10 7 t-e-CO2a-1 may be sequestrated in the phytoliths of world wetland plants. The data indicate that the management of wetland ecosystems (e.g. selection of plant species) to maximize the production of PhytOC have the potential to bio-sequestrate considerable quantities of atmospheric CO2 .
Occlusion of carbon(C) within phytoliths(Phyt OC) is becoming one of the most promising terrestrial C sequestration mechanisms. This study explored the production of Phyt OC within 35 bamboo species belonging to three ecotypes using methods of microwave digestion. The aim of this study is to explore the present and potential C sequestration rate within phytoliths of bamboo species from three ecotypes. Phyt OC content in bamboos of three ecotypes ranges from 0.07 % to 0.42 %. The mean Phyt OC production flux decreases as: clustered bamboo(0.050 ±0.016 t CO2ha-1a-1) & mixed bamboo(0.049 ± 0.016 t CO2ha-1a-1) [ scattered bamboo(0.038 ± 0.020 t CO2ha-1a-1). The phytolith carbon sequestration in Chinese bamboo is estimated to be 0.293 ± 0.127 Tg(1 Tg =1012g) CO2a-1; approximately 75 %, 3 %, and 22 % of which is contributed from scattered, mixed and clustered bamboo, respectively. Taking the Phyt OC production flux of 0.18 ± 0.12 t CO2ha-1a-1and current annual area increasing rate of 3 %, global bamboo phytoliths wouldsequester 11.9 ± 7.9 Tg CO2a-1by 2050. Consequently,bamboo forests have significant potential to mitigate the increasing concentration of atmospheric CO2 by maximizing Phyt OC production flux and expanding bamboos.
Beilei LiZhaoliang SongHailong WangFengshan GuoRenyi GuiXiaomin YangRuisheng Song
