绿竹和麻竹地上部植硅体碳封存潜力

可以在土壤中稳定存在数千年甚至上万年之久的植硅体碳(phytolith-occluded organic carbon,PhytOC)是陆地植物生态系统长期碳封存的重要机制之一。选取福建南靖地区绿竹(Dendrocalamopsis oldhami(Munro)Keng f.)和麻竹(Dendrocalamus latiflorus Munro)两种重要丛生竹为研究对象,采集其竹叶、竹枝和竹秆样品,用微波消解法提取植硅体,采用碱溶法测定植硅体中碳含量,以比较两种丛生竹的植硅体碳封存潜力和封存速率。结果表明:绿竹和麻竹林地上部不同器官中Si含量变幅分别为4.95—37.53 g/kg和2.01—34.05 g/kg,植硅体含量变幅分别为3.35—100.80 g/kg和1.57—84.06 g/kg,两者地上部不同器官中的含量大小顺序均为叶枝秆。绿竹和麻竹林地上部不同器官干物质中的植硅体碳含量变幅分别为0.51—2.85 g/kg和0.17—2.22 g/kg。绿竹和麻竹林地上部PhytOC储量变幅分别为5.1—13.9 kg/hm~2和1.2—6.3 kg/hm~2。绿竹和麻竹地上植株不同器官中的最高PhytOC储量分别为枝和叶。绿竹和麻竹地上部PhytOC总储量分别为24.3 kg/hm~2和11.1 kg/hm~2。绿竹和麻竹林地上部PhytOC封存速率分别为0.051—0.131 t-e-CO_2hm~(-2)a~(-1)和0.0099—0.0139 t-e-CO_2hm~(-2)a~(-1),以绿竹和麻竹的最高PhytOC封存速率计算,我国绿竹林和麻竹林的地上植株部每年可分别封存1965.29 t CO_2和1520.11 t CO_2。

Comparison of PhytOC sequestration rates in above-ground apart of Dendrocalamopsis oldhami (Munro) Keng f. and Dendrocalamus latiflorus Munro

Phytolith-occluded carbon (PhytOC), which can be stabilized in the soils for thousands of years, is one of the important mechanisms for long-term carbon sequestration in terrestrial plant ecosystems. In this study, we selected two typical sympodial bamboos Dendrocalamopsis oldhami (Munro) Keng f., (DOK) and Dendrocalamus latiflorus Munro, (DLM)] in the subtropical area of China as research subjects and collected the samples of leaves, branches, and culms in Nanjing, Fujian province. Phytolith in the samples were extracted using a microwave digestion method and their PhytOC content were determined using the alkaline solution method, with the aim of comparing the PhytOC sequestration rates and stocks of DOK and DLM. The results showed that silicon (Si) content in the above-ground parts of DOK and DLM ranged from 4.95 to 37.53 and from 2.01 to 34.05 g/kg, respectively, whereas phytolith content ranged from 3.35 to 100.80 and from 1.57 to 84.06 g/kg, respectively. The content of both Si and phytoliths decreased in the order: leaves > branches > culms. The PhytOC in above-ground parts of DOK and DLM ranged from 0.51 to 2.85 and from 0.17 to 2.22 g/kg, respectively, whereas their PhytOC stocks ranged from 5.1 to 13.9 and from 1.2 to 6.3 kg/hm² , respectively. The highest PhytOC stocks in the different organs of above-ground parts of DOK and DLM were observed in leaves and branches, respectively. The total PhytOC stocks in above-ground parts of DOK and DLM were 24.3 and 11.1 kg/hm², respectively. The PhytOC sequestration rates of above-ground parts of DOK and DLM were 0.051-0.131 and 0.0099-0.0139 t-e-CO₂ hm^-2 a^-1, respectively. The PhytOC amounts sequestrated by DOK and DLM stands in China are estimated to be 1965.29 and 1520.11 t CO₂/a, respectively.