中国荒漠C_(4)木本植物和土壤无机固碳研究回顾与展望

Review and prospect of the researches on C_(4) woody plants and soil inorganic carbon sequestration in deserts of China

碳是贯穿自然和社会的首要元素之一,碳循环是自然和社会系统的重要纽带。陆地生态系统的自然固碳途径有2种,一种是植物碳同化,另一种是土壤碳同化,人们一直关注植物的有机固碳,对于土壤的无机固碳重视不够。本文回顾了中国荒漠区固碳能力强的C_(4)木本植物和土壤无机固碳研究进展。通过解剖结构观察、δ^(13)C值和气体交换特征全面分析得出,荒漠植物梭梭(Haloxylon ammodendron)和沙拐枣(Calligonum mongolicum)为典型的C_(4)木本植物,梭梭同化枝有大量的含晶细胞,沙拐枣同化枝有大量的黏液细胞。干旱区荒漠的非生物固碳能力至今缺乏合理解释。通过对戈壁、沙漠和壤质荒漠土壤无机碳密度和碳储量分析,提出了土壤碳同化(soil carbon assimilation)概念,并给出了土壤碳同化途径的3个阶段,解释了土壤无机固碳这一现象;与植物碳同化比较,土壤碳同化是荒漠固碳的主要途径。最后,展望了荒漠C_(4)木本植物和土壤碳同化的研究方向及对中国2060年前实现碳中和目标的可能贡献。

Carbon is one of the primary elements,and the carbon cycle is an important link between nature and social systems.There are two pathways of natural carbon sequestration in terrestrial ecosystems,one is plant carbon assimilation,the other is soil carbon assimilation.People always pay attention to the plants organic carbon sequestration,and little attention on the soil inorganic carbon sequestration.In this paper,we reviewed the research progress on C_(4) woody plants which have strong carbon sequestration ability,and soil inorganic carbon sequestration in desert region of China.Comprehensive analysis of the anatomical structure observation,δ^(13)C values and gas exchange characteristics,it was concluded that the desert plants Haloxylon ammodendron and Calligonum mongolicum are typical C_(4) woody plants.The assimilation shoots of H.ammodendron has a large number of crystal-containing cells,while the assimilation shoots of C.mongolicum has many mucilage cells.The inorganic carbon sequestration capacity of deserts in an arid region has not been for a properly explained.By analyzing the soil inorganic carbon density and their storage in gravel desert(gobi),sand desert,and silt desert,Su Peixi et al.proposed the concept of soil carbon assimilation for the first time in 2018,and three stages of soil carbon assimilation were given to explain the phenomenon of soil inorganic carbon sequestration.Compared with the plant carbon assimilation,soil carbon assimilation is the major pathway of carbon sequestration in desert.Finally,we prospected the research direction of desert C_(4) woody plants and soil carbon assimilation,and discussed the possible contributions to China's carbon neutral goal before 2060.