植硅体元素封存研究进展

ADVANCE IN THE STUDY OF PHYTOLITH-OCCLUDED ELEMENT SEQUESTRATION

植硅体元素封存研究有利于揭示植硅体的化学组成及其与植物种类、植物生境之间的关系,同时为植硅体形成机制的解释提供依据。本文基于国内外学者在植硅体元素封存领域中的现有成果,综述了植硅体元素组成和其化学稳定性,并主要从植硅体碳汇、植硅体碳同位素和植硅体金属元素封存三个方面阐述了植硅体元素封存的研究进展。(1)植硅体碳汇方面:目前已开展了全球部分富硅植物地区的植物、土壤及生态系统的植硅体碳汇潜力评估工作,促进了碳循环和硅生物地球化学循环研究领域的发展。(2)植硅体碳同位素分析:运用植硅体中的14C放射性同位素和δ13C稳定同位素分别进行考古测年和推断环境中C3、C4植物组成,在不同时空尺度下的古植被、古气候重建研究领域中取得了重要进展。(3)植硅体金属元素封存研究:初步测定了部分富硅植物中植硅体包裹的金属元素类型及含量,这可能为未来植硅体在环境污染治理中的应用奠定基础。与此同时,本文还总结了当前植硅体元素封存领域中存在的主要问题,并对未来的研究方向进行了展望。

Phytolith formation,a long-term stable element accumulation mechanism,plays an important role in the biogeochemical cycles and paleoenvironmental reconstruction.Based on the past studies,this paper outlines the elemental composition and chemical stability of phytoliths.The progress of phytolith element sequestration is introduced mainly from three aspects:phytolith-occluded organic carbon(PhytOC)sink,phytolith-occluded carbon isotope,and phytolith-occluded metal element storage.(1)The PhytOC sink study in some silicon-rich plant regions around the world,the assessments of PhytOC sequestration potential in plants,soils and ecosystems have been widely carried out,providing a new perspective for the study of C biogeochemical cycle.(2)The phytolith-occluded carbon isotopes,such as the^(14)C andδ^(13)C in phytoliths have been broadly applied in the archaeological dating and speculation on the distribution of C_(3)and C_(4)plants,which significantly promotes the development of paleoenvironment reconstruction and other fields.(3)The phytolith-occluded metal element storage research at present mainly are in some silicon-rich plants,and the preliminary results have been obtained for the types and content of various metal elements.These works may lay a foundation for the future application of phytoliths for environmental pollution governance.Furthermore,we summary the main problems in the current study of phytolith element sequestration and provide some prospects for the future research fields.