植物地球化学找矿的进展与展望

Progress and Prospect of Plant Geochemical Prospecting

摘要: 随着全球矿产勘查重心向厚层覆盖区隐伏矿床转移，传统化探方法在运积物覆盖区面临信号衰减与多解性的严峻挑战。植物地球化学作为一种兼具深穿透能力与绿色非侵入性优势的勘查方法，近年来受到广泛关注，但其应用仍以经验类比为主，缺乏系统的机理认知与定量化判别标准。本文从“矿体–覆盖层–根际–植物器官”全链条视角出发，系统梳理了金属元素垂向迁移的四条并行路径——地下水溶解迁移、毛细管蒸发输运、地气纳米微粒携带及深根系直接吸收，解析了植物在金属过量胁迫下的跨膜转运蛋白调控与避性/耐性策略分异机制。在此基础上，引入科瓦列夫斯基生物屏障分类与胡西顺衬度极限系数(CM)，构建了有效指示植物与优势采样器官的定量化筛选框架。进而，本文按“元素–植物”配对关系的思路，系统梳理了金(Au)、稀土元素(REE)、铜多金属(Cu-Pb-Zn)、稀有金属(Li-U)以及铬镍铊等关键成矿元素的优势指示植物类群、富集强度与富集机制，其中重点涵盖了芒萁Si-细胞壁固定、桉树纳米金颗粒转运、乌毛蕨纳米独居石生物矿化等近年来标志性的机理发现。最后，本文指出了元素迁移路径多解性、源混淆及局地基体效应等现存挑战，并对原位微区分析技术与机器学习融合前景进行了展望，以期为覆盖区隐伏矿床的绿色深部探测提供理论参考与方法支撑。

Abstract: As global mineral exploration increasingly targets concealed deposits beneath thick transported cover, conventional geochemical methods face fundamental limitations in signal attenuation and source ambiguity. Phytogeochemistry—the use of plant tissue chemistry to detect buried mineralization—offers a deep-penetrating, non-invasive alternative, yet its application remains predominantly empirical, lacking a systematic mechanistic framework and quantitative discrimination criteria. This review synthesizes advances in phytogeochemical exploration from a holistic “orebody - cover - rhizosphere - plant organ” perspective. We delineate four coupled vertical transport pathways—groundwater advection and electrochemical gradient migration, capillary evaporation-driven ascent, gaseous nanoparticle transport via geogas, and direct deep-root uptake—and elucidate the molecular responses of plants to metal excess, including transmembrane transporter regulation and the exclusion-tolerance strategy continuum. Building on Kovalevsky’s biogenic barrier classification and Hu Xishun’s contrast-limit coefficient (CM), we present a quantitative framework for selecting effective indicator species and optimal sampling organs. We further organize the evidence by element-plant pairings, systematically reviewing the dominant indicator plant taxa, enrichment intensities, and underlying mechanisms for Au, REE, Cu-Pb-Zn, Li-U, and Cr-Ni-Tl, with emphasis on landmark mechanistic discoveries including Si-enhanced cell-wall sequestration in Dicranopteris, Au nanoparticle translocation in Eucalyptus, and nanoscale monazite phytomineralization in Blechnopsis orientalis. We identify persistent challenges including source apportionment ambiguity, exogenic noise, and local matrix effects, and highlight emerging opportunities in in situ microanalytical techniques and machine learning integration. This review provides a mechanistic foundation and practical roadmap for advancing phytogeochemistry as a quantitative green-exploration tool for concealed mineral resources.