关键词: 重金属镉, 转运蛋白, 螯合机制, 根际微生物互作, 植物修复技术

Abstract: Cadmium (Cd) contamination poses a significant threat to plant growth and ecosystem security. Elucidating the mechanisms underlying plant responses to Cd stress is critical for pollution remediation and agricultural safety. This review systematically examines Cd uptake, transport, physiological responses, and mitigation strategies in plants. Cd primarily enters plants through symplastic pathways (mediated by transporters such as Nramp and ZIP) and apoplastic pathways (e.g., cell wall adsorption and xylem transport), with its bioavailability significantly influenced by soil pH, organic matter, and microbial activity. At the physiological level, Cd stress induces reactive oxygen species (ROS) accumulation, activates antioxidant enzyme systems (SOD, CAT, APX) and chelation mechanisms (e.g., GSH, PCs, MTs), and reduces cytosolic Cd toxicity via vacuolar compartmentalization. Molecularly, transporter families such as Heavy Metal ATPase (HMA) and ATP-Binding Cassette (ABC) proteins synergistically regulate transmembrane Cd transport and detoxification processes. Practically, phytoremediation technologies utilizing hyperaccumulator plants (e.g., Salix spp. and Sedum spp.), combined with chelating agents (e.g., EDTA) and plant growth-promoting rhizobacteria (PGPR), enhance soil remediation efficiency. Additionally, low-Cd crops developed through gene-editing technologies (e.g., knockout of OsNramp5 and OsHMA3) exhibit significantly reduced grain Cd accumulation. This review provides a theoretical framework for understanding plant Cd tolerance mechanisms and offers technical references for Cd pollution control and safe crop production.

Key words: Heavy metal cadmium, Transporter protein, Chelation mechanism, Interaction between rhizosphere microorganisms, Phytoremediation technology