Heavy Metal Stress In Plants: Mechanisms, Impacts, And Mitigation Strategies- A Comprehensive Review

Abstract

The contamination of terrestrial and aquatic ecosystems by heavy metals (HMs) constitutes a pressing global environmental concern, particularly due to their toxicological impacts on plant systems, long-term persistence, and potential for food chain bioaccumulation. Both essential and non-essential HMs interfere with critical physiological and molecular pathways in plants, primarily through oxidative damage, disruption of enzymatic functions, nutrient imbalances, and genotoxic effects. Despite these challenges, plants possess an array of sophisticated defense systems—including enzymatic and non-enzymatic antioxidant responses, metal chelation, vacuolar sequestration,and hormonal signaling pathways—that enablemitigation of HM-induced toxicity. This review consolidates current knowledge on HM uptake, translocation, toxicity mechanisms, and plant adaptive responses, with an emphasis on phytoremediation technologies. Various remediation strategies, including phytoextraction, rhizofiltration, and phytostabilization, are critically evaluated based on their efficiency, limitations, and feasibility in practical applications. Emerging advancements such as molecular engineering, use of transgenic lines, and manipulation of rhizospheric microbiomes are also discussed as transformative approaches to enhance remediation outcomes. A systems-level understanding of plant–metal interactions is vital for the development of effective phytotechnologies and formitigating the ecological and agronomic consequences of HM pollution.