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By: Bangshidhar Goswami
Ex-Assistant Professor, Department of Metallurgical Engineering, Ran Vijay Singh College of Engineering and Technology, Jamshedpur, East-Singhbhum, Jharkhand, India.
This study investigates heavy metal uptake, tolerance, and sequestration mechanisms in various plants, focusing on crops, such as tea, vegetables, and fruit trees that are susceptible to heavy metal contamination. Trace elements in plants, if overabundant, pose toxicity risks by disrupting metabolic and physiological functions. Plants counteract heavy metal complexes by immobilizing them within cell walls or vacuoles or by binding them to organic compounds produced in situ. Elevated levels of reactive oxygen species (ROS) are often a byproduct, triggering oxidative stress that impacts plant homeostasis and cellular integrity. This stress response involves pro-oxidant and antioxidant imbalance, along with changes in enzymatic functions that affect oxygen activation, hydrogen peroxide production, and the release of defensive compounds like methylglyoxal. Seasonal and incidental contaminations vary by location and soil type, influencing the distribution of heavy metals between roots, stems, and leaves. Techniques, such as chelation, compartmentalization, and symbiotic interactions with mycorrhizal fungi are highlighted for their roles in reducing metal uptake. Analytical studies reveal that plant-derived substances like metallothioneins, phytochelatins, polysaccharides, and organic acids significantly mediate heavy metal immobilization. Given the long biological half-life of heavy metals in human tissues, the cumulative effects of consuming contaminated plant products require monitoring, particularly in consumer staples like tea. Findings underscore the need for stringent quality control measures and adaptive agricultural practices to mitigate heavy metal accumulation in edible plants, thus protecting human health and preserving soil quality.
Citation:
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