Biochar for the Mitigation of Metal/Metalloid Stress in Plants

Metal(loid) pollution has become one of the most pressing environmental issues, threatening all living organisms. Metal(loid) stress adversely impacts plant growth, physiology, and overall productivity. Numerous physicochemical approaches have been developed and employed to counteract and reduce the detrimental effects of metal(loid)s. However, these methods have raised environmental concerns, leading to questions about their appropriateness and efficacy. Consequently, alternative and eco-friendly solutions, such as the application of biochar, have gained prominence. Biochar is a carbon-rich material derived from the pyrolysis and hydrothermal processes of various organic materials. Due to its exceptional physicochemical properties, biochar is believed to enhance soil quality and fertility. Several global studies have underscored the positive role of biochar in reducing the uptake of metal(loid)s by plants in polluted soils. In this article, we explore various facets of plant reactions to metal(loid)s toxicity and attempt to draw links between biochar use and improvements in plant physiology and performance. We also review the effectiveness of biochar in phytoremediation, its influence on nutrient adsorption mechanisms, and its role in assisting plant growth and defense systems.