Relevance of cross talk between root exudates, hormones, and root-associated microbes in developing sustainable phytoremediation strategies: a comprehensive review.

The outcome of phytoremediation depends on complex interactions among root exudates, plant hormones, and root-associated microorganisms affecting metal bioavailability, absorption, translocation, and detoxification. The fluctuation in root exudation patterns across plant species and environmental conditions therefore limits the predictability and scalability of phytoremediation. Organic acids, flavonoids, sugars, and secondary metabolites are particularly important in rhizosphere modification and microbial recruitment even if their quick microbial degradation could reduce their long-term influence on metal bioavailability. The role of plant hormones is also yet unknown in metal stress responses. Auxins and cytokinins increase metal absorption and root growth; abscisic acid increases metal immobilization, so better suited for phytostabilization. Ethylene, a key stress signal, may have long-term deleterious effects on plant development, limiting its utilization in corrective treatment. Moreover very promising in enhancing metal solubility and plant tolerance is microbial-assisted phytoremediation using plant growth-promoting rhizobacteria and arbuscular mycorrhizal fungus. Still, soil heterogeneity, environmental fluctuations, and competition with native microbial populations restrict the long-term survival and efficiency of introduced microbial inoculants. This work investigates the molecular goals, advantages, and constraints of root exudates, plant hormones, and microbial interactions in phytoremediation with critical eye on maximizing phytoremediation as a scalable, site-specific approach for reducing heavy metal pollution depends on an awareness of this biological complexity.