Plant stress physiology under environmental emerging contaminant exposure: from molecular responses to...

The increasing occurrence of emerging environmental contaminants (EECs) in terrestrial and aquatic ecosystems is reshaping plant physiological performance, with implications extending from cellular metabolism to ecosystem function and phytoremediation performance. Pharmaceuticals, pesticides, PFAS, nanomaterials, and plastic-derived particles differ substantially in their physicochemical properties, uptake behavior, intracellular mobility, and biological targets, resulting in highly variable physiological outcomes. Here, we synthesize recent advances in plant stress physiology under EEC exposure through an integrated mechanistic framework linking contaminant uptake and translocation, detoxification pathways, oxidative stress dynamics, phytohormonal signaling, microbiome interactions, and translational phytoremediation strategies. Evidence compiled across contaminant classes demonstrates that plant toxicity is primarily governed by internal exposure dynamics rather than external concentrations alone. Across studies, plant responses frequently exhibit nonlinear physiological patterns, including antioxidant enzyme induction ranging from approximately 1.5- to 4.6-fold, glutathione depletion of 20-50%, nitrate reductase inhibition of 20-60%, and contaminant-specific hormonal responses varying from moderate abscisic acid increases (2-3-fold) to >10-fold jasmonate accumulation under severe stress conditions. Physicochemical properties, vascular transport constraints, and rhizospheric interactions collectively determine the compartmentalization of contaminants, ROS generation, metabolic disruption, and stress signaling outcomes. Oxidative stress emerges as a recurrent integrative regulatory interface linking xenobiotic perception with hormonal reprogramming, detoxification processes, and physiological acclimation, although its magnitude and mechanistic contribution remain dependent on the contaminant and tissue. Importantly, the literature reveals strong nonlinearities in plant responses to contaminant mixtures and co-occurring climate-related stressors, highlighting the limitations of reductionist single-stressor approaches. Recent findings have further demonstrated that plant-associated microbiota substantially influence contaminant fate, redox balance, and phytoremediation efficiency, supporting the concept of holobiont-mediated contaminant tolerance. Finally, advances in omics technologies, microbiome engineering, ecological treatment systems, and predictive modeling are progressively transforming phytoremediation into a physiology-informed and engineerable nature-based solution. Collectively, this review establishes a systems-level framework connecting contaminant transport, redox regulation, hormonal signaling, and microbiome functionality, providing mechanistic insights essential for environmental monitoring, risk assessment, and sustainable remediation under global-change scenarios.