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<p>Benzophenone-3 (BP-3), a widely applied anthropogenic UV filter, has emerged as a recalcitrant contaminant of escalating ecological concern, exerting severe ecotoxicological risks in aquatic ecosystems. The study investigates the phytotoxic effect of BP-3 in <i>Azolla pinnata</i> through growth assays, pigment analyses, biochemical markers, and chlorophyll <i>a</i> fluorescence (ChlF) analysis. The results delineated a hierarchical cascade of stress responses, initiated by pigment attrition and PSII disassembly, which curtailed excitation capture and restricted primary photochemistry. Crucially, toxicity was mediated through inactivation of reaction centers (RC/CSm) and disrupted electron transport beyond QA⁻, where impaired plastoquinone reduction and destabilization of the PQ pool suppressed downstream electron transfer and amplified photochemical dysfunction within PSII. These perturbations were reflected in distorted OJIP curves, progressive declines of quantum yields (φPo, φEo), alterations in phenomenological fluxes (ABS/CSm, TRo/CSm, ETo/CSm, DIo/CSm), and steep reductions in performance indices (PIabs, PIcsm), collectively signifying systemic destabilization of PSII reaction centers and the broader electron transport chain. Photochemical impairments converged with excessive ROS accumulation, lipid peroxidation, and membrane destabilization, while concomitant depletion of osmolytes (proline, soluble sugars, starch) revealed collapse of transient buffering capacity and irreversible metabolic breakdown. Ultimately, these disruptions culminated in biomass loss, reduced relative growth rate, and up to 76.3% inhibition at 6&#xa0;mg/L BP-3. This multi-tiered trajectory, spanning pigment depletion, disruption of electron transport, oxidative disequilibrium, and osmolyte exhaustion, establishes that BP-3 profoundly compromises photosynthetic performance and metabolic homeostasis. Given the keystone role of freshwater macrophytes in nutrient cycling, carbon sequestration, and ecosystem stability, these findings establish BP-3 as a potent ecological hazard and underscore the urgency of stricter discharge controls, regulatory interventions, and its inclusion in priority contaminant monitoring frameworks to safeguard aquatic biodiversity and ecosystem services. </p>

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Photophysiological dysfunction and growth suppression in freshwater macrophyte Azolla pinnata induced by the emerging anthropogenic UV filter Benzophenone-3

  • 期刊论文

  • 发表日期：

    2026年2月18日

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  • Dipti Agarwal,
  • Upma Bhatt ,
  • Vineet Soni

摘要

Benzophenone-3 (BP-3), a widely applied anthropogenic UV filter, has emerged as a recalcitrant contaminant of escalating ecological concern, exerting severe ecotoxicological risks in aquatic ecosystems. The study investigates the phytotoxic effect of BP-3 in Azolla pinnata through growth assays, pigment analyses, biochemical markers, and chlorophyll a fluorescence (ChlF) analysis. The results delineated a hierarchical cascade of stress responses, initiated by pigment attrition and PSII disassembly, which curtailed excitation capture and restricted primary photochemistry. Crucially, toxicity was mediated through inactivation of reaction centers (RC/CSm) and disrupted electron transport beyond QA⁻, where impaired plastoquinone reduction and destabilization of the PQ pool suppressed downstream electron transfer and amplified photochemical dysfunction within PSII. These perturbations were reflected in distorted OJIP curves, progressive declines of quantum yields (φPo, φEo), alterations in phenomenological fluxes (ABS/CSm, TRo/CSm, ETo/CSm, DIo/CSm), and steep reductions in performance indices (PIabs, PIcsm), collectively signifying systemic destabilization of PSII reaction centers and the broader electron transport chain. Photochemical impairments converged with excessive ROS accumulation, lipid peroxidation, and membrane destabilization, while concomitant depletion of osmolytes (proline, soluble sugars, starch) revealed collapse of transient buffering capacity and irreversible metabolic breakdown. Ultimately, these disruptions culminated in biomass loss, reduced relative growth rate, and up to 76.3% inhibition at 6 mg/L BP-3. This multi-tiered trajectory, spanning pigment depletion, disruption of electron transport, oxidative disequilibrium, and osmolyte exhaustion, establishes that BP-3 profoundly compromises photosynthetic performance and metabolic homeostasis. Given the keystone role of freshwater macrophytes in nutrient cycling, carbon sequestration, and ecosystem stability, these findings establish BP-3 as a potent ecological hazard and underscore the urgency of stricter discharge controls, regulatory interventions, and its inclusion in priority contaminant monitoring frameworks to safeguard aquatic biodiversity and ecosystem services.