Bisphenol-A incite dose-dependent dissimilitude in the growth pattern, physiology, oxidative status, and metabolite profile of Azolla filiculoides.

Abstract

Bisphenol-A (BPA) is a ubiquitous environmental pollutant affecting the growth and development of aquatic macrophytes. The present study was designed to evaluate the toxic effect of BPA on Azolla filiculoides. The plants were exposed to different concentrations of BPA and the effect was evaluated in terms of plant growth, physiological and oxidative status, responses of the antioxidative system, and changes in key metabolites. The results have shown that BPA (≥ 20mg L-1) incites a significant reduction in frond number, frond surface area, and growth rate of the plants along with severe frond damage, membrane peroxidation, and electrolyte leakage. Moreover, at higher concentrations, a significant reduction in the content of chlorophylls and carotenoids was observed, which was further amplified with the duration of treatments. Furthermore, excessive generation of O2•- and H2O2 invoked the antioxidative machinery under BPA exposure. However, sufficient activity of the antioxidative enzymes was observed in plants treated with ≤ 10mg L-1 of BPA. The untargeted metabolome profile revealed modulation of 29 metabolites including amino acids, sugar alcohols, organic acids, and phenolics in response to BPA. An increased amount of asparagine, lysine, serine, tryptophan, tyrosine, and valine after 3days of BPA exposure indicates their role in providing better stress tolerance. Therefore, the experimental findings suggest that A. filiculoides responds differently to BPA exposure. Higher BPA concentrations (≥ 20mg L-1) documented a greater impact in terms of plant physiology and metabolism whereas, the effect was minimal at lower concentrations (≤ 10mg L-1).