Abstract
Despite the prevalence of the common pharmaceutical ibuprofen (IBU) in water and sediments worldwide, the effects of IBU on plants are largely unknown. This study was designed to assess the ecotoxicological effects of emerging pharmaceutical pollutant IBU on plant growth and development in a series of toxicity experiments using cowpea (Vigna unguiculata). Plant growth parameters (morphological and physicochemical) were investigated under a series of IBU concentrations (0, 400, 800, 1200, 1600, 2000 ppm IBU). IBU exposure reduced the shoot and root lengths, fresh and dry weights, leaf area, and chlorophyll a and b, carotenoid, total chlorophyll, mineral (K and Mg), glutathione reductase, and soluble protein contents. Simultaneously, increases in Ca and Mn contents, sodium translocation from roots to shoots, H2O2, malondialdehyde, superoxide dismutase, catalase, ascorbate peroxidase, and IBU uptake were observed. The amount of bioaccumulated IBU varied between 7% and 8%. IBU was translocated from roots to shoots with a translocation factor of 3-16%. The IC50 values for biomass and plant length were 1253 and 1955 ppm IBU, respectively, which is much higher than the reported levels of IBU in the environment. This study demonstrates that cowpea plants develop several morphological and physicochemical adaptations to cope under ibuprofen stress; environmentally relevant concentrations of IBU are unlikely to produce negative impacts.