Azolla pinnata R.Br.: a reliable fern species to demonstrate satisfactory in-vitro anti-oxidation under herbicidal toxicity

Abstract

The paper reports the induced antioxidation property of Azolla pinnata R.Br. under elevated conditions of the herbicide 2,4-D. With respect to phenolic accumulation, the plant registered varied in-vitro antioxidation potentials. Total antioxidation through phosphomolybdenum complex, DPPH (2,2-Diphenyl, 1-picryllydrazyl), and ABTS (2,2′-azino-bis 3-ethylbenzo-thiazoline-6-sulfonic acid) radical scavenging activities were the most significant attributes of this plant species. A gradual fall in phosphomolybdenum complex suggested more involvement in the chelation of 2,4-D, with metal ligands. The plant was able to quench the reactive oxygen species (ROS) up to a certain level of 2,4-D but thereafter it failed. Another module with ABTS induced free radical antioxidation, the plant insignificantly responded to any changes of 2,4-D concentrations as compared to the control with reference to BHT (Butylated hydroxytoluene). The most stable phenolic glucoside as flavonoid had a significant and dose-dependent over expression under 2,4-D toxicity. In modules of enzymatic antioxidants, Azolla was quite sensitive to peroxidation of H2O2 by different isozymic proteins. A significant participation of polyphenol oxidase and catalase were more pronounced whereas peroxidases were least significant in in vitro assay. Taking altogether both enzymatic and non-enzymatic antioxidation indices, Azolla is an efficient quencher species for herbicide contaminated soils.