Phytoremediation of arsenic-contaminated water: the role of antioxidant metabolism of Azolla caroliniana Willd. (Salviniales)

Abstract

Phytoremediation has proven to be an effi cient technology for removing arsenic (As) from water, but the plants used in this process need to be tolerant to the damage caused by As. Th e toxic eff ect of As on growth and functioning of the antioxidant system was studied in individual plants of Azolla caroliniana exposed to fi ve concentrations of As (0.0, 0.25, 0.5, 1.0 and 1.5 mg L -1 ) for the course of fi ve days. Growth, As absorption, enzymatic activity, total and non-protein thiols and anthocyanin content were assessed. Azolla caroliniana was able to take up large amounts of the pollutant, reaching As concentrations of 386.1 µg g -1 dry weight without saturating the absorption mechanism. Th e tolerance index and the growth of A. caroliniana decreased with the increased As uptake. Superoxide dismutase, peroxidases, catalases and glutathione reductase activities increased at lower doses of As and subsequently declined with higher concentrations, whereas ascorbate peroxidase activity was reduced in all treatments. Unlike the enzymatic defence system, anthocyanin and thiol content increased consistently in all treatments and showed a positive correlation with As concentration. Th erefore, the increased synthesis of non-enzymatic antioxidants is most likely the main factor responsible for the high As tolerance of A. caroliniana.

Oxidative stress triggered by arsenic in a tropical macrophyte is alleviated by endogenous and exogenous nitric oxide

“…It is possible that even the high levels of ROS present in plants treated with As ? SNP compared with control plants were not enough to induce oxidative damage, yet similar levels of ROS have been previous demonstrated to induce oxidative stress in other aquatic plant species (Farnese et al 2014a;Leão et al 2017). Considering that the ROS levels measured in As ?…”

Azolla for Water and Land Phytoremediation Against Heavy Metals: A Mini Review

“…While Azolla filiculoides Lam is able to tolerate up to 4 mg L -1 hidrazin as well as Cd, Cr, Cu, Ni, and Zn at 10 000 mg L -1 , 1 990 mg L -1 , 9 000 mg L -1 , and 650 mg L -1 , consecutively [24,25], Azolla caroliniana Lam. is adept in absorbing pollutant up to the concentration of As 386.1 g g -1 dry weight [26] and Azolla pinnata R.Br. is capable of degrading pollutant in contaminated river water [27].…”

Sustainable Upcycling of Mushroom Farm Wastewater through Cultivation of Two Water Ferns (Azolla spp.) in Stagnant and Flowing Tank Reactors

“…Although a limited negative effect of toxic elements was observed on biomass production, a high decrease in Cd percentage (to around 22%) and less reduction in Pb (to around 90%) in wastewaters were noted. Wild A. caroliniana was assessed for its removal potential of arsenic (As) from polluted water [17]. Authors found a high tolerance of this species for As associated with a considerable removal of this toxic element from water.…”

“…Horticulturae 2022, 8, x FOR PEER REVIEW 3 of 13 [17]. Authors found a high tolerance of this species for As associated with a considerable removal of this toxic element from water.…”