Zinc Sulphate and Vermicompost Mitigate Phytotoxic Effects of Arsenic by Altering Arsenic Uptake, Biochemical and Antioxidant Enzyme Activities in Wheat (Triticum aestivum L.)

Abstract

Abstract: Seedlings of wheat genotype HUW-234 (Triticum aestivum L.) were raised in pot soil culture using eight different treatment combinations, enriched with inorganic arsenic (AsV at 0, 30 mg/kg soil), zinc sulphate (Zn at 0, 20 mg/kg soil) and vermicompost (at 0, 15 t/ha). Plants exposed to As toxicity were found significantly (P ≤ 0.05) lower in total chlorophyll, carotenoids and soluble protein content and higher in proline accumulation. A significant (P ≤ 0.05) reduction in nitrate reductase (NR) activity was also noticed under this As stress. As toxicity severely altered the activities of several antioxidant scavenging enzymes in the test seedlings. Superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities were found elevated, whereas, catalase (CAT) showed a decrease in its activity in seedlings exposed to As stress. As a consequence, a significant (P ≤ 0.05) reduction in grain yield (up to 42%) was also recorded. Mitigation of toxic effects of As with significant (P ≤ 0.05) alteration in the biochemical constituents, as well as antioxidant enzymatic activities, was observed when supplemented with zinc sulphate and vermicompost whether alone or in combination. All these examined parameters were correlated either positively or negatively with the concentrations of As in wheat grain, straw and root. The rate of translocation of As in plants was increased when solely treated with As; while a decreasing trend was noticed for those plants which received zinc sulphate and vermicompost as treatment. Hence, this study faithfully establishes the relationship of zinc sulphate and vermicompost application with reduced As content in the plant part, thus resulting in better crop growth and yield. © 2021, Pleiades Publishing, Ltd.