Exogenous Application of Salicylic Acid Mitigates the Toxic Effect of Pesticides in Vigna radiata (L.) Wilczek

Abstract

In this study, we evaluated the pesticide stress response of Vigna radiata (L.) Wilczek (Greengram) and explored the mitigative role of exogenous salicylic acid against pesticide toxicity by assessing various biochemical (enzymatic and non-enzymatic) parameters. The pesticides used in the present experiment were H.A.M-45 (fungicide), Termite kill (insecticide), and Anchor (herbicide), which are commonly used in agricultural fields and storage of grains. Primarily, LC50 was calculated, for defining the maximum permissible concentrations of pesticides which could be used, and thus experimental concentrations used were 1/2 LC50, LC50, and 2 LC50. Exposure of V. radiata to pesticide toxicity at the germination stage for 24 h significantly decreased their growth by reducing the growth-contributing parameters as compared with unstressed. Henceforth, a significant decrease was observed in photosynthetic pigments (chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid), whereas a significant increase was recorded in superoxide dismutase, peroxidase, and catalase (enzymatic biochemical parameters). Exogenous salicylic acid (1 mM) application mitigated the pesticide toxicity when applied together with the pesticide. The positive mitigative effect of salicylic acid was recorded in terms of significant increase in enzymatic biochemical parameters, thus revealing that exogenous application can minimize oxidative stress and consequently contribute to improvement of photosynthetic pigments. Therefore, salicylic acid-treated seeds of V. radiata grown under pesticide stress could be considered to be of improved quality compared to non-treated seeds.