MITIGATION OF ARSENIC TOXICITY BY FOLIAR APPLICATION OF SALICYLIC ACID IN WHEAT

Abstract

A pot experiment was conducted in the farm of Sher-e-Bangla Agricultural University, Dhaka, during rabi season, November 2015 to March 2016 to assess the contribution of Salicylic acid (SA) on mitigation of Arsenic (As) toxicity in wheat. In this experiment, the treatment consisted of four different As levels viz. As0 = without As (control), As1 = 30 mg As kg-1 soil, As2 = 60 mg As kg-1 soil, AS3 = 90 mg As kg-1 soil and three different levels of SA viz. S0 = 0 mM, S1= 0.2 mM and S2 = 0.4 mM. The experiment was carried out in two factors Completely Randomized Design (CRD) with four replications. The total treatment combinations were 12 (4x3).The experimental results showed significant variation on morpho-physiological, yield contributing character and yield other than SPAD value of wheat. The morpho-physiological, yield contributing characters and yield were noticeably affected by different levels of As. The greater amount of As caused greater reduction of growth which related to morphology and yield than control or without As. The morphological characters: plant height, number of leaf, tillers and effective tiller plant-1; physiological characters: membrane stability, yield contributing characters: number of spikelet, effective spikelet spike-1, spike length, number of grains spike-1, grain yield plant-1 and 100 grain weight of wheat were noticeably decreased due to As whereas exogenous application of SA improved the morpho-physiological, yield contributing characters and yield of wheat. The foliar application of SA increased plant height, leaf, tillers and effective tiller numbers plant-1, number of spikelet, effective spikelet spike-1, spike length, number of grains spike-1, grain yield plant-1 , and 100 grain weight of wheat. The physiological character, SPAD value which indicates chlorophyll content was not significantly changed due to salicylic acid. These results shows that salicylic acid has positive effect on both reproductive and vegetative attributes of wheat. The interaction between different levels of As and SA has significant effect on almost all the morpho-physiological parameters including yield contributing characters and yield of wheat. The highest grain yield plant-1 (2.4 g) was recorded at As0S2 (Without As + 0.4 mM SA) treatment combination. But the grain yield was gradually decreased with the increasing level of As toxicity. The application of SA increased the grain yield differently according to the levels of As. The minimum grain yield plant-1 were found 1.8 g, 1.5 g and 1.00 g at 30mg, 60mg, and 90mg As kg-1 soil, respectively. These yields were increased with SA (0.4 mM) from 1.8 to 2.2 g, 1.5 to 1.8 g and 1.0 to 1.20 g at 30mg, 60mg, and 90mg As kg-1 soil, respectively. These results suggest that SA mitigate the adverse effects of As toxicity and thereby increase the grain yield of wheat.