ALLEVIATION OF SALT STRESS IN WHEAT WITH SALICYLIC ACID

Abstract

A pot experiment was conducted in the farm of Sher-e-Bangla Agricultural University, Dhaka, during Rabi season, November 2014 to March 2015 to examine the role of salicylic acid on alleviation of salt stress in wheat. In this experiment, the treatment consisted of four different salinity levels viz. S0 = without salt (control), S1 = 2.8 g NaCl kg-1 soil ≈ 3-4 dSm-1, S2 = 6.0 g NaCl kg-1 soil ≈ 7-8 dSm-1, S3 = 9.0 g NaCl kg-1 soil ≈ 11-12 dSm-1 and three different levels of salicylic acid viz. A0 = 0 mM, A1= 0.2 mM and A2 = 0.4 mM. The experiment was laid out in two factors Randomized Complete Block Design (RCBD) with four replications. The total treatment combinations were 12 (4x3). Results of the experiment showed a significant variation among the treatments in respect of most of the studied parameters. The morpho-physiology, yield contributing characters and yield of wheat are affected by different levels of salinity. The higher levels of salinity showed greater reduction of growth, development and yield component to control or without NaCl. The morphological characters such as plant height, leaf number, both total tiller and effective tiller number plant-1; physiological parameter membrane stability, fresh and dry weight plant-1, yield contributing characters such as number of spikelet spike-1, number of grains spike-1, grain weight spike-1, 1000 grain weight and yield of wheat significantly decreased due to salinity. Separately exogenous application of SA improved the morpho-physiology, yield contributing characters and yield of wheat. The foliar application of SA increased plant height, leaf number, both total tiller and effective tiller number plant-1, fresh and dry weight plant-1, number of spikelet spike-1, number of grains spike-1, grain weight spike-1, 1000 grain weight and yield of wheat. At salt stress, the SPAD value which indicates chlorophyll content did not show any significant difference due to salicylic acid. These results indicate that salicylic acid has positive effect on reproductive attributes of wheat. The interaction between different levels of salinity and salicylic acid influenced on almost all morpho-physiological parameters and yield contributing characters and grain yield of wheat. The SPAD value of leaf of wheat did not show any difference with interaction effect of salinity and salicylic acid. The highest grain yields (1.55 t ha-1) were recorded at S0A2 (Without Salt + 0.4 mM SA) treatment combination which did not show any difference with S0A0 (Without Salt+ Without SA) and S0A1 (Without Salt + 0.2 mM SA). But the grain yield was gradually decreased with the increasing level of salinity. The application of SA increased the grain yield differently according to the levels of salinity. The minimum grain yields were found 1.14 t ha-1, 1.07 t ha-1 and 0.26 t ha-1 at 3-4 dSm-1, 7-8 dSm-1 and 11-12 dSm-1 NaCl respectively. These yields were increased with SA (0.4 mM) from 1.14 to 1.32 t ha-1, 1.07 to 1.14 t ha-1 and 0.26 to 0.31 t ha-1 at 3-4 dSm-1, 7-8 dSm-1 and 11-12 dSm-1 NaCl respectively. These results suggest that SA can alleviate the detrimental effects of salinity to increase the grain yield of wheat.