Effect of different levels of salicylic acid on growth improvement and some physiological and biochemical indices of sugarcane (Saccharum officinarum L.) under salinity stress

In order to study the effects of exogenous application of salicylic acid (SA) on the growth and some physiological and biochemical responses of sugarcane (Saccharum officinarum L.), a factorial experiment was conducted based on randomized completely design with three replications in a greenhouse at the Institute of Development Research and Training for Sugarcane Crop in Khuzestan, Iran in 2012. Treatments evaluated in this study were three levels of salt stress, including (ECW<1 dS / m, ECW = 3 dS / m, ECW = 6 dS / m), and four concentrations of (SA) including 0, 0.5, 1 and 1.5 mM. Results showed that the effect of salt stress and application of SA were significant (P < 0.05) on various physiological, biochemical and also morphological indices. The foliar application of SA during vegetative phase caused enhancements in plant height, aboveground fresh weight, root fresh weight and a reduction in cell membrane relative permeability. The most effective treatment was spraying with 1 mM SA which resulted in 11.38, 8.88, 18.23,10.61 and 55.80 % increase in plant height‚ shoot fresh weight, root fresh weight, total dry weight, shoot K+/Na+ ratio, respectively, and 15.28 % reduction in plasmalemma permeability in comparison with control treatment. The application of 1.5 mM SA showed less positive impact under salinity stress due to alterations of plant physiological traits compared to other SA concentrations. The results suggested that application of 1 mM SA was effective in reducing the damage of salinity and its foliar application under similar soil and water conditions could be helpful for sugarcane production with salinity up to 3 dS/m.