Effect of foliar application of salicylic acid on some physiological traits of sugar beet in salt stress conditions

To investigate the effect of salicylic acid (SA) on salinity tolerance of two sugar beet cultivars, this experiment was conducted as split factorial based on a randomized complete block design with three replications during growing seasons of 2012 and 2013 in Research Farm of Shahid Chamran University. The studied factors were three levels of SA (0 mM, 0.5 mM and 1 mM), two levels of salinity (150 mm sodium chloride and control) and two sugar beet cultivars (Jolgeh and Shariff). SA was applied as foliar spray along with salinity in the 4-leaf stage. Results showed that foliar application of SA caused significant increase of leaf area (LA), chlorophyll, stomatal conductance, ФPSІІ, Fv/Fm, proline and total soluble sugars, and decrease membrane permeability compared to control under salt stress conditions. Salinity caused a significant decrease in LA, Chlorophyll, stomatal conductance, ФPSІІ and Fv/Fm, while increase proline, total soluble sugars and membrane permeability. Therefore, according to the results of this research, it seems, foliar application of salicylic acid could enhance sugarbeet growth and increases resistance to salt stress.