Present research work was conducted to alleviate the salinity-induced harmful effect on biomass production and physiochemical attributes of fenugreek by foliar application of salicylic acid. Two varieties (Deli Kabul and Kasuri) were grown in salt treated (100？mM NaCl) and untreated (0？mM NaCl) growth medium. Two levels of salicylic acid (0？mg？L？1 and 100？mg？L？1) were applied through foliar method. Salinity stress significantly reduced the growth biomass in both varieties. Higher shoot fresh weight was recorded in Deli Kabul, while lower in Kasuri. Such reduction in growth biomass was mitigated by the foliar application of SA in both plants. Salinity caused a marked reduction in gas exchange attributes including net CO2 assimilation rate, transpiration rate, stomatal conductance, and substomatal CO2 concentration. Exogenous applied salicylic acid also overcomes the reduction in gas exchange attributes of the plants. The varieties “Deli Kabul” and “Kasuri” showed higher and lower net CO2 assimilation rate, respectively. These results indicate that growth medium salinity induced reduction in biomass production, gas exchange attributes, and also chlorophyll contents whereas the application of SA through foliar method can be used to protect plant growth and improve these attributes under salt stress. 1. Introduction Accumulation of salt whether in soil or water adversely affects various physiological and biochemical processes. For example, reduction in photosynthesis under saline conditions in Safflower [1] and sunflower [2]. Salt-induced reduction in photosynthesis depends on decrease in chlorophyll contents, leaf area, net photosynthetic rate, stomatal conductance, and substomatal CO2 concentrations [3]. Accumulation of salts in the growth medium induces the formation of toxic reactive oxygen species (ROS) including singlet oxygen and superoxide and hydroxyl radical. These reactive oxygen species injured chloroplasts and mitochondria by damaging their cellular structure [4]. To overcome these reactive oxygen species, plants generate antioxidant defense system. Antioxidant defense system produces antioxidant compounds or antioxidant enzymes [5]. It was also suggested that salt tolerance could be promoted by increasing antioxidant defense system in plants. Salicylic acid is a phenolic compound having ability of antioxidant defense system that regulates various physiological and biochemical processes in plant [6]. Salicylic acid has a key role in tolerance of abiotic stress such as salt tolerance in pea [7], wheat [8], rice [9], sunflower [10], and barley
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