Influence of exogenous application of salicylic acid on salt- stressed mungbean (Vigna radiata): Growth and nitrogen metabolism

To investigate the effect of salicylic acid (sa) on growth and nitrogen metabolism in mungbean grown under saline conditions,an experiment was conducted in wire house in plastic pots containing soil + sand at niab faisalabd. mungbean (vigna radiata l.) varieties,two salt tolerant (nm-98 and nm-92) and two salt sensitive (nm-54 and nm-13-1),identified in laboratory experiments,were grown under four salinity levels,i.e.,1.2,4,8 and 12 ds m-1. salicylic acid @ 0,100,200 and 300 mg l-1 was applied as foliar spray at vegetative and flowering stages. results indicated that salinity reduced the growth by decreasing plant height and fresh biomass of all the cultivars,however,the salt tolerant cultivars performed better than sensitive ones. foliar application of sa @ 100 mg l-1 significantly improved all the growth parameters in all the cultivars under saline conditions. the sa levels of 200 and 300 mg l-1 did not show appreciable performance regarding growth attributes under normal and saline conditions. similarly biochemical attributes like nitrate reductase activity (nra),nitrite reductase activity (nira),soluble proteins and n reduced while total free amino acids increased due to salinity and increase/decrease was progressively enhanced by the increase in salt concentration in the growth medium. application of sa @ 100 mg l-1 was helpful in reducing the adverse effects of salinity on all the above mentioned parameters while other levels of sa did not perform better under all salinity treatments.