Effect of salinity on root characteristics of Sahara 3771 (salt tolerant) and Clipper (salt sensitive) barley varieties

Salinity is one of the most important abiotic stresses that decreases agricultural production in arid and semi-arid soils. To study the effect of salinity on root characteristics, Sahara3771 (salt tolerant) and Clipper (salt-sensitive) cultivars were evaluated in a factorial experiment based on randomized complete block design with three replications under 100 mM NaCl and normal conditions in hydroponic culture. Salinity treatment was applied at three leaves stages and continued for five weeks. To establish salinity stress, 500 mL of NaCl along with the half concentration of Hoagland solution was added at first day of stress treatment and after second day and onwards, 1000 mL NaCl and complete concentration of Hoagland was used. Root length, volume, fresh and dry weight, chlorophyll fluorescence and K+/Na+ ratio were measured at 24 hours, three weeks and five weeks after stress application. Analysis of variance and mean comparisons revealed that 100 mM NaCl compared with normal condition caused a significant reduction in root fresh weight and the K+/Na+ ratio. Significant differences were observed among growth stages for root fresh and dry weight and K+/Na+ ratio and with advanced of growth stages, the mean of studied traits was increased. Significant differences were found between cultivars for root volume and fresh weight at 1% probability level. Maximum root length and volume was observed in Sahara 3771 at shooting stage. Salinity stress caused more reduction in root weight and K +/Na+ in the susceptible cultivar (Clipper) compared with tolerant one (Sahara 3771).