Comparative Study of Salinity Effect on Some Tunisian Barley Cultivars at Germination and Early Seedling Growth Stages

Abstract

In the present study we investigate the effect of two NaCl concentrations (100 and 200 mM) on the germination, growth (dry weight production, leaf area, water content) and physiology (ion content, proline and soluble sugar concentrations), chlorophyll content and fluorescence of three Tunisian barely cultivars: Rihane, Kounouz and Lemsi. Seeds were germinated and grown in Petri dishes on filter paper with solution of the respective treatment, then carried and grown out in pots under semi-controlled conditions. The barley cultivars were grown with 3 different treatments NaCl 0 mM as control, 100 mM and 200 mM of NaCl, added to the Hoagland’s nutrient solution. Salt stress decreased, daily germination, dry weight, leaf area, leaf water content and K+ contents in all varieties. Indeed, as salinity increased, a progressive and a significant increase of proline and Na+ contents were observed. Based on the Germination stress tolerance index (GSI), Kounouz cultivar tolerates the best salinity at germination stage. However, at tillering stage, the Sensitivity index (SI) shows that Rihane is the most tolerant cultivar. Indeed, it accumulates the highest content of proline in leaves as compared with the other cultivars and its accumulation rose with the increasing salt concentration and kept the higher K+/Na+ ratio.