Germination and Growth Characteristics of Knockout and Knockout Barley Lines under Salt Stress.

genes () and () play a regulatory role in cuticle organization. Because the cuticle is a key evolutionary acquisition of plants for protection against environmental factors, a knockout (KO) of each gene may alter their ability to adapt to unfavorable conditions. A potential pleiotropic effect of or gene mutations can be assessed under salt stress. Initial developmental stages are the most sensitive in living organisms; therefore, we evaluated salt tolerance of KO and KO barley lines at the seedling stage. Air-dried barley grains of the KO lines and of a wild-type (WT) line were germinated in NaCl solutions (50, 100, or 150 mM). Over 30 physiological and morphological parameters of seedlings were assessed. Potential pleiotropic effects of the gene KO under salt stress included the stimulation of root growth (which was lower under control conditions) and root necrosis. The pleiotropic effects of the gene KO under the stressful conditions manifested themselves as maintenance of longer root length as compared to the other lines; stable variation of most of morphological parameters; lack of correlation between root lengths before and after exposure to NaCl solutions, as well as between shoot lengths; and the appearance of twins. Salt tolerance of the analyzed barley lines could be ranked as follows: KO > KO ≈ WT, where KO lines were the most salt-tolerant. A comparison of effects of salinity and ionizing radiation on KO and KO barley lines indicated differences in tolerance of the lines to these stressors.