Changes in growth variables and potassium content in leaves of Black Barley in response to NaCl

Much attention is being focused on the Black barley (Hordeum distichum L.) as a local cultivar offering good model for a cereal crop has traits of resistance to drought and salinity during vegetative growth stages. Although Black was sensitive to salt stress during germination, it developed gradual tolerance with age and proved very tolerant during growth and development stages. The data of study clearly revealed how this cultivar was superior over Arivat (Hordeum vulgare L.) in many physiological aspects such as leaf growth variables (i.e. rate and duration) and processes (i.e. cell division), tiller production and potassium content. Black barley had more tillers, faster rate and longer duration of growth processes which was accompanied with potassium accumulation, as sodium chloride concentration increased in the growth medium. Thus, the ability of Black cultivar to accumulate K+ could have promoted growth variables (i.e. faster rate and longer duration of growth processes). Arivat, on the other hand, might have suffered from K+ deficiency; which could explain the adverse effect of salt stress on leaf growth variables and processes. Moreover, the relative water content (RWC) and proline can clearly distinguish the two cultivars; RWC was higher and proline concentration was lower in leaves of Black as compared with Arivat. Therefore, Black barley proved efficient in maintaining growth, ion homeostasis, and might sacrifice less in growth under osmotic stress conditions. The possible mechanism of the effect of sodium chloride on potassium accumulation in Black barley is discussed.