Responses of barley Albina and Xantha mutants deficient in magnesium chelatase to soil salinity

Soil salinity reduces the plant growth and grain yield in barley. The barley mutants Albina and Xantha, deficient in magnesium chelatase, represent a suitable model object for analysis of the roles of chloroplast in salt stress response. Spring barley (Hordeum vulgare cv. Svalofs Bonus) and four nonallelic Albina (alb-e16 and alb-f17) and Xantha (xan-s46 and xan-b12) mutants were used to investigate the effects of soil salinity on physiological traits of plants. Under salt stress, larger reduction in stomatal conductance and higher Na concentration was found in Albina and Xantha mutants compared with wild type (WT). In addition, the Albina and Xantha mutants had lower capacity of reactive oxygen species (ROS) scavenging while higher ROS generation rate compared with WT, exposed to soil salinity. Therefore, the limitations in chloroplast development affected Na+/K+ homeostasis and decreased the oxygen scavenging capacity, hence affecting the salt tolerance in barley.