Comparative analysis of salt impact on sea barley from semi-arid habitats in Tunisia and cultivated barley with special emphasis on reserve mobilization and stress recovery aptitude

Abstract

The considerable genetic variability of salt tolerance in Hordeum vulgare L. and its wild relative species Hordeum marinum Huds. (sea barley) is a potentially useful trait to develop well-adapted varieties to salt-affected areas. Here, two local barley (Manel and Rihane) cultivars and two local sea barley accessions (Kelbia and Soliman) were compared for their response to salt (up to 200 mM NaCl) exposure at the germination and seedling stages. Increasing salinity significantly decreased seed imbibition and seed reserve mobilization parameters (notably amylase activity), resulting in delayed germination, lower germination percentage and altered seedling root length. Interestingly, inter- and intra-specific variability was observed as cultivated barley (especially Rihane) was less salt-affected when considering final germination percentage. Yet, sea barley Soliman accession showed the highest values of seed vigor (seeds reaching the seedling stage) and efficiency of seed reserve mobilization under saline conditions. In addition, even at 200 mM NaCl, salinity impact was reversible on seeds of sea barley, in contrast with cultivated barley. Overall, while confirming the sensitivity of barley at the early developmental stages, this study provides additional criteria that would allow more accurately addressing inter-specific variability of plant behavior at this crucial step of its life cycle.