Exploring ion homeostasis and mechanism of salinity tolerance in primary tritipyrum lines (Wheat× Thinopyrum bessarabicum) in the presence of salinity

Abstract

Due to lack of water resources in irrigated agriculture, genetically improving plants to abiotic stresses such as salinity is a necessity for food and feed production. In this respect, the new third man-made amphiploid cereal, tritipyrum (2n=6x=42, AABBEbEb), is an example which is capable of tolerating a high level of NaCl. In order to determine the salinity tolerance mechanisms of this new cereal, an experiment was conducted using hydroponic technique. Ten tritipyrum lines and two wheat cultivars were tested under three levels of salinity (50, 100 and 200mM NaCl). The effect of salinity stress on Na+ and K+ concentration of leaf, shoot and root, proline and chlorophyll content were measured at 50% ear emergence and their grain yield plant-1 was evaluated at physiological maturity. Leaf Na+ concentration in tritipyrum lines increased with increasing salinity while K+ concentration did not show any especial pattern. The chlorophyll and proline content in tritipyrum lines were higher than that of wheat cultivars. Despite the high sodium concentration in tritipyrum lines in comparison with wheat, the grain yield of tritipyrum lines were less affected than that of wheat. There was also a negative correlation between proline content and grain yield plant-1 in tritipyrum lines. It can be concluded that mechanisms such as higher Na+ uptake along with appropriate ion compartmentation could be used by tritipyrum lines to combat with salt stress like some halophytes and it can make tritipyrum lines suitable for planting in saline soils and improving the salinity tolerance of wheat.