Comparative analysis of physiological and biochemical responses to salt-stress reveals key mechanisms of salt-tolerance in some Saudi Wheat Cultivars

Abstract

Wheat (Triticum aestivum) is one of the most essential staple food crops since thousands of years with a massive economic importance worldwide. Wheat has been widely considered to be a moderately salt tolerant plant and its tolerance and responses to salinity stress vary among different tissues and cultivars. This study was conducted to investigate the impact of salt stress on growth and yield of three Saudi bread wheat cultivars, Najran, Mebiah and Qiadh, and characterize the differential responses of the roots and shoots to reveal different underlying mechanisms for salt tolerance. One-month old plants grown under control and salinity conditions were harvested to measure growth parameters (including fresh weight, dry weight and plant length), biochemical response (i.e. proline, soluble sugars, starch and organic acids contents) and antioxidant activity (phenolics content). A distinctive variation was observed between the three cultivars, Najran was the most tolerant to salt stress while Qiadh was the most susceptible cultivar. Under salt stress, a dramatic decline in growth parameters was noticed across all cultivars however, Qiadh exhibited the most conspicuous reduction in growth as well as in yield. In contrast, a pronounced increase of metabolite contents was shown in the three cultivars under salinity stress and was different not only between these cultivars but also between root and shoot tissues. The obtained results confirm that different wheat cultivars employ various mechanisms to alleviate the harmful effects of salt stress. The diversity in salt stress responses among different wheat cultivars can offer a promising avenue for enhancing crop productivity. In this study, the salt-tolerant Najran cultivar can serve as genetic source for breeding programs aimed at developing new varieties with enhanced salt tolerance.