The Effect of Seed Inoculation with Funneliformis mossea Mycorrhiza on Some Morphophysiological and Biochemical Traits of Barley (Hordeum vulgare L.) Under Salinity Stress Conditions

Introduction Barley is the fourth most important cereal in the world and is considered one of the least expected crops that has adapted and distributed globally due to its resistance to salinity. The growing world's population has expanded the cultivated domain, which caused the utilization of extravagant chemical fertilizers in modern agricultural cropping systems. This approach has not been cost-effective and has caused severe environmental damages like contaminating the underground water and creating unusual salinity in the fields. Therefore, it seems to be essential to replace risky approaches with eco-friendlier methods. In addition, with increasing environmental stress as a result of climate warming, we need to understand better ways to reduce environmental stress for the sustainable production of barley. Mycorrhiza has been introduced as an essential portion of agricultural ecosystems because of its positive effect on the soil texture, growth, and productivity of almost all host plants. This trend is attributed to reduced chemical fertilizer demands. Mycorrhiza enhances the water relations under stress conditions, water and nutrient uptake by augmenting the hyphae network. In this study we aimed to investigate the role of mycorrhizal inoculation in alleviating the detrimental effects of salinity stress on barley. Our hypotheses were: (i) mycorrhizal inoculation can alleviate the detrimental effect of stress at low to medium levels but not at high levels of salinity, and (ii) there is an interaction effect of low levels of salinity and arbuscular mycorrhizal symbiosis lead to higher the performance of barley. Materials and Methods In order to evaluate the effects of Funneliformis mosseae mycorrhiza on morphological, biochemical and yield of barley, one experiment was conducted in research farm of School of Agriculture, Shiraz University. Field experiment was a split-plot in a randomized complete block design with three replications. Factors included salinity levels (0.4, 4, 8 and 12 dS m-1) as the main factor and the mycorrhiza (with and without) was applied as sub factor.  Data were analyzed by using SAS 9.2 software and the means were separated using LSD test at 5% probability level. Results and Discussion The results of the experiment showed that salinity decreased yield and vegetation traits, including plant height, number of tillers per plant, number of spikes per plant, number of seeds per spike, 1000-grain weight, grain yield, and biological yield. All the measured traits in plants inoculated with mycorrhizal fungi were higher than the non-mycorrhizal plants. The inoculation of plants in most cases improved the effects of stress; i.e., inoculation under high salinity stress (12 dS m-1) increased SOD by 5.7%, CAT by 8.0%, K concentration by 30.8%, K/Na ratio by 131.1%, plant height by 8.1%, number of spikes per plant by 9.4%, number of grain per spike by 6.6%, 1000-grain weight by 4.2%, grain yield by 20.2%, and biological yield by 11.0% compared with non-inoculation plants. Also, Fayaz and Zahedi (2021) reported that mycorrhizal inoculation could promote the growth and salt tolerance of wheat cultivars by improving osmoregulation and antioxidant enzyme activity and reducing the Na+/K+ ratio. Conclusion In this experiment, inoculation treatment alleviated the high salinity stress (12 dS m-1) effects in most cases and raised the grain yield and K+/Na+ ratio up to 20.2 and 131.1%, respectively, compared with non-inoculation plants. The results from this experiment showed that Funneliformis mosseae fungi inoculation could promote the growth and salt tolerance of barley by improving antioxidant enzyme activity, and ion homeostasis. In summary, the use of Funneliformis mosseae could reduce salinity damages by improving the physiological and biochemical responses of barley. This study highlighted the potential role of Funneliformis mosseae inoculation, in particular with native strains, as an innovative and eco-friendly technology for a sustainable crop-growing system in arid and semi-arid areas.