The effect of plant growth promoting potentials of rhizosphere bacteria isolated from several halophytic species on vegetative growth and ionic content of wheat

Salinity stress is an important challenge for wheat production in the world. Plant growth promoting rhizosphere bacteria, isolated from halophytic plants, can increase the tolerance of crop plants to salinity by direct and indirect mechanisms. In this study, plant growth-promoting traits of bacterial strains (Bacillus safensis, Bacillus pumilus and Zhihengliuella halotolerans), isolated from the rhizosphere of several halophyte plants, were deterimined and their effects on some vegetative traits and ionic content of wheat plant irrigated with saline water ( 0.2, as control,  4, 8 and 16 dS/m) were measured. Result showed that all three bacteria were able to produce auxin, hydrogen cyanide, siderophore, 1-aminocyclopropane-1-carboxylic acid deaminase and soluble phosphate. The increase in salinity levels caused increase in the concentration of sodium and decrease in the concentration of potassium, calcium and phosphorus in wheat leaves, as well as decrease in stem length, shoot and root dry weight, root to shoot dry weight ratio and total biomass. In wheat plants irrigated with saline water and inoculated with the bacterial strains, sodium concentration decreased up to 17.7% and concentrations of potassium, calcium, phosphorus and potassium to sodium ratio increased up to 33, 25.7, 200.4 and 41%, respectively. The most efficient bacterium was found to be Z. halotolerans. All bacterial isolates also increased stem length, shoot and root dry weight, root to shoot dry weight ratio and total biomass by 17, 58.6, 137, 88 and 66 %, respectively. The results of this study showed that the plant growth-promoting bacteria of rangeland halophytic plants potentionally improve the growth indices of wheat plants in saline conditions. These results also showed that the rhizosphere of halophytic plants in rangelands can be a good source for the isolation of salinity-resistant bacteria to improve the resistance of wheat plants to salinity.