The concentration of calcium and iron in wheat plants during the formation of Casparian strips under the influence of salinization and growth-stimulating bacteria

Both salinity and bacterial inoculation into the rhizosphere can negatively affect the uptake of mineral nutrients by plants, promoting the formation of apoplastic barriers. In this study, an attempt was made to study the effect of salinity and inoculation of wheat plants with growth-promoting bacteria Pseudomonas mandelii IB-Ki14 and Bacillus subtilis IB22 on the formation of Casparian bands and the concentration of calcium and iron ions important for plants. Under the influence of salinity, stimulation of the formation of apoplastic barriers in the roots was noted. When inoculated with bacteria both with and without the effect of sodium chloride, the most noticeable was the enhancement of the formation of Casparian bands under the influence of the P. mandelii IB-Ki14 strain. Both salinity and bacterization of wheat plants affected the content of calcium and iron in them. Some of these effects (reduction of calcium level in shoots under the influence of P. mandelii IB-Ki14 strain against the background of salinity, as well as changes in the distribution of calcium and iron between the shoot and root under salinity) can be explained by the strengthening of apoplastic barriers. However, the relationship between the change in the level of these elements and the formation of apoplastic barriers could not be traced in all cases. The dependence of the change in the level of calcium and iron on the effect of salinity and bacteria on the activity of ion transporters and the ability of bacteria to produce siderophores is discussed as a possible mechanism.