Efficiency of Plant Growth-Promoting Rhizobacteria <i>Pseudomonas </i>for Barley Growing on Pb-Contaminated Gray Forest Soil
The effects of plant growth-promoting rhizobacteria of the genus Pseudomonas on the growth and chemical composition of barley plants were examined in pot experiments on an artificially Pb-contaminated gray forest soil. Inoculation with bacteria enhanced the tolerance of plants to Pb contamination, decreased the Pb concentration in shoots by 2-6 times at the booting and heading stages, and had no effect of the soil pH. The maximum effect was found at the application of bacterium P. fluorescens 21. Bacteria slightly affected the contents of N, P, K, Ca, Mg, Na, and Mo in plants and increased the uptake of most nutrients, especially Na, by shoots from the contaminated soil. In spite of the decrease in the concentrations of Fe, micronutrients Zn, Mn, and especially Cu and Co in plants inoculated with P. fluorescens 21 under Pb contamination, the application of this strain increased the plant green mass by almost 20% compared to the uninoculated control and ensured the yield comparable to that obtained on the uncontaminated soil without inoculation. The elimination of toxic Pb effect and the decrease in the content of some elements in the inoculated plants could result in the formation of stable complexes of elements with bacterial siderophores. At the application of P. fluorescens 21, the effect was also related to the biological or plant growth dilution as a result of increase in plant biomass