Combined Effects of Phosphate Solubilizing Bacteria and Nanosilica on the Growth of Land Cress Plant

Abstract

The present study was done to isolate and characterize two strains of phosphate solubilizing bacteria from rhizospheres of acacia, sugar beet, and wheat, then determine synergic effects of nanosilica and these strains on the vegetative growth of land cress plant. Isolates identification was performed using physiological, morphological, biochemical tests, and 16S ribosomal ribonucleic acid sequencing. Nanosilica was extracted from Equisetum telmateia and characterized via X-ray diffraction, scanning electron microscopy, dynamic light scattering, Brunauer–Emmett–Teller, and X-ray fluorescence techniques. The size and the purity of extracted silica powder were about 30 nm, 97.5 %, respectively. Two strains, namely, Pseudomonas stutzeri and Mesorhizobium sp. were the most efficient strains to grow and solubilize phosphorus in the presence of 860 mM NaCl and various pH conditions. The highest growth of these two strains was observed at 0.05 and 0.07 ppm of nanosilica. The highest amount of dry weight of shoot and root of land cress plant was recorded with the simultaneous application of these strains in combination with nanosilica. The combination of nanosilica and these strains enhanced the soil nitrogen and phosphorus content and the vegetative growth of land cress plant.