Etude de l’effet du stress salin sur la croissance et le potentiel de production de quelques activités liées à la PGP par des Rhizobactéries

Abstract

PGPR are soil bacteria that can stimulate plant growth directly or indirectly by supplying substances that are usually in limited quantities in the soil. For the purpose of assessing the growth and determination of some activities of rhizobacteria under salt stress such as phosphate solubilization and production of indole acetic acid (IAA). Five isolated bacterial isolates from saline soils in the Relizane region were tested. The growth of these isolates on nutrient broth appreciated by the extent of the disorder to salt concentrations ranging from 0 to 500 mM revealed good tolerance up to 500 mM with high rates between 200 and 300 mM NaCl. The amount of phosphorus released by these bacteria leads to a strong solubilization with moderate salt concentrations, and a decrease in the amount of dissolved phosphate in excess of 400 mM NaCl. The maximum production of AIA was recorded in the S5 strain in the absence of salt 87.295 ± 2,033a mcg / ml, then decreased gradually in the presence of NaCl. The S5 strain was the most efficient, that she was able to solubilize phosphate and produce AIA with the highest amounts (941.619 ± 79,248a mcg / ml, 87.295 ± 2,033a mcg / mL), respectively.