Abstract
BACTERIAL species produce a variety of beneficial metabolites for plant growth and survival, as well as defend their hosts from attack of certain pathogens. The present study was carried out to investigate the impact of different bacterial isolates on the seed germination and seedling growth of Parkinsomia aculeata L. as a species of arid zones. Both soil samples and tested seeds were collected from El-Madina El-Monawara city, Saudi Arabia in May, 2013. Results evinced the promotion of seed germination by all bacterial isolates used. Isolates 6 and 7 (Micrococcous sp. and Sporosarcia sp.), respectively isolated from soils of extremely low salinity recorded the highest values of germination percentage (44 and 48). On the same time, the greater seed vigor index (83.04), and energy of germination (1.96) were given by isolate 7 at the 7 th day of the experiment. On the other hand, the highest R/S ratio (0.55), on the basis of length, and the highest dry weight of root and shoot were attained by Bacillus subtilis isolate.