Abstract:
Rhizosphere is defined as “the zone of soil immediately adjacent to legume roots that supports
high levels of bacterial activity’’ The goal of this study was to enhance or improve the
colonization of rhizosphere of tomato plants by plant growth promoting bacteria. PGPR has two
main mechanisms to improve colonization of rhizosphere , first the direct mechanism that
improve growth of plant and including the production of phytohormones and nitrogen fixation,
and the indirect mechanism which decrease the harmful effects of the growth of pathogens by
the production of antibiotics and synthesizing of the lytic enzymes. During this study, 12
bacterial strains were obtained from the rhizosphere of tomato. The greenhouse experiment
indicated that the treatment with Ser, B63, E31 had shown good capacities for tomato root
colonization. To improving the survival rate of tested bacterial isolates, micro- encapsulation
techniques of rhizosphere microorganisms by sodium alginate and calcium chloride was
conducted. The survival rate of bacteria in capsules was estimated during one month shelf life
experiment. Both tested methods free bacterial cells as well as encapsulation technique are
promising tools to be used as successful delivery methods of plant growth promoting bacteria
