Colonization of sweet potato roots by rhizobacterial isolates

Aim: to detect the colonization of pgpr strains on roots of sweet potato plantlets. root colonization by plant growth-promoting rhizobacteria establishes an efficient association with a more pronounced growth enhancing effect on plants. methods: in vitro scanning electron microscopy (sem) and transmission electron microscopy (tem) studies were conducted to examine the colonization of pgpr strains on roots of sweet potato plantlets. vine cuttings of sepang oren variety were washed several changes of sterilized distilled water and grown in nutrient solution at 7 days. the four bacterial strains klebisella sp. upmsp9,eriwina sp. upmsp10,azospirillum brasilense sp7 and bacillus sphaericus upmb10 were inoculated separately at the time of planting and two different colonization areas were studied root surface and internal region of plant roots. results: the bacteria on the colonized roots are either single or formed small aggregates along surface of sweet potato root-hair zone. the bacteria had colonized and penetrated the intercellular space in the cortex of the root tissues. conclusion: the results suggest that the four bacterial strains could effectively colonize the sweet potato root surface and internal region of 7 day old plantlets by using electron microscopy.