PREP activity
The PREP activity of the bacterial strains was determined in seed pack growth pouches either in the presence or absence of cadmium. The effect of each Cd-resistant strain on root elongation in B. napus is shown in Table 2. The addition of 0.4 mM Cd2+ inhibited root elongation of uninoculated seedlings by 24% (Duncan test, Pp0.05). All the inoculated strains showed PREP activity in the absence of Cd2+ and were also capable of significantly increasing the root length of Cd-treated seedlings. Specifically, the maximum root length promoting effect on un-treated and treated plants was observed after inoculation with P. fluorescens ACC9 and P. tolaasii ACC23. P. fluorescens