Fig. 3.
Competitive colonization root tip assay. The wild-type strain was used as the competitor in all the experiments. Alfalfa plants were inoculated 1:1 with the test strain and the competitor, root tips were collected after 2 weeks, and the bacteria present were resuspended and plated. Gray bars represent the percentages of colonies recovered from the tested strains; black bars represent the percentages of colonies recovered from the competitor (wild-type) strain. Arithmetic means and standard deviations are presented. Average recovered bacteria were 3.63 × 106 CFU/g root tip (fresh weight).