Fig. 3. Effect of rhizosphere suspension (Rhiz) or cultured rhizosphere microbes (Cul) on total Se volatilized in 15 d. The 300-mL half-strength Hoagland cultivation solutions were supplemented with either 20 µM sodium selenate or sodium selenite. Each data point represents the mean value of three replicates. Mean values of total volatilized Se ± standard deviation are presented only in Day 15. The mean percentage of Se volatilized during 15 d of incubation is shown in the bar graph along with ± standard deviation. Different letters accompanying mean values of total Se volatilized (left side) and in the bar graph represent means with significant differences (Duncan multiple range test, p < 0.05).