FIG. 4.

Survival on plastic beads of Rhizobium sp. strain SU343 and B. lupini WU425 cells. The numbers of viable cells that were recovered 30 min after inoculation onto beads from peat cultures were between 1 × 10⁵ and 3 × 10⁵ bead⁻¹ for SU343 and 1 × 10⁴ and 5 × 10⁴ bead⁻¹ for WU425. The numbers of viable cells after 24 h are expressed as a percentage of viable-cell numbers counted, as described, 30 min after inoculation onto the beads. The survival rate is significantly higher (P < 0.05) for SU343 cells from 14-, 24-, and 51-day-old peat cultures (more than 1%) than for those from 1-, 3-, and 10-day-old peat cultures (less than 0.1%). The survival rate is significantly higher (P < 0.05) for WU425 cells from 14-, 21-, 28-, 56-, and 85-day-old peat cultures (more than 5%) than for those from 1- and 6-day-old peat cultures (less than 0.5%). The data are the means of four samples taken from each of two individual packets of peat cultures. The error bars represent the standard deviation of the mean.