TABLE 2.

Soil representation and populations of P. fluorescens strains Pf0-2 and Pf0-5a (adnA mutant) at various depths from the inoculation plug

Strain or parameter	Populationa or parameter at following depth (cm)
	Inoculum	0–2	2–6.5	6.5–13	13–15.5	15.5–18	18–21.5	21.5–25
Pf0-2	7.62	6.6 ± 0.4	5.03 ± 0.41	4.4 ± 0.3	4.02 ± 0.3	4.05 ± 0.4	2.7 ± 0.35	1.38 ± 0.2
Pf0-5a	7.43	6.4 ± 0.4	4.2 ± 0.35	3.7 ± 0.28	2.3 ± 0.41	2.07 ± 0.6	1.9 ± 0.5	1.2 ± 0.2
Ratio (Pf0-2:Pf0-5a)bc	1.5:1	1.5:1	6:1∗∗	5:1∗	49:1∗∗	99:1∗	6:1∗	1.5:1
n		6	5	6	5	5	3	4

^aMean values for log CFU/gram of dry soil followed by standard error. Means of strains were determined using the values of each time sampled. 

^bWe used a Student's t test for paired observations to determine whether the ratio of the strains was significantly different from that at inoculation, i.e., 1.5:1. At each depth, the populations of both strains were paired and each time sampled was considered a replication. Results are representative of two experiments. 

^cSignificantly different ratios are indicated at P ≤ 0.1 (∗) and P ≤ 0.05 (∗∗).