TABLE 7.

Population densities of strains Q8r1-96Gm and Q2-87 bearing pME6010 or pME6010sss on the roots of wheat grown in Quincy virgin soil

Straina	Mean population densityb	AUCPCe
Q8r1-96Gm(pME6010)	7.6 a	43.7 ab
Q8r1-96Gm(pME6010sss)	7.8 a	44.6 a
Q2-87(pME6010)	6.5 b	38.9 c
Q2-87(pME6010sss)	6.9 ab	40.5 bc
Controlc	NDd	ND

^aRaw Quincy virgin soil was treated with ∼10⁴ CFU per g of soil of strain Q8r1-96Gm or Q2-87 containing the empty vector pME6010 or the pME6010 derivative with cloned sss. Rhizosphere population densities of bacteria were determined by the terminal dilution endpoint assay as described in Materials and Methods.

^bThe values are mean population densities in log CFU per g (fresh weight) of root for six cycles except cycle 0. Different letters after values in the same column indicate that there is a statistically significant difference as determined by Fisher's protected least-significant-difference test (P = 0.05).

^cTreatment without bacterial inoculation.

^dND, not detected.

^eThe values are areas under the colonization progress curves for introduced bacteria for six cycles. Different letters after values in the same column indicate that there is a statistically significant difference as determined by the Kruskal-Wallis all-pairwise comparison test (P = 0.05).