Table 2.

Counts (cfu cm⁻¹) for chloramphenicol-resistant, YFP-tagged Bacillus subtilis MBI600 strain on tomato roots grown in 4 different growth substrates.

Growing System	Days after Application a
	5	15	20
Gnotobiotic system	2 × 105 b b B c	1.3 × 103 bc B	3 × 102 c A
Commercial Peat mixture	3.2 × 105 b B	4 × 102 c A	2.5 × 102 c A
Vegetable soil	4 × 104 b A	2 × 103 bc B	1.7 × 102 c A
Hydroponic cubes	3 × 105 b B	2.4 × 103 bc B	4 × 102 c A

^a Initial application rate of Bs MBI600 was 2 × 10¹⁰ cfu mL⁻¹. ^b Mean values followed by different lowercase letters in the rows indicate significant differences among days for each treatment according to Fisher’s LSD test (p < 0.05). ^c Mean values followed by different capital letters in the columns indicate significant differences among treatments according to Fisher’s LSD test (p < 0.05). Comparisons were made with the initial application rate of 2 × 10¹⁰ cfu ml⁻¹.