TABLE 4.

Polygalacturonase activity and growth rate of rhizoplane microbial population

Samplea	Activity of polygalacturonase (U)		Bacterial cell no. after 12 h of incubation in pectin medium (cells/ml)b
	pH 6.0	pH 4.0	pH 6.0	pH 4.0
Mutsumi	1.2	0.78	2.7 (0.4) × 109	6.9 (2.2) × 106
Mutsumi with cycloheximide	NDc	0.41	1.9 (0.3) × 109	7.3 (2.1) × 106
Yamadai	0	0.32	3.1 (0.5) × 108	2.8 (0.9) × 106
Yamadai with cycloheximide	0.41	0	2.3 (0.6) × 108	2.3 (0.8) × 106

^aAlone or supplemented with cycloheximide (100 ppm) to suppress fungal activity. 

^bAs determined by microscopic counting (19). The standard errors are given in parentheses. The initial number was 1.0 × 10⁶ cells/ml. 

^cND, not determined.