TABLE 2.

Comparison of the frequencies of SRB subgroups detected in different macrophyte species and fractions of the sample

Plant or sample type	Macrophyte	na	Frequency of SRB subgroup
			Desulfoto- maculum	Desulfo- bulbus	Desulfo- bacterium	Desulfo- bacter	Desulfococcus- Desulfonema- Desulfosarcina	Desulfovibrio- Desulfomicrobium
C4 plant	Polygonum densiflorum	12	0.55	0.55	0.00	0.27	1.00	1.00
	Hymenachne donacifolia	6	1.00	1.00	0.00	0.33	1.00	1.00
C3 plant	Ludwigia helminthorrhiza	6	0.83	0.17	0.00	0.17	0.83	1.00
	Eichhornia crassipes	6	0.50	0.00	0.00	0.17	0.83	1.00
Roots only		10	0.60	0.40	0.00	0.30	0.90	1.00
Periphyton		10	0.80	0.60	0.00	0.10	1.00	1.00
Wholeb		10	0.60	0.30	0.00	0.30	0.90	1.00

^aNumber of samples analyzed.

^bRoots with periphyton.