TABLE 5.

Total bacteria, group A bacterial chitinases, and ammonia monooxygenase gene abundance in soils polluted with different Zn and Cd concentrations at the end of the experiment^a

Soil	Treatment (Zn/Cd) (mg kg−1 [DW])	Total bacteria (105 copies g−1 [DW] soil)	Chitinase group A (103 copies g−1 [DW] soil)	amoA (101 copies g−1 [DW] soil)
Unplanted	250/0	1,244 ± 332	135 ± 23	1,900 ± 77AB
	250/50	1,376 ± 545	253 ± 7	3,689 ± 134C
	250/250	228 ± 62	157 ± 26	1,667 ± 237AB
	500/0	102 ± 4	112 ± 25	1,360 ± 77AB
	500/50	646 ± 189	147 ± 20	1,690 ± 178AB
	500/250	389 ± 67	156 ± 19	1,907 ± 114AB
	1000/0	311 ± 51	110 ± 9	2,332 ± 481AC
	1000/50	335 ± 6	160 ± 22	815 ± 151AB
	1000/250	593 ± 96	212 ± 12	308 ± 77B
Planted	250/0	2,059 ± 499	179 ± 14	1,938 ± 445AB
	250/50	631 ± 76	118 ± 29	1,842 ± 326AB
	250/250	664 ± 201	161 ± 24	1,374 ± 206AB
	500/0	1,023 ± 295	151 ± 30	2,378 ± 454AC
	500/50	492 ± 61	180 ± 13	1,330 ± 135AB
	500/250	444 ± 132	102 ± 27	1,160 ± 393AB
	1000/0	894 ± 81	158 ± 8	1,563 ± 553AB
	1000/50	1,023 ± 254	166 ± 32	408 ± 54B
	1000/250	1,026 ± 139	156 ± 11	703 ± 124AB

^aValues labeled with different letters are significantly different (P < 0.05) according to the Tukey-Kramer test (statistics are shown only when, according to two-way ANOVA, a significant interaction was found between metal concentration and plant presence). Shown are mean values (n = 4) ± standard errors. ANOVA for columns from left to right (*, significantly different at a P value of < 0.05): plant, 0.0006*, 0.1778, <0.0001*; metal, 0.0096*, 0.4956, 0.0365*; plant × metal, 0.0644, 0.0046*, 0.0071*; unplanted, Zn, 0.0210*, 0.0785, <0.0001*; unplanted, Cd, 0.2152, 0.0022*, 0.0016*; unplanted, Zn × Cd, 0.0469*, 0.0310*, <0.0001*; planted, Zn, 0.1155, 0.7630, 0.0315*; planted, Cd, 0.0131*, 0.5622, 0.0218*; planted, Zn × Cd, 0.0501, 0.2055, 0.6405.