Arbuscular mycorrhizal fungi mitigates heavy metal toxicity adverse effects in sewage water contaminated soil on Tagetes erecta L

Figures & data

Table 1. Physical and chemical properties of the soil used in this study to grow arbuscular mycorrhizal and non-arbuscular mycorrhizal inoculated marigold plants.

Properties	Values
Sand	82.5%
Silt	7.5%
Clay	10%
Organic matter	0.62%
pH	7.63
Electrical conductivity	0.61 dS m^–1
Available N	22.28 mg kg^–1
Available P	5.72 mg kg^–1
K	72 mg kg^–1
Extractable Ni	1.32 mg kg^–1
Cu	29.4 mg kg^–1
Cd	1.62 mg kg^–1
Fe	27.53 mg kg^–1
Pb	1.7 mg kg^–1
Cr	4.26 mg kg^–1
Mn	10.3 mg kg^–1

Table 2. Chemical analysis of sewage irrigation water used in this study to grow arbuscular mycorrhizal and non-arbuscular mycorrhizal inoculated marigold plants.

Constituents	Concentration
E.C.	1.12 ds m^−1
pH	5.73
Total hardness	26.0 µg g^−1
Total suspended compounds	124 µg g^−1
Zn	10.53 µg g^−1
Cu	5.6 µg g^−1
Mn	31.3 µg g^−1
Co	1.23 µg g^−1
Phosphate	46 µg g^−1
Nitrate	15 µg g^−1
Organic matter	8.3%
Total N	0.32%

Table 3. Fresh and dry weight of both shoot and root systems, shoot height and tolerance indices of mycorrhizal and non-mycorrhizal marigold plants grown under sewage water contaminated soil.

Treatments		Shoot		Root
Sewage water level (%)	AM status	FW	DW	FW	DW	SH	Ti
Control	NM	29.89 c	1.65 c	1.07 c	0.34 c	17.45 bc	-
	M	50.15 b	2.25 b	2.51 b	0.41 b	19.35 b	-
25	NM	30.29 cd	1.79 c	1.25 bc	0.38 bc	18.26 b	1.05 b
	M	85.45 a	4.14 a	3.33 a	0.59 a	22.85 a	1.63 a
50	NM	24.86 d	1.41 cd	1.09 bc	0.31 c	15.85 c	0.75 c
	M	43.84 bc	2.44 b	1.49 b	0.43 b	19.62 b	1.03 b
75	NM	15.86 e	0.94 d	1.30 d	0.20 d	14.62 c	0.53 d
	M	37.13 c	1.66 cd	1.83 c	0.29 cd	17.46 bc	0.69 c
LSD at 0.05		9.24	0.35	0.31	0.31	2.36	0.23

There is no significant difference (P ≤ 0.05) between the mean values that are followed by the same letter (Duncan’s multiple range test) within columns; each value shows the mean of four replicates ± standard error (SE). AM = Arbuscular mycorrhiza; FW = Fresh weight (g plant⁻¹); DW = Dry weight (g plant⁻¹); SH = Shoot height (cm plant⁻¹); Ti = Tolerance indices; NM = Non-mycorrhizal; M = Mycorrhizal; LSD = Least significant difference.

Table 4. Relative content of chlorophyll, leaf area and leaf magnesium content of mycorrhizal and non-mycorrhizal marigold plants grown in sewage water contaminated soil.

Treatments		Chlorophyll content (mg g^−1 FW)	LA (cm^2 plant^−1)	Mg (mg g^−1 DW)
Sewage water level (%)	AM status
Control	NM	19.25 c	118.6 cd	1.54 c
	M	24.31 b	186.2 b	1.85 b
25	NM	20.65c	125.3 c	1.65 c
	M	26.49 a	170.5 a	2.21 a
50	NM	17.63 d	115.6 b	1.57 e
	M	18.12 cd	170.5 b	1.75 c
75	NM	10.54 e	67.5 d	1.15 d
	M	15.12 d	133.6 c	1.49 e
LSD at 0.05		2.08	19.65	0.25

There is no significant difference (P ≤ 0.05) between the mean values which are followed by the same letter (Duncan’s multiple range test) within columns; each value shows the mean of four replicates ± SE. AM = Arbuscular mycorrhiza; FW = Fresh weight (g plant⁻¹); LA = Leaf area; DW = Dry weight (g plant⁻¹); NM = Non-mycorrhizal; M = Mycorrhizal; LSD = Least significant difference.

Table 5. Flower diameter, flower fresh and dry weights and dependence on arbuscular mycorrhiza of mycorrhizal and non-mycorrhizal marigold plants grown in sewage water contaminated soil.

Treatments		Flower parameters per plant
Sewage water level (%)	AM status	FD	FW	DW	Dependence on AM (%)
Control	NM	4.5 d	3.75	0.75	-
	M	8.2 b	6.52	0.98	53 d
25	NM	6.4 c	6.23	0.89	-
	M	12.3 a	11.26	1.74	65 c
50	NM	6.5 c	4.26	.85	-
	M	9.6 b	9.26	1.92	94 b
75	NM	2.6 e	2.65	0.32	-
	M	4.9 d	5.26	0.42	117 a
LSD at 0.05		1.21	2.12	0.21	11.6

Dependence on AM = 100 × (flower fresh weight of arbuscular mycorrhizal plants − flower fresh weight of non-AM plants) flower fresh weight of non-AM plants. There is no significant difference (P ≤ 0.05) between the mean values which are followed by the same letter (Duncan’s multiple range test) within columns; each value shows the mean of 4 replicates ± SE. AM = Arbuscular mycorrhiza; FD = Flower diameter (cm plant⁻¹); FW = Fresh weight (g plant⁻¹); DW = Dry weight (g plant⁻¹); NM = Non-mycorrhizal; M = Mycorrhizal; LSD = Least significant difference.

Figure 1. Frequency, intensity of mycorrhizal colonization and arbuscular frequency in the root tissues of mycorrhizal marigold plants grown under sewage water contaminated soil. Non-mycorrhizal plants showed no colonization. There is no significant difference (P ≤ 0.05) between the mean values which are followed by the same letter (Duncan’s multiple range test). Each bar shows the mean of 4 replicates. F% = Frequency (%); M% = Intensity of mycorrhizal colonization (%); A% = Arbuscular frequency (%).

Table 6. Macronutrients concentrations in both shoot and root systems of mycorrhizal and non-mycorrhizal marigold plants grown under sewage water contaminated soil.

		Nutrients content (mg g^−1 DW)
Treatments		Shoot			Root
Sewage water level (%)	AM status	N	P	K	N	P	K
Control	NM	29.48 ab	2.46 b	14.05 c	18.65 b	1.87 d	11.23 c
	M	33.67 a	3.05 a	20.32 b	21.62 a	2.06 b	15.32 b
25	NM	30.25 b	2.65 b	17.21 bc	18.64 b	2.32 c	12.02 c
	M	35.62 a	3.29 a	23.62 a	21.63 a	3.01 a	17.25 a
50	NM	21.23 d	1.39 d	15.62 c	15.04 cd	1.32 f	11.62 d
	M	25.63 c	1.85 c	19.65 b	17.64 c	1.62 e	14.26 b
75	NM	16.64 e	1.12 e	12.64 d	12.65 d	1.02 g	9.95 e
	M	21.54 d	1.36 d	15.64 c	15.98 cd	1.25 f	12.32 c
LSD at 0.05		3.15	0.26	2.74	2.07	0.19	1.68

There is no significant difference (P ≤ 0.05) between the mean values which are followed by the same letter (Duncan’s multiple range test) within columns; each value shows the mean of four replicates ± SE. DW = Dry weight (g plant⁻¹); AM = Arbuscular mycorrhiza; NM = Non-mycorrhizal; M = Mycorrhizal; LSD = Least significant difference.

Table 7. Heavy metals concentrations in both shoots and roots of mycorrhizal and non-mycorrhizal marigold plants grown under sewage water contaminated soil.

		Heavy metals concentrations (µg^−1 DW)
Treatments		Shoot				Root
Sewage water level (%)	AM status	Zn	Cu	Co	Mn	Zn	Cu	Co	Mn
Control	NM	101 f	30.2 e	15.3 c	59 e	119 g	139.6 f	17.5 e	39 f
	M	115 ef	17.4 de	17.6 de	66 e	209 f	149.5 e	18.3 e	44 f
25	NM	165 d	24.3 c	24.3 c	109 de	179 de	179.4 c	31.2 d	68 d
	M	127 e	19.6 d	19.6 d	94 d	149 e	164.3 d	29.6 d	59 e
50	NM	225 c	32.6 b	29.4 b	149 c	312 c	214.6 b	44.8 b	129 b
	M	181 e	24.5 c	24.3 c	99 d	206 d	187.7 c	37.8 c	93 c
75	NM	339 a	44.7 a	44.6 a	179 a	509 a	294.3 a	55.4 a	145 a
	M	275 b	31.4 b	31.6 b	119 b	382 b	217.1 b	39.4 b	131 b
LSD at 0.05		25.2	5.73	5.76	9.5	29.6	12.21	7.12	10.5

There is no significant difference (P ≤ 0.05) between the mean values which are followed by the same letter (Duncan’s multiple range test) within columns; each value shows the mean of four replicates ± SE. DW = Dry weight (g plant⁻¹); AM = Arbuscular mycorrhiza; NM = Non-mycorrhizal; M = Mycorrhizal; LSD = Least significant difference.