Impact of an alien invasive plant Amaranthus retroflexus on wetland sediment properties under two growth stages

Figures & data

Table 1. Principal properties of the sediment and N-NH₄⁺ and P-PO₄³ˉ in interstitial water. MC, moisture content. ϕ, porosity. LOI, loss on ignition. TN, total nitrogen. TP, total phosphorus. N-NH₄⁺, ammonium. N-NO₃ˉ, nitrate. P-PO₄³ˉ, phosphate. The same as below.

Sediment							Interstitial water
MC (%)	Φ (%)	LOI (%)	TN (mg/g)	TP (mg/g)	N-NH4^+ (mg/g)	N-NO3ˉ (mg/g)	N-NH4^+ (mg/L)	P-PO4^3ˉ (mg/L)
52.03	73.32	10.44	0.717	0.362	0.018	0.013	0.103	0.013

Table 2. Morphological differences of A. retroflexus under two growth stages (n = 5). PH24 and PH11 were the experimental plants with early and late germination period, and plant height was 24 and 11 cm at the beginning of experiment, respectively. The same as below.

	PH24	PH11	t-value	p
Plant height (cm)	29.18 ± 2.30	17.30 ± 2.25	8.262	<0.000
Basic stem diameter (mm)	1.92 ± 0.18	1.18 ± 0.13	7.475	<0.000
Root length (cm)	13.62 ± 1.16	9.16 ± 1.43	5.429	0.001
Total biomass (g)	1.538 ± 0.092	0.411 ± 0.036	25.640	<0.000
Root-to-shoot ratio	0.195 ± 0.007	0.376 ± 0.014	−26.500	<0.000

Table 3. Sediment physicochemical properties over the vertical profile among treatments (n = 5).

Treatments	Profile (cm)	MC (%)	Φ (%)	LOI (%)	TN (mg/g)	TP (mg/g)	N-NH4^+ (mg/g)	N-NO3ˉ (mg/g)
PH24	0 ∼ 2	55.64	75.80	12.57	0.512	0.283	0.010	0.003
	2 ∼ 5	54.50	74.87	11.92	0.544	0.321	0.011	0.003
	5 ∼ 10	54.48	74.92	11.65	0.571	0.345	0.012	0.004
	10 ∼ 15	53.73	74.35	10.85	0.430	0.294	0.013	0.003
	15 ∼ 20	54.77	75.17	10.50	0.463	0.302	0.018	0.003
PH11	0 ∼ 2	54.84	75.07	11.67	0.524	0.334	0.011	0.003
	2 ∼ 5	53.71	74.30	12.69	0.417	0.297	0.011	0.003
	5 ∼ 10	52.92	73.75	14.15	0.503	0.340	0.009	0.004
	10 ∼ 15	52.64	73.53	14.90	0.461	0.310	0.012	0.003
	15 ∼ 20	50.57	71.87	14.55	0.553	0.358	0.017	0.004
CK	0 ∼ 2	51.40	72.53	16.27	0.839	0.280	0.011	0.009
	2 ∼ 5	53.23	73.99	16.23	0.703	0.321	0.012	0.008
	5 ∼ 10	51.76	72.83	15.33	0.598	0.355	0.012	0.008
	10 ∼ 15	52.74	73.47	13.48	0.788	0.244	0.013	0.008
	15 ∼ 20	52.42	73.36	10.47	0.631	0.290	0.015	0.009

Table 4. The mean values of sediment properties over the vertical profile (n = 5).

	Sediment							Interstitial water
	MC	ϕ	LOI	TN	TP	N-NH4^+	N-NO3ˉ	N-NH4^+	P-PO4^3ˉ
Treatments	(%)	(%)	(%)	(mg/g)	(mg/g)	(mg/g)	(mg/g)	(mg/L)	(mg/L)
PH24	54.62	75.02	11.50 a	0.504 a	0.309	0.013	0.003 a	0.112 a	0.011 a
PH11	52.94	73.70	12.99 b	0.492 a	0.328	0.012	0.003 a	0.120 a	0.013 b
CK	52.31	73.24	14.35 b	0.712 b	0.298	0.013	0.008 b	0.152 b	0.013 b

Table 5. Results of F-values and significance from one-way ANOVA among treatments of plant and sediment profile (n = 5). Plant: F-values and significance among the three treatments; Sediment profile: F-values and significance over the vertical profile.

		Sediment profile
Dependent variable	Plant	PH24	PH11	CK
Sediment
MC	2.740 ns	0.166 ns	0.617 ns	0.198 ns
ϕ	2.759 ns	0.176 ns	0.587 ns	0.188 ns
LOI	7.641**	10.139**	43.793***	56.86***
TN	11.324***	2.279 ns	0.562 ns	0.679 ns
TP	1.041 ns	2.473 ns	0.304 ns	1.385 ns
N-NH4^+	0.355 ns	19.073***	19.935***	1.973 ns
N-NO3ˉ	7.868**	0.213 ns	0.641 ns	1.387 ns
Interstitial water
N-NH4^+	4.770*	8.082**	16.481***	2.154 ns
P-PO4^3ˉ	3.411*	5.040*	1.234 ns	0.338 ns

ns, p > 0.05; *p < 0.05; **p < 0.01; ***p < 0.001.

Table 6. N-NH₄⁺ and P-PO₄³ˉ distribution in interstitial water (n = 5).

	PH24		PH11		CK
	N-NH4^+ (mg/L)	P-PO4^3ˉ (mg/L)	N-NH4^+ (mg/L)	P-PO4^3ˉ (mg/L)	N-NH4^+ (mg/L)	P-PO4^3ˉ (mg/L)
OW	0.013 ± 0.001	0.002 ± 0.001	0.021 ± 0.001	0.003 ± 0.001	0.035 ± 0.003	0.005 ± 0.001
0∼2	0.096 ± 0.030	0.007 ± 0.002	0.098 ± 0.020	0.011 ± 0.002	0.119 ± 0.011	0.012 ± 0.002
2∼5	0.089 ± 0.015	0.007 ± 0.001	0.099 ± 0.014	0.013 ± 0.002	0.156 ± 0.039	0.014 ± 0.002
5∼10	0.112 ± 0.018	0.011 ± 0.004	0.093 ± 0.006	0.016 ± 0.004	0.148 ± 0.004	0.013 ± 0.003
10∼15	0.111 ± 0.009	0.016 ± 0.002	0.114 ± 0.024	0.013 ± 0.002	0.150 ± 0.039	0.013 ± 0.004
15∼20	0.168 ± 0.039	0.011 ± 0.003	0.196 ± 0.022	0.015 ± 0.006	0.185 ± 0.025	0.015 ± 0.002