Allelopathy and potential allelochemicals of Ligularia sagitta as an invasive plant

Figures & data

Figure 1. Effects of L. sagitta extracts on seed germination of P. pratensis. a: roots ethyl acetate extract (R.EAE), b: roots n-butanol extract (R.BE), c: roots aqueous extract (R.AE), d: stems-leaves ethyl acetate extract (SL.EAE), e: stems-leaves n-butanol extract (SL.BE), f: stems-leaves aqueous extract (SL.AE). In each graph, different letters indicate significant differences between concentration treatments, p < .05. Concentration units for treatment groups are mg/mL. Error bars indicate standard deviation (SD). (GE) germination energy; (GR) germination rate; (CK) control group.

Figure 2. Effects of L. sagitta extracts on seed germination of F. ovina. a: roots ethyl acetate extract (R.EAE), b: roots n-butanol extract (R.BE), c: roots aqueous extract (R.AE), d: stems-leaves ethyl acetate extract (SL.EAE), e: stems-leaves n-butanol extract (SL.BE), f: stems-leaves aqueous extract (SL.AE). In each graph, different letters indicate significant differences between concentration treatments, p < .05. Concentration units for treatment groups are mg/mL. Error bars indicate standard deviation (SD). (GE) germination energy; (GR) germination rate; (CK) control group.

Figure 3. Effect of L. sagitta extracts on seed germination of E. nutans. a: roots ethyl acetate extract (R.EAE), b: roots n-butanol extract (R.BE), c: roots aqueous extract (R.AE), d: stems-leaves ethyl acetate extract (SL.EAE), e: stems-leaves n-butanol extract (SL.BE), f: stems-leaves aqueous extract (SL.AE). In each graph, different letters indicate significant differences between concentration treatments, p < .05. Concentration units for treatment groups are mg/mL. Error bars indicate standard deviation (SD). (GE) germination energy; (GR) germination rate; (CK) control group.

Figure 4. Effect of L. sagitta extracts on seed germination of A. cristatum. a: roots ethyl acetate extract (R.EAE), b: roots n-butanol extract (R.BE), c: roots aqueous extract (R.AE), d: stems-leaves ethyl acetate extract (SL.EAE), e: stems-leaves n-butanol extract (SL.BE), f: stems-leaves aqueous extract (SL.AE). In each graph, different letters indicate significant differences between concentration treatments, p < .05. Concentration units for treatment groups are mg/mL. Error bars indicate standard deviation (SD). (GE) germination energy; (GR) germination rate; (CK) control group.

Figure 5. Effects of L. sagitta extracts on seed germination of M. sativa. a: roots ethyl acetate extract (R.EAE), b: roots n-butanol extract (R.BE), c: roots aqueous extract (R.AE), d: stems-leaves ethyl acetate extract (SL.EAE), e: stems-leaves n-butanol extract (SL.BE), f: stems-leaves aqueous extract (SL.AE). In each graph, different letters indicate significant differences between concentration treatments, p < .05. Concentration units for treatment groups are mg/mL. Error bars indicate standard deviation (SD). (GE) germination energy; (GR) germination rate; (CK) control group.

Table 1. Effects of L. sagitta extracts on P. pratensis seedling growth.

Treatment solution		Inhibition（%）
		Roots extracts			Stems-Leaves extracts
		Shoots	Roots	Fresh weight	Shoots	Roots	Fresh weight
EAE (mg/mL)	0.25	16.47 ± 4.55 g	41.18 ± 0.52 g	16.87 ± 1.92 ef	18.59 ± 2.87 e	39.68 ± 1.11 f	25.76 ± 1.98 def
	0.50	44.41 ± 1.52 c	61.85 ± 0.71 b	36.15 ± 4.87 cd	47.52 ± 3.27 d	59.48 ± 2.90 e	30.09 ± 3.00 de
	0.75	62.49 ± 4.50 b	83.01 ± 2.05 c	50.12 ± 1.91 b	62.93 ± 4.29 c	76.83 ± 0.76 c	46.32 ± 4.35 c
	1.00	72.26 ± 3.19 a	89.96 ± 0.53 b	64.58 ± 1.91 a	72.63 ± 3.74 b	89.24 ± 0.46 b	59.52 ± 2.46 b
	2.00	——	——	——	87.65 ± 0.77 a	100.00 ± 0.00 a	72.08 ± 1.72 a
BE (mg/mL)	0.25	19.70 ± 2.92 fg	45.2 ± 1.07 f	11.33 ± 2.23 f	2.92 ± 2.00 f	33.10 ± 0.77 fg	9.96 ± 3.12 f
	0.50	22.46 ± 2.82 fg	45.88 ± 1.39 f	14.94 ± 3.56 ef	6.57 ± 3.54 f	36.64 ± 1.95 fg	13.64 ± 3.44 ef
	0.75	25.54 ± 1.45 fe	50.51 ± 3.39 e	19.52 ± 4.23 e	16.45 ± 2.37 f	58.51 ± 1.64 e	15.80 ± 2.93 ef
	1.00	30.15 ± 2.09 de	61.48 ± 0.93 d	34.94 ± 2.61 d	16.46 ± 2.37 e	58.79 ± 1.40 e	22.29 ± 4.70 def
	2.00	34.47 ± 1.24 d	83.70 ± 0.99 c	53.49 ± 5.47 b	18.87 ± 3.66 e	69.74 ± 3.28 cd	27.49 ± 3.25 de
AE (mg/mL)	0.25	8.74 ± 2.01 h	40.97 ± 1.20 g	20.00 ± 1.67 e	1.98 ± 1.30 f	27.63 ± 4.15 gh	9.31 ± 2.19 f
	0.50	21.93 ± 3.61 fg	62.59 ± 1.20 d	22.41 ± 3.52 e	20.21 ± 3.23 e	20.70 ± 4.43 h	12.34 ± 3.95 ef
	0.75	26.00 ± 4.25 ef	80.51 ± 0.08 c	31.33 ± 2.01 d	21.54 ± 3.25 e	63.47 ± 2.96 de	18.83 ± 3.90 ef
	1.00	45.74 ± 2.68 c	88.37 ± 0.43 b	35.42 ± 3.01 cd	20.93 ± 3.09 e	65.70 ± 2.52 de	29.65 ± 3.21 de
	2.00	46.37 ± 1.49 c	100.00 ± 0.00 a	42.89 ± 2.61 c	21.55 ± 3.07 e	69.87 ± 3.46 cd	37.66 ± 3.77 cd

Values in the table are average value ± standard deviation (SD), lower case letters in the same column indicate significant differences between treatments at p < .05; ——indicates that the germination rate is 0. Ethyl acetate extract (EAE), n-butanol extract (BE), aqueous extract (AE).

Figure 6. A, PCA score plot. b, HCA. Three biological repeat sequences were set up for each extraction phase (indicated by the numbers 1,2,3 at the end of the group name). Roots ethyl acetate extract (R.EAE), roots n-butanol extract (R.BE), roots aqueous extract (R.AE), stems-leaves ethyl acetate extract (SL.EAE), stems-leaves n-butanol extract (SL.BE), stems-leaves aqueous extract (SL.AE).

Figure 7. OPLS-DA score scatter plots. a: R.EAE vs. R.BE; b: R.EAE vs. R.AE; c: SL.EAE vs. SL.BE; d: SL.EAE vs. SL.AE. Roots ethyl acetate extract (R.EAE), roots n-butanol extract (R.BE), roots aqueous extract (R.AE), stems-leaves ethyl acetate extract (SL.EAE), stems-leaves n-butanol extract (SL.BE), stems-leaves aqueous extract (SL.AE). Three biological repeat sequences were set up for each extraction phase.

Figure 8. Volcano map of differential metabolites. a: R.EAE vs. R.BE; b: R.EAE vs. R.AE; c: SL.EAE vs. SL.BE; d: SL.EAE vs. SL.AE. Roots ethyl acetate extract (R.EAE), roots n-butanol extract (R.BE), roots aqueous extract (R.AE), stems-leaves ethyl acetate extract (SL.EAE), stems-leaves n-butanol extract (SL.BE), stems-leaves aqueous extract (SL.AE). Red, green and gray points indicate up-regulated, down-regulated and non-significant differential metabolites, respectively. Symbol size indicates VIP-value.

Figure 9. Venn diagram showing the number of overlapping and specific differential metabolites in the four comparison groups (R.EAE vs. R.BE, R.EAE vs. R.AE, SL.EAE vs. SL.BE, SL.EAE vs. SL.AE). Roots ethyl acetate extract (R.EAE), roots n-butanol extract (R.BE), roots aqueous extract (R.AE), stems-leaves ethyl acetate extract (SL.EAE), stems-leaves n-butanol extract (SL.BE), stems-leaves aqueous extract (SL.AE).

Table 2. Relative content of 9 common differential metabolites.

Compounds	Relative content (×10^9)
	R.EAE	R.BE	R.AE	SL.EAE	SL.BE	SL.AE
N,N-Dimethylaniline	116.72	1.47	1.67	47.56	5.25	1.01
Caffeic acid	54.65	16.00	6.16	14.23	1.90	4.23
2-Phenylethylamine	23.13	0.25	0.25	5.55	0.68	0.16
4-Hydroxybenzoic acid	18.78	3.28	0.42	13.13	5.04	0.66
Eupatilin	13.35	2.42	0.01	5.37	0.19	0.01
4-Hydroxybenzaldehyde	11.74	2.28	0.64	5.79	1.13	0.35
cis-9-Octadecenoic acid	9.97	2.82	0.70	3.99	0.43	0.25
Schizandrol A	7.10	0.56	0.14	4.11	0.22	0.04
1-Monolinolein	4.27	0.41	0.16	7.04	0.63	0.07

Roots ethyl acetate extract (R.EAE), Roots n-butanol extract (R.BE), Roots aqueous extract (R.AE), Stems-leaves ethyl acetate extract (SL.EAE), Stems-leaves n-butanol extract (SL.BE), Stems-leaves aqueous extract (SL.AE).