Responses of the invasive Ricinuscommunis seedlings to competition and light

Figures & data

Table 1  Photosynthetic photons flux density (PPFD) and ratio of red to far-red wavelengths (R/FR) at five treatments: zero to three layers of fine plastic mesh and a common purple cloth sustained above pots containing freshly harvested seeds of Ricinus communis without elaiosome (manually removed).

Treatment	PPFD (µmol m^−2 s^−1)	R/FR
0 layer	1571	1.10
1 layer	878	1.08
2 layers	512	1.11
3 layers	212	1.65
Purple cloth	113	0.36

Figure 1  Leaves and stem mass rations of Ricinus communis juveniles growing in pots at densities of 1–57 plants per pot. A, Number of leaves (No. leaves; r ² = 0.26). B, Stem mass ratio (SMR; r ² = 0.08) Each point represents the mean value per pot of the two variables measured.

Figure 2  Root and stem masses of Ricinus communis juveniles growing with Brachiaria decumbens in pots at densities of 3–53 plants per pot. A, Root dry mass (DM _root; r ² = 0.04). B, Stem dry mass (DM _stem; r ² = 0.11). C, Total dry mass (DM _total; r ² = 0.00). D, Root mass ratio (RMR; r ² = 0.02). E, Root/aerial system ratio (R/AS; r ² = 0.09). F, Stem mass ratio (SMR; r ² = 0.08). Each point represents the mean value per pot of the variables measured in Ricinus juveniles.

Table 2  Means (±SD, when data showed normality) or medians (with confidence interval of 95%, when data showed no normality) of biomass measurements of Ricinus communis juveniles growing in pots with co-specifics only (Intra) and Ricinus juveniles growing in pots with Brachiaria decumbens (Inter) at two plant density categories: 1. four or fewer established plants per pot, and 2. five or more established plants per pot.

	Root length (cm)					Stem length (cm)				No. leaves
	1		2			1		2		1
	Intra	Inter	Intra	Inter		Intra	Inter	Intra	Inter	Intra	Inter
Mean±SD			31.32±4.90	15.30±9.96				8.88±1.02	4.50±1.21
Median	49.40	26.00				10.30	5.50			3.00	1.00
95% CI upper	85.09	30.84				13.02	12.94			3.48	1.75
95% CI lower	43.24	12.74				8.92	2.26			2.90	0.29
t			3.79					8.93
U	150					133				159
df	1		24			1		24		1
P	0.001		< 0.001			0.01		0.001		<0.001
	Leaf area (cm^2)				DM root (g)
	1		2		1		2
	Intra	Inter	Intra	Inter	Intra	Inter	Intra	Inter
Mean±SD	63.03±40.94	2.36±2.13	19.69±13.64	3.42±2.02	0.35±0.35	0.05±0.02	0.15±0.07	0.06±0.05
T	9.75		6.91		4.19		4.27
Df	27		24		28		24
P	<0.001		<0.001		< 0.001		<0.001
	DM stem (g)				DM leaf (g)
	1		2		1		2
	Intra	Inter	Intra	Inter	Intra	Inter	Intra	Inter
Mean±SD			0.18±0.07	0.05±0.02	0.319±0.244	0.018±0.014	0.093±0.063	0.016±0.008
Median	0.32	0.06
95% CI upper	0.63	0.06
95% CI lower	0.23	0.04
T			7.88		8.10		7.30
U	157
Df	1		24		27		24
P	<0.001		<0.001		<0.001		< 0.001
	DMtotal (g)				RMR		R/AS
	1		2		1		1
	Intra	Inter	Intra	Inter	Intra	Inter	Intra	Inter
Mean±SD	1.10±1.02	0.12±0.03	0.43±0.18	0.13±0.05	0.30±0.07	0.43±0.08	0.45±0.15	0.79±0.25
t	5.89		6.03		4		4.4
df	28		24		28		28
P	<0.001		<0.001		<0.001		<0.001
	SMR		ROB (g/cm)				LMR
	1		1		2		1		2
	Intra	Inter	Intra	Inter	Intra	Inter	Intra	Inter	Intra	Inter
Mean±SD	0.37±0.05	0.44±0.11			0.021±0.009	0.009±0.003	0.33±0.08	0.15±0.12	0.20±0.07	0.14±0.07
Median			0.032	0.009
95% CI upper			0.04	0.012
95% CI lower			0.024	0.006
t	2.49				4.62		4.31		2.8
U			158
df	28		1		24		27		24
P	0.019		<0.001		<0.001		< 0.001		0.01
	LAR (cm^2/g)
	1		2
	Intra	Inter	Intra	Inter
Mean±SD	71.56±27.90	18.64±16.50	43.43±16.71	29.78±18.72
t	4.41	2.32
df	27	24
P	<0.001	0.029
Note: Values and probabilities of Mann–Whitney or t-tests are for comparisons between the biomass measurements of Ricinus growing at the different plant densities and only significant differences are shown. No. leaves, number of leaves; DM root, root dry mass; DM stem, stem dry mass; DM leaf, leaf dry mass; DM total, total dry mass; RMR, root mass ratio; R/AS, root/aerial system ratio; SMR, stem mass ratio; ROB, stem robustness; SLM, specific leaf mass; LMR, leaf mass ratio; id, leaf area ratio.

Figure 3  Means (± SD, when data showed normality) or medians (with confidence interval of 95%, when data showed no normality) of biomass measurements of Ricinus communis juveniles growing under different photosynthetic photon flux densities (PPFD). Each point was calculated with the mean value per pot of the variables measured in Ricinus juveniles growing in 10 pots at each light treatment. No. leaves, number of leaves; DM _root, root dry mass; DM _stem, stem dry mass; DM _total, total dry mass; RMR, root mass ratio; R/AS, root/aerial system ratio; SMR, stem mass ratio; ROB, stem robustness; SLM, specific leaf mass; LMR, leaf mass ratio; LAR, leaf area ratio. Same numbers represent statistically similar groups (P>0.05) and different numbers represent statistically distinct groups (P ≤ 0.05).

Figure 4  Means (± SD, when data showed normality) or medians (with confidence interval of 95%, when data showed no normality) of biomass measurements of Ricinus communis juveniles growing under different spectral qualities of light (R/FR). Each point was calculated with the mean value per pot of the variables measured in Ricinus juveniles growing in 10 pots at each light treatment. DM _root, root dry mass; RMR, root mass ratio; R/AS, root/aerial system ratio; SMR, stem mass ratio; ROB, stem robustness; SLM, specific leaf mass; LMR, leaf mass ratio; LAR, leaf area ratio.