Jatropha curcas L. Root Structure and Growth in Diverse Soils

Table 4

Average ± SD below-ground parameters in J. curcas seedlings grown in three different soils.

Parameter	Units	Sand	Sandy-loam	Clay-loam	PI
Root length	cm
Total		115.9 ± 17.0^b	132.0 ± 18.2^ab	144.6 ± 38.6^a	0.20
Taproot		36.1 ± 85.1^a	39.7 ± 95.9^a	41.1 ± 72.1^a	0.12
Four main laterals		27.7 ± 8.5^a	32.3 ± 10.1^a	37.5 ± 14.6^a	0.26
Basal diameter	mm
Taproot		8.2 ± 1.3^b	20.1 ± 4.4^a	18.4 ± 3.2^a	0.59
Four main laterals		2.9 ± 0.4^b	4.8 ± 1.9^a	5.2 ± 1.3^a	0.44
Apex diameter	mm
Taproot		0.70 ± 0.25^a	0.63 ± 0.17^a	0.70 ± 0.15^a	0.10
Four main laterals		0.41 ± 0.11^b	0.53 ± 0.09^ab	0.59 ± 0.19^a	0.31
Number of roots > 2.0 mm thick		5.13 ± 0.35^b	12.09 ± 5.85^a	13.89 ± 5.84^a	0.63
Root mass
Total	g	0.61 ± 0.20^b	5.33 ± 1.74^a	5.34 ± 3.02^a	0.89
Taproot	%	74.40 ± 9.85^b	85.48 ± 6.97^a	75.78 ± 7.05^b
Coarse root structure
TapIncAng	deg	−89.36 ± 4.48^a	−85.21 ± 3.72^a	−88.67 ± 6.12^a	0.05
𝜃	deg	−20.71 ± 4.79^a	−18.59 ± 3.05^a	−17.94 ± 3.31^a	0.13
LCM	cm	1.07 ± 0.41^a	1.36 ± 0.50^a	1.0 ± 0.38^a	0.26
𝛽	deg	89.3 ± 4.40^a	94.7 ± 3.7^a	91.3 ± 6.1^a	0.06
Similarity indexes
𝛽symm		0.02 ± 0.02^a	0.04 ± 0.03^a	0.03 ± 0.03^a
𝐷symm		0.24 ± 0.10^a	0.29 ± 0.09^a	0.25 ± 0.14^a
𝜃symm		0.27 ± 0.10^a	0.34 ± 0.11^a	0.35 ± 0.12^a
LCMsymm		0.12 ± 0.06^a	0.16 ± 0.13^a	0.11 ± 0.07^a
TapSymm		0.04 ± 0.04^a	0.04 ± 0.03^a	0.04 ± 0.03^a
SI		0.13 ± 0.05^a	0.15 ± 0.07^a	0.16 ± 0.03^a

^a,bMeans within a column which do not share the same letter are significantly different (𝑃< 0.05).