Table III. Effects of genotype (GT), soil bulk density (BD), and their interaction on root anatomical traits in embryonic and postembryonic roots after 23 d of growth, analyzed with ANOVA.

Root Class	Trait	ANOVA			Bulk Density Average
		GT	BD	GT-BD	1.3 g cm−3	1.45 g cm−3	1.6 g cm−3
Embryonic	Cross-section area (mm2)	**	**	n.s.	0.123 a	0.186 b	0.469 c
	Stele area (mm2)	**	**	*	0.049 a	0.059 b	0.059 b
	Cortical area (mm2)	*	**	n.s.	0.074 a	0.128 b	0.410 c
	RCA (mm2)	n.s.	**	n.s.	0.002 a	0.011 a	0.088 b
	RCA (%)	n.s.	**	n.s.	1.6 a	7.6b	21.8 c
	Cortical cell file number	**	**	*	2.3 a	3.0b	4.9 c
	Cortical cell diameter (mm)	*	**	n.s.	0.025 a	0.030 b	0.053 c
Postembryonic	Cross-section area (mm2)	**	**	n.s.	0.359 a	0.413 b	0.430 b
	Stele area (mm2)	**	**	n.s.	0.079 a	0.080 a	0.065 b
	Cortical area (mm2)	**	**	n.s.	0.281 a	0.333 b	0.365 b
	RCA (mm2)	**	**	n.s.	0.084 a	0.102 b	0.111 b
	RCA (%)	n.s.	n.s.	n.s.	29.9	30.5	30.3
	Cortical cell file number	**	n.s.	**	6.3	6.5	6.2
	Cortical cell diameter (mm)	n.s.	**	n.s.	0.027 a	0.030 a	0.037 b

Asterisks denote significant effects at P < 0.05 (*) and P < 0.01 (**); n.s. denotes nonsignificant effects (n = 4). Different letters indicate significant differences between levels of soil strength using Tukey’s honestly significant difference test at P < 0.05. RCA, Root cortex aerenchyma.