Table 3.

Effects of copper (Cu) and chromium (Cr) on MDA (nmol g⁻¹ FW), hydrogen peroxide (H₂O₂) (μmol g⁻¹ FW), superoxide radical (O₂^∙−) (nmol min⁻¹ g⁻¹ FW), and hydroxyl radical (⁻OH) (μmol g⁻¹ FW) in the roots of two Brassica napus cultivars under different metal treatments.

Cultivar	Treatment	Root MDA	Root −OH	Root H2O2	Root O2∙−
ZS 758	$\stackrel{\hspace{0.17em}}{\mathrm{C}\mathrm{K}}$	1.45 ± 0.14f	1.46 ± 0.07f	1.14 ± 0.07g	0.524 ± 0.0410g
	Cu 200 μM	22.53 ± 1.17e	27.45 ± 1.07e	24.12 ± 2.23f	1.043 ± 0.1031f
	Cr 200 μM	34.65 ± 0.83d	40.27 ± 2.20d	44.17 ± 1.85d	1.487 ± 0.0225d
	Cu 200 μM + Cr 200 μM	45.78 ± 1.16c	52.54 ± 1.58c	62.94 ± 2.66c	1.782 ± 0.0517c
ZD 622	$\stackrel{\hspace{0.17em}}{\mathrm{C}\mathrm{K}}$	1.48 ± 0.13f	1.48 ± 0.08f	1.06 ± 0.06g	0.543 ± 0.0270g
	Cu 200 μM	36.60 ± 1.46d	39.73 ± 1.09d	35.69 ± 2.34e	1.348 ± 0.0240e
	Cr 200 μM	53.07 ± 1.23b	56.97 ± 3.61b	69.72 ± 2.08b	1.943 ± 0.1009b
	Cu 200 μM + Cr 200 μM	72.72 ± 2.12a	73.68 ± 2.57a	92.82 ± 3.39a	2.665 ± 0.0705a

Data are the means of three replicates (mean ± SD). Values followed by different letters indicate significant differences followed by Duncan's multiple range test (P < 0.05) for each cultivar at different metal treatments.