Table 2.

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 leaves of two Brassica napus cultivars under different metal treatments.

Cultivar	Treatment	Leaf MDA	Leaf −OH	Leaf H2O2	Leaf O2∙−
ZS 758	$\stackrel{\hspace{0.17em}}{\mathrm{C}\mathrm{K}}$	6.02 ± 0.21e	1.88 ± 0.10g	1.57 ± 0.06f	0.013 ± 0.0035g
	Cu 200 μM	11.20 ± 0.71d	10.41 ± 0.88f	51.97 ± 2.06e	0.526 ± 0.0075f
	Cr 200 μM	17.81 ± 1.18c	19.43 ± 0.52d	71.05 ± 1.80c	0.770 ± 0.0280e
	Cu 200 μM + Cr 200 μM	25.95 ± 1.08b	25.92 ± 1.10c	96.19 ± 4.22b	0.945 ± 0.0305c
ZD 622	$\stackrel{\hspace{0.17em}}{\mathrm{C}\mathrm{K}}$	5.93 ± 0.12e	1.99 ± 0.11g	1.66 ± 0.06f	0.022 ± 0.0046g
	Cu 200 μM	16.83 ± 0.81c	16.74 ± 0.69e	65.50 ± 1.98d	0.882 ± 0.0160d
	Cr 200 μM	25.44 ± 2.11b	28.67 ± 1.13b	96.61 ± 3.14b	1.127 ± 0.0410b
	Cu 200 μM + Cr 200 μM	35.26 ± 1.85a	46.96 ± 2.07a	145.53 ± 4.89a	1.384 ± 0.0190a

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.