Table 2.

Effect of Si supply on activity of antioxidative enzymes and concentration of non-enzymatic antioxidants in the youngest fully expanded leaves.

Treatment	APX	CAT	SOD	GSH	Asc
C	0.120 ± 0.048 a	171 ± 29 a	134 ± 16 a	156 ± 10 b	2043 ± 205 a
-Si	0.051 ± 0.012 b	124 ± 27 b	133 ± 4 a	201 ± 9 a	2165 ± 185 a
+Si	0.143 ± 0.022 a	177 ± 10 a	124 ± 10 a	200 ± 12 a	2261 ± 228 a

Enzyme activities are given as u/mg protein; GSH and Asc in nmol g^-1 FW. The plants were treated as described in the legend of Figure 1 (C- control plants grown optimally supplied with Fe; -Si – plants grown in the absence of Fe and Si; +Si – plants grown in the absence of Fe and supplied with Si). Data shown are means ± s.d. (n = 3). APX, Ascorbate peroxidase; CAT, catalase; SOD, superoxide dismutase; GSH, glutathione; Asc, ascorbate. Significant differences (P < 0.05) between treatments are indicated by different letters.