Table 1.

Antioxidative enzyme activity of 20-day seedlings of F. esculentum exposed to the control and six concentrations of ZnO NPs for 5 days

ZnO NPs treatment (mg/L)	GSH concentration (μmol/mg protein)	Catalse activity (unit/mg protein)
Control	31.3 ± 9.7 a	99.5 ± 8.1 a
1	31.2 ± 7.1 a	140.1 ± 10.0 b
5	45.3 ± 5.4 b	109.3 ± 4.2 a
10	53.0 ± 8.0 c	136.7 ± 23.0 b
100	61.6 ± 7.6 c	152.8 ± 28.1 b
1,000	61.6 ± 3.8 c	109.2 ± 12.7 a
2,000	49.6 ± 2.6 b	108.0 ± 3.5 a

GSH level and catalase activity are shown as the mean and SD. The different small letters represent statistical significant differences (P < 0.05) from the Turkey's test