Table 2.

Enzyme activity levels (nmol min⁻¹ mg⁻¹ protein) in maize seedlings subjected to varying NaCl concentrations and irrigation levels.

Treatments	Catalase	Guaiacol peroxidase	Ascorbate peroxidase	Glutathione reductase	Glutathione-S-transferase
Control	0.026 ± 0.0001f	0.057 ± 0.002f	0.235 ± 0.021f	7.241 ± 0.627f	18.152 ± 1.028f
Salt stress
25 mM NaCl	0.038 ± 0.0002e	0.048 ± 0.001e	0.288 ± 0.012e	12.401 ± 0.348e	28.123 ± 1.230e
50 mM NaCl	0.045 ± 0.0001d	0.103 ± 0.003d	0.342 ± 0.011d	17.263 ± 0.221d	36.572 ± 1.053d
75 mM NaCl	0.058 ± 0.0002c	0.178 ± 0.004c	0.383 ± 0.022c	25.124 ± 0.212c	41.347 ± 1.203c
100 mM NaCl	0.089 ± 0.0001b	0.198 ± 0.003b	0.432 ± 0.001b	31.231 ± 1.023b	46.232 ± 1.220b
150 mM NaCl	0.098 ± 0.0002a	0.202 ± 0.002a	0.577 ± 0.031a	47.121 ± 1.002a	51.227 ± 1.392a
Drought stress
80% irrigation	0.023 ± 0.0001d	0.045 ± 0.001d	0.254 ± 0.029d	15.273 ± 0.967d	21.299 ± 1.022d
60% irrigation	0.067 ± 0.0002c	0.098 ± 0.002c	0.387 ± 0.072c	19.223 ± 0.789c	28.231 ± 1.079c
40% irrigation	0.072 ± 0.0001b	0.169 ± 0.001b	0.582 ± 0.028b	28.256 ± 1.072b	32.239 ± 1.002b
20% irrigation	0.099 ± 0.0002a	0.253 ± 0.002a	0.612 ± 0.021a	39.282 ± 1.291a	43.201 ± 1.220a

Treatment categories include control, salt stress (25 mM to 150 mM NaCl), and drought stress (80% to 20% irrigation). Distinct lowercase letters (a–d) indicate statistically significant differences between treatment means. Enzymes assessed include catalase, guaiacol peroxidase, ascorbate peroxidase, glutathione reductase, and glutathione-S-transferase (nmol min⁻¹ mg⁻¹ protein).