Fig. 7From: Effect of hydrogen sulfide (H2S) on the growth and development of tobacco seedlings in absence of stressThe effects of 0.0, 2.0, 4.0, 6.0, and 8.0 mM of NaHS on the SOD (A) and POD (B) enzymatic activities in tobacco plants treated for 0, 5, 10, and 15 days. Bars represent the mean ± SE. Different letters in lowercase denote significant differences between treatment groups at the 5% level, according to Duncan’s testBack to article page