Fig. 2. Apoptosis of S. pombe cells was evaluated using acridine orange–ethidium bromide dual staining. Viable, early and late apoptotic/necrotic cells were visualized using a fluorescent microscope after exposure to 0 (A, a1 and a2), 200 (B, b1 and b2), 400 (C, c1 and c2), 600 (D, d1 and d2), 800 (E, e1 and e2) mg L^–1 terpinolene and 3 mM arsenic(iii) (F, f1, f2) solutions. Arsenic(iii) was used as a positive control. Arrows: Late apoptotic/necrotic cells; dashed arrows: early apoptotic cells. At least 200 cells were counted in each biological replica (n = 5).