Fig. 3. Fluorescence micrographs of fat body (A–F), midgut (G–L) and salivary gland (M–P) treatments used to determine the role of aquaporins in freeze tolerance. The glycerol (A,G,M) and mercuric chloride control tissues (E,K) were kept at 4°C. The treated tissues were cooled from 4°C to –20°C over 2 h and left at –20°C for another 2 h. All tissues were frozen in Coast's solution (C,I,O), Coast's solution + 0.25 mol l^–1 glycerol (B,H,N), Coast's solution + 0.25 mol l^–1 glycerol + 0.2 mmol l^–1 mercuric chloride (D,J,P) or Coast's solution + 0.25 mol l^–1 glycerol + 0.2 mmol l^–1 mercuric chloride + 2 mmol l^–1 β-mercaptoethanol (F,L). The scale bar is 100 µm for J, M, N and O and 200 µm for all other micrographs.