Figure 5. Chlorophyll fluorescence and electrolyte leak- age of lettuce in response to cold shock. Untreated (open bars) and AIP-treated lettuce (shaded bars) plants were exposed to low temperature to low temperature (4 1C) for 24 h and the leaf fluorescence (A) and electrolyte leakage (B) were measured. The data indicate the means7S.E. (n ¼ 3).