Figure 2. The effect of pH on endogenous β-glucuronidase activity in Capsicum chinense leaves. The non-transformed leaves of four-week-old plantlets were subjected to the GUS histochemical assay at different pH values. The leaves were blanched with successive ethanol washes and photographed under a light microscope. (a) pH 4.0; (b) pH 7.0; (c) pH 8.0.