Figure 2. pH-Sensitive indicator bromocresol purple in gel.
A. Bromocresol purple; B. Calcium sulfate (CaSO4); C. Agarose; D. Bromocresol purple solution in sterile distilled water pH 5.7; E. The solution is heated in a microwave until agarose is completely dissolved; F. Gel containing bromocresol purple completely dissolved and ready to be poured. G. Gel being poured in a Petri dish. H. Plate containing the solidified gel and ready to receive the seedlings (top view). I. Lateral view of the plate shown in H. Gel should be about 0.4 cm thick and a dark yellow color is expected to allow detection of pH differences.