Raised calcium concentrations inside eukaryotic cells is a common component of cell signalling pathways (see pages 412 to 413 in the 6th edition of the Taiz et al (2015) textbook)

Raised calcium concentrations inside eukaryotic cells is a common component of cell signalling pathways (see pages 412 to 413 in the 6th edition of the Taiz et al (2015) textbook). This calcium enters cells from the apoplast (cell walls) through calcium channels during signalling events (see pages 150 to 151 in the textbook). but these calcium channels can be blocked with specific calcium channels inhibitors such as the drug verapamil or the metal ion La3+. If calcium channels were not a component of the signalling pathway that leads to gravitropic bending, what effect would inclusion of calcium channel blockers in the bromocresol purple plate experiment?