In lines 6 and 7, page 4 of our Bio-protocol paper www.bio-protocol.org/e2796, the unit “g” is incorrect, should be “mg”. The same mistake is repeated on page 7, lines 27 and 28. The correct text should be:

Page 4
Procedure

1. Add 0.006% (w/v) of bromocresol purple free acid reagent grade (60 mg L^-1); 1 mM of CaSO₄ (172 mg L^-1) in sterile distilled water. Adjust pH to 5.7 using KOH or HCl. Pour the solution into an Erlenmeyer.
   
   

Page 7
Recipes

2. Gel containing bromocresol purple (pH 5.7)
   0.006% (w/v) bromocresol purple (free acid reagent grade) (60 mg L^-1)
   1 mM of CaSO₄ (172 mg L^-1)
   Sterile distilled water
   Agarose (15 g L^-1)

Reference

1. Silva, A. L., Dressano, K., Ceciliato, P. H., Guerrero-Abad, J. and Moura, D. S. (2018). Evaluation of root pH change through gel containing pH-sensitive indicator bromocresol purple. Bio-protocol 8(7): e2796.