Fluorescent Dye Based Measurement of Vacuolar pH and K

A. Fluorescent dyes: 1. 2', 7'-Bis-(2-Carboxyethyl)-5-(and-6)-Carboxyfluorescein acetoxymethyl (BCECF, AM) (Invitrogen, catalog number: B-1170; TEFLabs, catalog number: 0062) 2. Potassium-binding benzofuran isophthalate acetoxymethyl ester (PBFI, AM) (Life Technologies, Invitrogen™, catalog number: P-1267MP; TefLabs, catalog number: 0021) B. Other materials: 1. Pluronic F127 (Life Technologies, Invitrogen™, catalog number: P-3000MP; Teflabs, catalog number: 2510) 2. Gramicidin (Sigma-Aldrich, catalog number: G5002) 3. 1/2 MS plates containing 0.8% sucrose, 0.8% agar pH 5.7 for seedling germination and growth 4. 1/10 strength MS medium (without sucrose) for dye loading 5. Sterile