Figure 1. Red beet protoplasts isolated from tissue incubated in the presence and absence of the membrane-impermeable, endocytic-marker blue-fluorescent Alexa-350.(A) Fluorescent micrograph of protoplasts isolated from tissue incubated in 200 mM sucrose and 100 μM Alexa-350. (B) Light micrograph of (A). (C) High magnification fluorescent micrograph of a protoplast demonstrating Alexa-350 blue fluorescence in the vacuole and vacuole derived vesicles. (D) Fluorescent micrograph of protoplasts prepared from control tissue incubated in betaine.