Viable protoplasts fluoresce green when stained with:
Viable protoplasts fluoresce bright green when stained with fluorescein diacetate FDA, vital fluorescent dye used routinely for viability assessment before fusion or transformation to ensure batch quality above 80 percent. FDA itself is non fluorescent lipophilic molecule that diffuses across intact plasma membrane permeable only to living cells with intact barrier. Inside cytoplasm active non specific esterases present exclusively in living cells hydrolyze ester bonds releasing fluorescein highly fluorescent polar molecule that accumulates inside membrane intact vesicle because its negative c
Ref: Widholm 1972 FDA viability; Larkin 1976 fluorescein diacetate Plant Physiol.
