Figure 1. Viable and non-viable cells and protoplasts stained with Evans blue and MTT.
(a) Protoplast stained with Evans blue, the viable protoplast is not stained, it is surrounded by non-viable blue cellular aggregates.
(b) Control of Non-viable cells stained with Evans Blue, the none-viable cells are blue.
(c) Protoplast treated with MTT, the purple cytoplasm indicates that this is a viable protoplast. 
(d) Cell treated with MTT, this colorless cell is non-viable.