Plant protoplasts, fluorescence microscopy. Protoplasts are plant cells without cell wall A protoplast is a plant cell that has had its tough outer cell wall removed by chemical treatment. This leaves an intact cell with its contents surrounded by its plasma membrane. The cell wall can later be regrown. These protoplasts are from an Arabidopsis (thale cress) plant. Chloroplasts, the site of photosynthesis, are shown in red. This fluorescence microscopy was carried out using green fluorescent protein (GFP).