9. Estimate the density and viability of protoplasts using a haemocytometer by staining the protoplasts with fluorescein
diacetate (FDA). Add some amount of the stock solution of FDA to the protoplast medium to obtain the final concentration
of 0.01% (w/v).
10. Incubate protoplasts with FDA for 30 min, then view the protoplasts under confocal laser scanning microscope (CLSM)
with 10Â objective. Set the excitation wavelength of the argon ion laser to 488 nm, and the dual regions of detection
between 505–530 nm and 650–730 nm. Viable protoplasts exhibited green fluorescence, accompanied with red
autofluorescence of chloroplasts Fig. 1. Count the total number of protoplasts within the red fluorescence field. Observe
10 different views for calculating the average viability.
11. Calculate the viability by dividing the total number of protoplasts by that of viable protoplasts. Perform three times
independent calculation, and record the average value as the protoplast yield.The microscopic pictures of protoplasts are
shown in Fig. 1.