The viability of 'Pera' orange (Citrus sinensis Osbeck) protoplasts, submitted to different dosages of Gamma radiation, was studied to determine the lethal dose (DL) 50. The analysis by fluorescence was employed using Fluorescein diacetate (FDA). The dilutions of FDA (1:50; 1:100 and 1:150) did not show any statistical difference: Then it was possible to use the 1:150 dilution in order to determine the protoplasts viability. The viability was inversaly proportional to Gamma radiation and the DL 50 was about 41 Gy. The non-irradiated protoplasts had their viability up to 84% when tested as soon after their isolation.
Citrus sinensis Osbeck; protoplasts; viability; Gamma radiation