Cytological Features of the Egg Cell Protoplasts Isolated from Gametophytes of Fern, Struthiopteris niponica (Kunze) Nakai

Egg cell protoplasts were isolated from the gametophyte of the fern, Struthiopteris niponica (Kunze) Nakai. Archegonia were excised from the prothallia and then digested in an enzyme solution that contained Cellulase "Onozuka" RS and Macerozyme R-10. After 3 hours of incubation, the egg cell protoplasts had separated completely from the somatic cells. The protoplasts had such cytological features as rich cytoplasm containing many granules, the absence of developed chloroplasts, irregular shape of the nucleus, and the presence of one or two spherical nucleoli. These isolated protoplasts gave a positive fluorochromatic reaction in the FDA test and viability was approximately 90%.