PHYSIOLOGY AND DEVELOPMENT OF PROTOPLASTS OBTAINED FROM FUCUS EMBRYOS USING LASER MICROSURGERY

Protoplasts from rhizoids of two-celled Fucus embryos were obtained using laser microsurgery. They were characterised by a membrane potential similar to that of a rhizoid cell in situ and a rapid regeneration of the cell wall. Nucleated subprotoplasts with regenerated cell wall were capable of photopolarisation as zygotes. These pseudozygote developed into miniature embryos similar to zygotic embryos. The nucleus appeared to be necessary for pseudozygote polarisation but the transcription inhibitor, actinomycin D, though preventing zygote polarisation, was inactive on pseudozygotes. A role for the nucleus as a geometric reference is discussed.