PHYSIOLOGY AND DEVELOPMENT OF PROTOPLASTS OBTAINED FROM FUCUS EMBRYOSUSING LASER MICROSURGERY

Protoplasts from rhizoids of two-celled Fucus embryos were obtained us ing laser microsurgery. They were characterised by a membrane potentia l similar to that of a rhizoid cell in situ and a rapid regeneration o f the cell wall. Nucleated subprotoplasts with regenerated cell wall w ere capable of photopolarisation as zygotes. These pseudozygote develo ped into miniature embryos similar to zygotic embryos. The nucleus app eared to be necessary for pseudozygote polarisation but the transcript ion inhibitor, actinomycin D, though preventing zygote polarisation, w as inactive on pseudozygotes. A role for the nucleus as a geometric re ference is discussed.