Gametogenesis and chromosome number in Postelsia palmaeformis (Laminariales, Phaeophyceae)


  • Raymond J. Lewis

    1. Marine Science Institute, University of California. Santa Barbara, California 93106, USA
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      Department of Forestry, Fisheries & Wildlife, University of Nebraska, Lincoln. NE 68583–0814, USA.

  • Communicating editor: J. Motomura


Gametophytes of the ‘sea palm’, the kelp Postelsia palmaeformis Ruprecht, produced gametes whether or not chelated iron was supplied in the culture medium, in contrast to the inhibition of gametogenesis seen with the absence of iron in many other kelps. As gametogenesis proceeded, every cell of the gametophytes was converted into a gamete so that the gametophytes did not continue to grow vegetatively. The portion of the life history from spore release through germination, gametophyte growth, gametogenesis, fertilization and growth of the young sporophyte was completed in 9–10 days under laboratory conditions. Chromosome counts showed that sporophytes had a diploid number of 26–34 chromosomes while sporangia and gametophytes had a haploid number of 14–17 chromosomes, indicating a typical haplodiplophasic life history as seen in other Laminariales.