Glycerol-activated cellular division and biosynthetic activity during growth and morphogenesis of carpospore seedlings of Grateloupia doryphora (Cryptonemiales, Rhodophyta)

Abstract

Tlie red alga Gmtdo~il~ici rloryplioro (Moritagne) 1-Iowe was grown in axenic culture in Provasoli's cnriched seawater mediun1 supplemented with glycerol as an organic carbon source. Carpospore seedlings showed a particular form of cell proliferation forming compact cell masses wilh many buds or prolrusions iifler 12 days oF growth. Histologic and Iiistocliemical tecliniques and studies at the eiectron microscope icvci revealeci: i i j a short-tenn effect in wiiicii ceii ciivision was aclivated within 2 h in the interna1 cell laycr of the carposporc seedling, and (2) buds derived from internal cell proliferation on the periphery. Glycerol was used to biosyntliesize polymers iieeded ror cell elorigation and division as evidenced by skrch accumulation and endomembrüne systeni activity. Wlien inorphogeriesis was completed, llie regeneration capability remained with tlie internal cells lhat maintained tlieir cell structure, including cliloropliists, and accumulated compounds in large vacuoles. Thcsc cells recominenced growth ií' cell masses were subcullured.