LIGHT AND GLYCEROL DRIVEN DEVELOPMENT OF GRATELOUPIA-DORYPHORA (RHODOPHYTA) IN-VITRO

The implications of light in structural changes during growth and deve lopment of a carpospore seedling from Grateloupia doryphora a cultivat ed in glycerol were studied by changing photon flux density from the s tandard white light of 30 mu mol photons m(-2)s(-1) to 20, 60 and 100 mu mol photons m(-2)s(-1) and spectra from white to both blue and red light (30 mu mol photons m(-2)s(-1) of 450 and 640 nm respectively). T he growth rate as well as morphogenesis (bud, shoot or simply producti on of new axes) increased with the photon fluence rate of white light, as well by changing cultures from white to both blue and red light. F riability was higher in blue and red light and when carpospore seedlin gs were cultivated under the highest photon fluence rates. At structur al-ultrastructural level it was observed that glycerol and light (in a ny light condition tested) promoted a short term induction of cell div ision and biosynthesis in the former cells of the carpospore seedling. As a result, new cell layers were formed concentrically arranged with respect to former cells. The division of these cells lead to the form ation of the new axes (morphogenesis). The accumulation and later degr adation of starch and intense proliferation of endomembranes accompani ed morphogenesis.