Effects of plant growth regulators and culture medium on morphogenesis of Solieria filiformis (Rhodophyta) cultured in vitro

Morphogenesis and plant regeneration were analyzed in axenic tissue culture of the red alga Solieria filiformis (Kutzing) Gabrielson. Thallus segments cultured in ASP 12-NTA synthetic medium showed growth of filaments formed by divisions of cortical, subcortical and medullary cells (filamentous explants). whereas in seawater enriched with Von Stosch's solution, thallus segments developed branches. Filamentous explants were able to regenerate plants when transferred from a solid to a liquid medium. Plant regeneration was significantly promoted by treatment with plant growth regulators on filamentous explants formed from intercalary segments, up to 67 plantlets per explant in treatments with 6-benzylaminopurine (5.0 mg l(-1)), in contrast to three plantlets in controls lacking plant growth regulators. These adventitious plantlets developed into plants morphologically similar to those originated from germinating spores. These results indicate that plant growth regulators play a role on the regulation of morphogenesis, and could be useful for micropropagation of colloid-producing red algae.