XVI International Botanical Congess

Axenic cultures of Gracilariopsis tenuifrons (Gracilariales, Rhodophyta) were established in ASP 12-NTA solid medium (0.4% agar and 1.0% sucrose)supplemented with indole-3-acetic acid (IAA), 2,4-dichlorophenoxyacetic acid (2,4-D), and 6-benzylaminopurine (BA). Calluses were originated from divisions of apical and cortical cells located at apical regions of thallus segments and branches. Low concentration of IAA (0.5 mg/L) enhanced callus induction, while IAA:BA (1.0:1.0 mg/L) or 2,4-D (0.5 mg/L) stimulated the callus growth. Regeneration of plantlets from calluses was stimulated by BA. These results suggest that auxin and cytokinin are involved in developmental regulatory processes in red algae. (Supported by CNPq).