Establishment of Effective Callus Induction in the Economically Important Brown Seaweed <i>Ecklonia cava</i>

Abstract

The edible brown seaweed, Ecklonia cava, is highly valued for its bioactive compounds, and is widely used in food supplements and functional foods. The increasing demand for this seaweed in the food industry emphasizes the necessity for sustainable cultivation practices. This study focused on inducing callus in the meristem and stipe of E. cava using different culture media: Provasoli's enriched seawater medium (PESI), enriched artificial seawater medium (ESAW), artificial enriched seawater medium (ASP2), or Von Stosch's enriched seawater medium (VS). Various abiotic stress factors (photoperiod, agar concentration, and temperature), growth regulators, carbon sources, polyamines, and plasma treatments were explored for their impact on callus induction. Both stipe and meristem explants developed callus within three to six weeks across all media except ASP2. Callus development was favored at temperatures between 8 to 13 degrees C and in the absence of light. Stipe explants showed a higher callus induction rate (up to 65.59 +/- 6.24%) compared to meristem (up to 57.53 +/- 8.32%). Meristem explants showed optimal callus induction in PESI medium with a low concentration of indole-3-acetic acid (IAA; 40.93 +/- 8.65%). However, higher concentrations of IAA and 1-naphthaleneacetic acid (NAA) reduced meristem callus induction. Stipe showed high induced-callus (up to 50.37 +/- 5.17%) in PESI medium with low concentrations of IAA, NAA, and 6-benzylaminopurine (BAP). Both stipe and meristem explants induced largest callus at 2% sucrose, but higher carbon source concentrations reduced callus induction. Spermine (Spm) at 1 mu M resulted in high induced calluses; however, increasing Spm concentrations decreased callus induction. This tissue culture technique not only supports mass cultivation of E. cava, but also holds potential for extending to other seaweed species, contributing to the sustainability of seaweed stocks for the food industry.