Gelidium floridanum is a red seaweed of economic importance as it yields high-quality agar which is extracted exclusively from material harvested from natural beds. Phytoregulators have not been explored in macroalgal culture as a probable alternative for large-scale farming of seaweed. Therefore, this study aimed to analyze the direct regeneration of G. floridanum explants using indole-3-acetic acid (IAA), jasmonic acid (JA), and gibberellic acid (GA). Explants (5 mm) were treated in liquid medium supplemented with IAA (0.57, 5.7, and 57 μM), JA (2, 4, and 8 mM), and GA (29, 43, and 58 mM) for 48 h and then further cultivated for 20 days. To observe the morphology and formation of new axes, micrographs were taken on the 5th day of culture using stereoscopic microscopy, and explants were processed for light and scanning electron microscopy. On the 20th day micrographs were obtained through stereoscopic microscopy for a final count of formed axes. After 5 days the formation of upright axes was greater and with a greater average size in the 2 and 4 mM JA treatments and floridean starch grains accumulated at the base, not being observed in the apical region. After 20 days the formation of new explants was higher in all treatments with IAA. We conclude that the direct regeneration of G. floridanum explants occurs from the medullary cells and starts in the first week of culture. Among the phytoregulators tested, JA contributed to the earlier formation of the upright axes, but after 20 days, IAA proved to be more efficient in the formation and size of these axes.

佛罗里达州的Gelidium floridanum是一种具有重要经济意义的红海藻，因为它产生的高质量琼脂仅从天然床上采集的材料中提取。在大型藻类养殖中尚未研究出植物调节剂作为海藻大规模养殖的可能替代品。因此，本研究旨在分析佛罗里达州立蘑菇的直接再生。外植体使用吲哚-3-乙酸（IAA），茉莉酸（JA）和赤霉素（GA）。将外植体（5 mm）在补充有IAA（0.57、5.7和57μM），JA（2、4和8 mM），GA（29、43和58 mM）的液体培养基中处理48小时，然后进一步栽培20天。为了观察形态和新轴的形成，在培养的第5天使用立体显微镜拍摄显微照片，并对外植体进行光和扫描电子显微镜处理。在第20天，通过立体显微镜获得显微照片，以最终形成轴数。5天后，在2mM和4mM JA处理中竖立轴的形成更大并且具有更大的平均尺寸，并且在根部积累了弗洛里丹淀粉颗粒，而在根尖区域没有观察到。20天后，在所有使用IAA的处理中，新外植体的形成都较高。我们得出的结论是G. floridanum外植体来自髓质细胞，开始于培养的第一周。在所测试的植物调节剂中，JA有助于较早地形成竖轴，但是20天后，IAA被证明在这些竖轴的形成和尺寸方面更有效。