Short note: Preliminary observations on the propagule production of Sargassum polycystum C. Agardh from stoloniferous branches

Sargassum polycystum has a unique morphology, i.e. stoloniferous branches that arise from primary axes. The regeneration ability of these stoloniferous branches as vegetative propagules was investigated to optimize the growth parameters. Pieces of stoloniferous branch (2-3 cm) were subject to a range of salinities (25-50 psu), photoperiods (24,0, 8,16, 10,14, 12,12, 14:10, 16:8 and 0:24 h L:D), irradiance (5, 25 and, 45 mu mol photons m(-2) s(-1)) and pH (7, 7.5, 8, 8.5 and 9) for a period of 35 days. The maximum daily growth rate (DGR) was observed under the conditions of: 35 psu salinity (1.18 +/- 0.35% day(-1)), 16:8 L:D photoperiod (0.94 +/- 0.08% day(-1)), 45 mu mol photons m(-1) s(-1) (1.13 +/- 0.28% day(-1)), and pH 7.5 (1.14 +/- 0.12% day(-1)). The vegetative propagules regenerated from stoloniferous branches were found to produce primary laterals (branches) and phyllodes (leaves) which, developed into new thalli, but without a holdfast.