Reproductive Biology of Sargassum thunbergii (Fucales, Phaeophyceae)

Sargassum thunbergii is an economically important brown alga that is used as a perferred food for sea cucumber in China. However, reports on the reproductive biology of S. thunbergii are limited. This study observed the characteristics of mature receptacles. The effects of different temperatures, light intensities, and photoperiods on the egg release of mature S. thunbergii receptacles were investigated. A liquid-phase oxygen electrode system was used to obtain light saturation and light compensation points of egg and young thalli of S. thunbergii. Results showed that, temperature was the key factor for the egg release of mature receptacles. The conditions most conducive to egg release were 20 degree Celsius to 23 degree Celsius temperature and 50 mu mol photons ... to 200 mu mol photons ... light intensity. In addition, the light saturation and compensation points of unfertilized eggs or young thalli at 2 d or 3 d postfertilization ranged from 90 mu mol photons ... to 120 mu mol photons ... and 14 mu mol photons ... to 22 mu mol photons ..., respectively. (ProQuest: ... denotes formulae/symbols omitted.)