Seasonal Variations in the Biomass, Quantity and Quality of Agar, from the Reproductive and Vegetative Stages of Gracilaria (verrucosa type)

Publisher Website
Google Scholar
Abstract
Optimum growth of Gracilaria (Verrucosa type) in British Columbia [Canada] occurred between 5-6 m below mean tide level and correlated with solar radiation throughout the season. Vegetative populations declined with a consequent increase in reproductive forms to a maximum in July. Tetrasporophytes dominated the reproductive population and in July attained the greatest seasonal biomass of all forms of the alga. Maximum population and biomass were attained by carposoporophytes in July and by male gametophytes 1 mo. earlier. An inverse relationship between biomass and yield of agar was apparent only for the vegetative and tetrasporic forms of the alga. Variations in yields, gel strengths and gelation characteristics of the isolated agars were demonstrated to be dependent on time of season and life stages of the alga. Ranked in the following decreasing order of merit as a source of agar were the cystocarpic, tetrasporic, vegetative and male gametophytic forms of Gracilaria (verrucosa type).