Studies on Gracilaria. 5. In vitro life history of Gracilaria sp. from the Maritime Provinces

Abstract

The life history of Gracilaria sp. was completed in culture demonstrating a typical Polysiphonia-type life history. Carpospores released by plants collected in nature developed into tetrasporophytes and subsequent release and germination of tetraspores gave rise to a gametophytic generation morphologically similar to the tetrasporophyte. Development of tetrasporophytes from carpospores released by the carposporophytic generation completed the life history. A male to female ratio of 1:1 was found for plants originating from tetraspores and only female plants grown in the presence of male plants formed fertile cystocarps. Detached plants showed the greatest reproductive potential; reproductive maturation of these plants occurred in 8–10 weeks after spore germination. Vegetative propagation through rapid regeneration of adventitious branches from wound tissue was observed.