Seasonal photosynthetic and respiratory responses of the red alga Bostrychia tenella (Ceramiales, Rhodophyta) from a salt marsh and mangal

Seasonal photosynthetic and respiratory responses of the red alga Bostrychia tenella (Lamouroux) J. Agardh to temperature, salinity, and desiccation were compared using native and reciprocal transplants of mangrove and salt marsh populations on the west coast of Florida. In over 70% of cases, plants showed higher photosynthetic and respiratory rates when exposed to 30 degrees C compared with 20 degrees C, both in 30 parts per thousand and in 15 parts per thousand salinity. There was no pattern in responses to temperature and salinity with regard to season or whether the plants were native or transplants. Furthermore, respiration did not show a pattern for native and transplanted populations from both coastal wetland communities. Photosynthetic and respiratory responses were mostly similar after 3- or 6-h periods of daily desiccation, when compared with responses of plants that were not desiccated. All plants, regardless of the period of desiccation, showed net photosynthesis. The broad tolerances of native and transplanted B. tenella indicate that the species is adapted to a range of salinity, temperature, and desiccation regardless of season or original wetland community.