Spore release and germling development on different substrates in the carrageenophyte Sarcothalia crispata from the southwestern Atlantic coast

Abstract

Sarcothalia crispata is a carrageenophytic red alga from South America. The gametophytes produce kappa/iota carrageenan and the tetrasporophytes, lambda carrageenan, each with different properties and uses. The aims of this study were to determine the most effective method for obtaining S. crispata carpospores and tetraspores from southern Argentina, to evaluate the germination process of these spores, and to assess their survival and growth on different substrates. Desiccation, osmotic shock, low temperature, and spontaneous discharge were tested in the laboratory as spore release methods. The settlement and growth of sporelings were assessed on glass, ropes, shells, and gravel. No differences were found among induction methods, obtaining a higher output of tetraspores per frond area than of carpospores. After 3 months, shells and gravel showed the highest densities of carposporelings and tetrasporelings, while the lowest were observed on ropes and glass, respectively. Carposporeling survival varied between 88% on gravel and 13% on ropes; for tetrasporelings, mean survival was 5%. Sporelings attained the largest basal discs and longest erect portions on glass, and the smallest and shortest ones on ropes, those on shells and gravel being of intermediate in size. Based on these results, it can be concluded that carpospores and tetraspores from S. crispata obtained by spontaneous discharge and inoculated on shells and gravel will result in good densities, allowing germlings to develop and grow. This is the first study on reproductive aspects of S. crispata from the southwestern Atlantic coast, presenting valuable information for reliably initiating specific spore cultures. Obtaining this specific raw material separately for the extraction of kappa/iota or lambda carrageenan would lead to a better management of the resource by the carrageenan industry.