Nardelli, Allyson E.
Floh, Eny I. S.
Total Authors: 4
 Univ Sao Paulo, Inst Biosci, Lab Marine Algae Edison Jose de Paula, Rua Matao 277, BR-05508090 Sao Paulo - Brazil
 Univ Sao Paulo, Inst Biosci, Plant Cell Biol Lab, Rua Matao 277, BR-05508090 Sao Paulo - Brazil
Total Affiliations: 2
Rev. bras. Bot.;
Web of Science Citations:
Sargassumspecies form extensive benthic beds in tropical and subtropical low intertidal and subtidal zones, acting as important drivers for marine community structure. Temperature, as one of the most important abiotic factor, affects seaweed performance and triggers changes in metabolic responses; therefore, laboratory experiments involving temperature ranges are tools for understanding seaweed engineering. The aim of this study was to assess the physiological vulnerability and sensitivity ofSargassum stenophyllumC. Martius exposed to five different temperatures by analyzing photosynthetic performance and chemical composition related to carbon and nitrogen metabolism. There were no significant differences in energy quenching between treatments, except at 35 degrees C, which showed decreased photochemical quenching and increased non-regulated non-photochemical quenching. Chlorophyllaand chlorophyllcat 15 degrees C and 35 degrees C exhibited lower amounts at the end of experiment. Protein content showed progressive diminution in the treatments. Total soluble carbohydrates content showed higher concentration as temperature increased. After 7 days, total amino acid content showed increase from 15 degrees C to 30 degrees C. No generalization between the amino acid patterns, although glutamine and glutamate content at 15 degrees C and 35 degrees C were reduced; and the highest values of isoleucine and leucine were detected at 35 degrees C. We postulated that accumulation of certain chemical compounds inS. stenophyllumresults from a reallocation of carbon and nitrogen, osmoregulation responses and protection against oxidative stress. Results suggest this species' tolerance ranges between 15 degrees C and 30 degrees C and sensitivity at 35 degrees C. (AU)