Anais CBFic - Volume 1 - 2018

Sociedade Brasileira de Ficologia - SBFic

Publicado em 26/11/2018

Volume 1 - 2019

Título do Trabalho

ENVIRONMENTAL STRESS TOLERANCE AND ANTIOXIDANT RESPONSE OF THE RED SEAWEED PALISADA PERFORATA (BORY) K.W.NAM FROM A TROPICAL REEF

Autores

JULIANE B. VASCONCELOS, EDSON R. T. P. P. DE VASCONCELOS, ADILMA L. M. COCENTINO, FUNGYI CHOW, MUTUE T. FUJII

Modalidade

Resumo

Área Temática

1 BIODIVERSIDADE, FILOGENIA E ECOFISIOLOGIA

Data de Publicação

26/11/2018

País da Publicação

Brasil

Idioma da Publicação

Português

Página do Trabalho

http://sbfic.org.br/anais_show/117

ISSN

Aguardando...

Palavras-Chave

Desiccation, intertidal, Palisada, oxidative damage

Resumo

The cosmopolitan Rhodophyta Palisada perforata dominates intertidal seaweed communities in Brazilian tropical reefs and occurs at different zonation levels. Due to tidal cycles, twice a day, intertidal seaweeds are exposed to a wide range of environmental stresses including high light, rapid fluctuations of temperature, osmotic stress and desiccation, which can be intensified in tropical regions. In this way, our hypothesis is P. perforata must display an efficient antioxidant defense system that allows it to cope with desiccation and fluctuations in seawater temperature and salinity during tidal cycles. So, antioxidant activity of P. perforata collected on four different reef microhabitats (sheltered, tide pool, plateau and exposed) was investigated through five spectrophotometric assays. We performed Permanova to verify the influence of environmental data on antioxidant activity and graphically presented through a Redundancy Analysis map. The same species was then subjected to laboratory experiments (temperature x salinity and desiccation) to verify the actual influence of environmental stresses on P. perforata. We also measured algal photosynthetic performance through chlorophyll fluorescence parameters. The position on reef microhabitats showed little influence on the antioxidant activity of P. perforata. In general, the activity varied among exposure gradient as following: exposed ≥ plateau > sheltered > tide pool. After experiment stress conditions, there was a tendency of fully recovered photosynthesis for all specimens. The ability to photosynthesize at considerable rates during the onset of light and temperature suggests reactive oxygen species (ROS) scavenging is a relevant anti-stress mechanism in P. perforata. Maximum photosynthetic efficiency decreased 23% its capacity from control to dehydrated plants to prevent PSII from damage, suggesting algae were indeed under stress. High intertidal species are tolerant to desiccation and that tolerance seems to be based on various mechanisms that efficiently attenuate ROS excesses. Apparently, 2 h of air exposure did not significantly influence the photosynthesis of P. perforata, as observed by Yu et al. (2012) for other seaweeds, indicating a short-term desiccation effect followed by a complete recovery. P. perforata is most affected by desiccation stress than by temperature or salinity variations. This agrees with the observed at reef microhabitats, were algae from plateau, and thus, exposed to air and UV radiation during low tides, had higher antioxidant activity to protect themselves from oxidative damage. The capacity to produce antioxidants to protect its photosynthetic apparatus makes P. perforata an adapted seaweed to inhabit harsh environments as the intertidal reefs of tropical regions.