Responses of the macroalgae Hypnea musciformis after in vitro exposure to UV-B

Éder C. Schmidt*, Beatriz Pereira, Rodrigo W. dos Santos, Claudiane Gouveia, Giulia Burle Costa, Gabriel S M Faria, Fernando Scherner, Paulo A. Horta, Roberta de Paula Martins, Alexandra Latini, Fernanda Ramlov, Marcelo Maraschin, Zenilda L. Bouzon

*Corresponding author for this work

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

The in vitro effects of UVBR were investigated in apical segments of Hypnea musciformis. The plants were cultivated and exposed to photosynthetically active radiation (PAR) at 80μmolphotonsm -2s -1 and PAR+UVBR at 1.6Wm -2 at 3h per day for 7 days. Toluidine Blue reaction showed metachromatic granulations in vacuole, and Periodic Acid Schiff stain showed a decrease in the number of floridean starch grains. UVBR also caused changes in the ultrastructure of cortical cells, which included increased thickness of the cell wall, reduced intracellular spaces, changes in the cell contour, destruction of chloroplast internal organization, and rough endoplasmic reticula increase. The algae cultivated under PAR-only showed growth rates of 9.7%day -1, while algae exposed to PAR+UVBR grew only 3.2%day -1. Furthermore, compared with control algae, phycobiliprotein contents (phycoerythrin, phycocyanin, and allophycocyanin) were observed to decrease after PAR+UVBR. However, chlorophyll a levels were not significantly different (ANOVA, P=0.52) after exposure to PAR+UVBR. As a photoprotective adaptation strategy against UVB damage, an increase of 58.9% phenolic compounds and 3.6% of carotenoids was observed. Overall, these results lead to the conclusion that both ultrastructural damage and observable changes in metabolism occurred in H. musciformis after only 3h of daily UVB exposure over a 7-d experimental period.

Original languageEnglish
Pages (from-to)8-17
Number of pages10
JournalAquatic Botany
Volume100
DOIs
Publication statusPublished - Jul 2012
Externally publishedYes

Keywords

  • Carotenoids
  • Carrageenan yield
  • Hypnea musciformis
  • Mitochondrial activity
  • Phenolic compounds
  • Photosynthetic performance
  • Ultrastructure
  • Ultraviolet radiation-B

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