Protoplasma

, Volume 243, Issue 1, pp 105–116

Physiological, biochemical, and ultrastructural responses of the green macroalga Urospora penicilliformis from Arctic Spitsbergen to UV radiation

  • Michael Y. Roleda
  • Ursula Lütz-Meindl
  • Christian Wiencke
  • Cornelius Lütz
Original Article

DOI: 10.1007/s00709-009-0037-8

Cite this article as:
Roleda, M.Y., Lütz-Meindl, U., Wiencke, C. et al. Protoplasma (2010) 243: 105. doi:10.1007/s00709-009-0037-8

Abstract

Exposure of the filamentous turf green alga Urospora penicilliformis to ambient and artificial ultraviolet radiation (UVR) revealed a considerable resilient species. This explains the ability of this alga to thrive in the middle–upper intertidal zones of the Arctic sea where it is periodically exposed to environmental extremes. A transient UVR effect on photosynthesis under photosynthetically active radiation (PAR) + UV-A and PAR + UV-A + UV-B was found, but dynamic recovery of photoinhibition was observed immediately after reduction of the photon fluence rate of PAR in the absence or presence of background UVR under laboratory and natural solar radiation, respectively. Chlorophylls, carotenoids, and xanthophyll cycle pigments (violaxanthin, antheraxanthin, and zeaxanthin) concentrations were not significantly different between freshly collected samples and filaments exposed to additional laboratory radiation treatment. The ultrastructure of the U. penicilliformis gametophytes showed that the cells are well adapted to UVR. No significant ultrastructural alterations were observed in filaments exposed to different spectral irradiance in the laboratory compared to in situ acclimated specimen. The antioxidant α-tocopherol was detected in minute quantity while the search for flavonoid-like compounds was negative. Other UV screening strategies or certain genetically fixed physiological protective mechanism could be operating in this species responsible for their occurrence in higher shoreline and ecological success. Further molecular and biochemical studies are needed to elucidate the stress resistance in this turf alga. There is an indication that the extremely thick cell wall of U. penicilliformis gametophytes covered with mucilage sheath and dense layer of mineral depositions may provide a shield against unfavorable environmental conditions in general and against UVR in particular.

Keywords

α-Tocopherol Carotenoids Cell wall mineral deposition Chlorophyll PE curve Photosynthesis Ultrastructure Xanthophyll cycle pigments 

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Michael Y. Roleda
    • 1
  • Ursula Lütz-Meindl
    • 2
  • Christian Wiencke
    • 3
  • Cornelius Lütz
    • 4
  1. 1.Institute for Polar EcologyUniversity of KielKielGermany
  2. 2.Plant Physiology Division, Cell Biology DepartmentUniversity of SalzburgSalzburgAustria
  3. 3.Section Functional Ecology, Department Seaweed BiologyAlfred Wegener Institute for Polar and Marine ResearchBremerhavenGermany
  4. 4.Department Physiology and Cell Physiology of Alpine Plants, Institute of BotanyUniversity of InnsbruckInnsbruckAustria