caa a22 4500 60620850X CHVBK 20210128101023.0 cr unu---uuuuu 210128e20150801xx s 000 0 eng 10.1007/s00425-015-2292-6 doi (NATIONALLICENCE)springer-10.1007/s00425-015-2292-6 Desiccation tolerance in the chlorophyte green alga Ulva compressa [Elektronische Daten] does cell wall architecture contribute to ecological success? [Andreas Holzinger, Klaus Herburger, Franziska Kaplan, Louise Lewis] Main conclusion : Desiccation leads to structural changes of the inner pectic cell wall layers in Ulva compressa . This contributes to protection against mechanical damage due to desiccation-rehydration cycles. Ulva compressa, characterized by rbcL phylogeny, is a common species in the Mediterranean Sea. Ulva as an intertidal species tolerates repeated desiccation-rehydration cycles in nature; the physiological and structural basis were investigated under experimental conditions here. Desiccation to 73% relative water content (RWC) led to a significant decrease of the maximum quantum yield of photosystem II (F v/F m) to about half of the initial value. A reduction to 48 or 27% RWC caused a more drastic effect and thalli were only able to recover fully from desiccation to 73% RWC. Relative electron transport rates were stimulated at 73% RWC, but decreased significantly at 48 and 27% RWC, respectively. Imaging-PAM analysis demonstrated a homogenous desiccation process within individual thallus discs. The different cell wall layers of U. compressa were characterized by standard staining procedures, i.e. calcofluor white and aniline blue for structural components (cellulose, callose), ruthenium red for pectins and toluidine blue for acidic polysaccharides. Already a reduction to 73% RWC caused severe changes of the cell walls. The inner pectin-rich layers followed the shrinkage process of the cytoplasm, while the outer denser fibrillar layers maintained their shape. In this way, the thalli were not plasmolyzed during water loss, and upon recovery not negatively influenced by any mechanical damage. Transmission electron microscopy corroborated the arrangement of the different layers clearly distinguishable by their texture and electron density. We suggest the flexibility of the pectin-rich cell wall layers as a major contribution to desiccation tolerance in Ulva. The Author(s), 2015 Cellulose nationallicence Imaging PAM nationallicence Intertidal zone nationallicence Macroalgae nationallicence Pectin nationallicence Photosynthesis nationallicence rbc L phylogeny nationallicence AB : Aniline blue nationallicence AIC : Akaike information criterion nationallicence α : Positive slope at limiting photon fluence rates nationallicence APX : Ascorbate peroxidase nationallicence ASW : Artificial sea water nationallicence CAT : Catalase nationallicence CFW : Calcofluor white nationallicence F m : Maximal fluorescence yield from dark-adapted material nationallicence F o : Basic fluorescence yield from dark-adapted material nationallicence F v/ F m : Maximum photochemical quantum yield of PSII nationallicence I k : Initial value of light-saturated photosynthesis nationallicence LhcSR : Light-harvesting complex stress-related nationallicence ML : Maximum likelihood nationallicence NA : Numerical aperture nationallicence PAM : Pulse amplitude modulation nationallicence PAUP : Phylogenetic analysis using parsimony nationallicence PSII : Photosystem II nationallicence rbc L : Large subunit of rubisco nationallicence rETRmax : Maximum relative electron transport rate nationallicence RH : Relative humidity nationallicence ROS : Reactive oxygen species nationallicence RR : Ruthenium red nationallicence RWC : Relative water content nationallicence SOD : Superoxide dismutase nationallicence TB : Toluidine blue nationallicence TEM : Transmission electron microscope nationallicence W 0 : Wet weight nationallicence W d : Dry weight nationallicence W t : Weight after t desiccation nationallicence Holzinger Andreas Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria aut Herburger Klaus Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria aut Kaplan Franziska Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria aut Lewis Louise Department of Ecology and Evolutionary Biology, University of Connecticut, 06269-3043, Storrs, CT, USA aut Planta Springer Berlin Heidelberg 242/2(2015-08-01), 477-492 0032-0935 242:2<477 2015 242 425 https://doi.org/10.1007/s00425-015-2292-6 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00425-015-2292-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Holzinger Andreas Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria aut NATIONALLICENCE 700 1- Herburger Klaus Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria aut NATIONALLICENCE 700 1- Kaplan Franziska Institute of Botany, Functional Plant Biology, University of Innsbruck, Sternwartestrasse 15, 6020, Innsbruck, Austria aut NATIONALLICENCE 700 1- Lewis Louise Department of Ecology and Evolutionary Biology, University of Connecticut, 06269-3043, Storrs, CT, USA aut NATIONALLICENCE 773 0- Planta Springer Berlin Heidelberg 242/2(2015-08-01), 477-492 0032-0935 242:2<477 2015 242 425