Michaela Grein

Modelling of stomatal density response to atmospheric CO2

Stomatal density tends to vary inversely with changes in atmospheric CO(2) concentration (C(a)). This phenomenon is of significance due to: (i) the current anthropogenic rise in C(a) and its impact on vegetation, and (ii) the potential applicability for reconstructing palaeoatmospheric C(a) by using fossil plant remains. It is generally assumed that the inverse change of stomatal density with C(a) represents an adaptation of epidermal gas conductance to varying C(a). Reconstruction of fossil C(a) by using stomatal density is usually based on empirical curves which are obtained by greenhouse experiments or the study of herbarium material. In this contribution, a model describing the stomatal density response to changes in C(a) is introduced. It is based on the diffusion of water vapour and CO(2), photosynthesis and an optimisation principle concerning gas exchange and water availability. The model considers both aspects of stomatal conductance: degree of stomatal aperture and stomatal density. It is shown that stomatal aperture and stomatal density response can be separated with stomatal aperture representing a short-term response and stomatal density a long-term response. The model also demonstrates how the stomatal density response to C(a) is modulated by environmental factors. This in turn implies that reliable reconstructions of ancient C(a) require additional information concerning temperature and humidity of the considered sites. Finally, a sensitivity analysis was carried out for the relationship between stomatal density and C(a) in order to identify critical parameters (= small parameter changes lead to significant changes of the results). Stomatal pore geometry (pore size and depth) represents a critical parameter. In palaeoclimatic studies, pore geometry should therefore also be considered.

MORPHYLL: A a database of fossil leaves and their morphological traits

Morphometric characters of fossil leaves such as size and shape are important and widely used sources for reconstructing palaeoenvironments. Various tools, including CLAMP or Leaf Margin Analysis, utilize leaf traits as input parameters for estimating palaeoclimate, mostly based on correlations between traits and climate parameters of extant plants. During the last few years, the scope of information extracted from the morphology of fossil leaves has been further expanded by including leaf economics, which describe correlations between functional leaf traits and ecological strategies. The amount and quality of available data are essential for a successful palaeoecological analysis utilizing leaf traits. Here, the database MORPHYLL is described. This database is devised to offer a web-based resource for fossil leaf trait data. For this purpose, fossil leaves from various collections were digitized and morphometric traits extracted from leaf outlines. Besides metadata such as accession number, repository, fossil site or taxonomic information (for identified specimens), MORPHYLL offers queries for several morphometric parameters and derived ecophysiological traits (e.g., leaf mass per area). Currently, the database contains data from about 6000 fossil leaves from sites in Central Europe, spanning almost the entire Paleogene and part of the early Neogene. The application potential of the database is demonstrated by conducting some exemplary analyses of leaf traits for the Paleocene, Eocene and Oligocene, with the results indicating changes of mean leaf traits through time. For example, the results show leaf mass per area to peak during the Eocene, which is in accordance with general climate development during the Paleogene. Christopher Traiser. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. traiser@smns-bw.de Anita Roth-Nebelsick. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. Traiser, Christopher, Roth-Nebelsick, Anita, Grein, Michaela, Kovar-Eder, Johanna, Kunzmann, Lutz, Moraweck, Karolin, Lange, Jörg, Kvaček, Jiří, Neinhuis, Christoph, Folie, Annelise, De Franceschi, Dario, Kroh, Andreas, Prestianni, Cyrille, Poschmann, Markus, and Wuttke, Michael. 2018. MORPHYLL: A database of fossil leaves and their morphological traits. Palaeontologia Electronica 21.1.1T: 117 https://doi.org/10.26879/773 palaeo-electronica.org/content/2018/2114-database-of-fossil-leaves Copyright: January 2018 Palaeontology Association. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ TRAISER ET AL.: DATABASE OF FOSSIL LEAVES anita.rothnebelsick@smns-bw.de Michaela Grein. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. michaela.grein@smns-bw.de; present address: Übersee-Museum Bremen, Bahnhofsplatz 13, 28195 Bremen, Germany. m.grein@uebersee-museum.de Johanna Kovar-Eder. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. johanna.eder@smns-bw.de Lutz Kunzmann, Senckenberg Natural History Collections Dresden, Königsbrücker Landstr. 159, 01109 Dresden, Germany. lutz.kunzmann@senckenberg.de Karolin Moraweck. Senckenberg Natural History Collections Dresden, Königsbrücker Landstr. 159, 01109 Dresden, Germany. karolin.moraweck@senckenberg.de Jörg Lange. State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. joerg.lange@smns-bw.de Jiří Kvaček. National Museum Prague, Václavské náměsti 68, 115 79 Prague 1, Czech Republic. jiri.kvacek@nm.cz Christoph Neinhuis. Technische Universität Dresden, Institute for Botany, Zellescher Weg 20b, 01217 Dresden, Germany. christoph.neinhuis@tu-dresden.de Annelise Folie. Royal Belgian Institute of Natural Sciences, rue Vautier 29, 1000 Brussels, Belgium. afolie@naturalsciences.be Dario De Franceschi. CR2P-Sorbonne-Universités, CP38, 57 rue Cuvier, 75231 Paris, France. dario.defranceschi@mnhn.fr Andreas Kroh. Naturhistorisches Museum Wien, Burgring 7, 1010 Vienna, Austria. andreas.kroh@nhmwien.ac.at Cyrille Prestianni. Royal Belgian Institute of Natural Sciences, rue Vautier 29, 1000 Brussels, Belgium. cprestianni@naturalsciences.be Markus Poschmann. Generaldirektion Kulturelles Erbe RLP, Direktion Landesarchäologie / Erdgeschichte, Niederberger Höhe 1, 56077 Koblenz, Germany. markus.poschmann@gdke.rlp.de Michael Wuttke. Senckenberg Research Institute, Senckenberganlage 25, 60325 Frankfurt am Main, Germany. michael.wuttke@senckenberg.de