A starting guide to root ecology: strengthening ecological concepts and standardizing root classification, sampling, processing and trait measurements Gregoire Freschet, Loic Pagès, Colleen Iversen, Louise Comas, Boris Rewald, Catherine Roumet, Jitka Klimešová, Marcin Zadworny, Hendrik Poorter, Johannes Postma, et al. To cite this version: Gregoire Freschet, Loic Pagès, Colleen Iversen, Louise Comas, Boris Rewald, et al.. A starting guide to root ecology: strengthening ecological concepts and standardizing root classification, sampling, processing and trait measurements. 2020. hal-02918834 HAL Id: hal-02918834 https://hal.archives-ouvertes.fr/hal-02918834 Preprint submitted on 21 Aug 2020 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. A starting guide to root ecology: strengthening ecological concepts and standardizing root classification, sampling, processing and trait measurements Grégoire T. Freschet1,2, Loïc Pagès3, Colleen M. Iversen4, Louise H. Comas5, Boris Rewald6, Catherine Roumet1, Jitka Klimešová7, Marcin Zadworny8, Hendrik Poorter9,10, Johannes A. Postma9, Thomas S. Adams11, Agnieszka Bagniewska-Zadworna12, A. Glyn Bengough13,14, Elison B. Blancaflor15, Ivano Brunner16, Johannes H.C. Cornelissen17, Eric Garnier1, Arthur Gessler18,19, Sarah E. Hobbie20, Ina C. Meier21, Liesje Mommer22, Catherine Picon-Cochard23, Laura Rose24, Peter Ryser25, Michael Scherer- Lorenzen26, Nadejda A. Soudzilovskaia27, Alexia Stokes28, Tao Sun29, Oscar J. Valverde-Barrantes30, Monique Weemstra1, Alexandra Weigelt31, Nina Wurzburger32, Larry M. York15, Sarah A. Batterman33, Moemy Gomes de Moraes34, Štěpán Janeček35, Hans Lambers36, Verity Salmon37, Nishanth Tharayil38, M. Luke McCormack39 1Centre d’Ecologie Fonctionnelle et Evolutive, UMR 5175 (CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE - IRD), 1919 route de Mende, 34293 Montpellier, France 2Station d’Ecologie Théorique et Expérimentale, UMR 5321 (CNRS - Université Toulouse III), 2 route du CNRS, 09200 Moulis, France 3INRA, UR 1115 PSH, Centre PACA, site Agroparc, 84914 Avignon cedex 9, France 4Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA 5USDA-ARS Water Management Research Unit, 2150 Centre Avenue, Bldg D, Suite 320, Fort Collins, CO 80526, USA 6Dept. of Forest and Soil Sciences, University of Natural Resources and Life Sciences, Vienna, Austria 7Department of Functional Ecology, Institute of Botany CAS, Dukelska 135, 37901 Trebon, Czech Republic 8Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland 9Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany 10Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109, Australia 11Department of Plant Sciences, The Pennsylvania State University, University Park, PA 16802, USA 12Department of General Botany, Institute of Experimental Biology, Faculty of Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, 61-614 Poznań, Poland 13The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK 14School of Science and Engineering, University of Dundee, Dundee DD1 4HN, UK 15Noble Research Institute,LLC, 2510 Sam Noble Parkway, Ardmore, Oklahoma 73401, USA 16Forest Soils and Biogeochemistry, Swiss Federal Research Institute WSL, Zürcherstr. 111, 8903 Birmensdorf, Switzerland 17Department of Ecological Science, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands 18Forest Dynamics, Swiss Federal Research Institute WSL, Zürcherstr. 111, 8903 Birmensdorf, Switzerland 19Institute of Terrestrial Ecosystems, ETH Zurich, 8092 Zurich, Switzerland 20Department of Ecology, Evolution and Behavior, University of Minnesota, St. Paul, Minnesota, 55108, USA 21Plant Ecology, University of Goettingen, Untere Karspüle 2, 37073 Göttingen, Germany 22Plant Ecology and Nature Conservation Group, Department of Environmental Sciences, Wageningen University and Research, PO box 47, 6700 AA, Wageningen, the Netherlands 23UCA, INRA, VetAgro Sup, UREP, 63000 Clermont-Ferrand, France 1 24Senckenberg Biodiversity and Climate Research Centre (BiK‐F), Senckenberganlage 25, 60325 Frankfurt am Main, Germany 25Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario, Canada P3E 2C6 26Geobotany, Faculty of Biology, University of Freiburg, Schänzlestr. 1, 79104 Freiburg, Germany 27Environmental Biology Department, Institute of Environmental Sciences, CML, Leiden University, Leiden, The Netherlands 28INRA, AMAP, CIRAD, IRD, CNRS, University of Montpellier, Montpellier, France 29Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China 30International Center for Tropical Botany, Department of Biological Sciences, Florida International University, Miami, FL 33199 USA 31Systematic Botany and Functional Biodiversity, Institute of Biology, Leipzig University, Johannisallee 21-23, Leipzig, Germany 32Odum School of Ecology, 140 E. Green Street, University of Georgia, Athens, Georgia 30602, USA 33School of Geography and Priestley International Centre for Climate, University of Leeds, Leeds, LS2 9JT, U.K. and Cary Institute of Ecosystem Studies, Millbrook, NY, 12545, USA 34Department of Botany, Institute of Biological Sciences, Federal University of Goiás, 19 74690-900, Goiânia, Goiás, Brazil 35Department of Ecology, Faculty of Science, Charles University, Vinicna 7, Prague 12801, Czech Republic 36School of Biological Sciences, The University of Western Australia, Crawley (Perth), Western Australia, Australia 37Environmental Sciences Division and Climate Change Science Institute, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA 38Department of Plant and EnvironmentalSciences, Clemson University, Clemson, SC 29634, USA 39 Center for Tree Science, Morton Arboretum, 4100 Illinois Rt. 53, Lisle, IL 60532, USA Author for correspondence: Grégoire T. Freschet Tel: +33 5 61 04 05 90 Email: [email protected] 2 Summary In the context of a recent massive increase into research on plant root functions and their impact on the environment, root ecologists currently face many important challenges to keep on producing cutting edge, meaningful and integrated knowledge. Consideration of the belowground components in plant and ecosystem studies has been consistently called for in recent decades, but methodology is disparate and sometimes inappropriate. This handbook, based on the collective effort of a large team of experts, is to be used not only as starting point by students and scientists who desire working on belowground ecosystems but also by confirmed experts for consolidating and broadening their views on root ecology. Beyond the classical compilation of measurement protocols, we have synthesized recommendations from the literature to provide key background knowledge useful for (i) defining belowground entities and giving keys for their meaningful dissection, classification and naming beyond the classical fine- versus coarse-root approach, (ii) considering the specificity of root research to produce sound laboratory and field data, (iii) describing typical but overlooked steps for studying roots, e.g. root handling, cleansing and storage, and (iv) gathering of meta-data necessary for the interpretation of results and their re-use. Most importantly, all root traits have been introduced with some degree of ecological context that will be a foundation for understanding their ecological meaning, their typical use and uncertainties, and some methodological and conceptual perspectives for future research. Considering all of this, we urge readers to not solely extract protocol recommendations for trait measurements from this monograph, but take a moment to sit down, read and reflect on the extensive information contained in this broader guide to root ecology, including parts I to VII and the many introductions to each section and root trait description. Finally, it is critical to understand that a major aim of this guide is to help break down barriers between the many subdisciplines of root ecology and ecophysiology, broaden researchers’ views on the multiple aspects of root study and create favourable conditions for the inception of comprehensive experiments on the role of roots in plant and ecosystem functioning. 3 Author contributions GTF initiated and coordinated the handbook project. GTF wrote chapter I. EG and GTF wrote chapter II with input from CR. GTF wrote chapter III. LP, MLM, GTF and BR wrote chapter IV. EG and CMI wrote chapter V. CR, HP, CMI, JP, MLM and TSA wrote chapter VI, with input from GTF. CR, CMI, MLM and TSA wrote chapter VII, with input from a range of authors. JK and JHCC wrote chapter VIII. CMI, HP, VS and JK wrote chapter IX, with input from GTF. LP and JP wrote chapter X, with input from GTF. LM, AW and LHC wrote chapter XI. PR and OJV wrote chapter XII, with input from GTF, LHC and LR. MZ, LHC and ABZ wrote chapter XIII, with input from MW and a range of authors. IB and NT wrote chapter XIV, with input from HP, MGM and SJ. AS