A PHYLOGENETIC PERSPECTIVE ON FINE ROOT ECOLOGY: ASSESSING THE ROLE OF ROOT EVOLUTION ON FINE ROOT FUNCTIONAL TRAITS AND ECOLOGICAL INTERACTIONS IN WOODY ANGIOSPERMS. 5 10 A Dissertation submitted to Kent State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy 15 20 by Oscar J. Valverde-Barrantes December, 2013 25 Dissertation written by Oscar J. Valverde-Barrantes B.S., Technological Institute of Costa Rica, 1997 M.S., University of Costa Rica, 2003 30 M.S., Iowa State University, 2006 Approved by: ___________________________________, Chair, Doctoral Dissertation Committee Dr. Christopher B. Blackwood ___________________________________, Members, Doctoral Dissertation Committee 35 Dr. Andrea Case ___________________________________ Dr. Oscar J. Rocha ___________________________________ Dr. Kurt A. Smemo 40 ___________________________________ Dr. Dr. Alison J. Smith Accepted by _______________________________, Acting Chair, Department of Biological Sciences 45 Dr. Laura G. Leff _______________________________, Associate Dean, College of Arts and Sciences Dr. Janice Crowther ii TABLE OF CONTENTS Chapter One: Introduction ............................................................................................................... 1 50 References .................................................................................................................................. 12 Chapter Two: Woody angiosperm fine root morphology is phylogenetically structured but chemistry is related to the plant economics spectrum .................................................................... 18 Summary .................................................................................................................................... 18 Introduction ................................................................................................................................ 19 55 Methods: .................................................................................................................................... 23 Study site and sample collection ............................................................................................ 23 Morphological and architectural traits ................................................................................... 25 Chemical traits ....................................................................................................................... 27 Phylogenetic data ................................................................................................................... 28 60 Data analysis .......................................................................................................................... 28 Results ........................................................................................................................................ 33 Discussion .................................................................................................................................. 44 References .................................................................................................................................. 51 Chapter Three: Phylogenetically structured traits in root systems influence arbuscular mycorrhizal 65 colonization in woody angiosperms. .............................................................................................. 69 Summary .................................................................................................................................... 69 Introduction ................................................................................................................................ 71 Methods ..................................................................................................................................... 75 Site description....................................................................................................................... 75 70 Phylogenetic background: ...................................................................................................... 76 Collection of root systems: .................................................................................................... 77 Chemical and morphological analyses: .................................................................................. 77 Root system anatomy and microscopic estimation of mycorrhizal colonization: .................. 78 Molecular estimation of mycorrhizal colonization: ............................................................... 79 75 Statistical analysis .................................................................................................................. 82 Results ........................................................................................................................................ 86 Hypothesis 1. Comparing changes in stele and cortex area across species: .......................... 86 Hypothesis 2. Integration of root traits across root orders: .................................................... 87 iii Hypothesis 3. Relationship between root traits and mycorrhizal colonization ...................... 91 80 Discussion .................................................................................................................................. 95 Root trait modifications during angiosperm evolution .......................................................... 95 Root trait integration across root orders ................................................................................. 98 Root trait integration and mycorrhizal colonization ............................................................ 101 Literature Cited ........................................................................................................................ 105 85 Chapter Four: The distribution of belowground traits is explained by intrinsic species differences and intraspecific plasticity in response to root neighbors ............................................................ 115 Summary .................................................................................................................................. 115 Introduction .............................................................................................................................. 117 Methods ................................................................................................................................... 121 90 Study site and data collection: ............................................................................................. 121 Statistical analysis: ............................................................................................................... 125 Results ...................................................................................................................................... 130 Root trait plasticity and species differences ......................................................................... 130 Root community assembly processes .................................................................................. 136 95 Community-aggregated traits ............................................................................................... 137 Discussion ................................................................................................................................ 139 Plasticity-mediated competitive trait displacement belowground ....................................... 140 Controls on community-aggregated root traits .................................................................... 142 Conclusion ........................................................................................................................... 143 100 References ................................................................................................................................ 144 Chapter Five: Aggregated and complimentary: fine root distribution patterns in a temperate deciduous forest. .......................................................................................................................... 163 Summary .................................................................................................................................. 163 Introduction .............................................................................................................................. 165 105 Methods ................................................................................................................................... 171 Site description ........................................................................................................................ 171 Vertical root distribution samples ........................................................................................ 172 Sampling roots across ecosystems and ecotones ................................................................. 173 Soil conditions and species distribution above and belowground ....................................... 174 iv 110 Molecular root identification ............................................................................................... 175 Root trait measurements ...................................................................................................... 176 Statistical analysis ................................................................................................................ 176 Results .....................................................................................................................................