UNIVERSIDAD COMPLUTENSE DE MADRID FACULTAD DE CIENCIAS BIOLÓGICAS DEPARTAMENTO DE ECOLOGÍA TESIS DOCTORAL Hipótesis sobre el origen y la función de la secreción de mucílago en semillas de especies Mediterráneas Mucilage secretion in seeds of Mediterranean species : hypotheses about its origin and function MEMORIA PARA OPTAR AL GRADO DE DOCTOR PRESENTADA POR Meike Engelbrecht Director Patricio García-Fayos Poveda Madrid, 2014 © Meike Engelbrecht, 2014 Hipótesis sobre el origen y la función de la secreción de mucílago en semillas de especies Mediterráneas Tesis doctoral 2014 UNIVERSIDAD COMPLUTENSE DE MADRID FACULTAD DE CIENCIAS BIOLÓGICAS Departamento de Ecología THESIS DOCTORAL Hipótesis sobre el origen y la función de la secreción de mucílago en semillas de especies Mediterráneas Mucilage secretion in seeds of Mediterranean species: hypotheses about its origin and function MEMORIA PARA OPTAR AL GRADO DE DOCTOR PRESENTADA POR Meike Engelbrecht Bajo la dirección del doctor Patricio García-Fayos Poveda © Meike Engelbrecht, 2014 Madrid, 2014 MUCILAGE SECRETION IN SEEDS OF MEDITERRANEAN SPECIES: HYPOTHESES ABOUT ITS ORIGIN AND FUNCTION HIPÓTESIS SOBRE EL ORIGEN Y LA FUNCIÓN DE LA SECRECIÓN DE MUCÍLAGO EN SEMILLAS DE ESPECIES MEDITERRÁNEAS DISSERTATION THESIS DOCTORAL Meike Engelbrecht Dr. Patricio García-Fayos Poveda, Investigador Científico del Centro de Investigaciones sobre Desertificación (CIDE) del Consejo Superior de Investigaciones Científicas (CSIC) certifica Que la memoria adjunta titulada "Hipótesis sobre el origen y la función de la secreción de mucílago en semillas de especies Mediterráneas - Mucilage secretion in seeds of Mediterranean species: hypotheses about its origin and function" presentada por Meike Engelbrecht ha sido realizada bajo mi inmediata dirección y cumple las condiciones exigidas para optar al grado de Doctor en Biología por la Universidad Complutense de Madrid. Y para autorizar su presentación y evaluación por el tribunal correspondiente, firman el presente certificado a día 10 de Marzo de 2014 Dr. Patricio García-Fayos Poveda Meike Engelbrecht INDEX ABSTRACT ................................................................................................................................................. 1 RESUMEN .................................................................................................................................................. 7 INTRODUCTION ....................................................................................................................................... 25 Bibliography ................................................................................................................................................... 40 CHAPTER 1 Mucilage secretion, an adaptive mechanism to reduce seed removal by soil erosion? .................................................................................................................................................................. 49 1. Introduction ........................................................................................................................................... 52 2. Material and Methods ........................................................................................................................... 55 2.1 Type of seed mucilage ...................................................................................................... 55 2.2 Seed resistance to drop impact ......................................................................................... 55 2.3 Seed resistance to runoff ................................................................................................... 56 2.4 Differences in amount of seed mucilage from plants growing under contrasting erosion regimes ... 57 2.4.1 Statistical analysis ............................................................................................................. 58 3. Results ................................................................................................................................................. 59 3.1 Type of seed mucilage ...................................................................................................... 59 3.2 Seed resistance to drop impact ......................................................................................... 61 3.3 Seed resistance to runoff ................................................................................................... 63 3.4 Differences in amount of seed mucilage from plants growing under contrasting erosion regimes ... 64 4. Discussion ............................................................................................................................................ 68 Bibliography ................................................................................................................................................... 70 CHAPTER 2 Post-dispersal seed anchorage to soil in semiarid plant communities, a test of the hypothesis of Ellner and Shmida ........................................................................................................... 79 1. Introduction ........................................................................................................................................... 82 2. Material and Methods ........................................................................................................................... 85 2.1 Study Area ......................................................................................................................... 85 3. Results .............................................................................................................................. 88 4. Discussion ............................................................................................................................................ 91 Bibliography ................................................................................................................................................... 94 CHAPTER 3 Mucilage secretion by seeds doubles the chance to escape ant removal ................... 99 1. Introduction ......................................................................................................................................... 102 2. Methods .............................................................................................................................................. 103 2.1 Study area ....................................................................................................................... 103 2.2 Plant species ................................................................................................................... 104 2.3 Ant species and their interaction with the target plant species ........................................ 104 2.4 Seed removal experiments and seed survival analysis ................................................... 105 3. Results ............................................................................................................................................... 106 3.1 Ant species and their interaction with the target plant species ........................................ 106 3.2 Seed removal experiments and seed survival analysis ................................................... 110 4. Discussion .......................................................................................................................................... 112 Bibliography ................................................................................................................................................. 115 CHAPTER 4 Phylogeny, biogeography and morphological ancestral character reconstruction in the Mediterranean genus Fumana (Cistaceae) ................................................................................... 121 1. Introduction ......................................................................................................................................... 124 2. Materials and Methods ....................................................................................................................... 126 2.1 Species sampling ............................................................................................................ 126 2.2 DNA extraction and amplification ..................................................................................... 127 2.3 Phylogenetic analyses ..................................................................................................... 128 2.4 Divergence time estimates and DIVA analysis ................................................................ 129 2.5 Ancestral state reconstruction ......................................................................................... 130 3. Results................................................................................................................................................ 131 3.1 Phylogenetic analyses ..................................................................................................... 131 3.2 Divergence time estimates and DIVA analysis ................................................................ 136 3.3 Ancestral state reconstruction ......................................................................................... 139 4. Discussion .......................................................................................................................................... 144 4.1 Phylogenetic analyses and systematic