Comparative Ecology and Physiology of Australian And
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COMPARATIVE ECOLOGY AND PHYSIOLOGY OF AUSTRALIAN AND BRAZILIAN MISTLETOE -HOST RELATIONSHIPS MARINA CORRÊA SCALON , BS C, MS C Thesis submitted in fulfil of the requirement for the degree of Doctor of Philosophy Department of Biological Sciences Faculty of Science Macquarie University Sydney, Australia May 2015 2 “Now, here, you see, it takes all the running you can do, to keep in the same place. If you want to get somewhere else, you must run at least twice as fast as that!” Lewis Carroll – Alice Through the Looking Glass 4 Table of contents Table of contents Figure list 9 Table list 13 Summary 15 Certificate of candidate 17 Acknowledgements 19 Statement of contribution 21 Chapter 1. General Introduction 23 General Introduction .................................................................................................... 25 Background .................................................................................................................... 25 The haustorium ...................................................................................................... 27 Differences between parasitic and non-parasitic angiosperms ............................. 27 Thesis outline ................................................................................................................. 30 References ...................................................................................................................... 35 Chapter 2. A global analysis of water and nitrogen relationship between mistletoes and their hosts: broad-scale tests of old and enduring hypotheses* 43 Abstract .......................................................................................................................... 45 Introduction ................................................................................................................... 47 Material and Methods ................................................................................................... 51 Data Analyses ........................................................................................................ 53 Results ............................................................................................................................. 53 Environmental effects ............................................................................................. 58 5 Table of contents Discussion ....................................................................................................................... 58 Water use efficiency and the N-parasitism hypothesis .......................................... 59 Mimicry hypothesis ................................................................................................ 61 Family differences between mistletoe traits ........................................................... 63 References ...................................................................................................................... 80 Supplemental Data ........................................................................................................ 90 Chapter 3. Photosynthetic trait adaptations of parasitic mistletoes and their hosts in sites of contrasting aridity 103 Abstract ........................................................................................................................ 105 Introduction ................................................................................................................. 106 Material and Methods ................................................................................................. 109 Sites descriptions ................................................................................................. 110 Traits measurement .............................................................................................. 116 Data analyses ....................................................................................................... 117 Results .......................................................................................................................... 117 Trait patterning with site aridity .......................................................................... 117 Trait differences between mistletoes and their hosts ........................................... 118 Discussion ..................................................................................................................... 124 Similar trait adaptation to aridity in mistletoes and hosts .................................. 124 Higher N area and P area at arid sites ...................................................................... 126 Mistletoes higher respiration costs ...................................................................... 127 Conclusions .................................................................................................................. 130 Acknowledgements ...................................................................................................... 131 References .................................................................................................................... 138 6 Table of contents Chapter 4. Nutrient resorption in mistletoes from three low-P sites in Australia and Brazil 149 Abstract ........................................................................................................................ 151 Material and Methods ................................................................................................. 156 Sites descriptions ................................................................................................. 160 Leaf trait measurements ....................................................................................... 161 Data Analyses ...................................................................................................... 162 Results ........................................................................................................................... 163 Discussion ..................................................................................................................... 170 Nutrient resorption and implications for the N-parasitism hypothesis ............... 170 Differences in nutrient economy between mistletoes vs. non-parasitic plants .... 172 Resorption and functional trait relationships ...................................................... 174 Resorption and implications for litter .................................................................. 175 Conclusion .................................................................................................................... 176 Acknowledgements ...................................................................................................... 177 References .................................................................................................................... 188 Chapter 5. Leaf lifespan, herbivory and leaf defence investment in mistletoes and their hosts 197 Abstract ........................................................................................................................ 199 Introduction ................................................................................................................. 201 Material and Methods ................................................................................................. 206 Leaf traits ............................................................................................................. 208 Leaf lifespan and herbivory rates ......................................................................... 209 Physical defences ................................................................................................. 210 7 Table of contents Data Analyses ...................................................................................................... 210 Results .......................................................................................................................... 211 Patterning of Mistletoe-Host differences among sites ......................................... 211 Relationships between Mistletoe and Host defence traits ................................... 212 Generalised defence syndromes vs. trade-offs between defence types ................ 214 Herbivory and leaf lifespan relationship with defence ........................................ 214 Batesian mimicry in Australian mistletoes .......................................................... 218 Discussion ..................................................................................................................... 218 Relationships between Mistletoe and Host defence traits ................................... 222 Generalised defence syndromes vs. trade-offs between defence types ................ 224 Herbivory and leaf lifespan relationships with defence ...................................... 225 Batesian mimicry in Australian mistletoes .......................................................... 228 Conclusion .................................................................................................................... 229 Acknowledgements ...................................................................................................... 230 References .................................................................................................................... 248 Chapter 6. General Discussion 261 General Discussion .....................................................................................................