Durham E-Theses The eect of an elevated atmospheric CO(_2) concentration on secondary metabolism and resource allocation in plantago maritima and armeria maritima Davey, Matthew Paul How to cite: Davey, Matthew Paul (2003) The eect of an elevated atmospheric CO(_2) concentration on secondary metabolism and resource allocation in plantago maritima and armeria maritima, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/3998/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 The effect of an elevated atmospheric CO2 concentration on secondary metabolism and resource allocation in Plantago maritima and Armeria maritima Matthew Paul Davey Submitted to the University of Durham for the degree of Doctor of Philosophy A copyright of this thesis rests with the author. No quotation from it should be published without his prior written consent and information derived from it should be acknowledged. School of Biological and Biomedical Sciences University of Durham 2003 I 3 JUL 2004 Plantago maritima (foreground) and Armeria maritima (midground in flower) on a coastal cliff-top in Shetland, UK (Photo. C. Gray) 11 Candidate's dedaration I declare that the material contained in this thesis has not been previously submitted for a degree in this or any other university. All the work recorded in this thesis is entirely my own, unless otherwise stated. Statement of Copyright © The copyright of this thesis rests with the author. No quotation from it should be published without prior consent and any information derived from it should be acknowledged. in Davey M. P. (2003) The effect of an elevated atmospheric CO2 concentration on secondary metabolism and resource allocation in Plantago maritima and Armeria maritima Ph.D. Thesis. University of Durham, UK. Abstract There are relatively few reports concerning carbon and nitrogen partitioning into secondary metabolism in plants grown in elevated atmospheric CO2. This thesis investigates the effects of changes in atmospheric CO2 and soil nitrogen availability on compatible solute accumulation and resource allocation in Plantago maritima and Armeria maritima. It was hypothesised that contrasting metabolic responses to abiotic stress cause a species-specific response in P. maritima and A. maritima in resource allocation. In response to drought, P. maritima accumulates the carbon based compatible solute sorbitol, whilst A. maritima accumulates the nitrogen based solutes betaine and proline. Over ten weeks, A. maritima was more responsive to changes in C and N availability than P. maritima, especially in the amount of C fixed into leaf matter. After elevated CO2 exposure for one year, the biomass of P. maritima increased and of A. maritima decreased, compared to the respective plants at ambient CO2. Compatible solute concentrations were increased by drought at ambient CO2 but decreased in droughted plants at elevated CO2. This was hypothesised to be due to lower transpiration rates. Rates of transpiration in P. maritima decreased in response to elevated CO2 huiA. maritima did not. Tissue water-potential was also lowered in response to elevated CO2. This thesis also examines resource allocation to other major C and N sinks. In P. maritima grown at elevated CO2 for one year, total soluble phenolic concentrations increased and the concentration of soluble protein decreased. In A. maritima, phenolic concentrations decreased and protein concentrations increased. The effect of enhanced CO2 on the secondary metabolism of P. maritima was investigated in greater detail. Six phenolics were identified using metabolite profiling, namely /7-coumaric acid, ferulic acid, caffeic acid, verbascoside, plantamajoside and luteolin. P. maritima exposed to elevated CO2 had higher concentrations of some of these individual phenolic compounds and histochemical analysis identified increases in the number of lignified vessels and a decrease of lignified vessel-wall thickness. IV Acknowledgements I would like to express my thanks to my supervisors Dr. Bob Baxter, Prof Robert Edwards and Prof Trevor Ashenden for discussion, ideas, support and most of all for giving me the freedom to explore my subject throughout the PhD. The studentship was ftinded by the Natural Environment Research Council (NERC) and the Centre for Ecology and Hydrology (CEH) (NERC-CASE grant award GT04/99/54/TS). First, I would like to thank people at the University of Durham. Members of the 'old' lab 9; Neil Ellwood, Hannah Drewitt, Ben Turner, Dim Giantzoudis, Dr. Dave Balbi and Prof Brian Whitton provided help, advice and made the work enjoyable. Members of Lab 2; Dr. Ian Cummins, Dave Bryant, Dr. David Dixon, Dr. Mark Skipsey, Melissa Brazier and Caroline Loutre provided extensive help, advice and patience with biochemical techniques, especially on the HPLC and mass spectrometer. Prof Brian Huntley, Dr. Judy Allen, Dr. Steve Willis, Trish Ranner, and Jon Bennie gave advice and computer support. Dr. Phil Gates and Christine Richardson helped with microscopy. 'Little' Vicky Wilkins helped with sample collection and road navigation around the Northumberland coast. Eric Henderson, Michael Bone, Gordon Bainbridge, Margaret Snow and members of the teaching staff provided practical help throughout the PhD. Dr. Michael Jones at the Department of Chemistry gave technical help and advice with the mass spectrometry. Mike Hughes and staff at the University botanical gardens looked after the plants. Dan Maltman gave advice on techniques, scientific and climbing. Thanks to Jackie Hay, Ruth Cox, Sue Lewis, Andy Dean, Claire McSorley and John Hamilton, to name but a few, for friendship over the years, also, to Dave Bryant and Kerrie Farrar for friendship and lifts to Bangor. Thanks to other residents at Shincliffe hall, in particular Yuka Tajiri and Ute Dreher for being the most fiiendly and eccentric people I have ever lived with. Secondly, I would like to thank people at CEH Bangor. In particular. Dr. Harry Harmens provided extensive advice on plant physiological techniques, especially with the IRGA. Phil Williams looked after my plants. Peter Hadfield maintained the domes and provided crash courses in fixing scientific equipment. Dr. Bridget Emmett gave support and opportunities for me to present my research at CEH and conferences. Thanks to Alwyn Sowerby for friendship, advice and accommodation, and Cathy Shields for sharing the pleasure and pain of working in the solardomes. Thanks also to staff at Bangor University; Prof. John Farrar and members of his lab for help with the oxygen electrode and carbohydrate analysis, Dr. John Gorham for advice on compatible solute analysis, psychrometry and for the loan of a psychrometer, and Gareth Williams for technical help and advice, particularly on the CO2 growth cabinets. Thanks to Jane Stott and Alison Johnston for friendship, help and accommodation. And finally, a huge thanks to staff at the University Hospital, Durham who scooped me off the road one evening and fixed a rather broken leg; to my family for providing great support and encouragement throughout the whole of my PhD and especially to Catherine Gray for interesting discussions, editorial comments and love and support. This thesis is dedicated to the memory of my best mate, Steve Lawrence. VI Table of Contents Candidate's declaration iii Statement of Copyright iii Abstract iv Acknowledgements v Table of Contents vii List of figures xii List of tables xv Abbreviations xvii Chapter 1: General introduction 1.1 Coastal cliff-top habitats 1 1.2 Compatible solute metabolism and drought tolerance..... 3 1.3 Compatible solute production and resource availability 9 1.4 Study species: Plantago maritima and Armeria maritima 13 1.5 Research aims and outline of thesis 17 Chapter 2: General materials and methods 2.1 Plant and soil material 18 2.2 Experimental growth conditions 18 2.2.1 Growth room facility at the University of Durham 18 2.2.2 CEH-Bangor plant growth cabinets 19 2.2.3 Solardome facility at CEH-Bangor 19 2.3 General growth conditions 21 2.3.1 Plant cultivation 21 2.3.2 Manipulation of nitrogen availability 21 2.3.3 Manipulation of water availability 23 2.4 Gas exchange measurements 23 2.4.1 Photosynthetic capacity/rate of shoot tissue 23 2.4.2 A/cj response curves 25 2.5 Plant water potential (thermocouple psychrometry) 25 2.6 Plant growth and anatomical measurements 26 2.6.1 Plant dry weight and leaf area measurements 26 2.6.2 Growth analyses 27 2.6.3 Anatomical and lignification analysis 27 2.7 Biochemical assays 28 vn 2.7.1 Sources of chemicals 28 2.8 Photosynthetic pigments in shoot tissue 28 2.9 Nitrogen concentrations of plant tissue 29 2.9.1 Extraction procedure for total nitrogen 29 2.9.2 Analysis procedure for total nitrogen 29 2.10 Osmolyte concentrations in plant tissue 30 2.10.1 Extraction procedure 30 2.10.2 Betaine analysis 31