Light as an Energy Source and Information Carrier in Plant Physiology PDF
Preview Light as an Energy Source and Information Carrier in Plant Physiology
Light as an Energy Source and Information Carrier in Plant Physiology NATO ASI Series Advanced Science Institutes Series A series presenting the results of activities sponsored by the NATO Science Committee, which aims at the dissemination of advanced scientific and technological knowledge, with a view to strengthening links between scientific communities. The series is published by an international board of publishers in conjunction with the NATO Scientific Affairs Division A Life Sciences Plenum Publishing Corporation B Physics New York and London C Mathematical Kluwer Academic Publishers and Physical Sciences Dordrecht, Boston, and London D Behavioral and Social Sciences E Applied Sciences F Computer and Systems Sciences Springer-Verlag G Ecological Sciences Berlin, Heidelberg, New York, London, H Cell Biology Paris, Tokyo, Hong Kong, and Barcelona I Global Environmental Change PARTNERSHIP SUB-SERIES 1. Disarmament Technologies Kluwer Academic Publishers 2. Environment Springer-Verlag 3. High Technology Kluwer Academic Publishers 4. Science and Technology Policy Kluwer Academic Publishers 5. Computer Networking Kluwer Academic Publishers The Partnership Sub-Series incorporates activities undertaken in collaboration with NA TO's Cooperation Partners, the countries of the CIS and Central and Eastern Europe, in Priority Areas of concern to those countries. Recent Volumes in this Series: Volume 284 - Advances in Morphometrics edited by Leslie F. Marcus, Marco Corti, Anna Loy, Gavin J. P. Naylor, and Dennis E. Slice Volume 285 - Molecular, Cellular, and Clinical Aspects of Angiogenesis edited by Michael E. Maragoudakis Volume 286 - Analytical Use of Fluorescent Probes in Oncology edited by Elli Kohen Volume 287 - Light as an Energy Source and Information Carrier in Plant Physiology edited by Robert C. Jennings, Giuseppe Zucchelli, Francesco Ghetti, and Giuliano Colombetti Series A: Life Sciences Light as an Energy Source and Information Carrier in Plant Physiology Edited by Robert C. Jennings and Giuseppe Zucchelli University of Milan Milan, Italy and Francesco Ghetti and Giuliano Colombetti CNR Institute of Biophysics Pisa, Italy Plenum Press New York and London Published in cooperation with NATO Scientific Affairs Division Proceedings of a NATO Advanced Study Institute on Light as Energy Source and Information Carrier in Plant Photophysiology, held September 26 - October 6, 1994, in Volterra, Italy NATO-PCO-DATA BASE The electronic index to the NATO ASI Series provides full bibliographical references (with keywords and/or abstracts) to about 50,000 contributions from international scieptists published in all sections of the NATO ASI Series. Access to the NATO-PCO-DATA BASE is possible in two ways: -via online FILE 128 (NATO-PCO-DATA BASE) hosted by ESRIN, Via Galileo Galilei, 1-00044 Frascati, Italy -via CD-ROM "NATO Science and Technology Disk" with user-friendly retrieval software in English, French, and German (©WTV GmbH and DATAWARE Technologies, Inc. 1989). The CD-ROM also contains the AGARD Aerospace Database. The CD-ROM can be ordered through any member of the Board of Publishers or through NATO-PCO. Overijse, Belgium. Library of Congress Cataloging-in-Publication Data On file ISBN-13: 978-1-4613-8039-9 e-ISBN-13: 978-1-4613-0409-8 001: 10.1007/978-1-4613-0409-8 © 1996 Plenum Press, New York Softcover reprint of the hardcover 1 st edition 1996 A Division of Plenum Publishing Corporation 233 Spring Street, New York, N. Y. 10013 10987654321 All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher PREFACE A NATO Advanced Study Institute on "Light as Energy Source and Information Carrier in Plant Photo physiology" was held at Volterra, Italy, from September 26 to October 6, 1994, in order to consider the fundamental role that light plays in plant growth and development. This book summarises the main lectures given at this meeting which concentrated on both photochemical energy conversion and signalling (photosensing) aspects. Light harvesting and conversion into chemical energy in photosynthesis occurs at the level of chlorophyll/carotenoid containing photosystems in plants. Pigments are non- covalently bound to a variety of polypeptides which serve as a specific scaffolding, necessary to determine the energy coupling between pigments and thus allowing rapid excitation energy trasfer from the antenna to the special reaction centre chlorophylls. Data from transient, time resolved spectroscopies, in the femtosecond and picosecond domain, together with model calculations, suggest that this process occurs in the 20-100 picosecond time span. The special ~ll u~ture of reaction centre complexes, ensures rapid primary charge separation, probably in the order of 1-3 picoseconds, with subsequent charge stabilisation reactions proceeding in the hundreds of picoseconds range. The recently resolved crystallographic structure of LHCII, the principal antenna complex of plants, allows precise determination of pigment-pigment distances and thus permits calculation of approximate chlorophyll-chlorophyll Forster hopping rates, which are in good agreement with time resolved measurements. A number of lectures dealt with the complex phenomenon of light induced inhibition of photosynthetic activity (photoinhibition) and the protective mechanisms plants have evolved to counteract this. These processes occur mainly at the level of photo system II with reaction centres of this photo system being particularly sensitive to high iight fluxes. Quenching mechanisms, which thermally degrade excited states and which appear to be mainly localised in the external antenna complexes of photo system II, are effective in reducing excited state levels many-fold, in a fashion which is modulated by the light flux itself. The fact that the chlorophyll spectral forms are not organised as an energy "funnel" with respect to reaction centres in photosystem II increases the effectiveness of such control mechanisms. The effect of ultraviolet radiation on both terrestrial and aquatic ecosystems was also dealt with. Increases in ultraviolet fluxes, particularly interacting with other environmental stress factors, can induce significant damage in plants, with photosystem II being particularly sensitive. The effect of ultraviolet radiation on the vertical distribution phytoplankton in the water column may be significant. Photosensing processes are based on a variety of strategies which detect either time- integrated light quantity, spectral quality, light direction via intracellular light gradients in which such optical phenomena as absorption, refraction, intereference and dichroism are involved. Action spectroscopy is the principal technique which permits identification of a photoreceptor though problems associated with host-induced absorption shifts, absorption v screening and scattering can be considerable. Genetic and molecular biological manipulations can also be an important tool in identifYing photoreceptors as demonstrated by recent studies on the different morphogenetic roles of the family of phytochrome types via the use of specific phytochrome mutants. Phytochrome, by far the best characterised photomorphogenic photoreceptor, has ideal absorption characteristics to sense the dramatic changes in the terrestrial light environment within and underneath plant canopies. Progress has been made in recent years in understanding phytochrome phytochemistry. Phototransformation involves Z{l5)--E{l5) isomerisation which occurs within a few picoseconds. Subsequent changes in the a-helical folding near the N-terminus may be important in determing the biochemical and physiological activity of the phototransformed molecule. R.C. Jennings G. Zuc~helli F. Ghetti G. Colombetti Milano, Italy Pisa, Italy vi CONTENTS Photosynthesis: An Overview ............................................. . G. Forti Photosynthetic Electron Transfer and Energy Transduction in Plants . . . . . . . . . . . . . .. 17 D. R. Ort and J. Whitmarsh Specific Features of Excitation Migration in Photosynthesis ..................... 31 A. Yu. Borisov Biochemistry and Molecular Biology of Pigment Binding Proteins . . . . . . . . . . . . . . .. 41 R. Bassi, E. Giuffra, R. Croce, P. Dainese, and E. Bergantino Spectral Heterogeneity and Energy Equilibration in Higher Plant Photosystems ..... 65 R. C. Jennings, G. Zucchelli, L. Finzi, and F. M. Garlaschi Photosynthetic Reaction Centers ........................................... 75 P. Mathis Photoinhibition of Photosynthesis .......................................... 89 N. R. Baker Nonphotochemical Quenching of Chlorophyll Fluorescence ..................... 99 P. Horton Regulation of Excited States in Photosynthesis of Higher Plants .................. 113 J.-M. Briantais Chirally Organized Macrodomains in Thylakoid Membranes. Possible Structural and Regulatory Roles .................. : ................................ 125 G. Garab Interaction ofUV Radiation with the Photosynthetic Systems .................... 137 J. F. Bornman Molecular Basis of Photoreception .......................................... 147 F. Lenci, N. Angelini, and A. Sgarbossa Photomorphogenic Systems ............................................... 159 W. R. Briggs, E. Liscum, P. W. Oeller, and J. M. Palmer vii Overview of Photos en sing in Plant Physiology ................................ 169 W. Haupt Mechanisms of Photoreception: Energy and Signal Transducers .................. 185 D.-P. Hader Light Signal Transduction Mediated by Phytochromes .......................... 197 D. Sommer and P.-S. Song Light Penetration into the Canopy of Terrestrial Ecosystems ..................... 219 M. G. Holmes Light Penetration and Effects on Aquatic Ecosystems ........................... 231 D.-P. Hader Interception of Light and Light Penetration in Plant Tissues ..................... 243 M. G. Holmes Photosensory Transduction in Flagellated Algae ............................... 263 R. Marangoni, E. Lorenzini, and G. Colombetti Action Spectroscopy ..................................................... 275 F. Ghetti and G. Checcucci Photoregulation of Fungal Gene Expression .................................. 285 E. Cerda-Olmedo and L. M. Corrochano Phototropism in Phycomyces .............................................. 293 E. Cerda-Olmedo and V. Martin-Rojas What Can Errors Contribute to Scientific Progress? ............................ 301 W. Haupt Index ................................................................. 311 viii Light as an Energy Source and Information Carrier in Plant Physiology PHOTOSYNTHESIS: AN OVERVIEW. Giorgio Forti Centro di Studio CNR sulla Biologia Cellulare e Molecolare delle Piante. Dipartimento di Biologia dell'Universita di Milano, Via Celoria 26, Milano, Italy. INTRODUCTION Oxygenic photosynthesis of green plants and cyanobacteria utilizes water as an electron donor, light energy and CO2 to generate carbohydrates and other organic substances, according to the overall equation : (1) The photochemical system involved, which is bound to the photosynthetic membranes (the thylakoids) utilizes two photochemical reactions in series to transfer electrons against the electrochemical gradient from H20 (Em= 810mY at pH 7) to the iron-sulphur protein ferredoxin (Fd, Em= -420 mY at pH 7). Reduced ferredoxin is then utilized by a membrane bound flavoprotein to reduce NADP (Em= -320 mY at pH 7). The electrochemical work of 1.23 ev is accomplished through the cooperation of two photochemical reactions. Electron transport is coupled to the synthesis of ATP from ADP+Pi (inorganic OIthophosphate). The stable products of photosynthetic electron transport ATP and NADPH are then utilized to activate and reduce CO2 to the level of carbohydrates by a muItienzyme system present as a dense protein solution in the stroma of the chloroplasts (or in the cytoplasm of cyanobacteria) where the thylakoids are embedded. This latter process will not be discussed in this paper, which is limited to the photochemical events and electron transport producing NADPH and ATP. In green plants, including the unicellular green eukariotes, the overall process of photosynthesis is therefore accomplished within the chloroplast (see fig. 1), through the cooperation of the events occurring within and on the surface of the thylakoids (light absorption and excitation energy migration to the reaction centres, primary photochemical reactions, electron transport and ATP synthesis) and those occurring in the stroma (C02 assimilation). Light as an Energy Source and Information Carrier in Plant Physiology Edited by Jennings et al.. PleI11Ull Press, New York, 1996
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