NITROGEN AND CARBON METABOLISM DEVELOPMENTS IN PLANT AND SOIL SCIENCES VOLUME 3 Other titles in this series: Volume 1 Soil-Water and Nitrogen in Mediterranean-type Environments edited by J. Monteith and C. Webb ISBN 90-247-2406-6 Volume 2 Nitrogen Losses and Surface Run-off from Landspreading of Manures. Proceedings of a Workshop in the EEC Programme of Coordination of Research on Effluents from Livestock, held at The Agricultural Institute, Johnstown Castle Research Centre, Wexford, Ireland, May 20-22, 1980 edited by J.C. Brogan ISBN 90-247-2471-6 In preparation: Structure and Function of Plant Roots. Proceedings of the Second International Symposium, held in Bratislava, Czechoslovakia, September 1-5, 1980 edited by R. Brouwer, O. Gasparikova, J. Kolek and B.C. Loughman NITROGEN AND CARBON METABOLISM Proceedings of a Symposium on the Physiology and Biochemistry of Plant Productivity, held in Calgary, Canada, July 14-17, 1980 edited by J. DEREK BEWLEY Department of Biology, University of Calgary. Alberta, Canada 1981 MARTINUS NIJHOFF / DRW. JUNK PUBLlSHERS THE HAGUE / BOSTON I LONDON Distributors: for the United States and Canada Kluwer Boston, Inc. 190 Old Derby Street Hingham, MA 02043 USA for alI other countries Kluwer Academic Publishers Group Distribution Center P.O.Box 322 3300 AH Dordrecht The Netherlands This volume is listed in the Library of Congress Cataloging in Publication Data ISBN-13: 978-94-009-8269-7 e-ISBN-13: 978-94-009-8267-3 DOI: 10.1007/978-94-009-8267-3 Copyright @1981 by Martinus Nijhoff / Dr. W. Junk Publishers, The Hague. Softcover reprint ofthe hardcover Ist edition 1981 Ali rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, mechanical, photocopying, recording, or otherwise, without the prior written permission ofthe publishers, Martinus Nijhoff / Dr. W. Junk Publishers, P.O.Box 566,2501 CN The Hague, The Netherlands. v CONTENTS Preface VII Chapter 1. Profound and Useful Discoveries. R.G.S. BIDlf\TELL 1 Chapter 2. Comparison of the Efficiency of Nitrate and Nitrogen Fixation in Crop Yield. J. RIGAUD 17 Chapter 3. Nitrate uptake, Production and Transport in the Whole Plant. L.E. SCHRADER and R.J. THOMAS 49 Chapter 4. Carbon and Nitrogen Partitioning in the Whole Plant - a Thesis based on Empirical Modeling. J.S. PATE and D.B. LAYZELL 94 Chapter 5. Relationships between Nitrogen Metabolism and ?hotosynthesis. J.A. BASSIIAM, P.O. LARSEN, A.L. LA1'NER and K. L. CORNv.7ELL 135 Chapter 6. Photosynthate Limitation of Symbiotic N2 Fixation. K. ANDERSEN, S.T. LIM, H. SPILLER, K.T. SHANMUGAM and R.C. VALENTINE 164 Chapter 7. Photorespiration and Nitrogen Metabolism. D.T. CANVIN 178 Chapter 8. Seed Storage Proteins: Genetics, Synthesis, Accumulation and Protein Quality. B.J. MIFLIN and P.R. SHEWRY 195 VII PREFACE This book results from a symposium on the theme of 'The Physiology and Biochemistry of Plant Productivity' which was held at the University of Calgary from July 14-18, 1980, and was jointly sponsored by the Canadian Society of Plant Physiologists and the International Association of Plant Physiologists. The subject matter of the book deals with various aspects of nitrogen and carbon metabolism, their interrelationships and interdependence. The topics covered in the chapters highlight various interesting and important lines of research that are in progress. There is no attempt to provide a comprehensive coverage of the basic physiological knowledge upon which this research depends - important references are to be found at the end of each chapter, however, and the reader will be able to pursue these as necessary. An introductory chapter by Dr. R.G.S. Bidwell (winner of the C.S.P.P. Gold Medal in 1979) considers some implications of plant physiological research and the aims and responsibilities of plant physiologists. In the next two chapters Drs. J. Rigaud and L.E. Schrader (with R.J. Thomas) elaborate on current research on nitrate metabolism and nitrogen fixation, and how an understanding of these phenomena might be usefully applied towards the manipulation of plants to improve productivity. Dr. J.S. Pate (with D.R. Layzell) introduces the topic of carbon and nitrogen interrelationships and develops models for their partitioning and transport within plants. Continuing this theme Drs. J.A. Bassham (with P.O. Larsen, A.L. Lawyer and K.L. Cornwell) and R.C. Valentine (with K. Andersen, S.T. Lim, H. Spiller, and K.T. Shanmugaml discuss the convergent pathways of carbon and nitrogen metabolism, the regulation of carbon flow from photosynthesis into sugars and amina acids, and how photosynthate production might limit symbiotic nitrogen fixation, an event whic~ has a high metabolic energy cost. Photorespiration is also closely and importantly associated with nitrogen metabolism VIII and Dr. D.T. Canvin explains the essential links between these processes. In the last chapter, Dr. B.J. Miflin (with P.R. Shewry) details the nature of seed storage proteins, a vital dietary source of amino acids, their synthesis and geno~e organization, informat ion which is necessary to accurately assess the prospects for improving protein quality. These chapters are based on papers presented at two symposia at the CSPP/IAPP conference, and I am grateful to Drs. R.H. Hageman and L. Beevers for their role as Chairmen of these sessions. The programme was arranged with the excellent cooperation of Drs. A. Oaks and F. Wightman, and the meeting itself relied upon the organizational skills of Dr. R.P. Pharis. Cooperation by Dr. A. Quispel on behalf of the IAPP is appreciated. I am very grateful to the authors for the prompt manner in which they provided me with their manuscripts, and to Erin Smith of the Biology Dept., University of Calgary for her secretari al skills and help in the final preparation of this book. September 1980 J. Derek Bewley Professor of Biology University of Calgary Calgary T2N lN4 Alberta, Canada CHAPTER 1 PROFOUND AND USEFUL DISCOVERIES R.G.S. Bidwell Wallace RR #1, Nova Scotia, Canada BOK lYO Introduction Tank Cultivation of Marine Algae: Background Gas Exchange in Marine Algae: The Air Suspension System Seaweed Cultivation: The Transfer of Ideas Industrial Research: Funding, Operation and Control References I.D. Bewley (ed.), Nitrogen and Carbon Metabolism Copyright@ 1981 Martinus Nijhoff ! Dr W. lunk Publishers, The Hague -Boston -London Al! rights reserved. 2 The Gold Medal Address was presented at the meeting by Dr. R. G. S. Bidwell, recipient of the Canadian Society of Plant Physiologists Gold Medal (1979) in recognition of his outstanding published contributions and for his service to plant physiology and the Canadian Society. lNTRODUCTlON The title of this chapter is not intended to refer to my own work, but is taken from an observation by J. B. Passioura, C.S.l.R.O., Canberra (11): Plant physiologists have two responsibilities to the public whose money supports them. One is to make profound discoveries. The other is to make useful ones. A discussion of the physiology and biochemistry of plant productivity implies practical application of laboratory research. There have been a number of notable successes in the transfer of laboratory research to agricultural 1 l gratefully acknowledge continued research support from the National Research Council of Canada while l was on the staff of Queen's University, Kingston, Ont. l am also deeply grateful to the Director of the N.R.C.C.'s Atlantic Research Laboratory, Halifax, N.S., for my appointment as Visiting Scientist during a Sabbatical year in 1976-7, and as Guest Scientist at intervals since then. 3 technology. But there have been agreat many more failures. To put the matter in a different perspective, we have made many Frofound discoveries that are inherently useless or inaccessible for the development of agricultural technology. This is not because they are bad science, or improperly done, or even in remote or inaccessible fields. It means that while most of us are more or less adept at making profound discoveries, few of us are good at making useful ones. I do not wish to belittle the importance of pure science. That activity leads, or should lead, to the profound discoveries that are essential for the continuation and development of science. Profound discoveries are able to take care of themselves because they generate new ideas, new questions, and new research. There are no dead ends in pure science. But they are not necessarily useful. Profound discoveries have another attribute: important ones are not made very of ten, or by very many scientists. This leaves the great majority of us with the sensible option of making useful discoveries. But considering the large amount of work done and the vast sums of money that support it, the size of the return in useful discoveries seems to be remarkably small. This suggests that perhaps many of us are not familiar with the techniques of making useful discoveries. It is my purpose in this paper to describe, as a case history, some research that was started with the hopeful intention of making profound discoveries but which, through a process that was largely serendipitous, began to make useful discoveries instead, and ultimately lead to a genuine (if small) break-through in agricultural technology. I refer to the technology of cost-effective on-shore cultivation of marine algae. My interest here is not 50 much in the research itself as in our discovery (hopefully profound) of how to make useful discoveries.