Seeds: Physiology of Development and Germination

451 Pages·1994·17.911 MB·English

by  J. Derek Bewley, Michael Black (auth.)

SEEDS
Physiology of
Development and
Germination
Second Edition
SEEDS
Physiology of
Development and
Germination
Second Edition
J. Derek Bewley
Department of Botany
University of Guelph
Guelph, Ontario, Canada
and
Michael Black
Division of Life Sciences
King's College
University of London
London, England
Springer Science+Business Media, LLC
Library of Congress Cataloging-in-Publication Data
Bewley, J. Derek, 1943-
Seeds : physiology of development and germination / J. Derek
Bewley and Michael Black. — 2nd ed.
p. cm.
Includes bibliographical references and index.
1. Seeds—Deve 1 opinent. 2. Germination. I. Black, Michael.
II. Title.
QK661.B49 1994
582' .0467—dc20 94-19278
CIP
J. Derek Bewley
Department of Botany
University of Guelph
Guelph, Ontario N1G 2W1
Canada
Michael Black
Division of Life Sciences
King's College
University of London
London W8 7AH
England
ISBN 978-0-306-44748-8 ISBN 978-1-4899-1002-8 (eBook)
DOI 10.1007/978-1-4899-1002-8
© Springer Science+Business Media New York 1994
Originally published by Plenum Press, New York in 1994
Softcover reprint of the hardcover 2nd edition 1994
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
Though I do not believe
that a plant will spring up
where no seed has been,
I have great faith in a seed.
Convince me that you have a seed there,
and I am prepared to expect wonders.
Henry D. Thoreau
Preface to the Second Edition
Since the publication of the first edition of this book there have been
enormous advances in certain areas of the subject, particularly those which are
amenable to study using the techniques and approaches of molecular biology and
mutant technology. This is especially apparent with respect to seed development,
effects of abscisic acid and gibberellin on gene expression and certain aspects
of dormancy. Sections of the book dealing with these topics have been exten
sively revised, to incorporate new information and concepts. In one case-seed
development-it has been necessary to allocate two chapters to the subject, to
separate reserve synthesis and its regulation from the more developmental
aspects of embryogenesis and seed maturation. As in the previous edition, we
have been mindful throughout of placing our discussion and considerations
firmly in the context of the seed, and where new knowledge at the molecular
level is included we have attempted always to emphasize its special relevance
to seed biology.
The reader will discern that some sections have been altered relatively little
from their state in the previous edition. These are areas in which, at least
according to our perceptions, advances have been more modest, especially as
regards the development of new concepts and interpretations. But some of these
are now opening up to the new approaches which are already having such
substantial impact in the realm of seed physiology.
We are grateful to those who have helped us in the production ofthis book.
Many researchers have contributed material or given us permission to use their
published findings. Laurie Winn of the Department of Botany, University of
Guelph, has done sterling work in converting our scrawl into a splendidly
presented transcript. Our thanks also to Sherry Hall, at Guelph, for helping out
when the pressure became too high. The wonders of computer technology have
been effectively harnessed by Wenjin Yu of the same Department in the produc
tion of many of the illustrations. We express our sincere appreciation of their
skills and patience.
J.D. Bewley
M. Black
vii
Contents
Chapter 1
Seeds: Germination, Structure, and Composition
1.1. Introduction ............................................. .
1.2. Seed Germination-Some General Features ................... 1
1.3. Measurement of Germination ............................... 2
1.4. Seed Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.1. Embryo........................................... 7
1.4.2. Nonembryonic Storage Tissues ....................... 8
1.4.3. Seed Coat (Testa) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
1.5. Seed Storage Reserves ..................................... 10
1.5.1. Carbohydrates ..................................... 12
1.5.2. Fats and Oils (Neutral Lipids) . . . . . . . . . . . . . . . . . . . . . . . . . 16
1.5.3. Proteins........................................... 18
1.5.4. Phytin ............................................ 30
1.5.5. Other Constituents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 31
Chapter 2
Seed Development and Maturation
2.1. Embryogeny and Storage Tissue Formation. . . . . . . . . . . . . . . . . . . . 35
2.1.1. Morphological Changes ............................. 35
2.1.2. Regulation of Development .......................... 39
2.2. Source of Assimilates for Grain and Seed Filling ............... 40
2.2.1. Cereals ........................................... 41
2.2.2. Legulnes.......................................... 42
ix
x Contents
2.2.3. Translocation of Assimilates into the Developing Seed. . . . 44
2.2.4. Environmental Effects on Seed Development . . . . . . . . . . . . 50
2.3. Deposition of Reserves within Storage Tissues ... . . . . . . . . . . . . . . 51
2.3.1. Starch Synthesis ................................... 52
2.3.2. Deposition of Polymeric Carbohydrates Other Than Starch 58
2.3.3. Triacylglycerol Synthesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
2.3.4. Storage Protein Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
2.3.4.1. Cereals ................................... 68
2.3.4.2. Dicots.................................... 73
2.3.4.3. Modifications to Synthesized Storage Proteins,
Their Sorting and Targeting to Protein Bodies ... 74
2.3.4.4. Seed mRNA Content and Storage Protein
Synthesis ................................. 81
2.3.5. Regulation of Storage Protein Synthesis ................ 83
2.3.5.1. Investigating Gene Expression in Seeds ........ 84
2.3.5.2. Expression of Storage Protein Genes. . . . . . . . . . . 86
2.3.5.3. Nutritional Effects on Storage Protein Synthesis. 92
2.3.5.4. Abscisic Acid and the Osmotic Factor. . . . . . . . . . 92
2.3.5.5. Molecular Action of ABA ................... 95
2.3.5.6. Mutants, Protein Content, and Nutritional
Quality of Seeds ........................... 97
2.3.6. Phytin Deposition .................................. 99
2.4. Hormones in the Developing Seed ........................... 100
2.4.1. Composition and Location. . . . . . . . . . . . . . . . . . . . . . . . . .. 101
2.4.1.1. Auxins ................................... 101
2.4.1.2. Gibberellins ............................... 102
2.4.1.3. Cytokinins ................................ 104
2.4.1.4. ABA..................................... 104
2.4.2. Possible Roles of Seed Hormones ..................... 105
2.4.2.1. Seed Growth and Development ............... 105
2.4.2.2. Fruit Growth and Development ............... 109
2.4.2.3. Hormones for Germination and Growth ........ 110
2.4.2.4. Other Effects of the Seed Hormones ........... 110
Chapter 3
Development-Regulation and Maturation
3.1. Germinability during Development .......................... 117
3.2. Viviparous Mutants and Precocious Germination ............... 119
3.3. Maturation Drying and the "Switch" to Germination ............ 124
Contents xi
3.3.1. The Acquisition of Desiccation Tolerance ............... 124
3.3.2. Changes in Metabolism Associated with Drying ......... 126
3.3.3. Metabolic Changes on Rehydration following Desiccation. 131
3.3.4. Seed Germination without Prior Desiccation ............ 134
3.4. The Dry Seed ............................. ; .............. 136
3.4.1. Bound Water and Vitrification ........................ 136
3.4.2. Metabolism in the Dry State .......................... 138
3.5. Recalcitrant Seeds. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 140
Chapter 4
Cellular Events during Germination and Seedling Growth
4.1. Imbibition ............................................... 147
4.1.1. Uptake ofWaterfrom the Soil ........................ 147
4.1.2. Water Uptake by Seeds ............................ " 149
4.1.3. Soaking Injury and Solute Leakage .................... 153
4.2. The Completion of Germination: Radicle Elongation and Its
Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 155
4.3. Respiration-Oxygen Consumption .......................... 160
4.3.1. Pathways, Intermediates, and Products ................. 160
4.3.2. Respiration during Imbibition and Germination .......... 161
4.4. Mitochondrial Development and Oxidative Phosphorylation ...... 163
4.4.1. Site of ATP Production during Early Imbibition .......... 163
4.4.2. The Route of Electrons between Substrate and Molecular
Oxygen ........................................... 164
4.4.3. Mitochondrial Development in Imbibed Seeds ........... 167
4.4.4. ATP Synthesis during Germination .................... 171
4.4.5. The Synthesis and Utilization of Reducing Power:
Pyridine Nucleotides ................................ 172
4.5. Respiration under Anaerobic Conditions ...................... 175
4.6. Protein Synthesis during Germination and Its Dependence on
mRNA Synthesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 178
4.6.1. Protein Synthesis in Germinating Embryos and Axes. . . . .. 178
4.6.2. Ribosomal and Transfer RNA Synthesis ................ 185
4.6.3. Enzymes and Precursors of RNA Synthesis ............. 187
4.6.4. Protein and RNA Synthesis in Storage Tissues. . . . . . . . . .. 187
4.7. DNA Synthesis and Cell Division .......................... " 188
4.8. Seedling Development. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 191
xii Contents
Chapter 5
Dormancy and the Control of Germination
5.1. Introduction ............................................. 199
5.2. Internal Controls. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .. 199
5.2.1. Dormancy-Its Biological Role. . . . . . . . . . . . . . . . . . . . . .. 199
5.2.2. Categories of Dormancy. . . . . . . . . . . . . . . . . . . . . . . . . . . .. 201
5.2.3. Mechanism of Dormancy ............................ 203
5.2.4. Embryo Dormancy-The Inherent Constraints ........... 203
5.2.5. Coat-Imposed Dormancy-The Constraints ............. 206
5.2.5.1. Interference with Water Uptake ............. " 206
5.2.5.2. Mechanical Restraint. . . . . . . . . . . . . . . . . . . . . . .. 207
5.2.5.3. Interference with Gas Exchange. . . . . . . . . . . . . .. 208
5.2.5.4. Prevention of Exit ofInhibitors ............... 213
5.2.5.5. Supply of Inhibitors to the Embryo ............ 214
5.2.6. Coat-Imposed Dormancy-A Summary ................ 215
5.3. Embryonic Inadequacy-the Causes ......................... 215
5.3.1. Metabolism of Dormant Seeds .. . . . . . . . . . . . . . . . . . . . . .. 215
5.3.2. Gene Expression and Dormancy ...................... 217
5.3.3. Membranes and Dormancy ........................... 218
5.4. Development of Dormancy ................................. 220
5.4.1. When Does Primary Dormancy Occur? ................ 220
5.4.2. Genetic Control of Dormancy ........................ 221
5.4.3. Correlative Effects in Dormancy ...................... 222
5.4.4. Dormancy Induction by Abscisic Acid ................. 222
5.4.5. The Environment in Dormancy Inception. . . . . . . . . . . . . .. 226
5.4.6. Development of Hard Coats ............ . . . . . . . . . . . . .. 229
5.4.7. Secondary Dormancy ............................... 230
5.5. The External Controls ..................................... 230
5.5.1. The Release from Dormancy ......................... 231
5.5.1.1. Afterripening .............................. 231
5.5.1.2. Low Temperatures (Chilling) ................. 232
5.5.1.3. Other Effects of Temperature on Dormancy ..... 236
5.5.1.4. Light ..................................... 237
5.5.1.5. Seeds with Impermeable Coats ............... 247
5.5.1.6. Breaking of Dormancy by Chemicals .......... 247
5.5.1.7. The Mechanism of Dormancy Release ......... 248
5.5.1.8. Hormones in Dormancy Breaking ............. 250
5.5.1.9. Dormancy Breakage and Metabolism .......... 253
5.5.1.10. Dormancy Breakage and Cell Enlargement ...... 257
5.5.2. Environmental Control of Germination. . . . . . . . . . . . . . . .. 258