An early application of pollen. Relief carving from the Palace of Syrian King Ashuir nasir-pal II. 883-859 B. c., discovered at N imrud, the modern Calah, now in the Metropolitan Museum of Art, New York. The standing figure, a human body with outspread wings, is fi'uctifying the tree, which has the form of a palm. The flowers of the tree are sprinkled with water fi'om the vessel in the left hand. The male palm flowers held in the right hand are used to transfer pollen to the female flowers. R. G. Stanley H. F. Linskens POLLEN Biology Biochemistry Management With 64 Figures and 66 Tables Springer-Verlag Berlin Heidelberg New York 1974 Professor ROBERTG.STANLEyt Formerly: University of Florida Institute of Food & Agricultural Sciences Gainesville, FL 32611, USA Professor H. F. LINSKENS Botanisch Laboratorium, Faculteit der Wiskunde en Natuurwetenschappen, Katholieke Universiteit, Toernooiveld, Nijmegen, Nederlande The cover design was kindly supplied by Prof. STANLEY Library of Congress Cataloging in Publication Data Linskens,H. F. 1921- Pollen: biology, biochemistry. and management. Bibliography: p. l. Pollen. I. Stanley, Robert G., joint author. II. Title. (DNLM: I. Agriculture. 2. Pollen. QK658 S788p) QK658. L56 582'.01'6 74-17437 ISBN-l3: 978-3-642-65907-2 e-ISBN -l3: 978-3-642-65905-8 DOl: 10.1007/978-3-642-65905-8 This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned. specifically those of translation, reprinting, re-use of illustrations, broadcasting. reproduction by photocopying machine or similar means, and storage in data banks. Under §54 of the German Copyright Law, where copies are made for other than private use, a ree is payable to the publisher, the amount orthe ree to be determined by agreement with the publisher. © by Springer-Verlag Berlin· Heidelberg 1974. Softcover reprint of the hardcover 1st edition 1974 The use or registered names, trademarks, etc. in this publication does not imply, even in the absence or a specific statement, that such names are exempt rrom the relevant protective laws and regulations and thererore rree ror general use. Preface Pollen transmits the male genetic material in sexual reproduction of all higher plants. This same pollen is also well suited as a research tool for studying many patterns of plant and animal metabolism. In addition, an increased knowledge of pollen may help plant breeders accelerate efforts to improve the world's food and fiber supply. This volume focuses upon pollen biology and chemistry; it attempts to inte grate these facts with management practices involved in pollen applications. People have long been involved with pollen. Pollen applications are recorded in the rites of ancient civilizations (see Frontispiece). From the earliest times many benefits have been attributed to the inclusion of pollen in man's diet; also, since the mid-19th century air-borne pollen has been recognized as detrimental to many people's health. Disciplines concerned with man's cultural history and the earth's changing ecology find pollen a particularly useful and accessible tool. Identifiable parts of pollen have survived over 100 million years. But most books dealing with pollen are generally concerned with the identification of the plant source, an aspect of the science of palynology; other books emphasize the natural vectors transmit ting pollen, the pollination mechanisms. Very few works include the biochem istry or biology of pollen. Yet extensive studies by physicians, as well as plant breeders and apiculturists, have contributed a sizeable body of research relating to pollen. We have endeavored to review these many historical and recent studies and to indicate some areas of pollen biology and biochemistry where critical knowledge is still lacking. These deficiencies in our knowledge, and their relation to im proved management practices, present significant research challenges for the fu ture. The main details of pollen germination and growth to fertilization will be cov ered in a related volume now in preparation. A second volume will include such topics as incompatibility reactions, stigma responses, population effects, tropism metabolic and cytological changes during growth, and the influence of different chemicals and treatments on in vitro and in vivo growth. Hopefully, this and the successor volume will encourage increased applications of pollen in research leading to an improved understanding of many basic cell processes, and provide insights to help improve the yields of desired crops. We would like to express our appreciation for the encouragement and assist ance provided by many colleagues during the years this volume was in prepara tion. Colleagues who have kindly reviewed parts of this volume include: G. BARENOSE, CHARLESA.HoLLIS, III, W.JORoE, EOWAROG.KIRBY, III, MARIANNE KROH, F.LuKOSCHUS, JAMESL.NATION, JooP K. PETER, FRANKA.RoBINSON,WAL- VI Preface TER G. ROSEN and INDRA VASIL. J. BRAD MURPHY patiently reviewed the total manuscript and creatively aided in its correction and improvement. Great devotion and care in preparing this manuscript was provided by Miss BONITA CARSON assisted by Miss ANN McLoCKLIN of the School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences at the University of Florida. PATRICIA STANLEY shared or assumed much of the burden of proof-reading drafts of the manuscript. All these many meaningful contributions to our effort are gratefully appre ciated and sincerely acknowledged. ROBERTG.STANLEY HANSF. LINSKENS Postscript A few weeks after delivering the manuscript to press BOB STANLEY died in a tragic way. This book will therefore be his last work, his ultimate contribution to a field of his special interest, to which he contributed so much. With melancholy and gratitude I recall the twenty years of our friendship and close scientific cooperation, which were brought to an abrupt end by Bob's un timely death. R. G. STANLEY t, April 15,1974 H. F. LINSKENS Contents I. Biology Chapter 1. Development 3 Terminology 3 Development Pattern 6 Induction of Meiosis 7 Induction of Polarity 8 Differentiation of Pollen Grain Nuclei 9 Origin of the Sperm Cells . . . . . 10 Chapter 2. Wall Formation . 13 Pollen Mother Cell Wall 13 Partition Walls in Microsporocytes 15 Plasma Connections between Microsporocytes 15 Wall Development . . . . . . 16 Pollen Wall as a Living Structure . . . 22 Chapter 3. Dehiscence, Size and Distribution 24 Dehiscence 24 Size Range 26 Quantity Produced 30 Distribution 33 II. Management 37 Chapter 4. Collection and Uses 39 Purpose and Quantities Collected 39 Non-seed Forming Uses 42 Species Effect on Pollen Collection 46 Collecting Methods ..... . 50 Chapter 5. Storage ........ . 56 Factors Affecting Viability in Storage 56 Freeze-drying of Pollen . . . . . . 62 Causes of Decreased Viability in Storage 64 Testing Methods ........ . 65 YIn Contents Chapter 6. Viability Tests 67 Germination Tests . 67 Non-germination Assays 81 Comparison of Viability Tests 85 Chapter 7. Nutritive Role 87 Bees ...... . 87 The Pollen Collecting Process 87 The Pollen Pellet .... 95 Storage of Pollen in the Hive 98 Digestion of Pollen 100 Nutritive Value of Pollen for the Honey Bee 102 Pollen Substitutes .... 105 Pollen in Analysis of Honey 106 Other Animals 108 Human Consumption 114 III. Biochemistry . . . . . . . . . . . . . . . . . . . . . . . . . 117 Chapter 8. General Chemistry 119 Gross Chemical Analysis 119 Minerals ...... . 119 Boron in Pollen and Floral Organs 122 Role and Distribution ..... 124 Chapter 9. Carbohydrates and Cell Walls ....... . 129 Low Molecular Weight Sugars and Related Compounds 130 Starch Content ...... . 132 Callose ......... . 133 Pectin and Other Polysaccharides 136 Cellulose and Sporopollenin 137 Pollen Destruction in Nature 142 Chapter 10. Organic Acids, Lipids and Sterols 145 Total Lipids .......... . 146 Fatty Acids . . . . . . . . . . . . 147 Alcohols and Long Chain Hydrocarbons 149 Chapter 11. Amino Acids and Proteins 154 Free Amino Acids . . . . 154 Amino Acids by Hydrolysis 158 Proteins ..... 159 Serological Reactions 161 Contents IX Chapter 12. Pollinosis 164 Plant Sources 165 Allergens . . .. 168 Testing Human Reactions to Pollen 176 Persorption . . . . . . . . . . 179 Chapter 13. Nucleic Acids ....... . 182 Nucleic Acids in Mature Pollen ... . 182 Nucleic Acids during Pollen Development 185 Nucleic Acids during Germination 188 Nucleotide Base Composition ..... 189 Chapter 14. Enzymes and Cofactors 193 Methods of Detection 193 Activities Detected . 195 Sources of Variation 204 Cofactors .... 209 Localization and Function 213 Chapter 15. Pollen Pigments 223 Carotenoids 223 Flavonoids . . . . . . 230 Chapter 16. Growth Regulators 248 Historical Background 248 Auxins .. 249 Brassins 252 Gibberellins 252 Kinins . 254 Ethylene 254 Inhibitors 254 Sources of Variation 255 Roles ..... . 257 References . 259 Subject Index 289 I. Biology