Current Trends in the Embryology of Angiosperms

Transcription

1 Current Trends in the Embryology of Angiosperms

2 Current Trends in the Embryology of Angiosperms Edited by S.S. Bhojwani University of D elhi, Delhi, India and W.Y. Soh Chonbruk National University, Chonju, Republic of Korea SPRINGER-SCIENCE+BUSINESS MEDIA, B.V.

3 A c.l.p. Catalogue record for this book is available from the Library of Congress. ISBN DOI / ISBN (ebook) Printed on acid~free paper All Rights Reserved 2001 Springer Science+Business Media Dordrecht Originally published by Kluwer Academic Publishers in 2001 Softcover reprint of the hardcover Ist edition 2001 No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, încludîng photocopying, recordîng or by any înformation storage and retrieval system, without written permission from the copyright owner.

4 CONTENTS INTRODUCTION 1. MALE GAMETOGENESIS Development and Structure of Sperm DARLENE SOUTHWORTH and SCOTT D. RUSSELL 2. SPERM AND GENERATIVE CELL Isolation and Manipulation DARLENE SOUTHWORTH 3. POLLEN GERMINATION AND POLLEN TUBE GROWTH Tip Growth Mechanism in Sexual Plant Reproduction A. MOSCATELLI and M. CREST! 4. FEMALE GAMETOGENESIS Ontogenesis of the Embryo Sac and Female Gametes SCOTT D. RUSSELL 5. EMBRYO SAC Isolation and Manipulation DAVID D. CASS and JOHN D. LAURIE 6. IN VIVO FERTILIZATION TATYANAB. BATYGINAandVALENTINAE. VASILYEVA 7. IN VITRO FERTILIZATION E. KRANZ 8. SEXUAL INCOMPATIBILITY F. CRUZ-GARCIA and B.A. MCCLURE 9. ZYGOTIC EMBRYOGENESIS Structural Aspects ROMAN A CZAPIK and ROMAN A lzmailow 10. ZYGOTIC EMBRYOGENESIS Hormonal Control of Embryo Development B. FISCHER-IGLESIAS and G. NEUHAUS vii ZYGOTIC EMBRYOGENESIS : DEVELOPMENTAL GENETICS 249 The Formation of an Embryo from a Fertilized Egg KA THRIN SCHRICK and THOMAS LAUX 12. SOMATIC EMBRYOGENESIS 279 TREVOR A. THORPE and CLAUDIO STASOLLA v

5 Vl Contents 13. SYNTHETIC SEEDS OF ASPARAGUS OFFICINALISL. 337 KANJI MAMIY A, YUH SAKAMOTO, NOBORU ONISHI and TAKA Y ASU HIROSA WA 14. ENDOSPERM DEVELOPMENT 353 P.W. BECRAFT, R.C. BROWN, B.E. LEMMON, 0.-A. OLSEN and H. G. OPSAHL FERSTAD 15. SEED MATURATION, GERMINATION, AND DORMANCY A. BRUCE DOWNIE 16. GAMETOPHYTIC APOMIXIS A Successful Mutation of the Female Gametogenesis YVES SA VIDAN 17. PARTHENOCARPY State of the Art ANGELO SPENA and GIUSEPPE LEONARDO ROTINO 18. ANDROGENESIS IN BRASSICA A Model System to Study the Initiation of Plant Embryogenesis J.B.M. CUSTERS, J.H.G. CORDEWENER, M.A. FIERS, B.T.H. MAASSEN, M.M. VAN LOOKEREN CAMPAGNE and C.M. LIU 19. ANDROGENESIS IN CEREALS SWAPANK. DATTA 20. IN VITRO GYNOGENESIS SANT S. BHOJWANI and T. DENNIS THOMAS INHERITANCE OF CYTOPLASMIC TRAITS- EMBRYOLOGICAL 509 PERSPECTIVES T. KUROIW A, H. KUROIWA, S. MIYAGISHIMA andy. NISHIMURA SUBJECT AND PLANT INDEX 525

6 INTRODUCTION Embryo, the progenitor of the next generation, is endowed with the unique capacity to withstand extreme desiccation and other environmental stresses without losing its viability and sprouts into a new plant under favourable conditions. Several floral structures and intricate processes are involved in the formation of embryo. These include the formation of haploid gametes inside the male (anther) and female (ovary) sex organs, fusion of the gametes of opposite sexes and the development of embryo (embryogenesis) and the nutritive (endosperm) and protective (seed-coat and fruit wall) structures. The sexual cycle in angiosperms has several unique features. For considerable time breeders have attempted, more often unsuccessfully than successfully, to manipulate the embryological processes to achieve their goal of creating improved varieties of plants with new genes. In his classic book, "An Introduction to the Embryology of Angiosperms", published in 1950, P. Maheshwari described in detail the development of male and female gametes, fertilization, embryo and endosperm development, polyembryony and the range of variation in these processes among the angiosperms. He also introduced the then emerging field of experimental embryology. During the last 50 years a huge arsenal of new techniques of electron microscopy, biochemistry, molecular biology, immunology, 3-D computer reconstruction, genetics and genetic engineering has been applied to understand finer details of the various structures and processes associated with embryo development, and considerable new data has been generated. Arabidopsis thaliana has emerged as a model system to study developmental genetics of zygotic embryogenesis (Chapter 11 ). Several mutants defective in embryo development have been isolated, and some embryo specific and embryo enhanced genes have been cloned. Embryo culture, which has been used to produce rare hybrids by embryo rescue for almost a century, is now being used to understand the physiology and biochemistry of embryogenesis (Chapter 1 0). To have a full appreciation of these modem areas of embryogenesis, it is important to have a good understanding of structural aspects of normal embryogenesis (Chapter 9). A better understanding of the embryological processes has enhanced our manipulative power to overcome the evolutionary barriers to crossability (Chapter 8). A major breakthrough in the field of experimental embryology during the last decade has been the development of reliable methods to isolate live male (Chapters 1, 2) and female (Chapters 4, 5) gametes, their fusion and culture of in vitro produced zygotes to obtain fertile plants (Chapter 7). With the availability of a reasonable numbers of viable naked gametes a host of basic aspects of gametic recognition and fusion are being investigated. These cells have also given a better understanding of the structure of the gametes. A new concept emerged from the research on vii

7 Vlll Introduction sperm isolation is of "male germ unit", which suggests that the fate of the two sperms in double fertilization is probably pre-determined. An entirely new field of Experimental Embryology has emerged. Formation of asexual embryos from somatic and gametic cells in tissue cultures has put to rest the myths that the egg holds the monopoly to form embryo, and that the embryo sac is a magic bath with a unique environment necessary for embryo development. Formation of embryos by single somatic cells and unicellular haploid microspores, under highly controlled conditions, are proving to be excellent systems to study the physiology, biochemistry and genetic control of embryogenesis in angiosperms, which was not possible earlier due to the inaccessibility of the zygotic embryo, seated under several layers of ovarian and ovular tissues. A large number of somatic embryos of different stages can be collected by fractionation for biochemical studies. Therefore, considerable attention is being paid to achieve controlled, synchronized development of somatic embryos. Considerable new information on induction, development, maturation and germination of somatic embryos has already become available (Chapter 12). Somatic embryogenesis is also looked upon as the future method of largescale clonal propagation of superior and genetically engineered crops, particularly woody perennials. To facilitate their direct field planting, somatic embryos are being manipulated to develop Synthetic Seeds (Chapter 13). Induction of male (androgenesis; Chapters 18, 19) and female (Gynogenesis; Chapter 20) gametes to develop into sporophytes independent of fertilization has opened up a new approach to plant breeding. Haploids can be used to produce homozygous plants in a single step, thus cutting down the breeding time to almost half. Several new varieties of crop plants developed with the aid of androgenesis have been commercialized. Haploids have many other applications. The possibility to change the fate of a unicellular, haploid microspore from gametophytic development to sporophytic development by a single physical treatment (e.g., high temperature shock, starvation) has made it an excellent system to understand the process of induction of embryogenesis (Chapter 18). The embryological processes are also being subjected to genetic manipulation. For example, eggplant has been engineered to produce parthenocarpic fruits (Chapter 17). There is renewed interest in understanding the mechanism of Apomixis (Chapter 16) because of its potential role in clonal propagation of large volume agronomic crops, such as rice. Recent embryological studies are providing some new insight into the mechanism of cytoplasmic inheritance (Chapter 21). The progress in embryological research during the last two decades has been so impressive that full issues of some journals have been devoted to reproductive biology of angiosperms. Books have been published on specific aspects of the embryology of angiosperms, such as Apomixis, Embryogenesis, Embryo Nutrition, Pollen Biology, Sexual Incompatibility

8 Introduction and Somatic Embryogenesis. However, a book with up-to-date chapters on all aspects of the embryology of angiosperms, written by experts in the field is lacking. The last book published with this objective is "The Embryology of Angiosperms", edited by Professor B.M. Johri in Since then, the trends in this fascinating area of research have considerably changed and the progress has been revolutionary, justifying the publication of this volume. The book includes 21 chapters written by scientists who have made substantial contributions to their respective areas. The chapters are illustrated with self-explanatory diagrams, pictures and/or flow charts. The students of plant sciences and researchers in the areas of Plant physiology, Growth and development, biochemistry and genetics would find it very useful. Besides a critical review of up-to-date literature on the subject, the authors have projected the future lines of research in their respective areas. We are very grateful to all the authors who extended their full cooperation to us in submitting the manuscripts in time and promptly returning the edited copies of their chapter. This enabled us to complete the book by the date committed to the publishers. We would like to thank profusely our students, particularly, Pradeep, Nidhi, Rekha and Anupam for their ready help in various ways. ix Sant Saran Bhojwani Woong-Young Soh Editors