The quality of human life has been maintained and enhanced for generations by the use of trees and their products. In recent years, ever rising human population growth has put tremendous pressure on trees and tree products; growing awareness of the potential of previously unexploited tree resources and environmental pollution have both accelerated development of new technologies for tree propagation, breeding and improvement. Biotechnology of trees may be the answer to solve the problems which cannot be solved by conventional breeding methods. The combination of biotechnology and conventional methods such as plant propagation and breeding may be a novel approach to improving and multiplying in large number the trees and woody plants. So far, plant tissue culture technology has largely been exploited in the propagation of ornamental plants, especially foliage house plants, by com mercial companies. Generally, tissue culture of woody plants has been recal citrant. However, limited success has been achieved in tissue culture of angiosperm and gymnosperm woody plants. A number of recent reports on somatic embryogenesis in woody plants such as Norway spruce (Picea abies), Loblolly pine (Pinus taeda), Sandalwood (Santalurn album), Citrus, Mango (Mangifera indica), etc. , offer a ray of hope of: a) inexpensive clonal propa gation for large-scale production of plants or "emblings" or "somatic embryo plants", b) protoplast work, c) cryopreservation, d) genetic transformation, and e) artificial or manufactured seed production.

The quality of human life has been maintained and enhanced for generations by the use of trees and their products. In recent years, ever rising human population growth has put a tremendous pressure on trees and tree products; growing awareness of the potential of previously unexploited tree resources; and environmental pollution have both accelerated the development of new technologies for tree propagation, breeding and improvement. Biotechnology of trees may be the answer to solve the problems which can not be solved by conventional breeding methods. The combination of biotechnology and conventional methods such as plant propagation and breeding could become a novel approach to improving and multiplying a large number of the trees and woody plants. So far, plant tissue culture technology has largely been exploited by commercial companies in propagation of ornamentals, especially foliage house plants. Generally, tissue culture of woody plants has been recalcitrant. However, limited success has been achieved in tissue culture of angiosperm and gymnosperm woody plants. A number of recent reports on somatic embryogenesis in woody plants such as Norway spruce (Picea abies), Loblolly pine (Pinus taeda), Sandalwood (Santalum album), Citrus and mango (Mangifera indica), offer a ray of hope for inexpensive clonal propagation for large-scale production of plants or 'emblings' or somatic seedlings; protoplast work; cryopreservation; genetic transformation; and synthetic or artificial or manufactured seed production.

In vitro Embryogenesis in Plants is the first book devoted exclusively to this topic. As the ultimate demonstration of totipotency in plants, somatic and haploid embryogenesis is of vital importance to all those working on or interested in basic and applied aspects of plantlet information and regeneration. The text includes comprehensive reviews written by experts, on all facts of in vitro and in vivo embryogenesis. Some chapters deal with the morphogenic, structural and developmental, physiological and biochemical, and molecular biological aspects of the subject. Chapters are also devoted to haploid embryogenesis, asexual embryogenesis in nature, zygotic embryogenesis, and zygotic embryo culture. Detailed tables summarizing successful somatic embryogenesis in all vascular plants are also included. This book, therefore, brings together previously scattered information to provide an indispensable reference book for both active researchers, graduate students and anyone interested in this aspect of tissue culture technology and plant development.

The quality of human life has been maintained and enhanced for generations by the use of trees and their products. In recent years, ever rising human population growth has put a tremendous pressure on trees and tree products; growing awareness of the potential of previously unexploited tree resources; and environ mental pollution have both accelerated the development of new technologies for tree propagation, breeding and improvement. Biotechnology of trees may be the answer to solve the problems which can not be solved by conventional breeding methods. The combination of biotechnology and conventional methods such as plant propagation and breeding may be a novel approach to improving and multiplying a large number of the trees and woody plants. So far, plant tissue culture technology has largely been exploited by commercial companies in propagation of ornamentals, especially foliage house plants. Gene rally, tissue culture of woody plants has been recalcitrant. However, limited success has been achieved in tissue culture of angiosperm and gymnosperm woody plants. A number of recent reports on somatic embryogenesis in woody plants such as Norway spruce (Picea abies), Loblolly pine (Pinus taedb), Sandalwood (Santalum album), Citrus, mango (Mangifera indica), etc. , offer a ray of hope of: a) inexpensive clonal propagation for large-scale production of plants or "emblings" or somatic seedlings; b) protoplast work; c) cryopreservation; d) genetic transformation; and e) synthetic or artificial or manufactured seed production.

World population is increasing at an alarming rate and this has resulted in increasing tremendously the demand for tree products such as wood for construction materials, fuel and paper, fruits, oils and medicines etc. This has put immense pressure on the world’s supplies of trees and raw material to industry and will continue to do so as long as human population continues to grow. Also, the quality of human diet, especially nutritional components, is adversely affected due to limited genetic improvement of most of fruit trees. Thus there is an immediate need to increase productivity of trees. Improvement has been made through conventional breeding methods, however, conventional breeding is very slow due to long life cycle of trees. A basic strategy in tree improvement is to capture genetic gain through clonal propagation. Clonal propagation via organogenesis is being used for the production of selected elite individual trees. However, the methods are labour intensive, costly, and produce low volumes. Genetic gain can now be captured through somatic embryogenesis. Formation of embryos from somatic cells by a process resembling zygotic embryogenesis is one of the most important features of plants. In 1958, Reinert in Germany and Steward in USA independently reported somatic embryogenesis in carrot cultures. Since then, tremendous progress in somatic embryogenesis of woody and non-woody plants has taken place. It offers a potentially large-scale propagation system for superior clones.

The quality of human life has been maintained and enhanced for generations by the use of trees and their products. In recent years, ever rising human population growth has put tremendous pressure on trees and tree products; growing awareness of the potential of previously un exploited tree resources and environmental pollution have both accelerated development of new technologies for tree propagation, breeding and improvement. Biotechnology of trees may be the answer to solve the problems which cannot be solved by conventional breeding methods. The combination of biotechnology and conventional methods such as plant propagation and breeding may be a novel approach to improving and multiplying in large number the trees and woody plants. So far, plant tissue culture technology has largely been exploited in the propagation of ornamental plants, especially foliage house plants, by com- mercial companies. Generally, tissue culture of woody plants has been recal- citrant. However, limited success has been achieved in tissue culture of angiosperm and gymnosperm woody plants. A number of recent reports on somatic embryogenesis in woody plants such as Norway spruce (Picea abies), Loblolly pine (Pinus taeda), Sandalwood (Santalum album), Citrus, Mango (Mangifera indica), etc. offer a ray of hope of: (a) inexpensive clonal propa- gation for large-scale production of plants or "emblings" or "somatic embryo plants"; (b) protoplast work; (c) cryopreservation; (d) genetic transforma- tion; and (e) artificial or manufactured seed production.

This volume presents an overview of recent advances, innovative applications, and future prospects of in vitro embryogenesis in higher plants. The book's chapters are divided into five parts: Part I contains reviews on general topics (microspore; zygotic and somatic embryogenesis; in vitro and in vivo asexual embryogenesis; advances on the genetic, physiological, and proteomic knowledge of somatic embryo formation; role of apoptosis and mitochondria in somatic embryogenesis; and innovation in the use of bioreactors). The remaining four parts discuss step-wise protocols on somatic embryogenesis in selected horticultural plants (Part II); forest trees (Part III); gametic embryogenesis (Part IV); and pivotal topics, such as the detection of epigenetics modifications during microspore embryogenesis, the in vitro embryogenesis and plant regenerations from isolated zygotes, the synthetics seed production, the induction and maturation of somatic embryos, and the cryostorage of embryogenic cultures (Part V). Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and thorough, In Vitro Embryogenesis in Higher Plants, is a useful source of information and ideas for plant tissue culturists, cell biologists, embryologists, horticulturists, and operators of commercial nurseries. This book will introduce the fascinating work in in vitro embryogenesis in higher plants to students and young scientists.

The rapid progress on somatic embryogenesis and its prospects for potential application to improving woody plants prompted us to edit this book initially in three volumes, and now an additional three more volumes. We were all convinced that such a treatise was needed and would be extremely useful to researchers and students. This volume 6 is dedicated to Prof. Harry Waris, Helsinki, Finland, who did pioneer work on somatic embryogenesis during the time when Prof. Steward and others were actively engaged in this area. His former student Prof. Liisa Simols, University of Helsinki, Finland, has written a dedication `Harry Waris, a pioneer in somatic embryogenesis' to her teacher Prof. Waris. This volume is divided into three sections and contains a total of 26 chapters. Section A comprises seven chapters covering topics such as: Historical insights into some contemporary problems in somatic embryogenesis (SE); Thin cell layer for somatic embryogenesis induction in woody trees; SE in tropical fruit and forest trees; SE in fruit and forest arid trees; Status of SE in Indian forest trees; SE research in fruit trees in India; Applications of SE for the improvement of tropical fruit trees. Section B comprises 15 chapters, dealing with: SE in oil palm, hazelnut (Corylus avellana L.), pistachio (Pistacia vera L.), Araucaria angustifolia, Quercus suber, Aspidosperma polyneuron, Acacia senegal, Simmondsia chiensis, Cupressus sempervirens, pecan (Carya illinoinensis), rattan (Calamus spp.), tamarillo (Cyphomandra betacea, longan (Dimocarpus longan Lor.), Aegle marmelos, and Euonymus europaeus. Section C comprises three chapters related to cryo-storage of citrus, conifers and rubber. All the chapters have been peer-reviewed and revised accordingly to improve the quality of the chapters. We are thankful to all: (a) contributory authors for their co-operation in submitting manuscripts in time, and (b) reviewers for spending their valuable time in reviewing the manuscripts.

Most forest tree species were considered recalcitrant a decade ago, but now with the improved in vitro techniques some progress has been made towards culture-of tree species. Micro propagation has been achieved from the juvenile tissues of a number of forest tree species. On the other hand, tissues from most mature trees are still very difficult to grow and differen tiate in vitro. Nevertheless, there has been slow but steady progress in the application of tissue culture technology for culture of tissues, organs, cells and protoplasts of tree species. As compared to most agricultural crops, and herbaceous plant species, trees are a different lot. They have long gene ration cycles. They are highly heterozygous and have a large reservoir of genetic variability. Because of this genetic variability, their response in vitro is also variable. On a single medium, the response of tissues from different trees (genotypes) of a single species may be quite different: some responding by induction of growth and differentiation, while others showing minimal or no growth at all. That makes the somatic cell genetics of woody plants somewhat difficult, but at the same time interesting.

This volume covers recent advances in the vegetative propagation of woody plants by tissue culture. A wide range of topics relevant to micropropagation of woody plants are discussed by renowned international scientists. These include cellular contro of morphogenesis, light regimes in tissue culture, maturation and rejuvenation, synthetic seed, genetics of micropropagated plants, haploid embryogenesis, protoplast culture, and acclimatization of ex vitro woody plants. In addition to micropropagation of selected woody plants, both gymnosperms and angiosperms, this volume also includes in vitro genetic selection, strategic planning for application of biotechnology for genetics and breeding, and clonal options for woody plant improvement. A balanced view of both perspectives and limitations of woody plant micropropagation is presented.