Developmental Biology of Fern Gametophytes

Biochemical Systematics and Ecology, VoI. 18, No. 6, pp. 471-474, 1990. Pergamon Press plc, Printed in Great Britain.

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Developmental Biology of Fern Gameto- data, the morphogenetic program of the germiphytes: V. Raghavan. Cambridge University nated spore, which leads to the formation of the Press, Cambridge. 1989. 361 pp. ISBN 0-521- rhizoid and protonema initials is presented. The author describes the cell determination induced 33022-X. Price $80.00. by the polarity of the germinated spore, its Since the last century, research workers have relationship with the first asymmetric cell division recognized the potentialities of the fern gameto- and the development of the daughter cells which phyte as a good experimental system to study are the initials of the rhizoid and protonema. We the close relationship between the development can easily understand the importance of the of simple organisms and the environmental molecular or biochemical events which detersignals inducing its morphogenesis. As recog- mine the formation of the initials and their fate nized by the author, the aim of the book was not and functions during spore germination. Howto collect all the references published since the ever, I was a little disappointed by the meagre first works of pioneers, but rather to present in a literature available in this area. This information, comprehensive account the story of the gameto- essentially focusing on the early phase of phyte in its familiar developmental sequence. germination, looks much like that presented elseInstead of writing a book with large phylogenic where for seed germination. and taxonomic considerations, the author The second section (chapters 6-9) directs collects together the physiological, cytological attention to the growth and the maturation of the and biochemical background of the topics under young gametophyte. This includes the growth of discussion since 1950. The phylogenic frame- the filament structure, the induction of planar work that he uses is briefly described in the morphology and the regulation of the growth of preface. In this way, the book does not read like the planar structure. These different topics are an encyclopaedic treatment despite its c a 950 treated as in the first part. The physiology of the references. germ filament, especially the effect of light on There are 14 chapters grouped into four cell elongation and/or division is discussed. The sections which cover the developmental land- review of photomorphogenetic studies attempts scape of the gametophyte beginning with the to describe the complex series of developmental single-celled progenitor of the sporophyte and processes and the signals which induce the ending with the fertilization of the gametes. The planar morphology. It pays particular attention to first section (chapters 2-5) focuses on the struc- the cytological changes of terminal cell of the ture, cytology and physiology of spores and their filament. Indeed, this cell governs the evolution germination. After a description of the cytology of the future morphology of the germ filament. of the sporogenesis and spore maturation, the This completes the part of the book which is the physiology of the onset of the germination is most interesting and relevant. To demonstrate discussed. The author mainly reviews a large the plasticity of the fern gametophyte, studies on number of studies on the effects of light which its regeneration ability have also been collected. initiate spore germination. In spite of the degree The author first reviews the growth requirement of complexity of the mechanisms of photo- for gametophytes in culture, and secondly the receptors, the interpretation given by the author experimentally induced regeneration. This is pleasant to follow. The other factors reviewed includes neoplastic and abnormal growth are water, medium composition, temperature, regeneration. pH, gases, chemicals and hormones. The third section (chapters 10-12), entitled Then, using cytological and physiological "Reproductive Strategies" describes the differen471

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tiation of the sex organs with an emphasis on the role of antheridiogens in the control of antheridium development. Unfortunately, the description of archegonium development does not receive much consideration. I would question the need for chapter 11. The author gives some consideration to the strategies of reproductive biology in fern gametophytes that have contributed to genetic diversity. Indeed, very little information is brought forward in it concerning the problem of the developmental and morphogenetic biology of gametophytes, which was the proposed aim of this book. Finally, spermatogenesis and oogenesis are examined essentially by cytological and ultrastructural descriptions. This chapter ends with fertilization which is purely described with reference to cytological studies, particularly concerning the locomotion of the spermatozoid. The fourth section is devoted to the alternate developmental programs of the life cycle; apogamy in chapter 13 and apospory in chapter 14. In both, the scheme of treatment is the same: first a description of natural apogamy or apospory, then a review of the external factors which experimentally induce one or the other. The nuclear cytology of both programs have also been reviewed because they are interesting and

BOOK REVIEWS

very useful in our understanding of the developmental options of the life cycle. Indeed, these organisms have deployed mechanisms to ensure the stability of chromosome number in the life cycle. As a minor comment, I have to express some regret at the lack of diagrams illustrating the various sequences of development (like Fig. 4.12 for spore germination). This concerns, for example, the description of the ontogeny of sporangium, antheridium and archegonium. The presence of such diagrams could have clarified the descriptions in the text. In all, this book provides a mass of information, well presented, about different topics of the development of fern gametophytes. Because of its clarity, students and researchers will find in it a thoroughly entertaining introduction to the current status of knowledge relating to development in fern gametophytes. O. LEPRINCE

Plant Morphology Laboratory Department of Botany Sart TilmanB22 B-4000Liege Belgium

Each chapter consists of two parts: a short theoretical introduction with a number of key references and detailed experimental procedures. Interestingly, a lot of short notes and remarks referring to specific points of the protoDuring the last 10 years, great advances have cols draw attention to the problems which can been made in the area of plant molecular arise at particular steps of the manipulations and biology. Transgenic plants carrying a variety of give the possible solutions. As recognized by the editors, many of the genetic constructions are now routinely produced allowing, for example, a detailed analysis techniques described in the manual depend of regulatory elements in plant genes. The upon specialized plant material, microbial strains evolution of the techniques is concomitantly very or recombinant plasmids. A list of the various impressive in this field. The editors have thus contributors to the manual, including their designed a laboratory manual which is both easy addresses, is given, and those people desiring to use and updated. They intend to periodically such material are invited to contact the relevant publish additional chapters that can replace authors directly. This will be very helpful for or be added to the first edition. This book is in those laboratories which intend to develop new fact a compilation of techniques described in 24 lines in plant molecular biology. The book is made up of three sections. The contributions by not less than 61 scientists.

Plant Molecular Biology: Edited by Stanton B. Gelvin, Robbert A. Schilperoort and Desh Pal. J. Verma. Kluwer Academic Publishers, Dordrecht. 1989. 479 pp. 0-7923-0240-0. $89.00.