Photoperiodism is the response to the length of the day that enables living organisms to adapt to seasonal changes in their environment as well as latitudinal variation. As such, it is one of the most significant andcomplex aspects of the interaction between plants and their environment and is a major factor controlling their growth and development. As the new and powerful technologies of molecular genetics are brought to bear on photoperiodism, it becomes particularly important to place new work in the context of the considerable amount of physiological information which already exists on the subject. This innovative book will be of interest to a wide range of plant scientists, from those interested in fundamental plant physiology and molecular biology to agronomists and crop physiologists. - Provides a self-sufficient account of all the important subjects and key literature references for photoperiodism - Includes research of the last twenty years since the publication of the First Edition - Includes details of molecular genetic techniques brought to bear on photoperiodism

Life evolves in a cyclic environment, and to be successful, organisms must adapt not only to their spatial habitat, but also to their temporal habitat. How do plants and animals determine the time of year so they can anticipate seasonal changes in their habitats? In most cases, day length, or photoperiod, acts as the principal external cue for determining seasonal activity. For organisms not living at the bottom of the ocean or deep in a cave, day follows night, and the length of the day changes predictably throughout the year. These changes in photoperiod provide the most accurate signal for predicting upcoming seasonal conditions. Measuring day length allows plants and animals to anticipate and adapt to seasonal changes in their environments in order to optimally time key developmental events including seasonal growth and flowering of plants, annual bouts of reproduction, dormancy and migration in insects, and the collapse and regrowth of the reproductive system that drives breeding seasons in mammals and birds. Although research on photoperiodic time measurement originally integrated work on plants and animals, recent work has focused more narrowly and separately on plants, invertebrates, or vertebrates. As the fields have become more specialized there has been less interaction across the broader field of photoperiodism. As a result, researchers in each area often needlessly repeat both theoretical and experimental work. For example, understanding that there are genetically distinct morphs among species that, depending on latitude, respond to different critical photoperiods was discovered separately in plants, invertebrates, and vertebrates over the course of 20 years. However, over the past decade, intense work on daily and seasonal rhythms in fruit flies, mustard plants, and hamsters and mice, has led to remarkable progress in understanding the phenomenology, as well as the molecular and genetic mechanisms underlying circadian rhythms and clocks. This book was developed to further this type of cooperation among scientists from all related disciplines. It brings together leading researchers working on photoperiodic timing of seasonal adaptations in plants, invertebrates, and vertebrates. Each of its three sections begins with an introduction by the section editor, and at the end of the book, the section editors present a synthesis of common themes in photoperiodism, as well as discuss similarities and differences in approaches to the study of photoperiodism, and future directions for research on photoperiodic time measurement.

(Chapters 11 to 14) summarise important features of the biological clock at the level of whole animal covering all vertebrate classes (fish to mammal). Chapters 15 and 16 are on long term (seasonal) rhythms in plants and higher vertebrates. Short term rhythms (ultradian rhythms), the significance of having a clock system in animals living in extreme (arctic) environments, and the diversity of circadian responses to melatonin, the key endocrine element involved in regulation of biological rhythms, have been discussed in Chapters 17 to 19. Finally, a chapter on sensitivity to light of the photoperiodic clock is added which, using vertebrate examples, illustrates the importance of wavelength and intensity of light on circadian and non-circadian functions. A well-known expert writes each chapter. When presenting information, the text provides consistent thematic coverage and feeling for the methods of investigation. Reference citation within the body of the text adequately reflects the literature as subject is developed. A chapter begins with an abstract that enables a reader to know at the first glance the important points covered in that chapter. The chapter concludes with a full citation of references included in the text, which could be useful for further reading. The book ends with a comprehensive subject index that may be useful for quick searches.

Biological Rhythms and Photoperiodism in Plants brings together disparate subject areas into one accessible text of interest to all plant biologists. In this comprehensive volume, leading international researchers review our current understanding of circadian rhythms from a broad perspective. The book begins with a description of well known rhythmic processes such as gene expression, stomatal guard cell opening, and the movement of petals and leaves. Photoperiodic responses such as dormancy, bulbing, tuberization and flowering are then discussed in terms of their rhythmic behaviour. The latest data from current studies with mutant and transgenic plants is also included.

Plants utilize light not only for photosynthesis but also as environmental signals. They are capable of perceiving wavelength, intensity, direction, duration, and other attributes of light to perform appropriate physiological and developmental changes. This volume presents overviews of and the latest findings in many of the interconnected aspects of plant photomorphogenesis, including photoreceptors (phytochromes, cryptochromes, and phototropins), signal transduction, photoperiodism, and circadian rhythms, in 42 chapters. Also included, is a prologue by Prof. Masaki Furuya that gives an overview of the historical background. With contributions from preeminent researchers in specific subjects from around the world, this book will be a valuable source for a range of scientists from undergraduate to professional levels.

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Photobiology is an important area of biological research since a very large number of living processes are either dependent on or governed by light that we receive from the Sun. Among various subjects, photosynthesis is one of the most important, and thus a popular topic in both molecular and organismic biology, and one which has made a considerable impact throughout the world since almost all life on Earth depends upon it as a source of food, fuel and oxygen. However, for growth of plants, light is equally essential, and research on photomorphogenesis has revealed exciting new developments with the application of newer molecular biological approaches. The present book brings together and integrates various aspects of photosynthesis, biology of pigments, light regulation of chloroplast development, nuclear and chloroplast gene expression, light signal transduction, other photomorphogenetic processes and some photoecological aspects under one cover. The chapters cover biochemical and molecular discussions of most of the above topics in a comprehensive manner and include a wide range of `hot topics' that are currently under investigation in the field of photobiology of cyanobacteria, algae and plants. The authors of this book are selected international authorities in their fields from USA, Europe, Australia and Asia. The book is designed primarily to be used as a text book by graduates and post-graduates. It is, however, also intended to be a resource book for new researchers in plant photobiology. Several introductory chapters are designed as suitable reading for undergraduate courses in integrative and molecular biology, biochemistry and biophysics.

There are many recent works on the topic of light and plant growth. These have not only been written by experts, but are also, in the main, written for experts (or, at least, for those who already have a fair understanding of the subject). This book has its origins in a six-week course in plant photophysiology, and its aim is to provide an introduction to the subject at an advanced undergraduate level. The imagined audience is simply a student who has asked the questions: In what ways does light affect plant growth, and how does it do it? The book is limited to aspects of photomorphogenesis. Photo synthesis is only considered where its pigments impinge on photo morphogenic investigations, or where its processes provide illustrative examples of particular interactions between light and biological material. Chapter 1 gives a general account of the various ways in which light affects plant development, and introduces topics which are subsequently covered in greater detail. In all the chapters, are special topic 'boxes', consisting of squared-off sections of text. These are simply devices for presenting explanatory background material, or material that I myself find particularly intriguing.

The discovery of the reversible red far-red control of plant growth and development and the subsequent in vivo identification and isolation of the photoreceptor pigment, phyto chrome, constitutes one of the great achievements in modern biology. It was primarily a group of investigators at the Plant Industry Station, Beltsville, Mary land, headed by the botanist H.A. BORTHWICK and the physical chemist S.B. HENDRICKS, who made the basic discoveries and developed a theoretical framework on which the current progress in the field of phytochrome is still largely based. While the earlier development of the phytochrome concept has been covered by a num ber of excellent articles by the original investigators [104,105,33,238] as well as by others who joined the field of phytochrome research later [72, 109, 219], a comprehensive and up-to-date treatment of photomorphogenesis is not available at present. Since it seems to be needed for teaching as well as for researchers I have tried to summarize the present state of the field, reviewing the historical aspects of the phytochrome story only insofar as they are required to understand the present situation. The emphasis of my treatment will be on developmental physiology ("photomorphogenesis") rather than on phytochrome per se.