Photosynthesis Under Fluctuating Light

Photosynthesis is a fundamental process that drives almost all life on Earth, and is the motor of agriculture and food production. For several decades, its basic functioning has been investigated mainly at steady-state, under constant illumination. This approach was necessary to understand the basic mechanisms underlying the light reactions and carbon assimilation. However, this condition does not reflect the natural environment, where plants experience changes in both the intensity and spectrum of irradiance in a wide range of time scales, spanning from seconds to several hours. In recent years, it has become clear that the processes allowing the photosynthetic apparatus to adapt to changes in irradiance are of paramount importance to plant fitness and productivity. Therefore, increased research effort has been directed towards studying the regulation of photosynthetic activity under fluctuating light, i.e. upon the variation of light intensity or light spectrum. This is important for understanding how photosynthetic organisms cope with natural environmental conditions. Fluctuating light itself constitutes a potentially stressful condition, because, depending on the scale of the fluctuation, it can transiently generate extreme redox and transthylakoid potentials, and forces the photosynthetic machinery to be re-adjusted. Not surprisingly, plants have evolved several mechanisms allowing a prompt response to these normal environmental events. In natural environments, photosynthetic organisms often have to cope with fluctuating light while experiencing other kinds of stress, such as heat, nutrient deficiency, drought, and pathogen attacks. Therefore, the study of combined stresses is essential for understanding the acclimation to realistic environmental conditions.

Since photosynthetic performance is a fundamental determinant of yield in the vast majority of crops, an understanding of the factors limiting photosynthetic productivity has a crucial role to play in crop improvement programmes. Photosynthesis, unlike the majority of physiological processes in plants, has been the subject of extensive studies at the molecular level for many years. This reductionist approach has resulted in the development of an impressive and detailed understanding of the mechanisms of light capture, energy transduction and carbohydrate biosynthesis, processes that are clearly central to the success of the plant and the productivity of crops. This volume examines in the widest context the factors determining the photosynthetic performance of crops. The emphasis throughout the book is on the setting for photosynthesis rather than the fundamental process itself. The book will prove useful to a wide range of plant scientists, and will encourage a more rapid integration of disciplines in the quest to understand and improve the productivity of crops by the procedures of classical breeding and genetic manipulation.

Photosynthesis and the Environment examines how photosynthesis may be influenced by environmental changes. Structural and functional aspects of the photosynthetic apparatus are examined in the context of responses to environmental stimuli; particular attention being given to the processing of light energy by thylakoids, metabolic regulation, gas exchange and source-sink relations. The roles of developmental and genetic responses in determining photosynthetic performance are also considered. The complexity of the responses to environmental change is demonstrated by detailed analyses of the effects of specific environmental variables (light, temperature, water, CO2, ozone and UV-B) on photosynthetic performance. Where appropriate attention is given to recent developments in the techniques used for studying photosynthetic activities. The book is intended for advanced undergraduate and graduate students and a wide range of scientists with research interests in environmental effects on photosynthesis and plant productivity.

Photosynthesis in Action examines the molecular mechanisms, adaptations and improvements of photosynthesis. With a strong focus on the latest research and advances, the book also analyzes the impact the process has on the biosphere and the effect of global climate change. Fundamental topics such as harvesting light, the transport of electronics and fixing carbon are discussed. The book also reviews the latest research on how abiotic stresses affect these key processes as well as how to improve each of them. This title explains how the process is flexible in adaptations and how it can be engineered to be made more effective. End users will be able to see the significance and potential of the processes of photosynthesis. Edited by renowned experts with leading contributors, this is an essential read for students and researchers interested in photosynthesis, plant science, plant physiology and climate change. Provides essential information on the complex sequence of photosynthetic energy transduction and carbon fixation Covers fundamental concepts and the latest advances in research, as well as real-world case studies Offers the mechanisms of the main steps of photosynthesis together with how to make improvements in these steps Edited by renowned experts in the field Presents a user-friendly layout, with templated elements throughout to highlight key learnings in each chapter

The photosynthetic fixation of carbon dioxide into organic compounds is mediated by the enzyme ribulose 1,S-bisphosphate (RuBP) carboxylase. The diversity of current research on this protein attests to its central role in biomass productivity, and suggests the importance of a timely and broadly based review. This Symposium was the first devoted exclusively to RuBP carboxylase and was attended by agronomists, plant physiologists, biochemists, molecular biologists, and crystallographers. Special efforts were made to involve young scientists in addition to established investigators. It is a pleasure to acknowledge financial support provided by the Department of Energy, the United States Department of Agricul ture, and the National Science Foundation, and the valued assistance of agency representatives, Drs. Joe Key, Robert Rabson, Elijah Romanoff, and Donald Senich. Thanks are due to Mrs. Margaret Dienes, without whose editorial skills this volume could not have been produced, and to Mrs. Helen Kondratuk as Symposium Coordinator. Finally, we wish to record our indebtedness to Dr. Alexander Hollaender for his tireless efforts in support of all aspects of this Symposium.

Beginning systematically with the fundamentals, the fully-updated third edition of this popular graduate textbook provides an understanding of all the essential elements of marine optics. It explains the key role of light as a major factor in determining the operation and biological composition of aquatic ecosystems, and its scope ranges from the physics of light transmission within water, through the biochemistry and physiology of aquatic photosynthesis, to the ecological relationships that depend on the underwater light climate. This book also provides a valuable introduction to the remote sensing of the ocean from space, which is now recognized to be of great environmental significance due to its direct relevance to global warming. An important resource for graduate courses on marine optics, aquatic photosynthesis, or ocean remote sensing; and for aquatic scientists, both oceanographers and limnologists.

This book covers the expression of photosynthesis related genes including regulation both at transcriptional and translational levels. It reviews biogenesis, turnover, and senescence of thylakoid pigment protein complexes and highlights some crucial regulatory steps in carbon metabolism.