The question of whether the earth's climate is changing in some significant human-induced way remains a matter of much debate. But the fact that climate is variable over time is well known. These two elements of climatic uncertainty affect water resources planning and management in the American West. Managing Water Resources in the West Under Conditions of Climate Uncertainty examines the scientific basis for predictions of climate change, the implications of climate uncertainty for water resources management, and the management options available for responding to climate variability and potential climate change.

This book focuses on the interactive effects of environmental stresses with plant and ecosystem functions, especially with respect to changes in the abundance of carbon dioxide. The interaction of stresses with elevated carbon dioxide are presented from the cellular through whole plant ecosystem level. The book carefully considers not only the responses of the above-ground portion of the plant, but also emphasizes the critical role of below-ground (rhizosphere) components (e.g., roots, microbes, soil) in determining the nature and magnitude of these interactions.* Will rising CO2 alter the importance of environmental stress in natural and agricultural ecosystems?* Will environmental stress on plants reduce their capacity to remove CO2 from the atmosphere?* Are some stresses more important than others as we concern ourselves with global change?* Can we develop predictive models useful for scientists and policy-makers?* Where should future research efforts be focused?

The United States Government, cognizant of its responsibilities to future generations, has been sponsoring research for nine years into the causes, effects, and potential impacts of increased concentrations of carbon dioxide (C0 ) in the atmosphere. Agencies such as the National Science Foun 2 dation, National Oceanic and Atmospheric Administration, and the U.S. Department of Energy (DOE) cooperatively spent about $100 million from FY 1978 through FY 1984 directly on the study of CO • The DOE, as the 2 lead government agency for coordinating the government' s research ef forts, has been responsible for about 60% of these research efforts. William James succinctly defined our purpose when he stated science must be based upon " ... irreducible and stubborn facts." Scientific knowledge can and will reduce the present significant uncertainty sur rounding our understanding of the causes, effects, and potential impacts of increasing atmospheric CO2• We have come far during the past seven years in resolving some underlyinig doubts and in narrowing the ranges of disagreement. Basic concepts have become less murky. Yet, much more must be accomplished; more irreducible and stubborn facts are needed to reduce the uncertainties so that we can improve our knowledge base. Uncertainty can never be reduced to zero. However, with a much improved knowledge base, we will be able to learn, under stand, and be in a position to make decisions.

This is the first comprehensive monograph on all emerging topics in plant signaling. The book addresses diverse aspects of signaling at all levels of plant organization. Emphasis is placed on the integrative aspects of signaling.

Respiration in plants, as in all living organisms, is essential to provide metabolic energy and carbon skeletons for growth and maintenance. As such, respiration is an essential component of a plant’s carbon budget. Depending on species and environmental conditions, it consumes 25-75% of all the carbohydrates produced in photosynthesis – even more at extremely slow growth rates. Respiration in plants can also proceed in a manner that produces neither metabolic energy nor carbon skeletons, but heat. This type of respiration involves the cyanide-resistant, alternative oxidase; it is unique to plants, and resides in the mitochondria. The activity of this alternative pathway can be measured based on a difference in fractionation of oxygen isotopes between the cytochrome and the alternative oxidase. Heat production is important in some flowers to attract pollinators; however, the alternative oxidase also plays a major role in leaves and roots of most plants. A common thread throughout this volume is to link respiration, including alternative oxidase activity, to plant functioning in different environments.

The importance of carbon dioxide extends from cellular to global levels of organization and potential ecological deterioration may be the result of increased CO2 in our atmosphere. Recently, the research emphasis shifted from studies of photosynthesis pathways and plant growth to ground-breaking studies of carbon dioxide balances in ecosystems, regions, and even the entire globe. Carbon Dioxide and Terrestrial Ecosystems addresses these new areas of research. Economically important woody ecosystems are emphasized because they have substantial influence on global carbon dioxide balances. Herbaceous ecosystems (e.g., grasslands, prairies, wetlands) and crop ecosystems are also covered. The interactions among organisms, communities, and ecosystems are modeled, and the book closes with an important synthesis of this growing nexus of research. Carbon Dioxide and Terrestrial Ecosystems is a compilation of detailed scientific studies that reveal how ecosystems generally, and particular plants specifically, respond to changed levels of carbon dioxide. - Contributions from an international team of experts - Empirical examination of the actual effects of carbon dioxide - Variety of terrestrial habitats investigated - Specific plants and whole ecosystems offered as studies

Below the soil surface, the rhizosphere is the dynamic interface among plant roots, soil microbes and fauna, and the soil itself, where biological as well as physico-chemical properties differ radically from those of bulk soil. The Rhizosphere is the first ecologically-focused book that explicitly establishes the links from extraordinarily small-scale processes in the rhizosphere to larger-scale belowground patterns and processes. This book includes chapters that emphasize the effects of rhizosphere biology on long-term soil development, agro-ecosystem management and responses of ecosystems to global change. Overall, the volume seeks to spur development of cross-scale links for understanding belowground function in varied natural and managed ecosystems. - First cross-scale ecologically-focused integration of information at the frontier of root, microbial, and soil faunal biology - Establishes the links from extraordinarily small-scale processes in the rhizosphere to larger-scale belowground patterns and processes - Includes valuable information on ecosystem response to increased atmospheric carbon dioxide and enhanced global nitrogen deposition - Chapters written by a variety of experts, including soil scientists, microbial and soil faunal ecologists, and plant biologists