Crops and Environmental Change: An Introduction to Effects of Global

Advanced books on scientific topics are often long compendia of papers presented at scientific conferences, lacking descriptions that explain the phenomena to a more general audience, and frequently varying widely in quality of the writing and relevance to the reader. This book on Crops and Environmental Change represents a refreshing improvement from that norm. Pritchard and Amthor have produced an understandable and clearly written work that provides an excellent overview of crop physiology and how four environmental factors impact crops. The authors concentrate on the effects of temperature, increasing carbon dioxide, ozone and soil salinization, factors which they state ‘‘are of greatest consequence’’ to crop production and for which ‘‘a significant knowledge base has been established’’. In the Introduction, the authors describe the changes in the four environmental factors, and show the dynamics of human population and the food supply over the centuries. The Introduction is followed by a chapter on methodology for studying plant responses to the environmental factors considered. The physiology of plant growth is then, in subsequent chapters, considered at the cellular level, with detailed treatment of the response of cells to stress. Chapters on water relations; photosynthesis, respiration and biosynthesis; partitioning of photosynthate; and mineral nutrition all take the same basic form: The processes are first described in detail, and then the influence of the four environmental factors on them is described. Each chapter is concluded by a summary that helps the reader obtain a quick overview of each topic. The final chapters on vegetative growth and development; sexual reproduction, grain yield and grain quality; and the biotic environment take a more holistic look at the influence of the environmental factors on crop productivity. In each chapter, clear diagrams and lengthy tables provide a good summary of the existing knowledge. The picture that emerges on the impact of the four factors is that the increases in carbon dioxide in the atmosphere are predicted to have largely stimulating effects on crop growth and productivity, helping to mitigate some of the effects of the other factors. Through its role in increasing temperature of the atmosphere, however, carbon dioxide exacerbates global warming, and this fact points out the complex interactions that make the ultimate effects of these environmental factors difficult to predict. Rising surface temperatures are predicted to increase crop stress levels in temperate and tropical areas, but may well result in a shift of warm-adapted crops to higher latitudes. The deleterious effects of ozone on crop growth appear to be clearer and are predicted to lead to declines of crop yield as industrial activity increases worldwide. The influence of increasing salinity on crop productivity is also clearly negative, stunting growth in the vegetative phase and reducing yields. Yet careful use of osmotic stress by greenhouse tomato growers can increase soluble solids and eating quality of the fruit. This point is not mentioned in the book and highlights that the primary emphasis of the authors is on the major cereal crops. Horticultural scientists will have to extrapolate from the examples given to their species of interest. Another relatively minor annoyance is the ways the chapters are organized. Consideration of the effects of the four environmental factors on vegetative and reproductive growth, for instance, seems repetitive and would have been better combined in one chapter. Nevertheless, the book provides a useful reference for plant scholars who would like to know more about response of crops to environmental change and to learn which cellular processes are key to those responses. Unfortunately, those looking for clear, decisive answers will be disappointed, because, to quote the authors, ‘‘considerable uncertainty surrounds the effects of environmental change on the yields of major grain crops, with sound cases to be made for enhancement of yield in some situation and equally sound cases to be made for new limitations placed on yield in other situations’’.