Inherent Variation in Plant Growth: Physiological Mechanisms and Ecological Consequences. Lambers, Hans, Hendrik Poorter, and Margret M.I. Van Vuuren, eds., 1998. ISBN 9073348-96-X (cloth US$152.00) 592 pp. Backhuys Publishers, PO Box 321, 2300 AH Leiden, The Netherlands.- Why some species grow slowly and others grow quickly has been a question that plant biologists have been asking for centuries. Earlier this century, Blackman (1919) started to develop quantitative plant growth analysis. Since then, many plant biologists (e.g., Kvet, et al., 1971; Evans, 1972; Causton and Venus, 1981; Hunt, 1982) have striven to understand the ecological and physiological implications of differences in relative growth rates among species. How is the relative growth rate of a species related to its physical environment, successional status, and place in a community? What are the driving factors that determine relative growth rates? How does growth rate affect other attributes of a plant?
The volume is the result of the workshop on Inherent Variation in Plant Growth Rate held at Utrecht University, The Netherlands, in June 1997. It is the second excellent volume from such a meeting, the first being Causes and Consequences of Variation in Growth Rate and Productivity of Higher Plants (ed. by Lambers, Cambridge, Konings, and Pons, 1990) based on the workshop held in 1988. This volume brings together contributions of scientists from many fields ranging from cell biologists, molecular biologists, biochemists, anatomists, physiologists, whole plant biologists, to community ecologists, each with their own perspective on the causes and consequences of variation of relative growth rate. This allows the reader, who probably is familiar with a few of these fields, to become acquainted with what others are studying at the different levels of plant organization and to integrate these levels and information.
This fine book is comprised of 28 chapters by various authors plus an introduction and epilogue by the editors. It is divided into four main sections:
I. Growth and anatomy of roots and leaves
Starting at the level of the cell, there are three chapters on cell cycling and cell expansion (focusing on cell wall components and turgor pressure), and their regulatory controls in roots and leaves. At the anatomical level, three chapters discuss the anatomy and morphology of roots of fast- and slow-growing grasses, leaf anatomy among different functional types of plants, and the leaf anatomy of seagrasses and how these leaf characteristics relate to specific leaf area (SLA), a key component of relative growth rate.
II. Carbon metabolism and nutrient acquisition
Five chapters deal with differences of growth rates at the physiological level. Variation in photosynthesis is explored with respect to leaf anatomy, as well as shade acclimation and hormonal effects on leaf longevity. Focusing on roots, respiration, nutrient uptake, and exudation, along with carbon budgets are contrasted in fast- and slow-growing species. One chapter discusses allocation patterns in relation to fast- and slow-growing spec How relative growth rate, physiology, and allocate patterns relate to strategies for acquiring nutrients n patchy environments are discussed in a chapter on plants in the wild. Another chapter suggests the use of transgenic plants to manipulate levels of certain enzymes to elucidate mechanisms for differences in growth rates at the genetic level.
III. Growth analysis of individual plants
Most of this section, six chapters, is devoted to the classical growth analysis approach to understanding the importance of relative growth rate components in contrasting environments. In other words, understanding how success in dealing with different environmental conditions results in trade-offs with a high relative growth rate. Relative growth rate is most often compartmentalized into two parts: net assimilation rate (NAR) and leaf area ratio (LAR), as well as the factors which influence each of these, including leaf mass ratio (LMR), specific leaf area (SLA), among other growth parameters. Differences in water use efficiency, nitrogen use efficiency, respiration, and leaf longevity are also related to differences in relative growth rates. Comparisons are made with alpine and lowland species, many Aegilops species and wheat cultivars, herbaceous plants grown at high and low irradiance, temperate woody species of different functional types and life-history strategies, and shade tolerant and pioneer tropical tree seedlings in high and low irradiance. Path analysis is also employed for determining the relative importance of each component of relative growth rate to the overall growth of the plant. One chapter addresses the use of resistance mutants to understand the tradeoffs between disease resistance and relative growth rate. The last chapter describes the potential use of quantitative trait loci (QTL) analysis to develop faster-growing and more water- and nutrient-efficient crops.
IV. Consequences for ecosystem functioning
The final section of this volume scales the effects of relative growth rates from that of the plant level to stand and ecosystem levels. The allocation to roots and leaves, as well as their morphology and architecture, is discussed in two chapters in relation to organ longevity, turnover rates, and nutrient uptake. These two chapters and a later one explore differences among functional types of plants, as well as the interactions between organ longevity, litter quality, nutrient availability in the ecosystem on a long-term basis, and succession. Another chapter describes the changes in relative growth rate and its components in communities during old-field succession over a thirty-five year period with different nutrient levels. A common definition of nitrogen use efficiency from the leaf level, to the plant level, to the stand level is called for in another chapter. Here possible trade-offs between its two components: nitrogen flux (mean residence time of nitrogen in the system) and mean annual nitrogen productivity (biomass increment per unit time and nitrogen) and how this may relate to variation in relative growth rate. Last in this section is a chapter on the proper phylogenetic analysis of variation among species within taxa.
In summary, this is an excellent volume, filled with many fruitful ideas. The editors address roots almost as thoroughly as leaves, something often lacking. Although it does not answer the question of why plants have different inherent growth rates, it compiles the knowledge to date from a variety of perspectives and it serves as a springboard for new and exciting research. The only complaint is a few typographical errors in several chapters (e.g., symbols in legend of Fig. 6, p. 109 are shifted or missing). We wholeheartedly recommend this book.
- Eva Grotkopp and Marcel Rejminek, Section of Evolution and Ecology,
University of California, Davis, CA 95616.