INHERENT VARIATION IN GROWTH-RATE BETWEEN HIGHER-PLANTS - A SEARCH FOR PHYSIOLOGICAL CAUSES AND ECOLOGICAL CONSEQUENCES

This chapter discusses the physiological causes and ecological consequences of inherent variation in growth rate among higher plants. When grown under optimum conditions, plant species from fertile, productive habitats tend to have inherently higher relative growth rates (RGR) than species from less favorable environments. The traits of a “typical fast-growing” and a “typical slow-growing” plant species are described. Fast-growing species have higher respiration rates per unit organ weight, due to demands of a higher RGR and higher rate of nutrient uptake. Fast-growing species have a greater capacity to acquire nutrients, which is likely to be a consequence of their higher RGR. The chapter analyzes variation in morphological, physiological, chemical, and allocation characteristics underlying variation in RGR. The lower specific leaf area (SLA) of slow-growing species is at least partly due to the relatively high concentration of cell-wall material and quantitative secondary compounds, which may protect against detrimental abiotic and biotic factors. © 1992, Academic Press Limited