ABSTRACT
This chapter addresses the following questions: Which physiological and morphological characteristics determine the potential growth rate of a plant? What are the inherent differences in these characteristics among species from nutrient-rich and nutrient-poor environments at nonlimiting nutrient supply? How are these characteristics influenced by nitrogen supply and what is their integrated effect on growth? What is the biochemical background of several of these physiological and morphological characteristics? S. A. Blackman pointed out the pitfalls and caveats in plant growth analysis. The chapter provides a hypothesis for the physiological regulation of partitioning of photoassimilates between roots and shoots as dependent on nitrogen supply on plants. Generally, fast-growing species have a lower nitrogen content and equal rate of photosynthesis, both expressed per unit leaf area, than slow-growing species and hence have a higher efficiency of photosynthesis per unit leaf nitrogen. The rate of photosynthesis per unit leaf area is not a factor explaining variation in growth rate between species of similar life-forms.
