ABSTRACT
A major goal of investigations of heterogeneity of light environments is an understanding of the role of light availability in species diversity and forest regeneration. Integration of the role of photosynthetic plasticity in enhancing plant function in heterogeneous light regimes requires an understanding of how leaf photosynthetic rates interact with and are determined by allocation patterns at the whole-plant level. Plants on the gap edges are usually in strongly directional light environments because of shading by adjacent plants on one side. The observed respiration rates of sun and shade plants reflect mostly the differing resource supplies and demands. The response of individual plants to spatial and temporal heterogeneity depends on the scale of the heterogeneity. Understanding the adaptive significance of plasticity of a character requires knowledge of how it scales up to whole-plant performance. The latter indicates a scale of sampling where more traditional statistical approaches can be used to analyze relationships between plant performance and light availability.
