Crop physiology in relation to agricultural production. The genetic link. Does light limit crop production? Eficiency of water, solar energy and fossil fuel use in crop production. Chloroplast structure and photosynthetic efficiency. Production efficiency of coniferous forest in the uk. Processes limiting photosynthetic conductance. Photorespiratory carbon dioxide loss. Leaf ontogeny and photosynthesis. Adaptation to chade. Photoperiodism and crop production. Water stress and crop growth. Short-term and long-term effects of drought on steady-state and time-integrated plant processes. Regulation of gas exchange in water-st ressed plants. Effects of low temperature stress and frost injury on plant productivity. Salt tolerance. Air pollution and plant productivity. Nutrient interception and transport by root systems. Nutrient uptake in relation to growth. Symbiotic nitrogen fixation. Towards the abolition of limiting factors.