ABSTRACT
This chapter discusses the studies on photosynthesis with crop species and cultivars, and native species and ecotypes. The facet of photosynthesis that is often measured by crop physiologists is the rate of carbon dioxide assimilation per unit of projected leaf area or per unit of ground area covered by the canopy. Crop plants are needed that are adapted to different environments. Differences among species in photosynthetic responses to environment are closely related to differences in adaptation and biomass production in natural environments. Thermal regimes with diurnal sinewave variation in temperature could be used in the controlled environments that approximate some natural environments. Original plantations were shaded by planting overhead trees to simulate the natural understory habitats in Africa where coffee bushes evolved. Photosynthetic responses to temperature provide an indication of the environments to which plants are adapted. The extreme sensitivity of leaves of shade plants to intense sunlight has not been well explained.
