RESPONSE OF CROP PHOTOSYNTHESIS TO CO2, TEMPERATURE, AND LIGHT: EXPERIMENTATION AND MODELING

Abstract

Increasing atmospheric carbon dioxide concentration [CO 2 ] is expected to result in a CO 2 level of 600 μL L -1 sometime during the 21st century, which will likely affect global climate primarily by increasing air temperature 3-6°C. Several studies were conducted on the interactive effects of [CO 2 ] and temperature in various combinations on cotton photosynthesis, respiration, transpiration, water use efficiency, and dry matter accumulation. The data were used to develop and test various types of photosynthesis models. The dependence of canopy light utilization efficiency and canopy conductivity for CO 2 transfer on temperature and CO 2 concentration was determined. The complete model of CO 2 , exchange for cotton as a function of environmental factors contains 7 parameters. Methods of validation, parameterization, and comparison of photosynthetic models are described.