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Leaf Photosynthesis: The Influence of Environmental Variables
Author(s) -
Incropera Frank P.
Publication year - 1975
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1975.00472425000400040004x
Subject(s) - photosynthesis , relative humidity , carbon dioxide , humidity , greenhouse , chemistry , light intensity , atmosphere (unit) , diffusion , atmospheric sciences , environmental chemistry , botany , environmental science , meteorology , biology , thermodynamics , biochemistry , physics , organic chemistry , optics , geology
A model is presented for the effects of light intensity and ambient temperature, relative humidity, and carbon dioxide concentration on leaf photosynthesis. The model treats diffusion and chemical processes occurring within the leaf, as well as the transfer of mass and energy between the leaf and its environment. Calculations have been performed for Zea mays L. (maize) which suggest the influence of environmental changes. Although leaf energy exchange processes act to moderate the effect of changes in the atmospheric temperature, a severe cooling trend may cause as much as 20% reduction in photosynthesis. Under most conditions, the rate of photosynthesis is further diminished by a reduction in relative humidity. In contrast, a 20% increase in the atmospheric CO 2 concentration, which is projected for the year 2000, will increase photosynthesis by approximately 15%. The calculations also suggest optimum ambient conditions for controlled growth environments, such as a greenhouse. In addition to a saturating light intensity of approximately 700 W/m 2 , these conditions include a temperature and relative humidity of approximately 30C and 90%, respectively, and a CO 2 concentration of approximately 1,500 ppm.