plant factories 2
Light, Temperature and Carbon
Dioxide Levels
The interaction of light, temperature and carbon dioxide
levels is critical to ensure good crop productivity. The basic
information on this was developed by P. Gaastra in the late
1950s, but it is possible this work is not particularly relevant for
plant factories, where the environment can be closely controlled. Gaastra’s research involved measuring photosynthesis
of individual plant leaves at three light intensities, two carbondioxide levels and two temperature levels. He found that at
CO2 levels of 300 ppm, and temperatures of 68 and 86°F,
the leaves are quickly light saturated. By increasing the CO2
concentration to 1,300 ppm and keeping the temperature at
68°F, photosynthesis increased.
Photosynthesis is limited at 300 ppm as the movement
of the gas through the stomata in the leaves to the site
of photosynthesis (chloroplasts) is determined by the
difference in concentration between the CO2 in the
outside atmosphere and that at the chloroplast. At
of light,
higher light intensities, the CO2 concentration at
temperature and carbon dioxide levels is
the chloroplasts becomes zero, when the CO2 in
the outside atmosphere is low (300 ppm), as the rate
critical to ensure good crop productivity.”
at which CO2 moves through the chloroplast depends
on the difference in concentration in the outside air and
the chloroplast. Clearly, the higher the concentration in the
outside air, the greater the photosynthesis rate.
The interaction
Fluorescent lights on floating raft lettuce.
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Maximum Yield USA | January 2015