PAR = photosynthetically active radiation.
Carbon dioxide is produced during the processes of ..
Carbon dioxide enters into the plant through the stomatal openings by the process of diffusion. Stomata are specialized cells located mainly on the underside of the leaves in the epidermal layer. The cells open and close allowing gas exchange to occur. The concentration of CO2 outside the leaf strongly influences the rate of CO2 uptake by the plant. The higher the CO2 concentration outside the leaf, the greater the uptake of CO2 by the plant. Light levels, leaf and ambient air temperatures, relative humidity, water stress and the CO2 and oxygen (O2) concentration in the air and the leaf, are many of the key factors that determine the opening and closing of the stomata.
the increased uptake of carbon dioxide into the oceans is ..
Ambient CO2 level in outside air is about 340 ppm by volume. All plants grow well at this level but as CO2 levels are raised by 1,000 ppm photosynthesis increases proportionately resulting in more sugars and carbohydrates available for plant growth. Any actively growing crop in a tightly clad greenhouse with little or no ventilation can readily reduce the CO2 level during the day to as low as 200 ppm. The decrease in photosynthesis when CO2 level drops from 340 ppm to 200 ppm is similar to the increase when the CO2 levels are raised from 340 to about 1,300 ppm (). As a rule of thumb, a drop in carbon dioxide levels below ambient has a stronger effect than supplementation above ambient.