The CO2 concentration in the atmosphere is quite constant and it is around 300-400 ppm, plants perform the process of photosynthesis under appropriate lighting (energy for reaction) and environmental (reaction reagents: CO2 and water level) conditions and by fixing this carbon dioxide and generating sugars or similar processes employed in breathing, cell division and growth. Photosynthesis occurs in the leaf cells stomatal chloroplasts which regulate gas exchange with the environment.
Contrary to the photosynthesis process is respiration, this process provides energy to all other physiological processes in the plant, producing CO2 and water, unlike photosynthesis that takes place during the day, respiration occurs throughout the day.
An appropriate rhythm of photosynthesis leads to a sustained growth (increase in dry matter). The rate depends on:
- Temperature conditions
- Light
- CO2 concentration
- Water status
Any of these factors can have a limiting factor, for example. low light, low CO2 concentration, elevated temperature, though, it is the lack of light the determining factor being the most difficult to correct. The aim of the plant production is to obtain optimal harvest in the shortest time, so it is vital optimally manage these three factors.
How to apply these factors in Greenhohuses crops?
In greenhouse industry, this aspect has even greater prominence, given the lighting and thermal environmental conditions in which concur productions.
If CO2 concentration in a greenhouse falls below the average concentration in the atmosphere, the photosynthetic rate will be reduced significantly.
700-800 ppm concentrations obtained by carbon dioxide enrichment increase the rate of photosynthesis, the potential gains, depend on each crop species, existing maximum limits from which no benefit is obtained, thus causing the closing of the stomata.
Fixation rates between 4-8 grams per square, meter and hour could be a reference, considering for sizing enrichment facilities a contribution of 8-20 grams, hour and square meter.
