Photosynthesis is the synthesis with the help of light. It is the process by which green plants use sunlight to manufacture food from simple molecules like CO2 and H2O. Photosynthesis is sometimes called carbon assimilation and is represented by following equation:
6CO2 + 6H2O ------> C6H12O6 + 6O2
During the process of photosynthesis, the light energy is converted into chemical energy and is stared in the organic matter which is usually carbohydrates and O2 is a byproduct of photosynthesis. CO2 and H2O are the raw materials for this process. CO2 is absorbed from the air and H2O from the soil. Chloroplasts are the sites of photosynthesis. Photosynthesis is important to mankind by the following points. It maintains equilibrium of O2 in the atmosphere. It provides food either directly as vegetable or indirectly as meat or milk of animals which in turn are fed on plants.Factors affecting photosynthesis are mentioned below:
Light: It is the most important factor of photosynthesis. Any kind of artificial light such as electric light can induce photosynthesis. Out of the total solar energy, only 1-2 % is used for photosynthesis and the rest is used for other metabolic activities.Light quality (wavelength):Photosynthesis occurs only in the visible part of the light spectrum i.e., between 400 and 700 nm. The maximum rate of photosynthesis occurs at red light followed by blue light. The green light has minimum effect and photosynthesis cannot take place either in the infrared or in the ultraviolet light.
Carbondioxide: CO2 is one of the raw materials required for photosynthesis. If the CO2 concentration is increased at optimum temperature and light intensity, the rate of photosynthesis increases. But, it is also reported that very high concentration of CO2 is toxic to plants inhibiting photosynthesis.
Temperature: The rate of photosynthesis increases by increase in temperature up to 40 oC and after this, there is reduction in photosynthesis. High temperature results in the denaturation of enzymes and thus, the dark reaction is affected.