The rate of photosynthesis increases with increasing light intensity. But too much light intensity can slow down the rate of photosynthesis because the light damages chloroplasts in the leaf.
The higher the temperature the greater the rate of photosynthesis as photosynthesis is a chemical reaction and chemical reactions increase with temperature. But at temperatures above 40 C the rate slows down because the enzymes involved are destroyed at high temperatures.
The higher the concentration of carbon dioxide, the greater the rate of photosynthesis.
Economics of greenhouses
Farmers can use their knowledge of factors limiting the rate of photosynthesis to increase crop yields.
This is particularly true in greenhouses, where the conditions are more easily controlled than in the open air outside:
The use of artificial light allows photosynthesis to continue beyond daylight hours. Bright lights also provide a higher-than-normal light intensity.
The use of artificial heating allows photosynthesis to continue at an increased rate.
The use of additional carbon dioxide released into the atmosphere inside the greenhouse also allows photosynthesis to continue at an increased rate.
However, the additional cost of providing extra lighting, heat and carbon dioxide has to be weighed against the increased crop yield and the extra income it will provide. The cost of should not exceed the additional income it generates for the farmer.
In practice, the farmer will need to find the optimum growing conditions for the crop, given the costs of providing extra lighting, heat and carbon dioxide.
Paraffin lamps have traditionally been used in greenhouses. Their use increases the rate of photosynthesis because as well as the light generated from the lamps, the burning paraffin produces heat and carbon dioxide too.
Storage and use of glucose
The glucose produced in photosynthesis may be used in