1. Light: Sunlight participates in the formation of chlorophyll, opens the stomata and helps in making food. The rate of photosynthesis increases when the amount of light increases up to a certain limit. However, if the amount of light is high, photosynthesis stops. Photosynthesis can be maximized by increasing the light from 100 foot candles to 3000 foot candles. If the light is continuous, photosynthesis can reach its maximum level in 10-12 hours. Violet, blue, orange and red light are mostly used in photosynthesis. The rate of photosynthesis is higher in red and blue light. However, as a single light, red light has the highest rate of photosynthesis. Scientists Hoover and Gabrielsen (1948) proved that photosynthesis occurs more in red light and less in green light.
2. Oxygen: Oxygen is a by-product of photosynthesis. As the amount of oxygen in the atmosphere increases, the rate of photosynthesis decreases. If its amount is more, photosynthesis stops.
3. Water: The raw material of photosynthesis is water. It increases the rate of chemical reactions. Water breaks down to produce O2 and NADPH+H+.
4. Carbon Dioxide: CO2 is the main raw material for making sugar. The amount of CO2 in the atmosphere is 0.04%. 1% of this CO2 is used in photosynthesis. Chemical reactions of water and CO2 occur in chloroplasts to produce sugars. The rate of photosynthesis increases when the amount of CO2 increases up to a certain limit. However, if the amount of CO2 is high, photosynthesis stops.
5. Temperature: A particular effector of photosynthesis is temperature. The optimum temperature for photosynthesis is 22-350C. At temperatures above 450C, photosynthesis in most plants ceases. For every 100C increase in temperature, the rate of photosynthesis increases about 2.2-2.6 times. Some bacteria and high-temperature blue-green algae can carry out photosynthesis at temperatures up to 700C.
6. Minerals: Magnesium and iron form chlorophyll. When these minerals are lacking, the production of chlorophyll decreases and the rate of photosynthesis also decreases.
7. Vitamins: Vitamins in algae and other plants keep photosynthesis going.
8. Chemicals: The presence of hydrogen sulphide, chloroform, methane, toxic gases etc. in the air disrupts or stops the photosynthesis process.