Question

What are the factors that are essential for photosynthesis?

Answer 1

Hint: Photosynthesis is an anabolic process in which the green plants synthesize the food in the presence of sunlight. The sunlight is captured by light absorbing pigments such as chlorophyll. Chloroplasts present in the mesophyll cells of the leaves which is responsible for fixation of carbon dioxide.

Complete answer:
Photosynthesis is under the influence of both external and internal factors. The internal factors include chlorophyll and the external factors include sunlight, temperature, carbon dioxide concentration and water.
External factors:
> Light: Light intensity between 400-700 nm wavelengths constitutes the photosynthetically active radiation (PAR). Maximum photosynthesis takes place in red and blue light and minimum photosynthesis takes place in green light.
> Carbon dioxide: Carbon dioxide is a major limiting factor. The $C{O}_2$ concentration is very low in the atmosphere which is far below the requirement for optimum photosynthesis.
> Temperature: Photosynthesis can take place over a wide range of temperatures. Temperature optimum for photosynthesis is depending on the habitat in which plants live. Tropical plants have higher temperature optimum than the plants adapted to temperate climates.
> Water: Water is one of the raw materials used in the process of photosynthesis. Photosynthesis utilizes less than 1% of the water absorbed by the plant.
Internal factors:
> Chlorophyll: Chlorophyll is the most important factor used in the process of photosynthesis. It traps light energy from the sun. There is no photosynthesis in the absence of chlorophyll.
In 1929, Emerson observed a direct relationship between the chlorophyll content of leaf and the rate of photosynthesis.

Note: Light duration does not affect the rate of photosynthesis but it affects the overall photosynthesis. $0-5^{\circ }C$ is the minimum temperature at which most plants start photosynthesis. $-{35}^{\circ }C$ temperature for gymnosperms.