Factors affecting photosynthesis

                          The process of photosynthesis is influenced by a no. of external and internal factors.

a) Light: It is the most important factor for photosynthesis. Light affects the rate of photosynthesis in three different ways:-

I) Light intensity: The rate of photosynthesis increases with the increase of light intensity but very high and very low intensity decrease the rate of photosynthesis.

ii) Light quality: The rate of photosynthesis is different in different wavelengths of light. It is more in red light which is followed by blue light while in green light, min. Photosynthesis takes place. It is more in white light than monochromatic light.

Iii) Duration of light: An increase in the duration of light increases the rate of photosynthesis but more than 12 hr. of light duration may decrease the rate of photosynthesis.

b) CO: Carbon dioxide is a source of carbon for various organic products formed in plants like glucose, starch, etc. If CO₂ concentration rises from 0.3% to 1 %, the rate of photosynthesis becomes high but t higher concentration of CO₂ decreases the rate of photosynthesis.

c) Water: Water is the essential raw material for photosynthesis because water and CO₂ undergo chemical reactions in the formation of carbohydrates. Therefore, a deficiency of water decreases the rate of photosynthesis. It also checks the rate of entry of CO_.

d) Temperature: The optimum temperature for photosynthesis is 20-30 ⁰ Below this temperature, the rate of photosynthesis decreases. In high temperatures, denaturation of enzymes takes place which is essential for dark reactions.

e) Chlorophyll contents: The rate of photosynthesis directly relates to the amount of chlorophyll because it is the main pigment for the absorption of light. Chlorophyll lacking plant i.e. fungi, bacteria are unable to show photosynthesis.

f) Anatomy of leaves: Anatomy of leaf-like structure, position, distribution of stomata, cuticle, and intercellular space directly affects the rate of photosynthesis.

g) Leaf age: rate of photosynthesis increases in young or mature leaves but decreases in aging leaves.

h) Accumulation of photosynthetic products: Accumulation of photosynthetic products decreases the rate of photosynthesis.

Significance of photosynthesis

I) It is the main process of making food.

ii) It balances the CO₂ and O₂ in atmosphere.