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Learn Introductory Crop Physiology with Braimy – B.SC Agriculture
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               Respiration is the process of breakdown of complex food materials into inorganic compounds with release of energy. Several factors affects the rate of respiration.

A) External factor :

  1. Temperature : The optimum temperature for respiration is 20-30 0C. The rate of respiration gets double for energy rise to 10 0C. There is initial increase , soon decrease due to denaturation of enzyme. Below the 00C, the rate of respiration decrease.

  1. Oxygen : Presence of oxygen is the first and most essential condition for respiration. If the concentration of oxygen goes below 5%, the respiration process falls rapidly.

  1. Light : The effect of light is indirect in rate of respiration. In bright light, respiration is greater than low light due to wide opening of stomata. In morning and evening, the rate of respiration is equal to rate of photosynthesis.

  1. Supply of water : The protoplasm is saturated with water . So, the rate of respiration increase in supply of water and decrease in decreased water as in dry seed.

  1. CO2: Increase in CO2 concentration decreases the rate of respiration due to toxic effect of CO2 in protoplasm.

  1. Chemical inhibitors : Chemicals like CN, Azides, CO , CHCl3, acetone, etc. in very small quantity increase the rate of respiration. If concentration increase , there is fall in the rate of respiration then kill the cell.

B) Internal factors:

  1. Protoplasmic factors: The rate of respiration depends upon quantity and quality of protoplasm of the cell. Younger cells which have more active protoplasm , respire more rapidly than the older cells.

  1. Age of plant : The rate of respiration decrease with the age of the plant.

3. Concentration of respiratory matrix : The rate of respiration depends upon the presence of respiratory materials in the matrix. The rate of respiration increase with the increase in respiratory substance in the matrix of the cell.

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