PHOTOSYNTHESIS

PHOTOSYNTHESIS:

·     During day time the stomata remain open. Through the stomata the leaves get air containing carbon-dioxide from the atmosphere.

·     Water, mixed with minerals reaches the leaves from the soil through the different parts i.e. roots, stem, branches and twigs.

·     Leaf cells have green pigment called chlorophyll.

·     The sunlight reaches the leaves through their skin and is absorbed by the chlorophyll.

·     Using the energy of sunlight absorbed by the chlorophyll leaves change water and carbon dioxide into sugar (glucose i.e. carbohydrates) and oxygen is given out.

·     Some of the sugar is used by the plant as food to grow. Some of the sugar is changed into starch.

·     The rest of the sugar and the starch are stored in different parts of the plant. 

The process of photosynthesis may be represented as-

FACTORS AFFECTING PHOTOSYNTHESIS

For a constant rate of photosynthesis, various factors are needed at an optimum level. Here are some of the factors affecting photosynthesis.

• Light Intensity: An increased light intensity leads to a high rate of photosynthesis
  and a low light intensity would mean low rate of photosynthesis
• Concentration of CO₂: Higher carbon dioxide concentration increases the rate of photosynthesis.
• Temperature: An efficient photosynthesis requires an optimum temperature range between 25 to 35^oC.
• Water: Lack of water leads to a problem for carbon dioxide intake. If water is scarce, the leaves refuse to open their stomata to keep water they have stored inside.
• Polluted Atmosphere: The pollutants and gases (impure carbon) settle on
  leaves and block the stomata, making it difficult to take in carbon dioxide. A
  polluted atmosphere can lead to a 15 percent decrease in the rate of
  photosynthesis.