FUNCTION OF LEAVES

STORAGE OF FOOD:

Some plants store excess food within the leaves. E.g. Cabbage

SYNTHESIS OF FOOD: 

·    Leaves are considered as the kitchen of a plant because within the leaves, plants make their food. This process is called photosynthesis.

          PHOTSYNTHESIS:

·  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-

RESPIRATION: 

Respiration is a process which majorly occurs during the night, when no photosynthesis occurs. Plant respiration occurs 24 hours per day, but night respiration is more evident since the photosynthesis process ceases.

·     During respiration, oxygen is taken in and carbon di oxide is given out. 

·      Here the leaves act as the breathing organ.

·    The stomata of leaves help plants to intake oxygen and give out carbon dioxide.

·     It is the reverse process of photosynthesis.

REMOVAL OF EXCESS WATER: 

·     Roots absorb more water than it is required by a plant.

·     Excess water is thrown out through stomata of leaves.

·     The process to get rid of excess water by a plant in the form of water vapour is called transpiration. So, transpiration occurs through the stomata.

 PLANT RESPIRATION AND PHOTOSYNTHESIS

 Respiration:  

oxygen + glucose -> carbon dioxide + water +
heat energy

Photosynthesis:   
carbon dioxide + water+ light energy -> oxygen + glucose

It Depends on the amount of sunlight, plants can give out or take in oxygen and carbon dioxide:

DARK:

·     Only respiration takes place.

·     Oxygen is consumed while carbon dioxide is released.

DIM SUNLIGHT

·     Photosynthesis rate is same as respiration rate.

·     A plant consumes all the oxygen photosynthesis generates.

·     It also uses all the carbon dioxide respiration creates.

·     As a result, no gas exchange takes place with the environment.

 BRIGHT SUNLIGHT

· Photosynthesis uses carbon dioxide and makes oxygen faster than respiration produces carbon dioxide and consumes oxygen.

·      Extra oxygen is released into the atmosphere.

  



















 
Reproduction:  

Young plants may grow from leaves of some plants. In case of bryophyllum, 

baby plants grow from the edge of its leaves if these are placed in moist soil.