Leave Functions and Modifications


 
 
Concept Explanation
 

Leave Functions and Modifications

Functions of leaf:

  •  Manufacture of food or Photosynthesis: A leaf prepares food for the plants in the presence of sunlight, carbon dioxide, water, chlorophyll. This process is known as photosynthesis.
  •     dpi{120} fn_jvn large Carbon: dioxide + Waterfrac{Chlorophyll}{light}rightarrow Glucose + Oxygen   

    This plant food is a kind of simple sugar called glucose. The glucose produced in the process of photosynthesis is utilised by plants for performing various activities. Excess of glucose is stored in the leaf as starch.

  • 2. Plants store food in the leaves, fruits and stems in the form of starch. 
  • 3.  Exchange of gases: Plants breathe with the help of leaves. Leaves have numerous tiny openings called stomata under their surfaces. The exchange of gases takes place through the stomata. The small openings called lenticels present on old stem also help in gaseous exchange.
  • 4. Transpiration: leaves also lose water through the stomata. The loss of water through the stomata is called transpiration. Transpiration help in cooling the plant body, just as loss of water during sweating helps us to keep cool. Leaves help im conduction of water and minerals through transpiration.   
  • Modification of leaf :

    Defence : In some plants, such as cactus, date palm and prickly poppy, either the entire leaf or a part of the leaf is modified into spines for defence. These spine prevents the loss of water and protect the plant from grazing animals as well. 

    Support : In some plants, such as pea, masur and glory lily, the stems are very weak to stand erect. In such palnts leaf or leaflets are modified into leaf tendrils. Leaf tendrils coil themselves around some support and help plants with weak stems to clumb up to expose their leaves to sunlight.

    Reproduction : In some plants, such as Bryophyllum and Begonia, buds develop on the leaves. These buds grow a new plants.

    Storage of food : In some plants, leaves are modified to store food. The leaves become thick and fleshy.For eg: onion.

                          

    Sample Questions
    (More Questions for each concept available in Login)
    Question : 1

    A leaf prepares food for the plants in the presence of ____________________.

    Right Option : D
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    Explanation
    Question : 2

    Which of the following are correct :

    (a) A leaf prepares food for the plants in the presence of sunlight, carbon dioxide, water, chlorophyll.

    (b) In some plants, such as Bryophyllum and Begonia, buds develop on the leaves. These buds grow a new plants.

    (c) The loss of water through the stomata in plants is called transpiration.

    Right Option : D
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    Explanation
    Question : 3

    The food prepared by leaves is stored as _______________

    Right Option : C
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    Explanation
     
     


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