Page 2 - 2. Lesson Notes- The Leaf, Functions and modifications of leaves

 Reticulate venation has a main vein running through the centre of the leaf with

a network of smaller veins and veinlets. They are found in dicots. Example

mango, kidney beans etc.

 When the veins run parallel to each other from the petiole to the tip of the leaf,

the venation is called parallel venation. This arrangement of veins in a leaf is

seen in monocots. Example grass, wheat, maize.

Functions of Leaves:

 Leaves prepare food for the plant using carbon dioxide and water in the

presence of sunlight and chlorophyll in the leaves. This process is called

Photosynthesis

.

 The stomata in the leaves facilitate exchange of gases for the process of

respiration and photosynthesis.

 The leaves also help in the process of transpiration ( loss of water in the form

of vapour, from the aerial parts of the plant).

 The process of transpiration helps in

 Transportation of substances dissolved in the water absorbed by the

roots.

 Maintain the temperature of the plant,

 Roots are able to steadily absorb water and mineral salts from the soil

and are able to conduct the same to the leaves for the process of

photosynthesis to happen.