Page 105 - Science Class 06
P. 105
a crisis for plant growth. The farmer should rest are tendrils which a ach the plants
strive to understand and correct the firmly to a support.
problem. Protec on
Arrangement of Leaves In some plants, leaves have modified into
Leaves grow from the nodes of a stem in the spines or thorns which protect plants from
following arrangements or pa erns: water loss by transpira on. The thorns of
Alternate : In this pa ern, only a single leaf the leaves also protect plants from grazing
comes out from a node, e.g., mango, sun- animals.
flower, etc.
Opposite : In the pa ern two leaves come
out from a node, e.g., calotropis, Jamun, etc.
Whorl : In this pa ern, three or more leaves
come out from a node, e.g., oleander.
Pea Gloriosa
Alternate Opposite Whorl
Func ons of Leaves
Modifica on of Leaves v The main func on of leaves is to
prepare food for the plants by the
In many plants, leaves get modified to
perform some special func ons other than process of photosynthesis.
the normal ones, such as photosynthesis v Leaves perform transpira on which is
and transpira on. the process though which leaves throw
out excess water absorbed by the roots.
Some mes, these modifica ons are in
Transpira on also helps to keep the
response to certain environmental condi ons.
plant cool during summers.
Storage of Food and Water
v During the process of respira on, leaves
Leaves of some plants grow inside the soil. take in carbon dioxide and release
These leaves also come out of the soil. oxygen.
These leaves synthesis food and store food v Modified leaves store food and water.
in their lower part (underground). In this
v Some other modified leaves give
way, they become fleshy.
support to plants.
For example, onion.
v Some modified leaves reduce trans-
Addi onal Support pira on.
Tendrils are some modified leaves. The v Beside, they also protect plants from
leaves of sweet pea have broad leaflets. The grazing animals.
Science-6 105
