Page 63 - ICSE Science 3 : E-book

Functions of the stem

• It holds the plant upright and straight.

• It bears other parts of the plant such as branches, leaves, fl owers and fruit.

• It carries water and minerals from the roots, and food from the leaves to various
parts of the plant.

• Some plants store food in their stem, such as sugar cane, potato and ginger.

These stems can be eaten by us.

Leaf

Leaf is the thin, fl at and usually green part that grows from the plant’s stem or
branch. A leaf looks very simple but it has many parts. Let’s know about them.

• The fl at and broad part of a leaf is called lamina
leaf blade
or leaf blade. (lamina)

• Petiole or stalk links the leaf to the plant’s main vein
petiole (midrib)
stem or branch. It provides a passage for
(stalk)
the transport of water and minerals to and veins

from the leaf. There are some leaves that lack
petiole. Structure of a leaf

• A number of tiny channels in the form of lines run all over the surface of a leaf.

They are called veins. They form a network, and carry water and minerals to all
parts of the leaves. The line running in the middle of the leaf

from the stalk to its tip is called the main vein or midrib. It
divides a leaf into two equal parts.

• A number of small openings called stomata are present on
stomata
the under surface of a leaf. They help in the exchange of

gases. Plants also lose extra water through stomata.

Leaves of diff erent plants diff er greatly in colours, shapes and sizes. They can be
green, red, purple, yellow or orange in colour. Plants like banana have large leaves

while plants like rose have small leaves. Some plants like Ashoka have long leaves

while plants like pines have needle-shaped leaves.

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