Behind the life-saving functions of the leaf, there are several basic parts of it that support it to provide these functions.

1. Parts of a Leaf and Their Life Saving Functions
Austin February 16, 2022 no Comments
A leaf is considered one of the most important parts of a plant as it is a
source of food for the plant itself and also for other animals who feed on
it. This increases the value of a leaf highly in our daily lives as well.
This flat green part of a plant helps it to be the primary producer of the
general food chain and it also helps maintain the right carbon -oxygen
balance in the environment. Without it we humans wouldn’t be able to
breathe in the clean air that we do.
Behind the life-saving functions of the leaf, there are several basic parts of
it that support it to provide these functions.
Parts of a leaf

2. The anatomy of a leaf reveals that the classification of leaf parts is usually
done based on two categories that include
1. External parts
2. Internal parts
Here you will find info about both classification and how these parts of a
leaf help it to sustain lives of its own and many others.
External parts
If we examine the leaf externally, there are six most important parts of a
leaf as mentioned below:
• Petiole
• Lamina
• Midrib
• Veins
• Leaf margin
• Leaf apex

3. Petiole
Petiolate: Includes the plants that are connected to the stem through the
petiole.
Sessile: Includes the plants that connect directly to the stem and lack
petiole.
More commonly known as the leaf stalk, the petiole of the leaf is the
branching part that attaches the leaf to its stem and supports it. Without
the presence of a petiole, the leaf would not be able to stay connected to
its stem body and there would be no activity to support its life.
Although there are some leaves that connect directly to the stem and do
not require the petiole, in most leaves, this stalk is a very important part.
The petiole basically connects the veins of the leaves to the tiny tubes that
are inside the petiole. In this way, the flow of minerals and water is made
possible through the stem to the leaf.

4. The length of the petiole varies with the type of plant. Plants such as
rhubarb or celery have a longer petiole whereas some plants have no
petiole like the grass.
Hence the petiole of a leaf serves two main functions. Firstly it supports
the leaf by connecting it to the stem body and secondly, it transports the
products of photosynthesis through the connection of the leaf to the stem.
The main functions of a petiole include
• Connecting the leaf to the stem.
• Supporting the leaf structure.
• Transporting water and minerals from roots to leaf.
• Transporting photosynthesis products to the plant.
Lamina

5. This is the main part of the leaf. Lamina is the flat green part of the leaf in
which photosynthesis is actively occurring. The lamina of a leaf is also
known as the leaf blade and it contains the veins that emerge from a main
mid vein. The midvein connects one lamina of the leaf to the other through
the petiole.
Without the lamina, there would be no photosynthesis and eventually, the
plant would not be able to provide the food and minerals for its own
survival.
There are several factors that make one lamina differ from the other
lamina. The differentiating factor could be the shape of the lamina which
is determined by its edges, the composition of veins and their pattern on
the lamina or it could be the number of laminae present in a particular leaf.
The main functions of a lamina include
• Absorbing sunlight to produce food for the plan t.
• Evaporating excess leaf water through the process of transpiration.
• Exchange of several gases including carbon and oxygen during
photosynthesis.
• Production of buds and flowers through vegetative propagation.
• Some plants store food and water in their lam ina such as onion or
desert plants.

6. Midrib
A midrib is the primary linear vein that runs through the length of the leaf.
It gives rise to other branching veins on the lamina of a leaf. It usually
extends from the leaf base to the apex of the leaf. The midrib is also
commonly known as the midvein and contains two major components
including the
Xylem: Helps in the transportation of water
Phloem: Helps in the transportation of food such as proteins and sugars.
The main functions of a midrib include:
• Provides a rigid shape to the leaf.
• Protect it from harsh environments.
• Facilitates the flow of nutrients.

7. Veins
The midrib gives rise to several other veins on the lamina of a leaf that
extends in the form of small branches from the midvein. These emerging
veins are composed of the xylem and phloem which as discussed earlier,
facilitate the passage of nutrients acro ss the plant.
The veins collectively make up the vascular system of the plant. This system
is the main source of facilitating the nutrients across the plant body.
The main functions of a vein or a vascular system include:
• Providing support and protection to the leaf.
• Transporting nutrients through xylem and phloem.

8. Leaf margin
The leaf margin is basically the lining or the edge of the leaf that defines
the shape of a particular leaf. The leaf shape is determined by the type of
leaf margin of that leaf. Based on the properties, there are several different
types of leaf margins giving rise to different leaf shapes. These different
types of leaf margins include:
ENTIRE
LOBED
TOOTHED
DENTATE
CRENATE
In this way, the leaf margins differ from each other giving rise to several
different shapes of a leaf.
The main functions of a plant margin include:

9. • Giving shape to the particular leaf.
• Supports the shape.
• Helps identify the different species of plant.
Leaf apex
The tip of the leaf where it all usually ends is known as the leaf apex. The
tip or apex of the leaf can vary in shape depending on the type of plant. It
can be bluntly sharp or smoothly rounded or it can be something between
these two ranges. Although there are not many specified functions related
to the apex of the leaf, it does help the leaf to stand erect in the straight
position
Internal parts
There are several important parts of a leaf that functions internally. These
parts usually include:
• Stomata

10. • Guard cells
• Epidermal cells
• Mesophyll cells
• Xylem
• Phloem
Stomata
In the internal layer of the leaf that is the epidermis, there are several
pores on the epidermis. These pores are collectively known as stomata and
individually each pore can be called a stoma. These pores are basically
responsible for the gaseous exchange between the plants and the
environment. It helps in the regulation of carbon diox ide and water
exchange happening between the atmosphere and the leaf.
Guard cells
Each stoma is surrounded by a layer of cells known as the guard cells. These
cells surrounding the stoma regulate the opening and closing of the pores.
The rate of exchange is regulated in this way. When there needs to be more
gaseous exchange, the guard cells allow the opening of stoma where it
restricts the opening when there needs a lesser amount of gaseous
exchange.
Epidermal cells
These cells make up the epidermis layer o f a cell and provide the leaf with
protection from external and internal factors. Externally, it protects the
leaf from restricting the entrance of unknown factors such as harmful
microorganisms. Whereas internally it protects the leaf by restricting the
excess loss of water during evaporation.
Hence these cells control the incoming and outgoing materials from and in
the plant respectively.
Mesophyll cells

11. These cells are usually located between two -layer epidermis cells. Being
tightly packed between these two layers, mesophyll cells are responsible
for the active occurrence of photosynthesis, and other than this it
facilitates the transportation of nutrients.
Vascular bundles
The vascular bundles mainly include the xylem and the phloem. Both of
these components are situated in the veins of the plant and serve individual
functions.
The xylem of the plant is responsible for the transportation of the water to
all parts of the plant whereas the phloem is responsible for the
transportation of food to all parts of the plant.
CONCLUSION
There are several parts of a leaf located on the external and internal levels
that collectively work to facilitate the normal functioning of a leaf and

12. support the survival of the plant eventually. Our private tutors provide
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