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Parts and Modification of plants for specific functions,
Grade 8 & O-levels Biology
Written by:- Maria Batool

Table of Contents
What are the parts of plants and their functions?
The most important parts of plants are:
Functions of different parts of plants:
1
...
Stem:
3
...
Flower:
Parts of Flowers:
Female part:
Male part:
What is chlorophyll?

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What are the parts of plants and
their functions?
Plants are living organisms that play an important part in our lives
...


The most important parts of plants are:
1
...
Flowers
3
...
Roots

Functions of different parts of plants:
1
...
Also the roots make sure that plants are firmly held in the
soil
...

Internal system of absorbing water and mineral salts
After root hairs, roots have a substance called cortex
...
In the cortex all the excess amount of food is saved
...

Now, what are xylem and phloem vessels?
Xylem Vessel:
These vessels are very important
...
It
functions throughout the plant
...
The walls of xylem vessels are
thick and have lignin in them which provides not only mechanical strength to the
plant holding it upright, but also it strengthens the walls of the vessels which
prevents them from tearing or wearing off because of the high pressure flow of the
water inside them
...

Phloem Vessel:
Unlike xylem vessels, phloem has a two way transporting path
...
These vessels take the
glucose from the plants, to the stem, and then to the roots
...


2
...
It holds the plant upright and
carries the water and mineral salts to the leaves and to the other parts of the plant
...


3
...
The material in the stem enters the leaves
and the process of photosynthesis takes place
...

Let us go through the external parts of leaves first:

External Parts:
Lamina:
It is the upper layer of the leaf that provides a larger surface area to the leaf so that it
can absorb maximum amount of sunlight
...


Midrib:
This is like a backbone to the plants
...


Petiole:
This at the very start of the leaf which connects the leaf with the stem
...


Internal Parts:
Stomata:
These are available on the upper and lower epidermis
...
It opens for
gas exchange
...

Waxy Cuticle:
It protects that plant from losing a lot of water in extreme weather
...
This layer is transparent so the sunlight absorbed by
the plants could reach further down the layers in the plants
...

Spongy Mesophyll:
It is just below the palisade layer which acts like a passageway for the exchange of
gases
...

Xylem:
These vessels transport water to the leaves which is essential for the process of
photosynthesis
...

Air spaces:
Just below the spongy mesophyll
...


Lower Epidermis:
This is a similar layer like upper epidermis but is found at the bottom of the leaf
...


*Look at the pictures of leaves' internal parts carefully and differentiate between the
stomata (also called stoma) and guard cells
...
It has 2 epidermises and 2 waxy cuticle
layers
...
Flower:
This is the most attractive part of the plant
...


Parts of Flowers:
Female part:
Pistil is known as the female part of the flower
...


1
...
Style (the tube in which the pollen from the stigma travels to the ovaries)
3
...
It consists of 2 other parts
...
Anther (produces pollens)
2
...
It traps sunlight
which is essential for the process of photosynthesis

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