Basic plant parts
External parts of a plant
Every plant is made up of four essential parts that help to scientifically classify it as a plant. Each
of these plant parts plays an important role in helping the plant to grow and thrive.
These are:
Roots
Roots are the most important and underground part of a plant, which are collectively called the root
system.
Function of root system
▪ Roots absorb water and minerals from the soil and transport them to the upper parts
like stem and leaves of the plant. The water and minerals are carried from roots to the upper
parts of the plants in an upward movement, against the gravity. Therefore, it requires some
force. This force is provided by the transpirational pull due to the process of transpiration
going on in the leaves.
▪ Roots also provide anchorage to the plants and keep them attached to the soil by binding
the soil around the roots. This is the reason why it is difficult to uproot a plant by hands.
▪ Roots are used to store reserve food; for example, fleshy roots like Carrot, Radish, Beet,
Turnip, and Mirabilis.
▪ Roots play an essential role in binding the soil. Roots help in preventing soil erosion and
land sliding in the hilly areas.
▪ Roots of plants like Corms, Stem Tubers, Rhizomes, and Stolon participate in vegetative
reproduction.
▪ In some week stemmed plants, roots help in clinging and, hence, climbing roots; for
example, Money Plant, Betel, Ivy, etc.
▪ Roots also take part in nitrogen fixation with the help of nitrogen-fixing bacteria present
in the soil. For example, nodulated roots Of Pea, Bean, Gram, Fenugreek, etc.
▪ Roots of some plants are present above the ground and known as Aerial Roots. For
example, pneumatophores are the type of specialized aerial roots present in Mangrove
plants. They help the plant to breathe.
▪ Roots of mangrove and epiphytic orchids play a significant role in the photosynthesis.
They become green upon exposure to light and start producing energy. There is even a
leafless orchid (Dendrophylax lindenii) which solely depends upon its roots for energy
production.
Types of Root System
,All roots have almost similar functions but they vary in structure and the site of origin. So, based
on these criteria, roots are mainly divided into three types, that is,
▪ Taproot System
▪ Adventitious Root System
▪ Fibrous Root System
Taproot System
Taproots appear from the radicle of the embryo of a germinating seed. In the taproot system, there
is one main root from which lateral root branches originate.
Upon germination, the first root that arises from the radicle is the main cylindrical root, also known
as the primary root, which grows vertically downward. From the main root, first-order roots arise
which are known as the secondary roots. And, then, from these secondary roots, the second-order
roots arise which are known as the tertiary roots. On the tip of tertiary roots, there are present thin
hair-like structures known as the ‘Rootlets.’ The primary root is the most prominent, thickest, and
longest of all. Taproots gradually become narrow towards the tip.
, Taproot s are present in dicotyledonous plants. Taproots can persist for a lifetime but are often
replaced by the fibrous root system in the later stages of plant development because the radicle of
most of the plant species dies after germination.
Taproots tend to be deep-rooted and are difficult to uproot. If during the process of uprooting a tap
root plant, the root breaks off, the part that is left in the soil often sprouts again.
Taproots grow in acropetal succession, that is, the youngest is present at the growing end while
oldest towards the base. Rootlets are very delicate structures and are the ultimate branches of a tap
root system. They are responsible for water absorption in plants. Primary roots always grow in the
vertical orientation while secondary and tertiary roots grow in the horizontal orientation.
Examples of the taproot system can be seen in a variety of plants, like Carrot, Radish, Turnip,
Dandelion, Parsley, Beetroot, Sugar beet and Rose plant
Adventitious Root System
External parts of a plant
Every plant is made up of four essential parts that help to scientifically classify it as a plant. Each
of these plant parts plays an important role in helping the plant to grow and thrive.
These are:
Roots
Roots are the most important and underground part of a plant, which are collectively called the root
system.
Function of root system
▪ Roots absorb water and minerals from the soil and transport them to the upper parts
like stem and leaves of the plant. The water and minerals are carried from roots to the upper
parts of the plants in an upward movement, against the gravity. Therefore, it requires some
force. This force is provided by the transpirational pull due to the process of transpiration
going on in the leaves.
▪ Roots also provide anchorage to the plants and keep them attached to the soil by binding
the soil around the roots. This is the reason why it is difficult to uproot a plant by hands.
▪ Roots are used to store reserve food; for example, fleshy roots like Carrot, Radish, Beet,
Turnip, and Mirabilis.
▪ Roots play an essential role in binding the soil. Roots help in preventing soil erosion and
land sliding in the hilly areas.
▪ Roots of plants like Corms, Stem Tubers, Rhizomes, and Stolon participate in vegetative
reproduction.
▪ In some week stemmed plants, roots help in clinging and, hence, climbing roots; for
example, Money Plant, Betel, Ivy, etc.
▪ Roots also take part in nitrogen fixation with the help of nitrogen-fixing bacteria present
in the soil. For example, nodulated roots Of Pea, Bean, Gram, Fenugreek, etc.
▪ Roots of some plants are present above the ground and known as Aerial Roots. For
example, pneumatophores are the type of specialized aerial roots present in Mangrove
plants. They help the plant to breathe.
▪ Roots of mangrove and epiphytic orchids play a significant role in the photosynthesis.
They become green upon exposure to light and start producing energy. There is even a
leafless orchid (Dendrophylax lindenii) which solely depends upon its roots for energy
production.
Types of Root System
,All roots have almost similar functions but they vary in structure and the site of origin. So, based
on these criteria, roots are mainly divided into three types, that is,
▪ Taproot System
▪ Adventitious Root System
▪ Fibrous Root System
Taproot System
Taproots appear from the radicle of the embryo of a germinating seed. In the taproot system, there
is one main root from which lateral root branches originate.
Upon germination, the first root that arises from the radicle is the main cylindrical root, also known
as the primary root, which grows vertically downward. From the main root, first-order roots arise
which are known as the secondary roots. And, then, from these secondary roots, the second-order
roots arise which are known as the tertiary roots. On the tip of tertiary roots, there are present thin
hair-like structures known as the ‘Rootlets.’ The primary root is the most prominent, thickest, and
longest of all. Taproots gradually become narrow towards the tip.
, Taproot s are present in dicotyledonous plants. Taproots can persist for a lifetime but are often
replaced by the fibrous root system in the later stages of plant development because the radicle of
most of the plant species dies after germination.
Taproots tend to be deep-rooted and are difficult to uproot. If during the process of uprooting a tap
root plant, the root breaks off, the part that is left in the soil often sprouts again.
Taproots grow in acropetal succession, that is, the youngest is present at the growing end while
oldest towards the base. Rootlets are very delicate structures and are the ultimate branches of a tap
root system. They are responsible for water absorption in plants. Primary roots always grow in the
vertical orientation while secondary and tertiary roots grow in the horizontal orientation.
Examples of the taproot system can be seen in a variety of plants, like Carrot, Radish, Turnip,
Dandelion, Parsley, Beetroot, Sugar beet and Rose plant
Adventitious Root System
