Internal Structure of Root, Stem, and Leaf

Have you ever considered how plants operate their functions? Plants might appear simple, yet internally, they consist of specialised tissues that carry out essential roles. Be it about supporting the plant, transporting nutrients, and producing food – there are components that carry out the tasks. The root, stem, and leaf are structured with tissues that carry out distinct but crucial functions.

To comprehend how plants function, it is vital to examine the internal composition of their three primary components: the root, stem, and leaf. Let’s explore what is going on inside!

Internal Structure of Root

Roots anchor the plant and absorb water and minerals from the soil. The internal structure differs slightly between dicot and monocot roots.

Dicot Root

Epidermis: Thin-walled cells without cuticle or stomata.
Cortex: Parenchyma cells store food and help with water movement.
Endodermis: Innermost layer of cortex, controls water flow to the xylem.
Pericycle: Helps in forming lateral roots.
Vascular Bundles: The xylem and phloem are arranged alternately in a radial manner.
Pith: Very small or absent.

Monocot Root

The structure is mostly similar to a dicot root.
The pith is large and well-developed.
More xylem and phloem patches.

Internal Structure of Stem

The stem provides support, conducts water and food, and may store nutrients.

Dicot Stem

Epidermis: Protective outer layer with a cuticle.
Cortex: Includes collenchyma (support) and parenchyma (storage).
Endodermis: Stores starch and is called the starch sheath.
Pericycle: Sometimes includes sclerenchyma fibres.
Vascular Bundles: Arranged in a ring. Each bundle is open (has cambium for secondary growth).
Pith: Present at the centre.

Monocot Stem

No distinct cortex or pith; the ground tissue is undifferentiated.
Vascular bundles are scattered and closed (no cambium).
Surrounded by the bundle sheath.

Internal Structure of Leaf

Leaves are the site of photosynthesis. Their internal layout supports gas exchange, light absorption, and water transport.

Dorsiventral Leaf (Typical Dicot Leaf)

Upper Epidermis: Covered with cuticle, no stomata.
Mesophyll: Two layers –
- Palisade: Closely packed, chlorophyll-rich cells.
- Spongy: Loosely packed with air spaces.
Vascular Bundles: Surrounded by a bundle sheath.
Lower Epidermis: Has more stomata for gas exchange.

Isobilateral Leaf (Monocot Leaf)

Both surfaces have cuticles and an equal number of stomata.
Mesophyll is not differentiated into palisade and spongy types.
Bulliform cells help the leaf roll in dry conditions.

Quick Comparison Table

Feature	Dicot Root	Monocot Root	Dicot Stem	Monocot Stem	Dicot Leaf	Monocot Leaf
Vascular Bundles	Fewer, radial	Many, radial	Ringed, open	Scattered, closed	Reticulate veins	Parallel veins
Pith	Small	Large	Large	Reduced/absent	Palisade + Spongy	Undifferentiated
Stomata	Mostly lower	Both surfaces	Present	Present	Lower epidermis	Both sides

Box to Remember

Dicot Root → Fewer vascular bundles, small pith
Monocot Root → Many vascular bundles, large pith
Dicot Stem → Vascular bundles in a ring, open type
Monocot Stem → Scattered bundles, closed type
Dicot Leaf → Dorsiventral with differentiated mesophyll
Monocot Leaf → Isobilateral with undifferentiated mesophyll

Summing Up

The internal structure of the root, stem, and leaf differ between dicots and monocots. But each is uniquely designed to support the plant’s life. Each tissue has a role to play:

Transporting water
Storing food
Performing photosynthesis

Understanding these structures helps build a strong foundation in plant anatomy and function.

FAQs

Q1. What are the basic plant anatomy parts?

The basic plant anatomy parts are roots, leaves, stems, flowers, fruits, and seeds.

Q2. What are the three internal structures of the stem?

The three internal structures of a plant stem are the vascular tissue, ground tissue, and epidermis.

Q3. What are the internal structures of the leaf?

The internal structure of a leaf includes the upper and lower epidermis, mesophyll (palisade and spongy layers), vascular bundles, bundle sheath, and stomata for gas exchange and photosynthesis.