Organs of Water Uptake and Mineral Salts

Organ for Water and Mineral Salts Uptake

3.2

Organ for Water and Mineral Salts Uptake

The Important of Root

Rroots are involved directly in plant growth.
Organ of mineral and water uptake in root.
There are two main functions of roots:
- Provide support and strength to anchor the plant in the soil.
- Absorb water and mineral salts from the soil and transport them to the stem and leaves.

The External Structure of Roots and Their Functions
Structures	Functions
Root collar	Part of the root connected to the base of the plant stem.
Root hairs	Adapted from epidermal cells of the roots. Increases the total surface area of the roots to increase the uptake of water and mineral salts.
Root cap	Located at the tip of the root. Protects the root from damage when going through the soil.

The Internal Structure of Roots and Their Function
Structures	Function
Epidermis	Epidermal cells are closely arranged. Thin cell walls and water-permeable cell membranes facilitate water movement in the roots. There are epidermal cells which form root hairs by elongating towards lateral sides from the outer walls. Root hair cells are not layered with cuticle to allow water absorption. The root hair cells also have big vacuoles to store water and mineral salts to increase water absorption.
Cortex	Cortex is located under the epidermal layer. Has thin cell walls, facilitating water movement in the roots. The cells are loosely arranged to facilitate gaseous exchange. Most of the cortex consists of parenchyma cells.
Endodermis	Separating layer between cortex and vascular cylinder. Endodermal cells are closely arranged and one cell thick. Most of the endodermal cells have suberin or lignin thickening at the walls which form Casparian strips. Endodermis allows water and mineral salts absorbed from the soil to enter the vascular cylinder, but not air bubbles.
Vascular cylinder	Vascular cylinder is the root core that consists of xylem and phloem tissues surrounded by one cell thick pericycle cell tissues. Pericycle is involved in secondary growth and the formation of lateral roots. Usually, xylem and phloem tissues are arranged in a star-shaped pattern. Xylem tissue transports water and mineral salts, whereas phloem tissue transports organic substances such as sucrose and plant hormone.

Organ for Water and Mineral Salts Uptake

3.2

Organ for Water and Mineral Salts Uptake

The Important of Root

Rroots are involved directly in plant growth.
Organ of mineral and water uptake in root.
There are two main functions of roots:
- Provide support and strength to anchor the plant in the soil.
- Absorb water and mineral salts from the soil and transport them to the stem and leaves.

The External Structure of Roots and Their Functions
Structures	Functions
Root collar	Part of the root connected to the base of the plant stem.
Root hairs	Adapted from epidermal cells of the roots. Increases the total surface area of the roots to increase the uptake of water and mineral salts.
Root cap	Located at the tip of the root. Protects the root from damage when going through the soil.

The Internal Structure of Roots and Their Function
Structures	Function
Epidermis	Epidermal cells are closely arranged. Thin cell walls and water-permeable cell membranes facilitate water movement in the roots. There are epidermal cells which form root hairs by elongating towards lateral sides from the outer walls. Root hair cells are not layered with cuticle to allow water absorption. The root hair cells also have big vacuoles to store water and mineral salts to increase water absorption.
Cortex	Cortex is located under the epidermal layer. Has thin cell walls, facilitating water movement in the roots. The cells are loosely arranged to facilitate gaseous exchange. Most of the cortex consists of parenchyma cells.
Endodermis	Separating layer between cortex and vascular cylinder. Endodermal cells are closely arranged and one cell thick. Most of the endodermal cells have suberin or lignin thickening at the walls which form Casparian strips. Endodermis allows water and mineral salts absorbed from the soil to enter the vascular cylinder, but not air bubbles.
Vascular cylinder	Vascular cylinder is the root core that consists of xylem and phloem tissues surrounded by one cell thick pericycle cell tissues. Pericycle is involved in secondary growth and the formation of lateral roots. Usually, xylem and phloem tissues are arranged in a star-shaped pattern. Xylem tissue transports water and mineral salts, whereas phloem tissue transports organic substances such as sucrose and plant hormone.