Internal Structure of Dicot Root Notes | Free Biology Notes

This article we will discuss about Internal Structure of dicot Root

The transverse section of a Dicot Root reveals the following structures

Epiblema / rhizoderm / piliferous layer

• Outermost layer of root & composed of thin, closely packed parenchyma
• The cuticle and stomata are absent
• Epidermal cells extend out in form of tubular hairs is called root hairs
• Epiblema has following functions: uptake of water and mineral salts from the soil and provide maximum surface area for absorption

Cortex

• It is situated below the epiblema
• Cortex consists of parenchymatous cells with intercellular spaces
• Cortex has following functions: store food and
• Conduct water from epiblema to the inner tissues

Endodermis

• This layer is barrel shaped cells present between the pericycle and cortex
• Casparian strips are present on wall of endodermis
• Casparian strip is made up of suberin & lignin
• Strip acts as a water dam or check post to prevent the flow of fluids between cortex and phloem
• Endodermis cells opposite to the protoxylem are without casparian strips is called passage cells
• These cells help move water and dissolved salts from the cortex to the xylem

Pericycle

• Pericycle present below the endodermis and made up of single layer of thick walled parenchymatous cells
• It is very important layer
• Pericycle has following functions: Lateral roots in dicot arise in this tissue and cork cambium also develops from it

Vascular bundles

• Vascular bundles are radial and exarch
• Xylem and phloem are separate and equal in number
• Tetrarch condition is found ( In some plants diarch to hexarch)
• Ficus bengalensis root is polyarch
• Parenchyma which is found between the xylem and phloem is called conjunctive tissue
• Vascular bundles has following functions: conduction of water and food materials

Pith

• Young root contains pith whereas in old root pith is absent.
• In young root only a small area in the center and consists of few compactly arranged, thin-walled parenchymatous cells

• Internal Structure of Dicot Stem Notes
• Internal Structure of Monocot Stem Notes
• Internal Structure of Monocot Root Notes