Model, T. S. Dicot Root

Quick Answer: The model, T.S. dicot root, is an enlarged transverse section of a young dicotyledonous root, such as that of gram or sunflower, showing its tissues from the outer layer to the centre. A dicot root model helps students identify the endodermis, the pericycle and the radial arrangement of xylem and phloem.

From Root Hair to Xylem

The outermost layer of a young root is the epiblema, or rhizodermis, a single layer without cuticle, some of whose cells extend into root hairs that absorb water and minerals. Inside it is a wide cortex of thin-walled parenchyma cells with air spaces, which stores food and passes water inwards.

The innermost cortical layer is the endodermis: barrel-shaped cells whose radial and transverse walls carry the Casparian strip, a band of suberin that forces water and dissolved minerals to pass through living cells rather than between them. Opposite the xylem, thin-walled passage cells let water through. Inside lies the pericycle, from which lateral roots arise and which, in dicots, helps form the vascular cambium.

The vascular bundles are radial, with separate groups of xylem and phloem alternating round the centre. A dicot root usually has two to four xylem groups (diarch to tetrarch), with the protoxylem on the outside (exarch), and a small pith or none. Format and size are not stated; the T.S. monocot root model shows the contrasting polyarch arrangement.

Root Anatomy Lessons

• Root anatomy and the path of water from soil to xylem
• The role of the Casparian strip in controlling mineral uptake
• The origin of lateral roots from the pericycle
• Distinguishing dicot and monocot roots in practical spotting tests

Care & Handling

• Hold the dicot root model by its frame or edges and do not rest other objects on its face.
• Clean it with a dry brush; moisture can damage the painted cell walls.
• Store it out of sunlight so the tissue colours stay distinct.

Specifications

Why Choose LabEquip

Schools and colleges teaching plant anatomy usually buy the dicot and monocot root sections as a pair for spotting practice. LabEquip includes this model in its biology lab products, and a dicot root structure chart carries the same labels. Ask for quantities through the contact page.

Frequently Asked Questions

What is the Casparian strip?

The Casparian strip is a waterproof belt of suberin, with some lignin, running round the radial and transverse walls of every endodermal cell. It blocks water moving between cells, so water and minerals must cross cell membranes, which lets the root control which ions enter the xylem.

Why are the xylem and phloem arranged radially in a root?

In roots, xylem and phloem form separate strands on different radii, alternating around the centre. This differs from stems, where xylem and phloem lie together on the same radius in conjoint bundles.

What does exarch xylem mean?

Exarch means the first-formed protoxylem lies towards the outside and the later metaxylem towards the centre. It is characteristic of roots, while stems have endarch xylem.

How can a dicot root be told from a monocot root?

A dicot root usually has two to four xylem groups and a small or absent pith, and it can undergo secondary growth. A monocot root has many xylem groups, often more than six, and a large central pith.

What is the job of the pericycle?

The pericycle is the layer just inside the endodermis. Lateral roots originate from it, and in dicot roots it also contributes to the vascular cambium and the cork cambium during secondary growth.

Do root cells contain chloroplasts?

Normally no. Roots grow in darkness, so their cortex cells store starch rather than carrying out photosynthesis. Some aerial and aquatic roots are exceptions.

Last Updated: September 2026