T.S. Dicot Leaf Model

Quick Answer: The model, T.S. dicot leaf, is an enlarged transverse section of a dicotyledonous leaf, showing its tissues from the upper to the lower surface. A dicot leaf model is used in botany to teach leaf anatomy, the dorsiventral arrangement of the mesophyll and how leaf structure suits photosynthesis.

Tissues of a Dorsiventral Leaf

A dicot leaf such as that of mango, sunflower or peepal is dorsiventral: its upper and lower sides differ in structure because they face the light differently. At the top, a single layer of upper epidermis coated with a waxy cuticle has few or no stomata. Below it lies the palisade mesophyll, elongated cells packed with chloroplasts and set at right angles to the surface, the main site of photosynthesis.

Beneath the palisade, the spongy mesophyll has loosely arranged, rounded cells with large air spaces that connect with the stomata in the lower epidermis, where gas exchange takes place. Veins run through the mesophyll; the midrib’s vascular bundle carries xylem on its upper side and phloem on its lower side, enclosed in a bundle sheath. The guard cells around each stoma are bean-shaped in dicots.

The title names the section and leaf type but not the format, size or plant species. For comparison with an isobilateral leaf, see the T.S. monocot leaf model.

Specifications

Model of	Transverse section (T.S.) of a dicot leaf
Leaf type	Dorsiventral
Tissues shown	Cuticle, upper and lower epidermis, palisade and spongy mesophyll, vascular bundle, bundle sheath, stomata
Level	Secondary and undergraduate botany
Species, format and size	Confirm at enquiry

Care & Handling

Handle the dicot leaf model by its edges or frame so the raised cell detail on its face is not rubbed.
Dust gently and keep it away from damp, which can lift painted layers.
Store it flat, or hang it securely, out of direct sunlight.

Botany Practical Uses

Leaf anatomy and adaptations for photosynthesis
Gas exchange through stomata and air spaces
Comparing dicot and monocot leaf structure in practical examinations
Preparing for students’ own leaf sections or epidermal peels under the microscope

Why Choose LabEquip

Botany teachers use the transverse leaf section to connect structure with photosynthesis, and often buy dicot and monocot versions together. LabEquip lists this model among its biology lab products, and the dicot leaf chart shows the same section for revision. Enquiries go through the LabEquip contact page.

Frequently Asked Questions

Why is a dicot leaf called dorsiventral?

It means the upper (adaxial) and lower (abaxial) surfaces differ. In a dicot leaf the palisade mesophyll lies under the upper epidermis and the spongy mesophyll above the lower, and most stomata are on the lower surface.

Why is the palisade layer at the top of the leaf?

It receives the most light. Its tall, tightly packed cells contain many chloroplasts, which can move within the cell to make full use of the light for photosynthesis.

Why are stomata mostly on the lower surface?

The lower surface is shaded and cooler, so less water is lost by transpiration when the stomata open. Air spaces in the spongy mesophyll then carry carbon dioxide from the stomata to the photosynthesising cells.

Which way round are xylem and phloem in a leaf vein?

In a dicot leaf the xylem faces the upper surface and the phloem faces the lower surface. It mirrors the stem, in which xylem sits on the inner side of each bundle and phloem on the outer side.

How is a dicot leaf different from a monocot leaf?

A dicot leaf is dorsiventral with distinct palisade and spongy mesophyll, reticulate venation and bean-shaped guard cells. A monocot leaf is usually isobilateral, with undifferentiated mesophyll, parallel veins and, in grasses, dumbbell-shaped guard cells.

What is the function of the cuticle?

The cuticle is a film of wax and cutin laid down over the epidermis. It cuts down evaporation and keeps out fungal spores, and on most dicot leaves it is heavier on the sunlit upper side.

Last Updated: September 2026