The document describes the structure of a leaf, including the upper and lower epidermis, palisade and spongy mesophyll layers, stomata, and vascular bundles. The upper epidermis has a waxy cuticle and protects the leaf from water loss. The palisade mesophyll below contains chloroplasts and carries out photosynthesis by being located on the upper surface near sunlight. The lower spongy mesophyll contains loosely packed cells that facilitate gas exchange near the stomata on the underside of the leaf. Vascular bundles in the center transport water and photosynthates throughout the leaf.
1. Structure of Leaf
Dr Mehak
Assistant Professor
Department of Science
Khalsa College for Women
Amritsar
2. • Upper Epidermis
Function: Main function is
water conservation (secretes
cuticle to create a waxy
outer boundary)
Distribution: On top of
leaves where light intensity
and heat are greatest
3. • Palisade mesophyll is the
site of photosynthesis
contains many
chloroplasts) and hence is
located on the upper
surface of the leaf (facing
sunlight)
Palisade mesophyll
4. Spongy mesophyll
Spongy mesophyll is the main
site of gas exchange (made of
loosely packed cells with
spaces) and is hence located
on the lower surface of the leaf
(near stomata)
5. • Function: control the exchange of
gases—most importantly water
vapour and CO2 — between the
interior of the leaf and the
atmosphere
• Distribution: Stomata are on the
underside of the leaf
Stomata
6. Vascular
bundle
Function: Transport of water
(xylem) and the products of
photosynthesis (phloem)
Distribution: Found in middle
of leaf to allow for optimal
access by all leaf cells
