ANATOMY OF DICOT LEAF!

The leaf blade is placed horizontally.

Upper surface is more strongly illuminated than lower. The anatomy is different on the two sides(upper and lower).

ADAXIAL EPIDERMIS(upper epidermis)
•single layered
•closely packed
•thick cuticle
•few or no stomata

ABAXIAL EPIDERMIS(lower epidermis)
•thin cuticle
•numerous stomata: a stomata leads to air cavity.
(Function: exchange of gases and transpiration)

MESOPHYLL TISSUE
consists of parisade parenchyma and spongy parenchyma
1) Parisade parenchyma: three layers of closely packed cylinderical cells.
2)Spongy parenchyma: oval and spherical cells in between inter-cellular spaces.
   *CHLOROPLAST is present along the walls of parisade and spongy parenchymatous cells in order to capture maximum light for photosynthesis.

VASCULAR BUNDLE
*each vein is a vascular bundle running through the mesophyll.
1)XYLEM
   •Towards the upper side
    •Contains vessels, tracheids, xylem parenchyma and xylem fibres
2)PHLOEM
  •towards the lower side
   •Contains seive tubes and   companion cells
(Patches of sclerenchyma is associated with xylem and phloem)

Vascular bundles are surrounded by layer of thin walled parenchyma called Border Parenchyma which forms the bundle sheath. Bundle sheath may show extensions towards upper and lower epidermis.