Internal Structure of Dicot Leaf Notes | Free Biology Notes

This article we will discuss about Internal Structure of dicot leaf

The transverse section of a Dicot leaf reveals the following structures

Epidermis

• A dicot leaf is generally dorsiventral
• It has upper and lower epidermis

I) upper epidermis

• Outermost layer present on the upper side of the leaf
• Upper epidermis is made up of a single layer of parenchymatous cells without intercellular spaces
• Thick cuticle layer is present on the upper epidermis
• Stomata are generally absent in the upper epidermis

II) lower epidermis

• Outermost layer present on the lower side of the leaf
• It is a single layer, parenchymatous & covered with cuticle
• Stomata are more on lower epidermis
• Chloroplasts present only guards cells of the epidermis
• Function of epidermis
  • Protective layer
  • Exchange of gases
  • Facilitates the transpiration

Mesophyll tissue

• Present between upper and lower epidermis, there is an entire mass of ground tissue called mesophyll
• Consists of two different kinds of parenchyma cells

I) Palisade parenchyma

• Present below the upper epidermis
• Elongated parenchyma cells as they have more chloroplasts
• Helps in the process of photosynthesis

II) Spongy parenchyma

• Present below the palisade parenchyma tissue
• They are arranged irregularly with intercellular spaces
• Helps in gaseous exchange

Vascular bundle

• Vascular bundles occur at the midrib and veins of the leaf
• Vascular bundle is collateral and closed
• Vascular bundle consists of xylem and phloem
• They are surrounded by parenchyma is bundle sheath
• Functions of vascular bundle: conduct water and food materials