Question

Look at figure and find the position of xylem in the vascular bundle.

Answer 1

Part 1: Definition of dorsiventral leaf
Dorsiventral leaves are majorly found in dicot plants. In such leaves the structure varies from upper to lower surface.

Part 2: Internal structures of dorsiventral leaf
The internal structures of dorsiventral leaf are, epidermis, mesophyll and vascular system.

Part 3 : Epidermis
The outermost layer of the leaf is called epidermis. The upper (adaxial) and lower (abaxial). The upper epidermis consists of very less or no stomata, whereas the number of stomata is more in the lower epidermis. This arrangement of stomata in the dorsiventral leaves reduces the loss of water due to transpiration.

Part 4: Mesophyll
The parenchymatous cells present between the upper and lower epidermis in a dorsiventral leaf are called mesophyll cells. These cells play a major role in the process of photosynthesis. There are two types of mesophyll cells - palisade parenchyma and spongy parenchyma. Palisade parenchyma :Elongated mesophyll cells, which are located near the upper epidermis. Spongy parenchyma : Irregular shaped cells that are loosely arranged towards the lower epidermis.

Part 5 : Vascular system
Vascular system is a means of transport in vascular plants. They help in transporting water, minerals and various organic substances throughout the plant’s body.
In dicot leaf xylem and phloem are the two vascular structures helping in the transportation of water and minerals. They are arranged as follows inside the bundle sheath :

1. Xylem is present towards the upper epidermis.
2. Phloem is present towards the lower epidermis