Question

Differentiate between root apex and shoot apex.

Answer 1

The root and shoot apices are the extreme ends of the plant where meristematic tissue is present and constantly dividing to help the plant grow. As the tissues are present in two different sections of the plant, their functions are also different.

Complete step by step answer:
The differences are as follows:

Root Apex	Shoot Apex
The apical region of the root is the root apex. It is short in length, less than $1 \ ㎜$.	The apical region of the shoot is the shoot apex. It is relatively larger, around $1 \ ㎝$ in length.
It is negatively phototropic and positively geotropic.	It is positively phototropic and negatively geotropic.
The apical meristem is sub-terminal in position due to the presence of the root cap.	The apical meristem is truly terminal in position.
It is protected by a root cap.	It is protected by a crown of juvenile leaves.
It is hemispherical or cup-shaped in outline.	It is dome-shaped in outline.
Leaf primordia are absent. The primordia of branches develop much beyond the root apex.	Primordia are present and develop in the axils of leaves in the region of the apex.
A quiescent center is present and surrounds the root apex.	A quiescent center is absent.
The organization can be explained on the basis of the histogen theory.	The organization can be explained on the basis of the tunica corpus theory.
Nodes and internodes are not formed.	Nodes and internodes are produced alternatively.
No changes occur during the reproductive phase.	Changes occur during the reproductive phase.

Additional Information:
- Plants continue to grow throughout their life, unlike animals due to the presence of meristematic tissue.
- The meristematic cells are characterized by dense cytoplasm and relatively few small vacuoles.
- The types of primary meristems are - the protoderm (epidermis); the ground meristem(ground tissues) that include parenchyma, collenchyma, and sclerenchyma cells; and the procambium,(vascular tissues) that include xylem and phloem.

Note:
- Meristematic cells also help the cells of the root cap as they shed. The calyptrogen is the internal layer of meristematic tissue that adds the new cells.
- Some cells are known as initials that maintain the meristem and continue to function as meristematic in nature. They may undergo mitosis (cell division) several times before differentiating into the specific cells required for a root or shoot growth.