Why do new plants arise from nodes and not from internodes?

New plants arise from nodes rather than from internodes due to the presence of meristematic tissue at the nodes. Meristematic tissue is responsible for the growth and development of plants. It consists of undifferentiated cells that have the ability to divide and differentiate into various types of plant tissues.

Nodes and internodes
- Nodes are the points on a stem where leaves, branches, or buds arise.
- Internodes are the segments of the stem between two consecutive nodes.

Meristematic tissue
- Meristematic tissue is found at the nodes and is responsible for the growth and development of plants.
- It contains actively dividing cells that give rise to new cells, which further differentiate into various types of plant tissues.
- Meristems are responsible for both primary and secondary growth in plants.

Types of meristems
1. Apical meristem:
- Present at the tips of stems and roots.
- Responsible for the elongation of the plant body.
- It helps in the growth of the plant in length.
- Primary growth occurs due to the activity of apical meristems.

2. Lateral meristem:
- Found in the cambium region of stems and roots.
- Responsible for the thickening of the plant body.
- It helps in the growth of the plant in girth or diameter.
- Secondary growth occurs due to the activity of lateral meristems.

Reason for new plants arising from nodes
- Nodes contain meristematic tissue, which is responsible for cell division and differentiation.
- Meristematic cells at the nodes give rise to new shoots, roots, or buds.
- These meristematic cells divide and differentiate into new plant parts.
- The presence of meristematic tissue at the nodes ensures the continuous growth and development of the plant.

Importance of nodes in plant propagation
- Nodes are essential for vegetative propagation, where new plants are produced from the existing plant without involving seeds.
- Stem cuttings, where a portion of the stem with one or more nodes is used to grow a new plant, rely on the ability of nodes to produce roots and shoots.
- Nodes play a crucial role in the formation of adventitious roots and shoots, which are essential for the successful establishment of new plants.

In conclusion, new plants arise from nodes rather than internodes because the nodes contain meristematic tissue, which is responsible for the growth and development of plants. The presence of meristematic tissue at the nodes ensures continuous cell division and differentiation, leading to the formation of new shoots, roots, or buds. Nodes are important for vegetative propagation and play a crucial role in the successful establishment of new plants.