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Let us look at what meristematic tissues are.
Take 2 onions and put them in 2 separate jars as shown below
Observe how the roots grow each day for 3 days
Now, cut the root tips of the onion in both the jars and observe the growth for another 3 days.
What do you observe?
We observe that plant growth is restricted to certain regions , in this case, the roots.
This is because the dividing tissues responsible for growth is present only in these regions
These dividing tissues are called meristematic tissues .
Characteristics of meristematic tissues
|
Characteristic |
Remarks |
|
Structure |
All cells are similar with thin cell wall made of cellulose |
|
Shape |
Spherical, oval, polygonal, rectangular |
|
Cellular arrangement |
Compact without intercellular space (no space between cells) |
|
Cellular content |
They have dense cytoplasm and single large nucleus Few or no vacuoles at all |
|
Position |
Tips of roots and shoot, bark or stem, base of leaves etc. |
Based on their positions, meristematic tissues can be classified further.
Types of Meristematic tissues based on positions
Apical Meristem
- They are present at the growing apices (tips) of stems and roots and sometimes leaves as well
- They increase the length of the roots and shoot
- This results in increase in height of the plant
- This is called primary growth
2. Lateral Meristem
- They are also called Cambium
- They increase the girth or thickness of the root or bark/ stem
- This is called secondary growth
3. Intercalary Meristem
- It is present at the base of the leaves or internodes (on either side of the node) on twigs
- It increases the length of an organ like internode or leaves
