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प्रश्न
List the characteristics of cork. How are they formed? Mention their role.
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उत्तर
Cork covers the old stems of woody trees. Characteristics of cork are as follows:
- Cells of cork are dead at maturity.
- These cells are compactly arranged.
- Cells do not possess intercellular spaces.
- Cells possess chemical substance suberin in their walls.
- They are several layers thick.
- Cork is impervious to gases and water.
As plants grow older, a strip of the secondary lateral meristem (called cork cambium) develops in the cortical region. It cuts cells towards both outer and inner sides. Gradually, this secondary tissue replaces the epidermal layer of the stem. This forms the several-layer thick cork.
The role of cork is as follows:
- It protects the internal tissues from mechanical injury and from parasitic attacks.
- It contains small pores (called lenticels) for gaseous exchange.
- It provides mechanical strength.
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