Which of the following statement is correct?a)The collenchyma occurs i...
Sclerenchyma cells are usually dead and without protoplasts because they characteristically very thick , hard secondary walls lined with lignin ; consequently , sclerenchyma provide additional support and strength to the plant body .
Which of the following statement is correct?a)The collenchyma occurs i...
**Statement b) Sclerenchyma cells are usually dead and without protoplasts.**
**Explanation:**
**1. Introduction to Sclerenchyma Cells:**
Sclerenchyma is a type of plant tissue that provides mechanical support and strength to the plant. It is composed of cells with thick, lignified cell walls.
**2. Characteristics of Sclerenchyma Cells:**
- Sclerenchyma cells are usually dead at maturity.
- They have thick, secondary cell walls that are heavily lignified.
- These walls provide rigidity and strength to the cells, allowing them to withstand mechanical stress.
- Sclerenchyma cells lack living protoplasts at maturity, meaning they have no cytoplasm or cellular contents.
**3. Structure and Types of Sclerenchyma Cells:**
There are two main types of sclerenchyma cells: fibers and sclereids.
- Fibers: These are long, slender cells with tapered ends. They occur in bundles and provide strength and support to plant tissues. Examples include the fibers found in the phloem of vascular bundles and the fibers in the hard shell of a coconut.
- Sclereids: These are short, irregularly shaped cells that occur in various plant organs. They provide mechanical protection and support. Examples of sclereids are found in the seed coats of nuts and the hard shells of fruits like pears and apples.
**4. Function of Sclerenchyma Cells:**
Sclerenchyma cells provide mechanical support to the plant by:
- Strengthening the plant's structural framework.
- Providing rigidity to tissues and organs.
- Preventing collapse or deformation under mechanical stress.
**5. Conclusion:**
In conclusion, statement b) is correct. Sclerenchyma cells are usually dead and lack protoplasts. They have thick, lignified cell walls that provide mechanical support and strength to the plant.
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