Question

It is difficult to pull out the husk of a coconut tree due to
a. Presence of parenchyma
b. Presence of sclerenchyma
c. Presence of collenchyma
d. Presence of aerenchyma

Answer 1

Hint: Sclerenchyma tissue is one of the ground tissues of the plant. It is referred to as strengthening tissues of the plant. The cell walls are divided into the primary and secondary cell walls. The cell walls consist of cellulose, hemicellulose, and lignin. The secondary cell wall is highly lignified which imparts hardening of the tissue.

Complete answer:
- Parenchyma cells are thin-walled, flexible, and loosely packed cells. They are often alive at maturity. Their shape changes as per function. They are filler tissue in the soft parts of a plant.
- Collenchyma cells are thin-walled with some areas of secondary thickening. They provide extra structural support to plants. Coconut husk is not made of collenchymatous cells.
- Parenchyma cells have large air cavities to give buoyancy to the plant and enable them to float in water. Such parenchyma cells are called aerenchyma and are found in aquatic plants.
- Sclerenchyma is dead, long, thin narrow cells. Walls of sclerenchyma are lignified, which make them thick. This tissue makes the plant hard and stiff. Coconut husk is very hard and is made of such thickened, lignified cells. Such cells make it very hard to pull out the coconut husk.
- Intercellular spaces in sclerenchyma are absent because they have lignin around which makes them hard.
- Sclerenchyma in plants supports tissue composed of any of various kinds of hard woody cells. The mature sclerenchyma cells are dead cells that have heavily thickened secondary walls containing lignin. The cells are rigid and are usually found in non-growing regions of plant bodies, such as the bark or mature stem.
- Sclerenchyma cells have two types of cell walls: primary and secondary walls. The secondary wall is very thick and highly lignified (15%–35%) and imparts a great rigidity and hardness to the cell and tissue.
- Sclerenchyma cells occur in many different shapes and sizes, but two main types are fibers and sclereids.
- Fibers are elongated cells whose long, tapering ends interlock, thus providing maximum support to a plant.
- Scleritis is variable in shape and are present in various tissues of the plant, such as the xylem, and phloem
- So, it is difficult to pull out the husk of a coconut tree due to the Presence of Sclerenchyma.

Hence, the correct answer is option (B).

Note: The ground tissue of plants includes all tissues that are neither dermal nor vascular. It is divided into three types based on the nature of the cell walls. Parenchyma cells, Collenchyma cells, Sclerenchyma cells Sclerenchyma cells have thick lignified secondary walls and often die when mature provides the main structural support to a plant.
The cells are important for strengthening and supporting elements in plant parts that have ceased elongation.