Question

The grittiness of pulp of wood apple is due to
a) Macrosclereids
b) Brachysclereids
c) Osteosclereids
d) Astrosclereids

Answer 1

Hint: Sclereids are the type of sclerenchyma tissues. They are highly thickened dead cells along with very narrow cavities. They are usually found in the pulp of fruits like guava, pear; fruit wall of nuts and also in seed coats of legumes.

Complete Answer:
The important function of sclerenchyma tissue is to provide mechanical support. Types of sclereids are
1) Brachysclereids: Resemble parenchyma cells in shape, but are made of secondary cells.
 They form the "grit" and hence these non living cells are also called as stone cells

2) Macrosclereids: They are elongated sclereids usually present in the outer layer in the seed coat of legume seeds.
They are responsible for restricting water uptake by hard-seeded legumes.

3) Osteosclereids: They have columnar cells similar to macrosclereids except they are enlarged at the ends that resemble the bone. So they are also called bone cells or hour-glass cells.
Macerated pea seed coats show groups of osteosclereids.

4) Astrosclereids: They are pointed, irregular, branched sclereids. They are unique types of sclereids.
They are found in specialized tissues like the floating leaves of water lilies.

5) Trichosclereids: These types of cells are long and tubular in structure.
They are present in the aerial roots of the Swiss cheese plant and leaves of olive.

Hence the correct answer is (b) Brachysclereids.

Note: Presence of large quantities of sclereids in the plants forms the core of the fruits as well as they are responsible for the gritty texture.