Question

Choose the correct combination of labelling of stomatal apparatus of dicot and monocot leaves.

• A. a- epidermal cells, b- subsidiary cells, c- chloroplast, d- guard cells, e- stomatal aperture
• B. a- epidennal cells, b- guard cells, c- chloroplast, d- subsidiary cells, e- stomatal aperture
• C. a- epidermal cells, b- subsidiary cells, c- chloroplast, d- stomatal aperture, e- guard cells
• D. a- subsidiary cells, b- epidermal cells, c- chloroplast, d- stomatal aperture, e- guard cells
• E. a- guard cells, b- epidennal cells, c- stomatal aperturet, d- subsidiary cells, e- chloroplast

Answer 1

Answer: (A)

a- epidermal cells, b- subsidiary cells, c- chloroplast, d- guard cells, e- stomatal aperture

Epidermal cells are on the upper and lower surfaces of a leaf. They have two features which prevent evaporative water loss: they are packed densely together and they are covered by a cuticle, a waxy layer secreted by the cells. The epidermis usually consists of a single layer of cells, although the specialized leaves of some desert plants have epidermal layers which are several cells thick. In plants, a specialized cell on the under surface of leaves for controlling gas exchange and water loss. Guard cells occur in pairs and are shaped so that a pore, or stomata, exists between them. They can change shape with the result that the pore disappears. During warm weather, when a plant is in danger of losing excessive water, the guard cells close, cutting down evaporation from the interior of the leaf.

Subsidiary cells- The stoma are protected by subsidiary cells that have papillae that arch across the stoma, creating a mini-depression. This will tend to retain escaped water, giving it time to diffuse back into the stoma instead of being immediately blown away by a breeze. Stoma (plural stomata) is a pore, found in the epidermis of leaves, stems and other organs that is used to control gas exchange. The pore is bordered by a pair of specialized parenchyma cells known as guard cells that are responsible for regulating the size of the opening. Chloroplast is a green coloured pigmented organelles found in leaves.

Thus, the correct answer is option A.