Question

In majority of plants, the guard cells are

• A. Dumb-bell shaped
• B. Reniform
• C. Rounded
• D. Polygonal

Answer 1

The correct option is B Reniform

Stomata are small openings on the leaves which help in transpiration and gaseous exchange. The cells of stomata are known as guard cell. The guard cells are bean or kidney-shaped in surface view so it is known as reniform which literally means kidney-shaped.

Kidney-shaped guard cells are found in dicotyledons whereas dumb-bell-shaped guard cells are found in grasses. Dumb-bell shaped guard cells are more advanced in evolutionary terms and more efficient physiologically because guard cells of grasses require fewer solutes and less water to achieve a given unit increase in aperture.

So, the correct answer is option B.