Question

Which of the following statements is NOT true for stomatal apparatus?

• A. Guard cells invariably possess chloroplasts and mitochondria.
• B. Guard cells are always surrounded by subsidiary cells.
• C. Stomata are involved in gaseous exchange.
• D. Inner wall of guard cells are thick.

Answer 1

The correct option is

B

Guard cells are always surrounded by subsidiary cells.

The epidermal surface of the leaf exhibits 1,000 to 60,000 minute openings called stomata. The stomata are bordered by two specialized epidermal cells, called the guard cells which, only in some cases, are accompanied by subsidiary cells. The walls of guard cells are unevenly thickened. Each guard cell has a thick, inelastic inner wall and a thin, elastic outer wall. Stomatal aperture is present in between the guard cells.

Figure : Guard cells