Which of the following facilitates opening of stomatal aperture?
Correct answer: B. Radial orientation of cellulose microfibrils in the cell wall of guard cells
- A. Decrease in turgidity of guard cells
- B. Radial orientation of cellulose microfibrils in the cell wall of guard cells
- C. Longitudinal orientation of cellulose microfibrils in the cell wall of guard cells
- D. Contraction of outer wall of guard cells
Explanation
When turgidity increases within the two guard cells flanking each stomatal aperture or pore, the thin outer wall bulge out and force the inner walls into a crescent shape. This results in the opening of stomata. The opening of stomata is also aided by the radial orientation of cellulose microfibrils in the cell wall of guard cells rather than longitudinal orientation. Decrease in turgidity closes the stomata. Radial orientation of cellulose microfibrils in the cell wall of guard cells causes opening of stomata. Contraction causes decrease in turgidity hence closing of stomata. So option B is correct.
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