Opening and closing of stomata is due to the:
Correct answer: B. Change in turgor pressure of guard cells
- A. Hormonal signals affecting guard cells
- B. Change in turgor pressure of guard cells
- C. Role in gaseous exchange
- D. Impact of plant respiration
Explanation
The correct answer is that the opening and closing of stomata are driven by changes in the turgor pressure of guard cells (Option B). When guard cells absorb water, they become turgid, causing the stomatal pores to open. Conversely, when they lose water, they become flaccid, leading to the closure of the pores. Option A, concerning hormonal signals, does play a regulatory role but does not directly cause the movement. Options C and D, which mention gaseous exchange and plant respiration, describe processes facilitated by stomata but do not influence their opening and closing directly.
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About Forms and Functions of Plants
Plant nutrition and transport cover mineral uptake, photosynthesis, xylem movement of water and minerals, and phloem translocation of sugars. Plant growth regulators include auxins, gibberellins, cytokinins, abscisic acid and ethene, whose effects on cell division, elongation, dormancy, fruit ripening and tropic responses should not be confused with mineral nutrition.
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