Ques. 1AIPMT 2003
Stomata of a plant open due to
- influx of potassium ions
- efflux of potassium ions
- influx of hydrogen ions
- influx of calcium ions
Answer
(1) influx of potassium ions
Solution
Stomata open when the guard cells become turgid.
During opening, K+ ions actively move into the guard cells (with Cl-/malate as counter-ions), lowering their water potential.
⇒ Water enters the guard cells by osmosis, their turgor rises and the thin outer walls bulge out, pulling the inner walls apart, so the pore opens.
∴ Stomata open due to influx of potassium ions.
Answer: (1)
Out of syllabus