alleryWhich ions enter guard cells to help open stomata?
- Sodium ions
- Potassium ions
- Calcium ions
- Iron ions
Show answer and solution
Correct answer: B. Potassium ions
Potassium uptake increases solute concentration in guard cells, helping water enter.
ICSE Class 10 Plant Physiology — practice questions — page 4
Explore 212 free Plant Physiology questions in ICSE Class 10 Biology. Open each question or exercise to read its content, reference answers and available explanation.
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Showing questions 91–120 of 212.
Which ions enter guard cells to help open stomata?Read the answer and worked solution →What happens when potassium leaves guard cells?Read the answer and worked solution →Which hormone helps close stomata during drought?Read the answer and worked solution →What does stomatal closure during drought help reduce?Read the answer and worked solution →What surrounds each stoma and helps control it?Read the answer and worked solution →How are guard cells arranged around a pore?Read the answer and worked solution →Which side of a guard cell is thicker?Read the answer and worked solution →Why does a turgid guard cell bend outward?Read the answer and worked solution →What is transpiration stream water replaced by?Read the answer and worked solution →What does cavitation do to xylem water transport?Read the answer and worked solution →When may cavitation occur?Read the answer and worked solution →What can a plant do overnight to help refill cavitated xylem?Read the answer and worked solution →What is the source of water that exits through stomata?Read the answer and worked solution →What can close stomata when water loss exceeds root uptake?Read the answer and worked solution →What does closing stomata trade off during drought?Read the answer and worked solution →A high humidity gradient at a leaf pore helps determine what?Read the answer and worked solution →Where is water vapour inside a leaf before it exits?Read the answer and worked solution →How does transpiration affect plant nutrient flow?Read the answer and worked solution →Which structural adaptation helps desert plants reduce water loss?Read the answer and worked solution →Why do open stomata cause gas gain and water loss?Read the answer and worked solution →What did van Helmont observe about soil as a potted plant grew?Read the answer and worked solution →Priestley found that a plant could restore air that had been:Read the answer and worked solution →What did Ingenhousz show was needed for a plant to revive air?Read the answer and worked solution →What did Senebier show green plants do in light?Read the answer and worked solution →What did de Saussure identify as another input to plant growth besides CO2?Read the answer and worked solution →What did radioactive-isotope studies identify as the source of released O2?Read the answer and worked solution →In Hill’s test, illuminated isolated chloroplasts released which gas?Read the answer and worked solution →What did Hill add to isolated chloroplasts in the light reaction?Read the answer and worked solution →Which scientists traced photosynthetic oxygen to water?Read the answer and worked solution →What source supplies electrons for green-plant oxygenic photosynthesis?Read the answer and worked solution →
Worked practice questions
What happens when potassium leaves guard cells?
- Water enters the root hair
- Stomatal pores widen
- Stomatal pores close
- The leaf begins mitosis
Show answer and solution
Correct answer: C. Stomatal pores close
Potassium release draws water out and causes stomatal closure.
Which hormone helps close stomata during drought?
- Auxin hormone
- Gibberellin
- Cytokinin
- Abscisic acid
Show answer and solution
Correct answer: D. Abscisic acid
Abscisic acid is produced in response to drought and triggers stomatal closure.
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