CHT Plant Physiology & Growth 1 — Questions and Answers
Question 1: Which plant hormone is primarily responsible for promoting cell elongation and is produced in the apical meristem?
- Cytokinin
- Auxin (Correct answer)
- Gibberellin
- Abscisic acid
Correct answer: Auxin
Auxin (IAA) is produced in apical meristems and promotes cell elongation by loosening cell walls, driving stem extension.
Question 2: What is transpiration in plants?
- The absorption of water through roots
- The transport of sugars through phloem
- The loss of water vapor through stomata and leaf surfaces (Correct answer)
- The conversion of CO2 into glucose
Correct answer: The loss of water vapor through stomata and leaf surfaces
Transpiration is the process by which plants release water vapor, primarily through stomata, driving water uptake from the soil.
Question 3: Which organelle is the primary site of photosynthesis in plant cells?
- Mitochondria
- Nucleus
- Vacuole
- Chloroplast (Correct answer)
Correct answer: Chloroplast
Chloroplasts contain chlorophyll and are the organelles where light energy is captured and converted into chemical energy (glucose).
Question 4: What is the term for the seed dormancy-breaking process that requires exposure to cold, moist conditions?
- Vernalization
- Scarification
- Stratification (Correct answer)
- Etiolation
Correct answer: Stratification
Cold stratification mimics winter conditions and breaks physiological dormancy in seeds of many temperate species.
Question 5: Which macronutrient is most critical for vegetative (leaf) growth and gives plants their green color?
- Phosphorus
- Potassium
- Nitrogen (Correct answer)
- Calcium
Correct answer: Nitrogen
Nitrogen is a key component of chlorophyll and amino acids, making it essential for lush vegetative growth.
Question 6: What is osmosis in the context of plant physiology?
- Movement of minerals through xylem against gravity
- Passive movement of water across a semipermeable membrane from low to high solute concentration (Correct answer)
- Active transport of sugars into phloem cells
- Diffusion of CO2 into leaf cells through stomata
Correct answer: Passive movement of water across a semipermeable membrane from low to high solute concentration
Osmosis drives water into root cells and maintains turgor pressure by moving water from areas of low solute concentration to high solute concentration.
Question 7: Which process in plant respiration breaks down glucose to release energy in the absence of oxygen?
- Aerobic respiration
- Photorespiration
- Anaerobic fermentation (Correct answer)
- Transpiration
Correct answer: Anaerobic fermentation
Anaerobic fermentation (anaerobic respiration) allows plants to produce limited ATP without oxygen, though it yields ethanol and CO2 as byproducts.
CHT Plant Physiology & Growth 1
Which plant hormone is primarily responsible for promoting cell elongation and is produced in the apical meristem?