Plant Hormones: Auxin
Indole-3-acetic acid (IAA) predominantly promotes which process?
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About This Question
- Subject
- biology
- Chapter
- plant physiology
- Topic
- plant hormones: auxin
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
Cell elongation
- IAA (Auxin): The most common naturally occurring auxin in plants.
- Acid Growth Hypothesis: Auxin stimulates proton pumps in the cell membrane, which pump H+ into the cell wall. The resulting acidity activates enzymes (expansins) that loosen the cellulose fibers.
- Result: Turgor pressure then causes the cell to expand, leading to cell elongation, particularly in stems.
- Other Effects: Auxin also promotes apical dominance, root initiation, and prevents premature fruit/leaf drop.
This medium difficulty biology question is from the chapter plant physiology, covering the topic of plant hormones: auxin. It appeared in the 2025 exam.
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