Roots exhibit negative phototropism.To demonstrate the reason of this phenomenon, the roots of a potted plant are placed parallel tothe soil. The result shows that auxin gathers in the
Correct answer: B. lower half of the root and slows down the growth.
- A. lower half of the root and stimulates growth.
- B. lower half of the root and slows down the growth.
- C. upper half of the root and slows down the growth.
- D. Upper half of the root and stimulates growth
Explanation
In a root placed horizontally, the bottom side contains more auxin and grows less, causing the root to move away from light. So option B is correct. All other options are incorrect.
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About Plant Growth Regulators
Plant growth regulators are chemical messengers that control growth, development and responses to the environment. The topic covers auxins, gibberellins, cytokinins, abscisic acid and ethylene, including cell elongation, apical dominance, tropisms, seed germination, dormancy, fruit ripening and leaf fall, with growth promoters distinguished from inhibitors.
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