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NEET 2022 · BiologyPrevious Year Question

The gaseous plant growth regulator is used in plants to:

Answer: (B) Promote root growth and root hair formation to increase the absorption surface. Answer: (B) Promote root growth and root hair formation to increase the absorption surface.

  1. A.Speed up the malting process
  2. B.Promote root growth and root hair formation to increase the absorption surface✓
  3. C.Help overcome apical dominance
  4. D.Kill dicotyledonous weeds in the fields

Correct Answer

(B) Promote root growth and root hair formation to increase the absorption surface

Solution & Explanation

Answer: (B) Promote root growth and root hair formation to increase the absorption surface. Solution: The gaseous PGR ethylene promotes root growth and root hair formation, thereby increasing the absorption surface of the plant. Speeding up malting is a GA3 effect, overcoming apical dominance is a cytokinin effect, and killing dicot weeds is a 2,4-D (auxin) effect, so those options are wrong. NCERT: Ch 13, p.177, line ~28: "Ethylene also promotes root growth and root hair formation".

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