Q.127 Botany ⭐ 360° Option Elimination Active

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NEET 2026 Botany Question 127 Solution

Topic: Plant Growth and Development · Official NTA Booklet Code 50

Question

Which of the following plant growth regulators promotes internode elongation prior to flowering in cabbage?

(1)Abscisic acid
(2)Gibberellin
(3)Indole butyric acid
(4)Ethephon

✓

Verified Against NTA Final Answer Key

Option (2) : Gibberellin

📚 Plant Growth and Development Easy

📋 Given Parameters & Problem Setup

Physiological Phenomenon Internode elongation prior to flowering (bolting)

Target Plant Cabbage (Brassica oleracea var. capitata)

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The 30-Second Exam Hall Shortcut: ⚡ Bolting = Gibberellin Rule

⏱️ Save ~40 seconds

Bolting in Cabbage and Beet is ALWAYS stimulated by Gibberellin!

1 Recall definition of Bolting: Internode elongation just prior to flowering in plants with rosette habit (e.g. cabbage, beet).

2 Identify the responsible phytohormone: Gibberellins (GA).

3 Look at Option (2): Gibberellin.

4 Mark Option (2) in under 3 seconds!

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Plant Growth and Development (Gibberellin Physiology: Promotes bolting in rosette plants and stem elongation).

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Definition of Bolting and Rosette Habit

Plants like cabbage and beet exhibit a rosette habit during their vegetative phase, characterized by clustered leaves and compressed, stunted internodes close to the soil surface. Before entering the reproductive flowering phase, rapid and massive elongation of the internodes occurs, an event termed bolting.

\text{Rosette habit} \xrightarrow{\text{Bolting}} \text{Elongated flowering stem}

• Naturally triggered by long days or cold exposure (vernalization).

Step 2

Hormonal Control by Gibberellins

Exogenous application of gibberellins (specifically gibberellic acid, $GA_3$ ) induces prompt internodal elongation and flowering in cabbage and beet without requiring cold or photoperiodic induction.

\text{Gibberellins (GA)} \implies \mathbf{Promote\text{ bolting in cabbage and beet}}

• NCERT explicitly mentions: "Gibberellins also promote bolting (internode elongation just prior to flowering) in beet, cabbages and many plants with rosette habit."

Step 3

Eliminate Other Plant Hormones

Abscisic acid (Option 1) inhibits growth, induces dormancy, and closes stomata. Indole butyric acid (Option 3) is an auxin used for rooting cuttings. Ethephon (Option 4) is an ethylene-releasing compound used to accelerate fruit ripening. Only Gibberellin promotes bolting.

\text{Correct PGR} = \mathbf{Gibberellin} \implies \text{Option (2)}

• Matches official NTA final answer key Option B / (2).

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan

1 A

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. ABA is a growth inhibitor that promotes dormancy, not stem elongation.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing growth promoter with inhibitor.

2 B

✓ 100% Correct

Verdict & Scientific Reason:

100% accurate. Canonical NCERT hormone responsible for bolting in rosette plants.

💡

Why this is airtight: None; classic textbook recall.

3 C

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. IBA is a natural/synthetic auxin used to induce root initiation in stem cuttings.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing auxin with gibberellin.

4 D

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Ethephon decomposes to release ethylene gas, promoting fruit ripening and abscission.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing ethylene donor with gibberellin.

⚠️

NTA Trap Alert: Auxin vs Gibberellin for Stem Elongation

While auxins promote cellular elongation in coleoptiles and apical dominance, intact stem internode elongation (and bolting) is the hallmark diagnostic function of GIBBERELLINS.

🛡️ How to avoid the -1 mark: Remember: G for Gibberellin = Giant stem growth (Bolting).

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Core NEET Syllabus Standard

NEET Biology Core Syllabus · Plant Growth and Development Standard Benchmark

Core Scientific Principle Tested:

"Gibberellins promote internodal elongation prior to flowering, a phenomenon designated as bolting in rosette plants such as cabbage and beet."

Syllabus Focus: Plant Growth Regulators - Gibberellins

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

Gibberellin gives Growth to Cabbage stalks: Bolting shoots before it walks!

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NEET 2026 Botany Question 127 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Bolting = Gibberellin Rule

Step-by-Step Rigorous Workflow & Mathematical Proof

Definition of Bolting and Rosette Habit

Hormonal Control by Gibberellins

Eliminate Other Plant Hormones

360° Option Elimination Engine Key Feature

NTA Trap Alert: Auxin vs Gibberellin for Stem Elongation

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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