Q.108 Botany ⭐ 360° Option Elimination Active

NEET 2025 Botany Question 108 Solution

Topic: Plant Growth and Development · Official NTA Booklet Code 45

Question

Which one of the following phytohormones promotes nutrient mobilization which helps in the delay of leaf senescence in plants?

(1)Ethylene
(2)Abscisic acid
(3)Gibberellin
(4)Cytokinin

✓

Verified Against NTA Final Answer Key

Option (4) : Cytokinin

📚 Plant Growth and Development Easy

📋 Given Parameters & Problem Setup

Function 1 Promotes nutrient mobilization

Function 2 Delay of leaf senescence

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The 30-Second Exam Hall Shortcut: ⚡ Cytokinin Anti-Aging Fingerprint

⏱️ Save ~25 seconds

Cytokinin = Cell division + Overcomes apical dominance + Nutrient mobilization delaying senescence (Richmond-Lang effect)!

1 Match the physiological role directly to NCERT verbatim lines:

2 - "They help overcome the apical dominance."

3 - "They promote nutrient mobilisation which helps in the delay of leaf senescence."

4 - Ethylene and ABA promote senescence and abscission.

5 - Cytokinin actively DELAYS senescence!

6 Select Option (4) Cytokinin!

🛡️

Why You Can 100% Trust This Shortcut: Phytohormone Physiological Roles (NCERT Biology · Plant Growth and Development: Cytokinins promote nutrient mobilization and delay senescence).

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Physiological Roles of Cytokinins

Cytokinins (kinetin, zeatin) have specific effects on cytokinesis and plant morphogenesis:

• Help produce new leaves, chloroplasts in leaves, lateral shoot growth, and adventitious shoot formation.
• Help overcome apical dominance imposed by auxins.
• Promote nutrient mobilisation, which mobilises amino acids, mineral ions, and sugars towards treated tissues, thereby delaying senescence (aging) of leaves.

Step 2

Contrast with Other Phytohormones

Understanding the opposing actions of growth promoters vs inhibitors:

• Ethylene: Promotes senescence and abscission of plant organs, especially leaves and flowers.
• Abscisic Acid (ABA): General plant growth inhibitor, induces dormancy, abscission, and accelerates senescence.
• Gibberellins: Promote stem elongation, bolting in rosette plants, and breaking of seed dormancy, but do not specifically delay leaf senescence via nutrient mobilization.

Step 3

Conclusion

The unique role of promoting nutrient mobilization to delay leaf senescence belongs specifically to Cytokinin (also known as the Richmond-Lang effect).

\text{Nutrient Mobilization} + \text{Delay Senescence} \implies \text{Cytokinin}

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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. Ethylene stimulates and promotes senescence and abscission, the exact opposite of delaying senescence.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing senescence delay with senescence promotion.

2 B

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. ABA is a stress hormone that accelerates senescence and abscission of leaves.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing senescence inhibition with senescence acceleration.

3 C

✗ Incorrect

Verdict & Scientific Reason:

Incorrect. Gibberellins delay senescence in fruits (preventing premature drop in citrus), but do not cause nutrient mobilization to delay leaf senescence.

⚠️

Student Fallacy (Why candidates pick this trap): Confusing fruit senescence delay with leaf nutrient mobilization.

4 D

✓ 100% Correct

Verdict & Scientific Reason:

100% correct. NCERT states: "They promote nutrient mobilisation which helps in the delay of leaf senescence."

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Why this is airtight: None; textbook verbatim mastery.

⚠️

NTA Trap Alert: Fruit Senescence vs Leaf Senescence

Gibberellin delays fruit senescence (keeps fruits on trees longer to extend market period). Cytokinin delays leaf senescence via active nutrient mobilization. Read the organ specified!

🛡️ How to avoid the -1 mark: Leaves staying green by nutrient mobilization = Cytokinin (Richmond-Lang effect).

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Core NEET Syllabus Standard

NEET Biology Core Syllabus · Plant Growth and Development Standard Benchmark

Core Scientific Principle Tested:

"Cytokinins promote nutrient mobilization which helps in the delay of leaf senescence."

Syllabus Focus: Plant Growth Regulators · Cytokinins

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

CYTO-kinin Keeps Cells (CYTO) Young by Mobilizing Nutrition!

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NEET 2025 Botany Question 108 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Cytokinin Anti-Aging Fingerprint

Step-by-Step Rigorous Workflow & Mathematical Proof

Physiological Roles of Cytokinins

Contrast with Other Phytohormones

Conclusion

360° Option Elimination Engine Key Feature

NTA Trap Alert: Fruit Senescence vs Leaf Senescence

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Plant Growth and Development

Auxins & Synthetic Auxin Applications as Herbicides

Physiological Effects of Gibberellins - Bolting in Rosette Plants

Mathematical Modeling of Arithmetic Growth (Linear Growth Kinetics)

Differentiation, Dedifferentiation, and Redifferentiation

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