Q.136 Botany ⭐ 360° Option Elimination Active

NEET 2023 Botany Question 136 Solution

Topic: Plant Kingdom · Official NTA Booklet Code G5

Question

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R: Assertion A: In gymnosperms the pollen grains are released from the microsporangium and carried by air currents. Reason R: Air currents carry the pollen grains to the mouth of the archegonia where the male gametes are discharged and pollen tube is not formed. In the light of the above statements, choose the correct answer from the options given below:

(1)A is false but R is true.
(2)Both A and R are true and R is the correct explanation of A.
(3)Both A and R are true but R is NOT the correct explanation of A.
(4)A is true but R is false.

✓

Verified Against NTA Final Answer Key

Option (4) : A is true but R is false.

📚 Plant Kingdom Medium

📋 Given Parameters & Problem Setup

Assertion (A) In gymnosperms pollen grains are released from microsporangium and carried by air currents.

Reason (R) Air currents carry pollen grains to mouth of archegonia where male gametes are discharged and pollen tube is not formed.

⚡

The 30-Second Exam Hall Shortcut: ⚡ Gymnosperms ARE Siphonogamous: Pollen Tube IS Formed!

⏱️ Save ~25 seconds

Gymnosperms are wind pollinated (anemophilous) -> Assertion is TRUE! But Reason claims "pollen tube is not formed". Gymnosperms develop a pollen tube that grows towards the archegonium to discharge male gametes (siphonogamy)! Reason is FALSE! Select Option (4)!

1 Check Assertion A: Pollen grains are carried by air currents (anemophily) -> True.

2 Check Reason R: Gymnosperms produce pollen tubes to deliver male gametes to the archegonia -> Reason claims "pollen tube is not formed" -> Blatantly False.

3 Assertion is true but Reason is false.

4 Match Option (4) A is true but R is false.

🛡️

Why You Can 100% Trust This Shortcut: Canonical NCERT Gymnosperm reproductive biology and siphonogamy.

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Evaluation of Assertion A (Anemophily in Gymnosperms)

In gymnosperms, pollen grains develop inside microsporangia on male strobili. Upon maturity, the microsporangia dehisce and pollen grains are shed and transported through the atmosphere exclusively via wind currents:

\text{Microsporangium} \xrightarrow{\text{Dehiscence}} \text{Pollen Grains} \xrightarrow{\text{Air Currents (Anemophily)}} \text{Ovular Micropyle} \implies \text{Assertion A is } \mathbf{\text{TRUE}}

Step 2

Evaluation of Reason R (Siphonogamy in Gymnosperms)

Pollen grains land on the micropyle of the naked ovule, NOT at the mouth of archegonia directly. Pollen grains germinate to produce a pollen tube that digests nucellar tissue, grows toward the archegonium, and discharges sperm contents. Hence, gymnosperms are siphonogamous:

\text{Pollen Germination} \implies \mathbf{\text{Pollen Tube IS Formed (Siphonogamy)}} \implies \text{Reason R is } \mathbf{\text{FALSE}}

Step 3

Verbatim NCERT Reference

NCERT states verbatim: "The pollen tube carrying the male gametes grows towards archegonia in the ovules and discharge their contents near the mouth of the archegonia."

⭐

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 1

✗ Incorrect

Verdict & Scientific Reason:

Assertion is true (wind carries gymnosperm pollen); Reason is false (pollen tube is formed).

⚠️

Student Fallacy (Why candidates pick this trap): Doubting wind pollination in gymnosperms.

2 2

✗ Incorrect

Verdict & Scientific Reason:

Reason is false because pollen tubes are formed in all seed plants (siphonogamy).

⚠️

Student Fallacy (Why candidates pick this trap): Believing gymnosperms rely on flagellated swimming sperm without pollen tubes.

3 3

✗ Incorrect

Verdict & Scientific Reason:

Reason is demonstrably false according to plant morphology.

⚠️

Student Fallacy (Why candidates pick this trap): Failing to notice the statement "pollen tube is not formed".

4 4

✓ 100% Correct

Verdict & Scientific Reason:

Assertion A is correct, but Reason R is false because a pollen tube is definitively formed in gymnosperms.

💡

Why this is airtight: None; rigorous embryological understanding.

⚠️

NTA Trap Alert: Zoidiogamy vs. Siphonogamy Trap

Although primitive gymnosperms like Cycas retain motile ciliated male gametes, they STILL produce a haustorial pollen tube. Higher gymnosperms like Pinus are strictly siphonogamous.

🛡️ How to avoid the -1 mark: Never accept that seed plants do not form pollen tubes; gymnosperms and angiosperms are both siphonogamous.

📖

Core NEET Syllabus Standard

NCERT Biology · Plant Kingdom Standard Benchmark

Core Scientific Principle Tested:

"Pollen grains are released from the microsporangium and carried in air currents. The pollen tube carrying the male gametes grows towards archegonia in the ovules."

Syllabus Focus: Gymnosperms

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2023 Botany Question 136 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Gymnosperms ARE Siphonogamous: Pollen Tube IS Formed!

Step-by-Step Rigorous Workflow & Mathematical Proof

Evaluation of Assertion A (Anemophily in Gymnosperms)

Evaluation of Reason R (Siphonogamy in Gymnosperms)

Verbatim NCERT Reference

360° Option Elimination Engine Key Feature

NTA Trap Alert: Zoidiogamy vs. Siphonogamy Trap

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Plant Kingdom

Life Cycle and Morphological Features of Gymnosperms

Classification of Pteridophytes - Class Sphenopsida

Life Cycle and Alternation of Generations in Pteridophytes

Life Cycle and Chronology of Reproductive Events in Bryophytes

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