Q.64 Find the right combination for P, Q, R and S with respect to gametophyte development in flowering
plants.
(A) P-Meiosis, Q -Generative cell , R- Pollen Tube, S- 2 Sperm Cells
(B) P- Meiosis, Q- Pollen Tube, R- Generative Cell, S- 2 Sperm Cells
(C) P-Mitosis, Q- Generative Cell, R- Pollen Tube, S- 2 sperm Cells
(D) P- Growth, Q- 2 Sperm Cells, R- Pollen Tube, S- Generative Cell

Introduction

Gametophyte development in flowering plants is a crucial topic in plant reproduction and is frequently tested in exams such as CSIR-NET, GATE, JAM, CUET-PG, and NEET-PG.

In male gametophyte development, a microsporocyte undergoes meiosis to form microspores, which further divide mitotically to form the vegetative cell and generative cell. The generative cell later divides to form two male gametes (sperm cells).

This article explains the given diagram and identifies the correct combination of P, Q, R, and S, along with a detailed explanation of all answer options.

Understanding the Diagram

The diagram shows the following sequence:

1. Microsporocyte → 4 Microspores

2. Mitosis → Vegetative cell and Generative cell

3. Vegetative cell → Growth

4. Generative cell → Mitosis → Two sperm cells

Correct Identification of Labels

P

• Represents the process by which one microsporocyte forms four microspores

• ✅ Meiosis

Q

• Product of vegetative cell growth

• ✅ Pollen tube

R

• Cell that undergoes mitosis to form sperm cells

• ✅ Generative cell

S

• Final products after mitosis of generative cell

• ✅ Two sperm cells

Correct Answer

✅ Option (B)

P – Meiosis, Q – Pollen tube, R – Generative cell, S – 2 sperm cells

Option-Wise Explanation

Option (A)

❌ Incorrect

• Q is wrongly identified as generative cell.

• Vegetative cell forms pollen tube, not generative cell.

Option (B)

✅ Correct

• P correctly represents meiosis.

• Q is correctly identified as pollen tube.

• R is the generative cell.

• S correctly represents two sperm cells.

Option (C)

❌ Incorrect

• Microsporocyte does not undergo mitosis; it undergoes meiosis.

• Hence P is incorrect.

Option (D)

❌ Incorrect

• Growth does not directly produce two sperm cells.

• Generative cell is incorrectly placed at S.

Concept Summary: Male Gametophyte Development

• Microsporocyte → Meiosis → 4 Microspores

• Microspore → Mitosis → Vegetative cell + Generative cell

• Vegetative cell → Pollen tube

• Generative cell → Mitosis → Two sperm cells

This sequence ensures successful double fertilization in angiosperms.

Conclusion

Accurate interpretation of gametophyte development diagrams requires a clear understanding of cell divisions and functional roles. Among all the given options, Option (B) correctly matches all stages and structures shown in the diagram.

Final Answer

✅ Option (B)