Which one of the following types of pollination brings genetically different types of pollen grains to the stigma?

Related Formula

Developmental Sequence: Sporogenous tissue arrow$\rightarrow$ Pollen Mother Cell (PMC) Meiosis$\xrightarrow{\text{Meiosis}}$ Microspore tetrad arrow$\rightarrow$ Pollen grains.

Core Logic

During microsporogenesis:

• Sporogenous tissue (B)
• Differentiates into Pollen Mother Cells / PMCs (D)
• Undergoes meiosis to produce Microspore tetrads (A)
• Tetrads dissociate into mature Pollen grains (C)

Step 1: Conclusion

The correct sequence is B arrow$\rightarrow$ D arrow$\rightarrow$ A arrow$\rightarrow$ C. Correct option is (3).

Pattern Recognition

Sporogenous tissue (B) is the initial source tissue; Pollen grain (C) is the final product. Only option (3) begins with B and ends with C.

Chapter Mix

Class 12 Biology: Sexual Reproduction in Flowering Plants

Related Formula

Ploidy Levels: Synergid = n$n$ Central cell = n + n = 2n$n + n = 2n$ (before triple fusion) Zygote = 2n$2n$ Primary Endosperm Cell (PEC) = 3n$3n$ (after triple fusion)

Core Logic

Triple fusion between one male gamete (n$n$) and the secondary nucleus (2n$2n$) forms the triploid (3n$3n$) Primary Endosperm Nucleus (PEN) within the Primary Endosperm Cell (PEC).

Step 1: Selection

Primary endosperm cell is triploid (3n$3n$). Option (2) is correct.

Pattern Recognition

Endosperm cell / PEC in angiosperms = Triploid (3n$3n$).

Chapter Mix

Class 12 Biology: Sexual Reproduction in Flowering Plants