Question

Which one of the following is a triploid cell ?

• A. Zygote
• B. Central cell
• C. Primary endosperm cell
• D. Synergid

Hint:

Endosperm = \textbf{3}n (Triple fusion). Most other structures in the embryo sac are \textbf{1}n, and the zygote is \textbf{2}n.

Answer 1

The Correct Option is C

In angiosperms, double fertilization leads to the formation of structures with different ploidy levels:
• Primary endosperm cell (PEC): During double fertilization, one male gamete ($n$) fuses with the two polar nuclei ($n+n$) of the central cell. This process is called triple fusion, resulting in a triploid ($3n$) Primary Endosperm Nucleus (PEN) within the PEC.
• Zygote: Formed by the fusion of a male gamete ($n$) with an egg cell ($n$). It is diploid ($2n$).
• Central cell: Before fertilization, it contains two polar nuclei ($n+n$). While often treated as diploid ($2n$) in simplified contexts, it is technically dikaryotic.
• Synergid: Part of the egg apparatus in the embryo sac, these cells are haploid ($n$).