Question

The process of double fertilization in plants results in the formation of

• A. Embryo and fruit
• B. Zygote and endosperm
• C. Overy and seed
• D. Stigma and ovule

Hint:

In double fertilization: Sperm 1 + Egg = Zygote (2n) $\to$ embryo. Sperm 2 + 2 Polar nuclei = Primary Endosperm Nucleus (3n) $\to$ endosperm. This is unique to angiosperms (flowering plants). The endosperm is the food reserve for the developing embryo (examples: the white part of a coconut is endosperm; rice grains are mostly endosperm).

Answer 1

The Correct Option is B

Concept:

Double fertilization is a unique and defining characteristic of

angiosperms (flowering plants). It involves two separate fertilization events occurring simultaneously within the embryo sac (female gametophyte). This process was first described by Sergei Nawaschin in 1898.

Step 1: Understand the structure involved in double fertilization.
During pollination, a pollen grain lands on the stigma and germinates, forming a

pollen tube that grows down through the style to the ovule. The pollen tube carries

two male gametes (sperm cells). The mature embryo sac (inside the ovule) contains:

• 1 egg cell (at the micropylar end)

• 2 synergids (beside the egg cell)

• 3 antipodal cells (at the chalazal end)

• 2 polar nuclei (at the center, forming the central cell)

Step 2: The two fertilization events.
When the pollen tube reaches the ovule and releases the two male gametes:

Fertilization 1 (Syngamy):
The zygote develops into the

embryo (the future plant).

Fertilization 2 (Triple fusion):
The primary endosperm nucleus develops into the

endosperm --- the nutritive tissue that provides food to the developing embryo.

Step 3: Final products of double fertilization.
The direct products of double fertilization are:

• Zygote (2n) --- from syngamy (egg + sperm).

• Primary endosperm nucleus (3n) --- from triple fusion, which develops into

endosperm.
So: Double fertilization $\Rightarrow$

Zygote + Endosperm.

Step 4: Why other options are wrong.

• (A) Embryo and fruit: The embryo develops from the zygote (later stage), and the fruit develops from the ovary wall. These are later consequences, not the direct products of double fertilization.

• (C) Ovary and seed: These are structural parts of the flower/fruit, not products of double fertilization. The seed forms after fertilization, not directly from it.

• (D) Stigma and ovule: These are parts of the pistil (female reproductive organ), not products of double fertilization. They exist before fertilization.