Embryology (Class XI/XII)

As ovum is formed after meiosis, it is haploid in nature.

To avoid self pollination, maturation of stamens and pistils occurs at different times, which is called dichogamy.

The pappus is the modified calyx, the part of an individual floret that surrounds the base of the corolla tube in flower heads of the plant family Asteraceae. It helps in seed and fruit dispersal.

It is a complex fertilisation mechanism of flowering plants (angiosperms). This process involves the joining of a female gametophyte with two male gametes (sperms).

False fruit is a fruit in which some of the flesh is derived not from the ovary but from some adjacent tissue exterior to the carpel. In apple, it is derived from thalamus.

After fertilisation, diploid secondary nucleus becomes triploid. Initially it is diploid, but it fuses with one of the male gametes which is haploid; so finally after fusion, it becomes triploid i.e. 3n. Hence, it is the correct answer.

Coconut is also a drupe, but the mesocarp is fibrous or dry (termed a husk); so this type of fruit is classified as a simple dry fruit, fibrous drupe.

The receptacle or torus of a flower is called thalamus. Edible part of an apple is thalamus.

The base of the embryo (cotyledon) swells into an absorbing organ. Endosperm forms a solid jelly-like substance that may be eaten with a spoon.

Mesocarp of mango is fleshy and is eaten.

In a process called microsporogenesis, four haploid microspores are produced from each diploid sporogenous mother cells.

If a megaspore mother cell has 12 chromosomes, it suggests that haploid number will be 6. The zygote formed will contain 12 chromosomes and the endosperm being a triploid tissue will have 18 chromosomes.

Pollen grains are the haploid structures which represent male or micro gametophytes.

It is formed by an enlarged, fleshy, hollow receptacle with multiple ovaries on the inside surface. In essence, it is really a fleshy stem with a number of flowers, so it is considered both a multiple and accessory fruit. It develops from hypanthodium inflorescence.

Microsporogenesis comprises the events which lead to the formation of the haploid unicellular microspores. It occurs in anther.