Sexual Reproduction in Flowering Plants

Sexual reproduction in angiosperms starts with the flower, which acts as a specialized reproductive shoot. The androecium carries stamens and the gynoecium carries carpels. In NEET, these words are often hidden inside structure-function statements rather than asked directly.

Each anther usually has four microsporangia. Inside them, pollen mother cells undergo meiosis and produce haploid microspore tetrads. This process is called microsporogenesis. The microspores later develop into pollen grains, which represent the male gametophyte.

Another recurring trap: most angiosperm pollen is shed at the 2-celled stage, not after complete male gamete formation. At shedding stage, it usually contains one vegetative cell and one generative cell.

The ovule contains the nucellus, integuments, micropyle, chalaza, and funicle. Among these, the micropyle is one of the most tested parts because it is the usual entry point of the pollen tube.

During megasporogenesis, the megaspore mother cell undergoes meiosis and forms four megaspores. Usually only one megaspore remains functional; the rest degenerate. This functional megaspore develops into the embryo sac.

The common angiosperm embryo sac is called monosporic because it develops from one functional megaspore. NEET also likes the phrase filiform apparatus, which belongs to synergids and helps guide the pollen tube.

Pollination means transfer of pollen from anther to stigma. You should not only memorize names but also understand their genetic meaning.

Plants avoid inbreeding through outbreeding devices such as herkogamy, dichogamy, self-incompatibility, and unisexuality. These terms are standard trap options in NEET.

After a compatible pollen grain lands on stigma, it hydrates, germinates, and forms a pollen tube. This recognition process between pollen and pistil is called pollen-pistil interaction.

This is the core of the chapter. Angiosperms show double fertilisation, meaning two fusion events occur in the same embryo sac.

• Syngamy: one male gamete fuses with the egg and forms the diploid zygote
• Triple fusion: the second male gamete fuses with the two polar nuclei and forms the triploid primary endosperm nucleus

Together, these two events are called double fertilisation. A very common mistake is to think this means two zygotes form. That is incorrect.

After fertilisation, the ovule becomes the seed and the ovary becomes the fruit. The endosperm develops as the nutritive tissue for the embryo. In many seeds it persists, while in others it gets consumed during development.

Apomixis means seed formation without fertilisation. Polyembryony means more than one embryo develops in a seed. Parthenocarpy means fruit develops without fertilisation and often results in seedless fruits.

These three terms are similar in sound but different in meaning, and NEET frequently tests that distinction directly.

If you can mentally run that sequence forward and backward, this chapter becomes extremely reliable in the exam because every question fits somewhere inside that chain.