Sexual Reproduction In Flowering Plants Class 12 Biology NCERT PDF

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Sexual Reproduction in Flowering Plants

Chapter 2: Sexual Reproduction in Flowering Plants

Are we not lucky that plants reproduce sexually? The myriads of flowers that we enjoy gazing at, the scents and the perfumes that we swoon over, and the rich colors that attract us, are all there as an aid to sexual reproduction.

Flowers do not exist only for us to be used for our own selfishness. All flowering plants show sexual reproduction.

A look at the diversity of structures of the inflorescences, flowers, and floral parts, shows an amazing range of adaptations to ensure the formation of the end products of sexual reproduction, the fruits, and seeds.

In this chapter, let us understand the morphology, structure, and processes of sexual reproduction in flowering plants (angiosperms).


Human beings have had an intimate relationship with flowers since time immemorial.

Flowers are objects of aesthetic, ornamental, social, religious, and cultural value – they have always been used as symbols for conveying important human feelings such as love, affection, happiness, grief, mourning, etc.

List at least five flowers of ornamental value that are commonly cultivated in homes and in gardens.

Find out the names of five more flowers that are used in social and cultural celebrations in your family. Have you heard of floriculture – what does it refer to?

To a biologist, flowers are morphological and embryological marvels and the sites of sexual reproduction. In class XI, you have read the various parts of a flower.

Figure 2.1 will help you recall the parts of a typical flower. Can you name the two parts in a flower in which the two most important units of sexual reproduction develop?


Much before the actual flower is seen on a plant, the decision that the plant is going to flower has taken place.

Several hormonal and structural changes are initiated which lead to the differentiation and further development of the floral primordium.

Inflorescences have formed that bear the floral buds and then the flowers. In the flower, the male and female reproductive structures, the androecium and the gynoecium differentiate and develop.

You would recollect that the androecium consists of a whorl of stamens representing the male reproductive organ and the gynoecium representing the female reproductive organ.

As each cell of the sporogenous tissue is capable of giving rise to a microspore tetrad. Each one is potential pollen or microspore mother cell.

The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called microsporogenesis.

The microspores, as they are formed, are arranged in a cluster of four cells–the microspore tetrad (Figure 2.3 a).

As the anthers mature and dehydrate, the microspores dissociate from each other and develop into pollen grains (Figure 2.3 b). Inside each microsporangium, several thousands of microspores or pollen grains are formed that are released with the dehiscence of the anther (Figure 2.3 c).

Pollen grain: The pollen grains represent the male gametophytes. If you touch the opened anthers of Hibiscus or any other flower you would find deposition of yellowish powdery pollen grains on your fingers. Sprinkle these grains on a drop of water taken on a glass slide and observe under.

Language English
No. of Pages23
PDF Size34.2 MB

NCERT Solutions Class 12 Biology Chapter 2 Sexual Reproduction in Flowering Plants

Q1. Name the parts of an angiosperm flower in which the development of male and female
gametophytes takes place.

In an angiosperm plant, the development of male gametophyte occurs in the pollen chamber
while that of female gametophyte takes place in nucellus.

Q3. Arrange the following terms in the correct developmental sequence: Pollen grain,
sporogenous tissue, microspore tetrad, pollen mother cell, male gametes.

The correct developmental sequence is as follows: Sporogenous tissue Pollen mother cell Microspore tetrad Pollen grain male gametes

Q5. What is meant by monosporic development of female gametophyte?

The female gametophyte of flowers develops from a single functional megaspore after continuous mitotic divisions. This type of development of female gametophyte from a single uninucleate megaspore is called monosporic development of female gametophyte.

Q7. What are chasmogamous flowers? Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.


Flowers can be of two types i.e. chasmogamous flowers or cleistogamous flowers. Chasmogamous flowers are open flowers that have their anthers and stigma exposed.

These flowers facilitate cross-pollination. On the other hand, cleistogamous flowers are closed flowers whose anthers and stigmas are not exposed.

Since these flowers do not open at all, only self-pollination occurs in these, and cross-pollination is never seen. Thus. cross-pollination cannot occur in cleistogamous flowers.

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