Sexual Reproduction in Flowering Plants

Sexual reproduction in flowering plants requires both male and female gametes, and the process of such reproduction engages different parts of a flower. It also requires external pollinating vectors.
Read on to know more about reproduction in flowering plants.
Reproductive Structure of Flower 
A flower is the reproductive organ of a plant, consisting of both male and female reproductive parts.

  1. Androecium 

The male reproductive organ in plants is androecium. The main function of androecium is the production and storage of pollen.
Unit of androecium is stamen. Androecium is made up of numerous stamens. A stamen has two parts – filament and anther.
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  • Filament 

Filament resembles a stalk attached to a flower and provides support to another.

  • Anther 

Anther is an oval-shaped pollen-producing part of a flower.

  1. Microsporogenesis 

The creation of microspores by way of meiotic division is known as Microsporogenesis. Microspores originate from microspore mother cells.
Microspores are responsible for the development of male gametophyte. The inner layer of the male gamete is made up of cellulose and pectose, and the outer layer is formed by sporopollenin.
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  1. Gynoecium 

The female reproductive organ in plants is gynoecium. It undertakes internal production of ovules which eventually produces an egg. Gynoecium has three parts – stigma, style and ovary.
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  • Stigma 

Stigma is the anterior part of a carpel, where pollen germinates.

  • Style

Style is a tube like filament connecting stigma and ovary. It helps in the passage of pollen from stigma to ovary.

  • Ovary

Ovary acts in a small chamber where ovules are produced.

  1. Megasporogenesis

Megasporogenesis means the formation of megaspores within megasporangium. Megaspores originate from ovules by way of meiosis.
It is these megaspores that lead to formation of the female gametophyte. One megaspore converts into gametophyte and the others eventually degenerate. The basal megaspore develops into embryo sac.
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The male and female gametes developed from microsporogenesis and megasporogenesis respectively are the basic units of sexual reproduction in flowers.
Pollination is an external process that includes transfer of pollen grains from the anther to stigma. There are two types of pollination – self-pollination and cross-pollination.

  1. Self-Pollination 

The pollen grains remain in the originating flower.

  1. Cross-Pollination 

Pollen from one flower passes on to another through vectors like bees and air.
Fertilisation takes place after pollination where the pollen grains reach the ovary. Here, the male gamete fuses with the female gamete, ovule, to form a zygote. The ovary turns into a fruit, and fertilised ovules convert to seed.
You may read in detail to find out more about how pollination and fertilisation play a crucial role in sexual reproduction in flowering plants.
Do You Know?
Reproduction can also take place by way of fragmentation. The fragmented segments of the plant body give rise to a newer organism. Plants are usually artificially harnessed in horticulture. Thereby, different parts of the plant such as branches, roots or stems are cut for reproduction to culture a desirable variety of plant. This process is significantly different from the natural flower reproductive system.
Test Yourself 

  1. Female gametophyte is represented by which of the following in angiosperms?

(a) Embryo sac
(b) Embryo
(c) Endosperm
(d) Synergid

  1. In absence of ovary fertilisation, development of fruit is known as –

(a) Parthenogenesis
(b) Agamospermy
(c) Parthenocarpy
(d) Apomixis
[To check your answer, see the solution mentioned at the end of the article]

FAQ (Frequently Asked Questions)

  1. Mention Various Stages of Plant Life-Cycle.

Ans. The different stages of plant life cycle are – seed stage, germination, growth, reproduction, pollination, dispersal of seeds. In addition, the reproductive cycle of flowering plants includes – pollen on stigma, growth of pollen tube and male gamete fusing with female gamete.

  1. What are the Different Types of Pollination?

Ans. Pollination is the initial stage of flower reproduction. Pollination can be of two types – self-pollination and cross-pollination. Self-pollination involves a single flower, whereas cross-pollination requires a vector in the form of birds, bees, wind etc.

  1. What are the Main Components of the Reproductive Structure of a Plant?

Ans. The main components of reproductive structure of a plant are – sepals, petals, carpels, and stamen. Stamens form male reproductive organ and carpels form the female reproductive organ are also essential.

  1. (a) Embryo sac
  2. (c) Parthenocarpy

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