How does the process of fertilization take place in flowers?
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Pre-fertilization events in a flower
Events that take place before fertilization are termed as Pre-fertilization events. Following events would occur before actual fertilization takes place in a plant:
Gametogenesis
Development of male & female reproductive structures
Formation of male & female gametes
Gamete transfer
Bringing together male & female gamete
Pollination occurs in plants to facilitate gamete transfer
We will now understand the formation of male & female gametes in a plant. It is important to understand the structure of male & female reproductive parts in detail.
Male reproductive structure in a Flower : Stamen
Stamens are the male reproductive structures in a plant. The structure of a stamen consists of 3 important parts:
Filament
Stalk that bears anthers
Anther
Bilobed, dithecous structure at the tip of filament
Each lobe has 2 pollen sacs/ microsporangia
A total of 4 microsporangia are present in a anther
Each microsporangia produce spores, which later develop into pollen grains
Connective
Part attached to the back of anther

Detailed structure of Microsporangium
If the transverse section of a microsporangium is observed carefully, it is seen that there are 4 layers surrounding the microsporangia:
Epidermis
Endothecium
Middle layers
Tapetum
The first three ensure protection of the microsporangium, while the innermost layer, Tapetum provides nourishment to the pollen grains.
Sporogenous tissue is present at the centre of each microsporangium.

Microsporogenesis
Formation of microspores is termed as Microsporogenesis. Microspores are formed inside microsporangium.
Sporogenous cells differentiate to form meiocytes
Meiocytes under meiosis
4 haploid microspores are formed (Microspore tetrad)
Microspores dissociate & develop to form Pollen grains
Pollen grains are male gametophyte

Pollen grains
Each pollen grain is a tiny spherical structure, surrounded by 2 layers:

Exine
Hard, outer layer
Composed of sporopollenin
Highly resistant
Intine
Thin inner layer
Composed of cellulose & pectin
Formation of a pollen grain from microspore involves the following changes:
Expansion of the microspore
Formation of a large vacuole
Microspore nucleus displaced to an eccentric position against microspore wall
Nucleus undergoes first pollen mitosis
A large vegetative cell & a small generative cell are formed. This is the 2-cell stage. In many plants, pollen grains are released at this 2-celled stage. However, in some others, they are released at a 3-celled stage.
Generative cell detaches from pollen grain wall
Generative cell is engulfed by the vegetative cell
Question :-
How does the process of fertilization take place in flowers.
Answer :-
❥・ In plants, fertilization is a process of sexual reproduction, which occurs after pollination and germination.
❥・ Fertilization can be defined as the fusion of the male gametes (pollen) with the female gametes (ovum) to form a diploid zygote.
❥・ It is a physicochemical process which occurs after the pollination of the carpel.
❥・ The complete series of this process takes place in the zygote to develop into a seed.