Question

What is porogamy? Explain.

Answer 1

Hint: The given term ‘’Porogamy’’ is related to fertilization in angiosperms. It is also associated with the path that the pollen tube takes during fertilization.

Complete answer:
Fertilization refers to the fusion of male gametes i.e. pollen grains with the female gametes i.e. the egg cell to form a zygote. This process is initiated when a pollen grain comes in contact with the surface of the stigma of a pollinated flower. This pollen grain then develops a pollen tube to facilitate the transfer of the male gametes from the stigma, through the style and into the ovary.

When the pollen tube passes through the style and reaches the ovary, it has three different possibilities of entering into the embryo sac. It can either penetrate through the integuments and reach synergids. This type of entry into the embryo sac is called Mesogamy.

When the pollen tube enters the embryo sac from the chalazal end i.e. from the side where the antipodal cells are located, then it is referred to as Chalazogamy.

Finally, when the pollen tube enters the embryo sac from the micropylar end i.e. the side where the filiform apparatus is located, then it is said to be Porogamy. It is the most commonly seen form of fertilization in flowering plants.

While Mesogamy and Chalazogamy are indirect pathways of entering the embryo sac, Porogamy is a direct pathway for the entry of the male gametes into the embryo sac.

Note: All flower producing plants are known as angiosperms. The term angiosperm is derived from the Greek words, ‘angeion’ and ‘sperma’ which mean ‘case’ and ‘seed’ respectively. They are called so because the seeds of these plants are enclosed in a case which we commonly refer to as fruits. Hence, we can also say that they are fruit-bearing plants.