Post-Fertilisation Events in Flowering Plants MCQ - Practice Questions with Answers

• During sexual reproduction, the events which take place after the formation of the zygote are called post-fertilization events.
• These include the development of zygote and embryogenesis.

Development of Zygote:

• Development of zygote depends on:
  • Type of life cycle of the organism.
  • The environment it is exposed to.
• In the fungi and algae, the zygote before germination undergoes a resting period. 
• A thick wall is developed around the zygote and forms a structure called zygospore which prevents it from desiccation and damage.
• The zygospore undergoes meiosis to produce haploid individuals.
• In most animals and plants, the zygote undergoes mitosis to form an embryo which would then develop into a new organism.

Embryogenesis:

• The process of development of the embryo from the zygote is called embryogenesis.
• It involves the following steps:
  • Cell division to increase in the number of cells.
  • Cell enlargement or growth to increase in mass/volume of living matter.
  • Cell differentiation for the formation of different types of tissues.
• Based on whether the development of the zygote takes place outside or inside the body of the female parent, animals are divided into two categories:
  • Oviparous: Those animals, in which the development of zygote takes place outside the female parent, are called oviparous. They lay fertilized eggs covered with hard calcareous shell in a safe place in the environment, e.g., reptiles and birds. After a period of incubation, the young ones hatch out of the egg.
  • Viviparous: The animals in which the development of zygote takes place into a young one inside the body of the female parent, arc called viviparous. After attaining a certain stage of growth, the young ones are delivered out of the body of the female organism. The chances of survival of young ones are greater in these because of proper embryonic care and protection.
• In angiosperms, the zygote is formed inside the ovule. 
• In most of the plants, with the formation of the zygote, all the parts of the flower except the pistil wither and fall off. 
• In some plants, such as tomato and brinjal, the sepals are persistent and remain attached to the developing fruit.
• In ovule, the zygote divides several times to form an embryo.
• Meanwhile, the wall of the ovule becomes hard and it develops into a seed. 
• With these developments, the wall of the ovary also starts to swell. 
• As a result, the ovary develops into the fruit. 
• A thick wall that covers fruit is called the pericarp. 
• It is protective in function. 
• When seeds mature, they are dispersed. 
• Under favourable conditions, these seeds germinate to produce new plants.