Question

Study the diagram given below and name the parts marked as A, B and C. What happens when B reaches C in the ovary? Mention its significance.

Answer 1

Step 1: Understanding the parts of the diagram:
The diagram involves three main parts involved in the process of fertilization in plants:
A: Stigma – The part of the pistil that receives the pollen.
B: Pollen tube – A tube that grows from the pollen grain to deliver the male gametes to the ovule.
C: Ovule – The structure in the ovary that contains the egg cell (female gamete).

Step 2: Pollination:
Pollination is the first step in fertilization, where pollen grains (containing male gametes) land on the stigma (A). This can happen through various methods like wind or pollinators such as insects.

Step 3: Formation of the Pollen Tube:
Once the pollen grain lands on the stigma, it begins to germinate, forming a pollen tube (B). This tube grows down the style and into the ovary, providing a pathway for the male gametes to reach the ovule.

Step 4: Fertilization:
As the pollen tube (B) reaches the ovule (C) inside the ovary, the male gametes are transferred into the ovule, where fertilization occurs. The male gamete fuses with the egg cell inside the ovule, forming a zygote.

Step 5: Conclusion:
Fertilization results in the formation of a zygote, which will develop into a seed. The ovule matures into a seed, which will eventually grow into a new plant.