Question

Arrange the following steps of double fertilization in proper sequence:
A. Pollen germinates and reaches embryo sac,
B. Pollen tube penetrates stigma and enters ovary,
C. One male gamete fuses with egg cell,
D. Second male gamete fuses with polar nuclei, E. Seed formation. Choose the correct answer from the options given below:

• A. A, B, C, D, E
• B. B, A, C, D, E
• C. C, A, B, D, E
• D. D, C, B, A, E

Hint:

Double fertilization includes syngamy and triple fusion, both occurring inside the embryo sac.

Answer 1

The Correct Option is A

Concept:
Double fertilization is a characteristic feature of angiosperms. It involves two fusion events.

Step 1: Pollen germination.
After pollination, pollen grain germinates on stigma and starts forming pollen tube. \[ A=\text{Pollen germinates} \]

Step 2: Pollen tube growth.
The pollen tube grows through stigma and style and reaches the ovary. \[ B=\text{Pollen tube enters ovary} \]

Step 3: Syngamy.
One male gamete fuses with egg cell to form zygote. \[ C=\text{Fusion with egg cell} \]

Step 4: Triple fusion.
The second male gamete fuses with polar nuclei to form endosperm nucleus. \[ D=\text{Fusion with polar nuclei} \]

Step 5: Seed formation.
After fertilization, ovule develops into seed. \[ E=\text{Seed formation} \] Therefore, the correct sequence is: \[ A,B,C,D,E \] \[ \therefore \text{Correct Answer is (A)} \]