Question

Which of the following in female gametophyte of an angiosperm helps in guiding the pollen tube for fertilizing the eggs ?

• A. Polar nucleus
• B. Antipodals
• C. Synergids
• D. Central cells

Hint:

• The filiform apparatus is located at the micropylar end of the synergids.

• Once the pollen tube enters a synergid, the synergid degenerates, releasing the two male gametes to carry out double fertilization (one fuses with the egg cell, and the other fuses with the polar nuclei of the central cell).

Answer 1

The Correct Option is C

Concept:

• The mature female gametophyte of an angiosperm (embryo sac) typically exhibits a 7-celled, 8-nucleate structure: itemize

• Egg Apparatus (Micropylar end): Contains one egg cell and two flanking

synergids.

• Central Cell: Contains two polar nuclei.

• Antipodals (Chalazal end): Three cells located at the chalazal pole.
Synergids possess specialized cellular structures at their micropylar tip known as the

filiform apparatus. itemize

Step 1: Understand the fertilization pathway in angiosperms
Upon reaching the stigma, the pollen grain germinates to produce a pollen tube, which grows down through the style toward the ovary. The pollen tube enters the ovule through the micropylar opening.

Step 2: Examine the role of the filiform apparatus and synergids
As the pollen tube approaches the embryo sac, it must find the precise path to deliver male gametes to the egg cell. The filiform apparatus, which consists of prominent finger-like projections on the synergid cell walls, secretes chemical signals (chemotropic substances). These chemical secretions guide the pollen tube's growth into one of the synergids, facilitating the fertilization process.

Step 3: Confirm the correct cellular structure
The cells responsible for this chemotropic guidance are the synergids, which contains the filiform apparatus. This matches option (C).