Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Sexual Reproduction in Flowering Plants

Question:

Which among the following statement is incorrect :

Statement I :  Pollen tube, enters the ovule through the micropyle and then enters one of the synergids through the filiform apparatus.

Statement II:  Filiform apparatus present at the micropylar part of the synergids guides the entry of pollen tube .

Options:

Statement I is correct but Statement II is incorrect .

Statement I is incorrect but Statement II is correct .

Both the statements are correct .

Both the statements are incorrect .

Correct Answer:

Both the statements are correct .

Explanation:

The correct answer is Option (3)- Both the statements are correct .

The process described here involves several important steps in the interaction between pollen and the pistil of a flower, which is commonly referred to as pollen-pistil interaction. Here's a breakdown of the events:

  1. Pollen Deposition on the Stigma: Pollen grains are deposited on the receptive surface of the stigma, which is part of the pistil. This can occur through various means such as wind, insects, or other pollinators.

  2. Pollen Germination: Once on the stigma, the pollen grains germinate and produce a pollen tube. This tube is responsible for delivering the male gametes (sperm cells) to the ovule for fertilization.

  3. Pollen Tube Growth: The pollen tube elongates and grows through the tissues of the pistil, including the style, which connects the stigma to the ovary. It navigates its way towards the ovule, which is located within the ovary.

  4. Entry into the Ovule: After reaching the ovary, the pollen tube enters the ovule through a small opening called the micropyle. The micropyle provides a pathway for the pollen tube to access the interior of the ovule.

  5. Filiform Apparatus and Synergid Entry: Upon entering the ovule through the micropyle, the pollen tube then encounters the synergids, which are specialized cells located at the micropylar end of the embryo sac within the ovule. The synergids have a structure called the filiform apparatus, which guides and facilitates the entry of the pollen tube into one of the synergids.

The combined series of events, starting from pollen deposition on the stigma until the pollen tubes successfully enter the ovule and interact with the synergids, is collectively referred to as pollen-pistil interaction. This interaction is crucial for the successful fertilization and reproductive process in flowering plants.