Pollen Pistil Interaction, Definition, Events, and MCQs for NEET

Pollen pistil interaction  is a crucial process in sexual reproduction in flowering plants. This biological phenomenon ensures that the pollen from the male part of a flower (anther) successfully fertilizes the ovules in the female part of a flower (pistil). This interaction is essential for the formation of seeds, which eventually grow into new plants.

Definition of Pollen Pistil Interaction

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Events in Pollen Pistil Interaction

Recognition of Compatible Pollen

• Compatible Pollen: If the pollen is of the right type (genetically and species-specific), the pistil accepts it and promotes subsequent processes like pollen germination and pollen tube growth, ultimately leading to fertilization.
• Incompatible Pollen : If the pollen is of the wrong type, the pistil rejects it by either preventing its germination on the stigma or halting the growth of the pollen tube in the style. This selective process ensures reproductive success and prevents wastage of resources.

Germination of Pollen Grains

• Germination Process: The pollen grain produces a pollen tube through one of its germ pores. The contents of the pollen grain , including the vegetative nucleus and generative cell, move into the growing pollen tube.
• Pollen Tube Growth : The pollen tube penetrates the tissues of the stigma and style, guided by chemical signals, and grows towards the ovary, forming a pathway for the male gametes.

Development of Male Gametes

• Two-Celled Pollen Grains : In plants that shed pollen in a two-celled condition (containing a vegetative cell and a generative cell), the generative cell divides while the pollen tube grows, forming two male gametes.
• Three-Celled Pollen Grains: In plants where pollen is shed in a three-celled condition, the pollen tube carries two fully-formed male gametes from the start.

Entry of Pollen Tube into the Embryo Sac

• Guidance by Filiform Apparatus: The filiform apparatus, located in the micropylar part of the synergids, directs the pollen tube towards the embryo sac.
• Release of Male Gametes : Upon entering the embryo sac, the vegetative nucleus of the pollen tube degenerates. The tip of the pollen tube swells and bursts due to endosmosis, releasing its contents, including the two male gametes, into a degenerating synergid. This ensures the delivery of male gametes for fertilization.

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MCQs of Pollen Pistil Interaction

Q1. The function of the filiform apparatus is to;

1. Guide the entry of the pollen tube.
2. Produce nectar.
3. Stimulate division of generative cells.
4. Recognise suitable pollen at the stigma.

Q2. Recognisation of pollens whether it is of the right type or wrong type is done by;

1. Pistil
2. Style
3. Pollen itself
4. Ovary

Q3. Pollen tube enters into embryo sac of angiosperm through the;

1. Egg cell
2. Any one of the antipodal cell
3. Any one of the synergids
4. None of these

Answers of MCQs of Pollen Pistil Interaction