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🔬 Biology  ·  Sexual Reproduction in Flowering Plants  ·  NEET

Self-incompatibility (SI) in plants prevents self-fertilization by:

  • A Physical separation of stamens and pistil onto entirely different flowers altogether
  • B Molecular recognition between pollen and pistil S-gene products rejecting same-genotype pollen
  • C Releasing volatile insect repellents that actively prevent pollinator visits to the flower
  • D Producing no functional pollen grains whatsoever throughout anther development

Correct answer: B. Molecular recognition between pollen and pistil S-gene products rejecting same-genotype pollen

Explanation: SI: stigma or pistil cells express S-gene products that recognize matching pollen S-alleles. If pistil and pollen share S alleles, pollen tube growth is inhibited, preventing inbreeding.

Concept context

Flower structure, pollination, double fertilization, and seed/fruit development — the highest-scoring Class 12 biology chapter in NEET.

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