Multiple choice

In 1925, the Japanese biologist Kurosawa showed that the bakanae (foolish seedling) disease of rice was caused by a substance produced by the fungus Gibberella fujikuroi. The substance was named gibberellin and was shown to cause elongation of stem tissues. Which of the following statements about gibberellins is false?

  1. The gibberellins produced by the fungus caused normal healthy rice plants to become unusually tall.

  2. Dwarf pea plants have a mutation in the gibberellin biosynthesis pathway.

  3. If gibberellin is applied to the stems of dwarf pea plants, the stems elongated so that the plant reach normal health.

  4. Pea plants carrying the dwarf mutation would be expected to have higher levels of gibberellin in their stems than normal plants.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The question asks for the FALSE statement. Dwarf pea plants have mutations that REDUCE gibberellin production or sensitivity, which is why they're dwarf. Therefore, they would have LOWER levels of active gibberellin, not higher. Option D correctly identifies this as false by stating they would have 'higher levels' - this is the lie. Options A, B, and C are all true statements about gibberellins.

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