[Campbell Biology P.899] Which of the following best describes the roles of hormones in main... | Practice Question

Which of the following best describes the roles of hormones in maintaining apical dominance in an intact plant, according to the provided text?

  • A: Auxin directly promotes axillary bud growth, while cytokinins inhibit it.
  • B: Strigolactones, produced due to auxin flow, directly repress bud growth, and cytokinins from roots counteract this.
  • C: Cytokinins are primarily responsible for apical dominance, with auxin having a secondary role.
  • D: Removal of the apical bud increases auxin and strigolactone levels, which promotes lateral bud growth.

Explanation

The text explains that polar flow of auxin down the shoot triggers strigolactone synthesis, which directly represses bud growth. Cytokinins from roots then counter this action, allowing some axillary bud growth. This detailed interaction is best described by option B.