- A Primary root elongation by suppressing meristematic cell division at the root tip
- B Shoot branching (axillary bud outgrowth) and promote mycorrhizal symbiosis
- C Seed germination in the surrounding rhizosphere soil community
- D Stomatal opening by maintaining elevated guard cell turgor pressure
Correct answer: B. Shoot branching (axillary bud outgrowth) and promote mycorrhizal symbiosis
Explanation: Strigolactones: inhibit shoot branching (synergistic with auxin, antagonistic with cytokinin); promote mycorrhizal fungus hyphal branching for symbiosis; germination stimulant for parasitic plants.
Concept context
Phases of plant growth, the five classical plant hormones plus newer ones, photoperiodism, vernalization, and seed dormancy.