Chapter 20 Study Questions

  1. Define the terms “floral evocation” and “phase change.” How is phase change regulated by microRNAs?

    Textbook Reference: Floral Evocation: Integrating Environmental Cues, p. 592; The Shoot Apex and Phase Changes, pp. 592–594

  2. Define the following terms in relation to circadian rhythm: period; phase; amplitude; entrainment; zeitgeber; free-running; temperature compensation; subjective day; subjective night.

    Textbook Reference: Circadian Rhythms: The Clock Within, pp. 594–596

  3. What is the ecological function of photoperiodism? Discuss variations in the photoperiodic response.

    Textbook Reference: Photoperiodism: Monitoring Day Length, pp. 597–599

  4. Define the “clock hypothesis” of photoperiodism and describe the evidence that supports it. What is the relationship between the clock hypothesis and the coincidence model of oscillating light sensitivity?

    Textbook Reference: Photoperiodism: Monitoring Day Length, pp. 599–603

  5. What is the evidence that phytochrome is the primary photoreceptor in photoperiodism?

    Textbook Reference: Photoperiodism: Monitoring Day Length, pp. 603–604

  6. Define “vernalization” and discuss the role of epigenetic changes in gene expression. Textbook Reference: Vernalization: Promoting Flowering with Cold, pp. 605–608
  7. Discuss how grafting studies led to the hypothesis of a phloem-transmissible floral stimulus called “florigen.”

    Textbook Reference: Long-distance Signaling Involved in Flowering, pp. 608–610

  8. Discuss the mechanism of action of florigen in stimulating flowering in Arabidopsis. What other factors influence flowering?

    Textbook Reference: The Identification of Florigen, pp 610–612

  9. What are the major categories of genes that regulate floral development and how do they interact to regulate floral organ formation?

    Textbook Reference: Floral Meristems and Organ Development, pp. 613–618

  10. Describe the “quartet model” of floral organ specification.

    Textbook Reference: Floral Meristems and Organ Development, pp. 618–619