[Campbell Biology P.906] According to the provided text, which of the following is a primary... | Practice Question

According to the provided text, which of the following is a primary physiological response typically triggered by the Pfr form of phytochrome?

  • A: Inhibition of branching.
  • B: Promotion of vertical growth.
  • C: Seed germination.
  • D: Degradation of chlorophyll.

Explanation

The text and Figure 39.17 explicitly state that seed germination is one of the primary physiological responses triggered by the Pfr form of phytochrome. Sunlight, which contains more red light, leads to an increased Pfr/Pr ratio, thereby triggering germination.