[Campbell Biology P.909] Consider the 'VISUAL SKILLS' prompt: 'Under long-day conditions as ... | Practice Question

Consider the 'VISUAL SKILLS' prompt: 'Under long-day conditions as in the top panel or under short-day conditions as in the second panel , how would a single flash of far-red light during the dark period affect flowering?' Based on the provided text and Figure 39.20, what is the most accurate conclusion?

  • A: In long-day plants, flowering would be inhibited, while in short-day plants, flowering would be promoted.
  • B: A single flash of far-red light alone would have no significant effect on flowering in either long-day or short-day plants under these specific conditions.
  • C: Both long-day and short-day plants would cease to flower because far-red light acts as a strong inhibitor.
  • D: The effect would depend on the previous light exposure, but if no red light was given, it would enhance flowering in both types of plants.

Explanation

The text explains that far-red light fr primarily 'cancels the red flash's effect.' If no red light r flash occurs to interrupt the dark period, a single far-red flash alone would not initiate a change in the phytochrome state that would affect flowering in either long-day or short-day plants.