Plants often use changes in day length (photoperiod)to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes
A) are more predictable than air temperature changes.
B) alter the amount of energy available to the plant.
C) are modified by soil temperature changes.
D) can reset the biological clock.
E) are correlated with moisture availability.

Question

Quizplus · Accepted Answer

Photoperiod changes are more predictable than air temperature changes, which can fluctuate rapidly and unpredictably. Therefore, plants have evolved to use photoperiod as a cue for important developmental events such as flowering and dormancy.

Answer: B
 Changes in photoperiod can affect the amount of energy available to the plant, as longer periods of daylight allow for more photosynthesis and energy production. Thus, plants have evolved to use photoperiod as a way to optimize energy use and growth.

Answer: D
 Photoperiod changes can reset the biological clock in plants, as they use light as a cue to regulate their physiological processes. The precise timing and duration of light exposure can affect the timing of important developmental events such as flowering and dormancy.

Note: Choices C and E are not accurate explanations for why plants use changes in photoperiod to trigger developmental events.

Plants Often Use Changes in Day Length (Photoperiod)to Trigger Events