The owner of a plant nursery is introducing the new night janitor to his duties. “Behind this door are the poinsettias,” she said, “Please don’t clean this room, and leave the door closed.” Why might the owner say this?

Question

A.  Poinsettias are short-day plants that require a long uninterrupted period of darkness to flower. Even a short flash of light at night could prevent flowering.
B.  Poinsettias are very sensitive to the chemicals used in cleaning, which can interfere with the gibberellin-dependent pathway and disrupt flowering.
C.  Poinsettias are tropical plants and require constant warm temperatures for flower formation.
D.  Poinsettias are long-day plants that require a long period of light for flower formation, and this light might disrupt the day-night cycles of other plants outside the room.

Clarify Question
What is the key concept addressed by the question?
What type of thinking is required?

Gather Content
What do you already know about short-day and long-day plants? What other information is related to the question?

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?

Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

A.  Poinsettias are short-day plants that require a long uninterrupted period of darkness to flower. Even a short flash of light at night could prevent flowering.

Clarify Question
What is the key concept addressed by the question?
        · This question is asking about the role of light in the life cycle of poinsettias.
What type of thinking is required?
        · Analyze level:
            o This is an analyze question because you have to break poinsettia life cycles and the influence of photoperiod into their component pieces to understand how they function.

Gather Content
What do you already know about short-day and long-day plants? What other information is related to the question?
        · Short-day plants flower when the photoperiod falls below a critical level.
        · Even a short burst of light can interrupt the period of uninterrupted darkness that is required for short-day plants.
        · Long-day plants flower when the photoperiod exceeds a certain level.

Choose Answer
Given what you now know, what information is most likely to produce the correct answer?
        · The nursery manager is trying to ensure that the poinsettias have uninterrupted darkness. Long-day plants do not require this, but this is a requirement of short-day plants.

Reflect on Process
Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        · Analyze level:
            o Answering this question correctly depended not only on distinguishing between long-day and short-day plants, but on your ability to break down, or analyze, the flowering requirements of a poinsettia. If you got an incorrect answer, did you remember that components of light requirements for flowering include periods of darkness, or that bursts of light would likely affect the required period of darkness for short-day plants? Did you have trouble breaking down the light requirements for flowering to determine the correct answer?