Research has shown that cytokinin levels fluctuate seasonally in temperate plants. What season would you expect to see the lowest levels of cytokinins and why would this be adaptive?
A. Spring, because lower levels of cytokinin allow auxin to promote rapid growth in stem height. This will allow the plant to compete effectively for sunlight.
B. Summer, because lower levels of cytokinin would slow growth down and delay leaf aging. This will allow the plant to maximize the production of starch and increase it's sugar reserves. This will help ensure the plant's survival through Autumn and Winter.
C. Autumn, because lower levels of cytokinin at this time of year will induce the production of ethylene. This will result in maturation of fruit and ensure effective seed dispersal before Winter.
D. Winter, because lower levels of cytokinin will place buds into a dormant state. This will protect the underlying tissues from freezing until Spring.
Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?
Gather Content
· What do you already know about cytokinin levels and seasonality? How does it relate to the question?
Consider Possibilities
· What other information is related to the question? Which information is most useful?
Choose Answer
· Given what you now know, what information and/or problem solving approach 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?
D. Winter, because lower levels of cytokinin will place buds into a dormant state. This will protect the underlying tissues from freezing until Spring.
Clarify Question
· What is the key concept addressed by the question?
o This question is asking about seasonal fluctuations in the levels of cytokinins.
· What type of thinking is required?
o This question is asking you to evaluate-the changes that occur in cytokinin levels in plants as the seasons change in a temperate climate.
· What key words does the question contain and what do they mean?
o Temperate, which refers to climates that have moderate temperature changes between seasons.
o Cytokinin, which are plant hormones that promote cell division in plants.
Gather Content
· What do you already know about cytokinin levels and seasonality? How does it relate to the question?
o Highest growth rates for temperate plants occur in warmer months.
o In the Winter, cytokinin levels drop in temperate plants. This places buds into a state of dormancy during the cold and dark Winter. This will protect the delicate tissues until the Spring when cytokinin levels will increase again and buds will break dormancy and grow.
Consider Possibilities
· What other information is related to the question? Which information is most useful?
o During warmer months, biochemical activities and plant growth would occur at a higher rate than they would in colder months.
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
o To answer this question, you must connect the ideas of cold weather and the inhibition of metabolic activity. This is adaptive, because plant growth at this time would leave the tissues vulnerable to damage due to freezing.
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?
· Evaluate level:
This question asked you to evaluate the importance of seasonal changes on cytokinin activity. Answering this question correctly depended on your ability to evaluate how living tissues react to temperature changes. If you got the correct answer, well done! If you got an incorrect answer, where did the process break down? Did you remember that freezing temperatures destroy living tissue? Did you have trouble weighing the merits of plant growth to environmental extremes to determine the correct answer?
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