An application of too much fertilizer will negatively affect the movement of materials in the phloem.

Question

Answer the following statement true (T) or false (F)

Answer 1

True

Clarify Question
• What is the key concept addressed by the question?
        For water to move into plant roots, the water potential must be less inside of the plant than it is outside of the plant.
• What type of thinking is required?
        You are being asked to take what you already know and apply it to the effects of changing tonicity in the soil around a plant.
• What key words does the question contain and what do they mean?
        o Fertilizer, which is an applied substance that increases plant growth.
        o Phloem, which is vascular tissue that transports nutrients.

Gather Content
• What do you already know about water potential and how it effects the movement of water in plants? How does it relate to the question?
        o Adding fertilizer to the soil increases the solute concentration of the soil.
        o If the solute concentration of the soil is too high, the water potential will decline below that of the plant.
        o If the water potential is lower outside of the plant, water will flow out of the plant.
        o If water flows out of the plant, it will not be drawn into the xylem.
        o If water flow in the xylem ceases, the phloem will also be affected.
        o Without water flow from the xylem, nutrients will not be pushed from the phloem into the tissue.

Consider Possibilities
• What other information is related to the question? Which information is most useful?
        o Since fertilizer is a solute, adding it to the soil would affect the tonicity of the soil, which will affect water flow in the plant.

Choose Answer
• Given what you now know, what information and/or problem-solving approach is most likely to produce the correct answer?
        o You need to connect the presence of fertilizer with increased tonicity.
        o Increased tonicity in the soil can result in water loss from the plant.
        o With water loss, the flow of water and nutrients in the xylem and phloem are impeded.

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?
        o This question asked you to predict the effects of increasing tonicity by the additional of fertilizer. Answering this question correctly depended on your ability to use your knowledge of water flow in a new situation. If you got the correct answer, great job! If you got an incorrect answer, where did the process break down? Did you remember that water flows into xylem under normal conditions, or that water in the xylem flows into the phloem. which pushes nutrients into the tissues? Did you have trouble extending these ideas of nutrients and water flow to determine the correct answer?