Plants that sequester heavy metals utilize pressure-flow where they move toxins from the source (soil) to a sink (such as the leaves).

Question

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

Answer 1

False

Clarify Question
• What is the key concept addressed by the question?
        o The question asks how a plant can move heavy metal from one tissue to another.
• What type of thinking is required?
        o You are being asked to take what you already know and apply it to the movement of a toxin from one location in a plant to another.
• What key words does the question contain and what do they mean?
        o Pressure flow, which explains the movement of sugar within the phloem of a plant from source to sink.
        o Source, which is a nutrient producing structure such as a leaf.
        o Sink, which is an area in a plant where nutrients are delivered and used.

Gather Content
• What do you already know about heavy metals in plants? How does it relate to the question?
        o The phloem contains sugars that are made within the leaves of the plant.
        o Phloem transports materials from the leaves to the stem and roots.
        o Water enters the plant through the roots and is carried upward to other tissues via the xylem.
        o Heavy metals may be present in the soil, so if they enter the plant, they would enter through the roots.

Consider Possibilities
• What other information is related to the question? Which information is most useful?
        o Phloem carries nutrients made within the plant, usually from leaves to other tissues.

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 need to connect the idea that the toxins are found in the soil with what you know about the transport system that moves water up from the roots. It is the xylem, not the phloem and pressure flow, that accomplishes this movement.

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?
• Apply level:
       o This question asked you to apply what you knowabout transport within a plant. Answering this question correctly depended on your ability to use transport of material from the roots 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 xylem moves material up from the roots, or that phloem moves material from source to sink? Did you have trouble extending how material moves upward in a plant to determine the correct answer?