1. Discuss the use of potting soil, which is completely organic matter, and how this is different from the soil of our yards. Explain why plants can grow in such an environment.
2. Give an example of the cohesion-tension model that students know about from their own experienceóhaving blood drawn at the doctor's office, where the blood fills the tube without suction. Discuss how the same thing is going on in a plant's xylem, but that there is also a pull exerted by the evaporation of water from the stomata as water moves in to replace the water vapor in the spongy mesophyll air pockets.
3. Discuss the uses of various minerals in the plant, such as nitrogen in proteins and nucleic acids, magnesium in chlorophyll, and other mineral ions in various hormones and enzymes.
4. Describe the benefits to the plant and its symbiote
in the relationships between legumes and nitrogen-fixing bacteria
or between many forest trees and their mycorrhizae. Mention the
relationship between the death angel mushroom or the edible truffles
and oak or apple trees, for example, and their mycorrhizae.