7. Cells in lower layers of your skin divide and replace dead cells sloughed from the surface. Why is it inaccurate to compare such regions of cell division to a plant meristem? 8. Roots and stems grow indeterminately, but leaves do not. How might this benefit the plant? 9. Suppose a gardener picks some radishes and finds that they are too small. Since radishes are biennials, the gardener leaves the remaining plants in the ground, thinking that they will grow larger during their second year. Is this a good idea? Explain. 10. Describe how roots and shoots differ in branching.
11. Contrast primary growth in roots and shoots.
12. When grazing animals are removed from grasslands, eudicots often replace grasses. Suggest a reason why. 13. If a leaf is vertically oriented, would you expect its mesophyll to be divided into spongy and palisade layers? Explain. 14. A sign is hammered into a tree 2 meters from the tree’s base. If the tree is 10 meters tall and elongates 1 meter each year, how high will the sign be after 10 years? 15. Stomata and lenticels are both involved in gas exchange. Why do stomata need to be able to close, but lenticels do not? 16. Would you expect a tropical tree to have distinct growth rings? Why or why not? 17. If a complete ring of bark is removed around a tree trunk (a process called girdling), the tree usually dies. Explain why. 18. What attributes of the weed Arabidopsis thaliana make it such a useful research organism? 19. How can two cells in a plant have vastly different structures even though they have the same genome? 20. Explain how the fass mutation in Arabidopsis results in a stubby plant rather than a normal elongated one. 21. In some species, sepals look like petals, and both are collectively called “tepals.” Suggest an extension to the ABC model that could hypothetically account for the origin of tepals. [pic]
Structure & Function of Plants Review: Resource Acquisition and Transport in Vascular Plants 1. Why is long distance transport important for vascular plants? 2. What architectural features influence self-shading?
3. Why might a crop develop a mineral deficiency after being treated with a fungicide? 4. Some plants can detect increased levels of light reflected from leaves of encroaching neighbors. This detection elicits stem elongation, production of erect leaves, and reduced lateral branching. How do these responses help the plant compete? 5. If you prune a plant’s shoot tips, what will be the short term effect on the plant’s branching and leaf area index? 6. If a plant cell immersed in distilled water has a ΨS of -0.7 MPa and a Ψ of 0 MPa, what is the cell’s ΨP? If you put it in an open beaker of solution that has a Ψ of -0.4 MPa, what would be its ΨP at equilibrium? 7. How would an aquaporin deficiency affect a plant cell’s ability to adjust to new osmotic conditions? 8. How would the long distance transport of water be affected if vessel elements and tracheids were alive at maturity? Explain. 9. What would happen if you put plant protoplasts in pure water? Explain. 10. How do xylem cells facilitate long distance transport? 11. A horticulturalist notices that when...