|Introduction to Organismal Biology (BIOL221) - Dr. S.G. Saupe; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321; firstname.lastname@example.org; http://www.employees.csbsju.edu/ssaupe/|
Plant Transport & Gas Exchange Study Guide
Goal: The goal of
this unit is to provide a basic understanding of the process xylem and phloem
transport and gas exchange in plants.
II. Learning Objectives: Upon completion of this unit you should be able to:
Explain what is meant by the "photosynthesis/transpiration compromise".
Describe the structure of the stomatal apparatus and the mechanism of action for opening and closing the guard cells.
Describe the effect of the following on guard cell activity - light, carbon dioxide, drought, abscisic acid (ABA), circadian rhythms - and explain how each relates to the photosynthesis/transpiration compromise
Identify some of the functions of transpiration (water transport, evaporative cooling, minerals)
Describe the structure of the phloem (sieve tube members, companion cells, sieve tube members, sieve plates, companion cells, plasmodesmata)
Explain how aphids were important to our understanding of the phloem
Describe the mechanism by which solutes are transported in the phloem (pressure-flow hypothesis, double osmometer).
Identify the major cell types in the xylem (tracheids, vessels, fibers, parenchyma) and describe their function
Explain how water is transported in plants. Cite the three major hypotheses (root pressure and guttation, capillary action, transpiration-pull or cohesion tension) for water transport and explain how each works. Which is our best explanation for water transport?
Explain how the root acts like an osmometer
Explain the process of guttation and the conditions that favor this process. What is a hydathode?
Outline and describe the pathway that water takes into the root.
Identify the structure and function of the following features of a root: root cap, root hair, cortex, endodermis, casparian strip, pericycle, stele
Explain the concept of water potential. Identify factors that influence water potential. What is the water potential of pure water?
Important Terms/Concepts: (can
you use the following terms conversationally?
can you write a dialog using these terms?)
V. Additional Questions
Cite three pieces of evidence that the cohesion-tension theory is responsible for water transport in the xylem.
Review the Spuds demo. Do you understand the main concepts?
Some Suggested Learning Activities:
prepare written answers to the objectives
write a dialog using as many of the terms in the chapter as possible
prepare a concept map for this material
answer the questions at the end of the chapter or online
go through the CD-ROM & web site that accompanies the text.
write a definition for each of the terms listed in the text/notes above. Give a specific example of each term
spend approximately 2 hours per class studying this material
read the summary at the end of each chapter; then re-read each chapter summary.
Last updated: February 25, 2009 � Copyright by SG Saupe