Concepts of Biology (BIOL116) - Dr. S.G. Saupe; Biology Department, College of St. Benedict/St. John's University, Collegeville, MN 56321; ssaupe@csbsju.edu; http://www.employees.csbsju.edu/ssaupe/ |
Plant Transport & Gas Exchange Study Guide
I.
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?
III.
Reading(s):
Purves
et al, Ch 35 (only the parts of chapter covered in class or on this study
guide will be included on the exam)
IV.
Important Terms/Concepts: (can
you use the following terms conversationally?
can you write a dialog using these terms?)
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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?
VI.
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.
References:
Dr. Berg's Favorite Water Relations Stories - a good web site for an overview of water and plants
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Last updated: January 29, 2004 � Copyright by SG Saupe