Plant Physiology

Plant Physiology (Biology 327) - Dr. Stephen G. Saupe; College of St. Benedict/ St. John's University; Biology Department; Collegeville, MN 56321; (320) 363 - 2782; (320) 363 - 3202, fax; ssaupe@csbsju.edu

Quiz: Soil & Plant Water Uptake

True/False Questions: Answer the following True (T) or False (F). Then, correct any false questions.

1.		water movement through a plant is driven by an active pumping system
2.		soil is a mixture of organic and inorganic molecules
3.		silt particles are larger than clay particles
4.		loam and humus are synonymous
5.		saturated soil has a very negative water potential
6.		at field capacity, the water potential is ca. -0.01 MPa
7.		the field capacity of sand, silt and clay is the same
8.		the amount of water held by sand, silt and clay at field capacity is the same
9.		the permanent wilting percentage (pwp) for most plants is -5 MPa
10.		all plants have the same PWP
11.		sand holds water more tightly than clay
12.		soil water potential is a function of osmotic potential and pressure (or matric potential which refers to the tension generated because of the adhesion of water to soil particles

Diagram Question: The diagram below represents a cross section of a typical eudicot root.

Label the diagram by drawing a line from each of the following terms to the appropriate structure in the diagram. Then, describe the function of each structure.

Casparian strip

cortex

epidermis

endodermis

pericycle

phloem

stele

xylem

On the diagram, draw lines representing the following:

water moving from soil to xylem following an apoplastic route

water moving from soil to xylem following a symplastic route

water moving from soil to xylem following a transmembrane route

Short Answer Question: Using complete sentences, answer the following questions.

What is the apoplast? symplast? Give examples of each.
What is a hydathode?
What is guttation?
Identify two conditions that favor guttation
a. __________________________
b. __________________________
How do roots develop a root pressure?

Osmometer Question: The root is analogous to an osmometer (see diagram). For each of the following root structures, indicate the component of the osmometer to which it is analogous (glass tube, membrane, water in beaker).

Root Structure	Analogous Osmometer Structure
cortex
endodermis
xylem
symplast
apoplast

Drawing Question: Draw a long section of a root tip. Include and label the following structures: root cap, root hairs, zone of cell division, zone of elongation, zone of differentiation, zone of maturation. Where does the greatest water uptake occur?