Colorado Agriscience Curriculum
Section:
Plant & Soil Science
Unit:
Plant Physiology and Growth
Lesson Number:
4
Lesson Title:
Transpiration and Translocation Systems
Colorado Agricultural Education Standards:
Agriculture Science 11/12.4: The student will demonstrate and understanding of
physiological processes in agriculturally important plants.
Enabler AGS 11/12.4.8: Identify plant structures and their functions
Colorado Science Standards:
SCI 3.3.1, SCI 3.3.5
Student Learning Objectives (Enablers)
As a result of this lesson, the student will …
1. Understand the actions involved in transpiration and translocation
2. Demonstrate an understanding of transpiration through a lab
Time: Instruction time for this lesson: 50 minutes.
Resources:



AgriScience Lesson Plan Library, Unit C, Problem Area 4, lesson 2
AgriScience Fundamentals and Applications, Third Edition, Cooper and Burton
Principles of Field Crop Production, Fourth Edition, Martin, Waldren, and Stamp
Tools, Equipment, and Supplies
One copy, per student, of U3, L4 Lab Worksheet
A rapidly growing plant in a pot, bucket, or container (one per three students)
Plastic bag or sheet of clear plastic that will cover entire plant or a branch of plant
including 10-12 leaves (one per three students)
String, rubber bands, or other suitable materials to hold plastic in place over the plant
(one
per three students)
Stake to support the weight of the plastic (one per three students)
Plastic straw or other suitable tube for drain (one per three students)
Graduated beaker or measuring cup (one per three students)
One copy per student, slides 2-7
Unit 3, Lesson 4, Transpiration and Translocation Systems
1
Key Terms.
Osmosis
Xylem
Petiole
Translocation
Stomata
Transpiration
Phloem
Sieve Cells
Interest Approach
Allow students to role play, with them as a farmer and you as the crop consultant. The scenario
is a result of transpiration, which is the loss of water from a living plant, through the stomata.
Students should try to guess the problem, which is too little water because of transpiration.
Role play here with me for a moment. You are Tom Green, a young alfalfa farmer in Eastern
Colorado. I, on the other-hand, am Dave, the crop consultant. The problem is this: You are
applying 1” of water to your circles of alfalfa once every week, yet your plants are dried up and
brown. Temperatures are hovering around 95 degrees during the day, with 30% humidity. You
sure can’t make any money at this rate! As I come in to access the situation, I come upon the
solution immediately. Can you guess what the problem is?
Summary of Content and Teaching Strategies
Objective 1. Understand how plants absorb and transport materials
Transpiration is a given in our dry environment here in Colorado. Before we can counter the
effects of transpiration with more irrigation water, we need to understand how and why it
happens. Transpiration is based on a balance of water in the environment with water in the plant,
and if they two aren’t equal, the plant will loose or gain water to match the water in the
environment. Transpiration is actually the end step of a long process of water and nutrient
movement in the plant. We are about to discover just how water and nutrients are carried in that
alfalfa plant that Mr. Green is trying to grow.
Use slides 2-7 of the corresponding Powerpoint presentation to present the concepts in this
objective. It is suggested that you print these slides out for the students, as there are quite a few
notes. If not, have them take notes in their notebook.
How do Plants Absorb and Transport Materials?
• Step 1: Roots have tiny hairs covered with thin membranes that allow water and
nutrients to enter.
– Osmosis is the movement of water from an area of higher water concentration to
an area of lower water concentration.
– Water enters the roots until the concentration in the root is equal to the
concentration outside the root.
Unit 3, Lesson 4, Transpiration and Translocation Systems
2
•
•
•


– The water entering the root also carries substances (nutrients)
Step 2: After absorption by the roots, water is passed from cell to cell until it reaches the
xylem.
– Xylem is tissue, formed as tubes, that conducts water up the stems and to the
leaves.
– The petiole of the leaf takes the water from the xylem in the stem of the leaf veins,
which distribute it throughout the leaf.
***Remember…xylem move nutrients UP!
Step 3: Leaves loose water by transpiration.
– Transpiration occurs through tiny stomata (microscopic pores on the underside of
leaves).
– Transpiration creates somewhat of an upward pull that assists the xylem in
moving water and nutrients.
***Remember, translocation is the movement of sugars from the leaves through the
phloem.
Step 4: Manufactured food (created by plant) is sent back out from the leaves, through
the stems, and down to the roots in the phloem tissue.
– Phloem is the tissue, or plant tubing, that allows sugars, proteins, hormones,
dissolved materials, and salts to move from the leaves to the other parts of the
plant.
– Phloem are composed of sieve cells, which when hooked end to end, create a tube
for transport.
***Remember, phloem carries sugar products back down
Slide 6 depicts stomata on a leaf
Slide 7 depicts the xylem and phloem in a cross-section of a stem
Objective 2. Demonstrate an understanding of transpiration through a lab
Have the lab handout ready for each student (U3, L4 Lab).
Students will complete a lab based on the information they just learned, and to put transpiration
into context. Place students into groups of three …appoint one-third of the group as group
leaders, and have them select their two partners. If this wouldn’t work in your classroom, use an
alternate method of selecting partners. The lab will be set-up today and measurements will be
taken and compared tomorrow.
In order to really see how transpiration works, we are going to complete a lab. I need you to get
into groups of three. _________, __________, __________, and __________, you are going to
be the group leaders. I need you to select your two assisting scientists in order to complete this
lab. From this point, you can come get a lab worksheet. Read through all the directions and
steps, and if you have any questions, let me know. Next, collect your materials and get your lab
set up. Get started!
Assist students in getting the lab set-up.
Unit 3, Lesson 4, Transpiration and Translocation Systems
3
Review/Summary
Have students create a short skit or mime out the actions listed in Objective 1. They should
include parts such as the roots, water, stems, leaves, stomata, etc.
Time for some drama! To better reinforce the concepts we just learned, I need you to create a
short silent play or skit that depicts the steps that water and nutrients take to enter, travel inside,
and then exit a plant. Use the information we covered in objective 1 to help you. When I say
“mime”, elect a class leader, who will then assign parts. You will have 5 minutes to create your
silent skit and then 1 minute to present the skit. MIME!
Application
Extended classroom activity:
 Students could use a crops textbook to summarize and calculate how much water is
needed to produce one pound of dry matter for crops grown in their area. This would tie
transpiration into practical agriculture applications they may encounter.
 Determine the number of stomata on a leaf using a microscope. Biology textbooks have a
great lab for this activity.
FFA activity:
 For students with a greenhouse, nursery, or crop production SAE, encourage them to
complete the activity listed below and use it on a State Degree or Proficiency Application.
SAE activity:
 For students with a greenhouse, nursery, or crop production SAE, encourage them to
calculate how many gallons of water are need to produce their product. By measuring
the dry matter at the end of production, they can calculate how much was lost to
transpiration.
Evaluation.
See page 7, (U3, L4, Evaluation)
Answers to evaluation
1. D
2. G
3. A
4. F
5. E
6. B
7. C
Unit 3, Lesson 4, Transpiration and Translocation Systems
4
Unit 3, Lesson 4, Lab
Name:
Date:
Materials Needed:
A rapidly growing plant in a pot, bucket, or container (one per three
students)
Plastic bag or sheet of clear plastic that will cover entire plant or a
branch of plant including 10-12 leaves (one per three students)
String, rubber bands, or other suitable materials to hold plastic in place
over the plant (one per three students)
Stake to support the weight of the plastic (one per three students)
Plastic straw or other suitable tube for drain (one per three students)
Graduated beaker or measuring cup (one per three students)
Procedure:
1. Be sure the Plant is well watered
2. Cover the entire vegetative portion of the plant with plastic material
3. Locate tubing at bottom of plastic covering to serve as a drain, and
place beaker at the end of tube.
4. Place plant in sunny location for an entire day to encourage
transpiration
3. Collect and measure the water that is transpired during daylight hours;
record the measurement, and empty the beaker.
6. Collect and measure the water that is transpired during the night
hours; record the measurement, and empty the beaker.
7. Compare the differences in the amount of water collected
Questions:
1. What is the class average for the amount of water transpired during
the day?
2. What is the class average for the amount of water transpired at
night?
3. Which period produced the most water in the container (day or night)?
Why?
4. Does temperature have an effect on transpiration? How?
5. Does air humidity have an effect on transpiration? How?
Unit 3, Lesson 4, Transpiration and Translocation Systems
5
U3, L4, Evaluation
Name:
Date:
Match the following terms with their definitions.
___1. Transpiration
___2. Translocation
___3. Xylem
___4. Phloem
___5. Stomata
___6. sieve cells
a. Tubing that allows
nutrients to move up from
the roots
b. Cells that join together
end to end to form
phloem
c. Movement of water from
an area of higher
concentration to an area
of lower concentration
___7. Osmosis
d. Release of water from the
plant
e. Opening in plant leaves to
release water back into
the atmosphere
f. Tubing that allows
processed food to move
from the leaves back
down to the roots.
g. Movement of water and
nutrients in the phloem
Unit 3, Lesson 4, Transpiration and Translocation Systems
6