How do we know that the germinating seeds giving out CO₂?

Seeds that are purchased for planting are viable. Viable seeds are
alive but show no signs of any life processes. Scientists refer to
seeds In this condition as being dormant. When dormant seeds are
soaked In water, they respond by showing evidence of life processes.
Seeds that show evidence of life processes are called
germinating seeds. One of the life processes carried out by seeds Is
respiration. During respiration, a seed takes In oxygen from the air
and gives off carbon dioxide. The volume of oxygen taken in and
carbon dioxide given off is about equal.
OBJECTIVES
• Prepare respiration chambers to measure the
amount of oxygen used by dormant and
germinating seeds.
• Compare the respiration rate of dormant and
germinating seeds.
MATERIALS ~ ~ n
• Predict the volume of oxygen used by seeds In
several experimental conditions.
• Hypothesize how much oxygen Is used by
dormant and germinating seeds.
test tubes (3)
bean seeds, soaked (5)
bean seeds, dry (5)
absorbent cotton
PROCEDURE
metric ruler
soda lime
small beaker
water, colored
measuring half-teaspoon
masking tape
marking pen
rubber band
laboratory apron
Dorman
1. Place five dry, dormant bean seeds Into a test
tube.
2. Add a small cotton plug just above the seeds.
Pack the cotton just tightly enough so that the
seeds cannot fall out when the tube Is turned
upside down.
3. Add a half-teaspoon of soda lime (a carbon
dioxide gas absorber) to the test tube.
CAUTION: Do not handle soda lime with bare
hands.
4. Insert a second cotton plug over the soda lime
as shown in Figure 1.
5. Use masking tape and a pen to label the test
tube "dormant." Place the label near the middle
of the test tube.
6. Prepare a second test tube in a similar manner.
However, put five soaked, germinating seeds In
this test tube. Label this test tube "germinating."
Figure 1.
Cotton plug
Soda lime
Cotton plug
Dry seeds
(dormant)
Cotton plug
Cotton plug
Soaked seeds
(germinating)........