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 |
Determining the Q10 for the Potato Experiment
(note:
I haven't tried this one yet - consider this lab experimental. It may need
work!)
Q10 refers to the
temperature quotient and is a ratio of the velocity of a process at a given
temperature to that at a temperature 10 C lower.
The advantage of Q10 is that it enables us to determine if a
process is a physical or chemical one. Chemical
reactions like those that occur in organisms, typically have a Q10 of
ca. 2.0 – 3.0. However, purely
physical processes have a Q10 of approximately 1.0.
The following equation is used to calculate the Q10:
where
T2
= higher temperature (in K or C)
T1
= lower temperature (in K or C)
K2
= rate of reaction at higher temperature
K1
= rate of reaction at lower temperature
To determine the Q10 of water uptake into the potato cores we will perform the Gravimetric experiment at different temperatures.
Protocol:
Set
up the gravimetric experiment as
previously described with the exception that only the 0.6 and 0.7 molal
sucrose solutions will be used. Prepare two samples of each.
Incubate one
sample of each at room temperature and the other at a higher (or lower)
temperature.
Record the temperatures
for all samples and time of
incubation in Table 1.
Complete
Table 2.
Table
1: Tuber Data |
||
Higher |
Lower |
|
Temperature
(C) |
||
Incubation
Period (minutes) |
Table 2: Potato Tuber Data | |||||
[Sucrose]
(molality) |
Water
Uptake at lower temperature (cm3) |
Water Uptake per minute at lower temperature (cm3
min-1) |
Water
Uptake at higher temperature (cm3) |
Water
Uptake per minute higher temperature (cm3
min-1) |
Q10 |
0.6 |
|||||
0.7 |
|||||
Mean |
Data/Analysis:
Is
water uptake a physical or chemical process?
Explain.
Reference:
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Last updated:
01/07/2009 � Copyright by SG
Saupe