Making Measurements
CO2 Response Curves
4-32
Using the LI-6400
4
flow/humidity status during the measurement, without having to leave the
graphics display. (Figure 4-3 on page 4-27).
Step-By-Step
HereÕs how to make an automatic CO
2
response curve. It uses the AutoPro-
gram ÒA-CiCurveÓ, described on page 9-21.
1
Set the chamber conditions
Light: Set the desired value. If not using the LED source, note that constant
light is critical for this measurement.
Flow: Fixed at 300 µmol s
-1
.
CO
2
: Constant reference CO
2
, at about 40 or 50 µmol mol
-1
above ambient.
2
Clamp onto the leaf
3
Set the humidity control
Note the value of
H2OS_mml
. Then change the flow control to constant mole
fraction, and target this value. The flow should be 300 µmol s
-1
or so. WeÕll
need room for it to increase, because the conductance will likely increase dur-
ing the measurement as the chamber CO
2
decreases.
4
Set the temperature
Set the temperature control for constant leaf temperature.
5
Open a log file
Make sure you have the computations, prompts, log list, etc. that you need.
6
Area and Stomatal Ratio
Are they correct?
7
Establish the Real Time Graphics display
Pick the display (
f2
level 4)
ÒA-Ci, RH_Flow, totalCVÓ
(press
4
then
f1
).
You might wish to adjust the scale of the Photo vs. Ci plot.
8
Match the IRGAs
Be sure
CO2S_µml
is stable before you do this.
9
Launch the ÒA-CiCurveÓ Autoprogram
Press
5
then
f1
. Pick ÒA-CiCurveÓ from the list.
When asked Ò
Append to current data file?
Ó Press
Y
Summary of Contents for LI-6400
Page 1: ...Using the LI 6400 Portable Photosynthesis System ...
Page 15: ...Part I The Basics ...
Page 16: ......
Page 174: ...Making Measurements Answers to Questions 4 56 Using the LI 6400 4 ...
Page 175: ...Part II Useful Details ...
Page 176: ......
Page 200: ...Standard Tools Power ON Hooks 5 24 Using the LI 6400 5 ...
Page 214: ...Real Time Data Real Time Graphics 6 14 Using the LI 6400 6 ...
Page 234: ...Environmental Control Light Control 7 20 Using the LI 6400 7 ...
Page 244: ...Light Sensor Considerations Gallium Arsenide Phosphide GaAsP Sensor 8 10 Using the LI 6400 8 ...
Page 288: ...Data Logging Making Your Own AutoPrograms 9 44 Using the LI 6400 9 ...
Page 289: ...Part III Working With Files ...
Page 290: ......
Page 312: ...The LPL File System Troubleshooting 10 22 Using the LI 6400 10 ...
Page 340: ...Downloading Files Using a Data Capture Program 11 28 Using the LI 6400 11 ...
Page 375: ...Part IV Configuration Issues ...
Page 376: ......
Page 420: ...Defining User Variables Old Style vs New Style 15 18 Using the LI 6400 15 ...
Page 454: ...Using an Energy Balance Further Reading 17 12 Using the LI 6400 17 ...
Page 455: ...Part V Maintenance Troubleshooting ...
Page 456: ......
Page 572: ...Troubleshooting Useful Information 20 46 Using the LI 6400 20 ...
Page 593: ...Part VI Programming ...
Page 594: ......
Page 622: ...Programming with LPL Compiler Directives 22 28 Using the LI 6400 22 ...
Page 846: ...Index I 16 Using the LI 6400 ...