Making Measurements
Light Response Curves
Using the LI-6400
4-27
AutoPrograms
There are at least two possibilities here: ÒLightCurveÓ (described on page
9-27) and ÒTimedLampÓ (described on page 9-30). ÒLightCurveÓ lets you
specify the sequence of light values you want. A minimum and maximum
wait time is specified. (Logging canÕt occur before the minimum time ex-
pires; after that, a record is logged when a stability variable (TotalCV%)
drops below some threshold that you specify, such as 1%. ÒTimedLampÓ also
lets you specify a sequence of light values, but at each one, you specify a) how
long to maintain that light level, and b) how often to log data within that pe-
riod. This program is good for recording events throughout the experiment,
letting you record how the leaf responded with time, as well as with light.
Rapid Light Curve, Step-By-Step
HereÕs how to make an automatic light response curve. It uses ÒLightCurveÓ,
and does a rapid response curve.
1
Prepare the chamber
Light: Typically 1500 µmol s
-1
for C
3
plants, or 2000 for C
4
plants.
CO
2
: Constant reference CO
2
, about 400 µmol mol
-1
, or your choice. (This is
temporary - weÕll switch to constant sample in a few minutes.)
Flow: Constant flow, 500 µmol s
-1
.
2
Clamp onto the leaf
Figure 4-3. The ÒA-Q, RH_Flow, totalCVÓ configuration.
When doing constant humidity control, watch the
horizontal position to make sure the flow rate
doesnÕt get too low or too high. If it gets close to
700, increase the desiccant scrub. If it gets close
to 100, increase the bypass.
When doing fixed flow,
watch the vertical position
to make sure the humidity
stays about where you
want it.
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 ...