Technical information

PHOTOSYNTHESIS, TRANSPIRATION AND STOMATAL CONDUCTANCE
3/31/2008 Rev. 4.3 7-4
are using fully covers the leaf chamber window, enter the area of the window. Table 7-1 and 7-2 at
the end of this chapter list the window sizes of all the leaf chambers CID, Inc. manufactures.
Flow rate? (lpm)
___
Enter the intended flow rate (in lpm). The pump and flow sensor have been designed to operate under
controlled specifications. Use a flow rate between 0.1 and 1 lpm. But if the CI-301AD is used, the
flow rate should be < 0.5 lpm.
Finally, the CI-340 will ask whether an open or closed system measurement will be conducted. The
default entry is for the open system (press
to use the default). Press “C” to select the closed
system measurement or “O” for open system. The closed system function will ask for the chamber
volume (in liters). Refer to Table 7-2 for closed system chamber information. Closed system
measurements can be terminated when a certain change in time (ΔT) or change in CO
2
(ΔCO
2
) has
been measured, or the
key can be pressed. Press “T” for ΔT or press “C” for ΔCO
2.
The
system will then ask for the length of time or the change in CO
2
required for the measurement. Also,
refer to the CLOSED AND OPEN SYSTEMS section for further elaboration of measuring
procedures.
The instrument will be stabilizing for several seconds. Then data output will be displayed. Use the
arrow keys on the keypad to scroll up and down to view all the data.
CLOSED AND OPEN SYSTEMS
The CI-340 promotes a portable solution to the concept behind open and closed systems. A closed
system environment can measure the CO
2
concentration in the chamber over a given period of time.
An open system environment can measure CO
2
concentration in the chamber by a steady air stream
flow. At any rate (0.2 to 1.0 lpm), this instrument provides another practical method to determine
photosynthesis, transpiration, and stomatal conductance.
The physical distinction between the two systems is with the accessory tubing attachment (Figure 7-
1). The open system utilizes a steady stream of fresh air; the closed system recirculates the air within
the analyzer environment. Figures 7-2 and 7-3 illustrate further the CI-340’s closed and open system
flow chart, respectively.
Figure 7-1. The CI-340 accessory tubing attachment.