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Appendix B
•
PAR Clip
PAR Clip
The PAR leaf Clip is designed to provide data to the OS1p system on Photosynthetically
Active Radiation, or PAR and leaf temperature conditions. This clip resembles the
standard 45
0
angle open body clip provided with the OS1p, with two additional features.
A thermistor for measuring leaf temperature and a PAR sensor for measuring light
radiation on the leaf are included. The PAR sensor is mounted in a small support
extending into the leaf measuring area. The thermistor is tethered below the support to
measure leaf temperature.
Unlike other brands of PAR Clips, the OS1p PAR Clip measuring jaw opens from the
bottom. This prevents the unwanted opening of the PAR Clip when measuring high
leaves or when the PAR Clip is used on a tripod stand for longer quenching
measurements.
The default equation for ETR when using the PAR Clip is:
ETR=Y(II) x PAR x 0.84 x 0.50. This equation uses average plant values for relative
comparison between samples of the same species. For more exacting ETR values the leaf
absorption and the ratio of PSII reaction centers may be changed in the Y(II) protocol.
See the section on Quantum Photosynthetic Yield of PSII in chapter one and the section
on ETR in chapter three for more details.
Connection
The fiber optic light guide is positioned in the PAR Clip in the same manner as the dark
clip. Insert the single cylindrical barrel all the way into the PAR clip as shown below. A
nylon locking screw secures the fiber end. The PAR clip is connected to the “accessory”
port on the OS1p.It is recommended that the OS1p should be turned off when connecting
the electronic PAR clip connector to the fluorometer.
Technical specs
Weight:
0.6 Lbs. or .27kg
Cable length: 1 m.
Tripod Thread Mount ¼ inch 20 thread (Standard 35mm camera mounts use the same
thread)
Temperature Sensor: Thermister
Temperature Range 5~60
o
C.
Temperature Accuracy
±
1.0
o
C (worst case).
