F-900RK: Using the Research Kit Fruit Chamber

To use the F-900 Research Kit in the field or laboratory, attach a hose of the chamber wand to the IN port on the front panel. Slide the end of the wand into the chamber and tighten the thumb-screw. Make sure the connection is snug. The fans inside the chamber will begin to spin when the connection is established. The fruit chamber available is 2L in volume. The chamber either has a flat-bottom or a bottom-slit to allow for non-destructive sampling. A fruit stem or petiole that is attached to the plant is passed through the slit and then closed in the chamber. This allows C₂H₄ levels to be recorded during ripening without damaging the fruit. Leaf chambers available for the CI-340 Photosynthesis System, from CID Bio-Science, Inc. (http://www.cid-inc.com) are compatible and interchangeable with the F-900 Research Kit.

If the tube is not connected to the OUT port, ambient air will be used to replenish the fruit chamber.

If the gas returning to the fruit chamber needs to be conditioned, consumables should be placed in Chamber Out and it should be turned on. Possible reasons to condition the air returning to the fruit chamber include scrubbing humidity (with silica gel) or scrubbing CO₂ (with soda lime). Build-up of carbon dioxide may inhibit fruit respiration at high concentrations. At high concentrations, the sensor fails to consume all the ethylene, so KMnO₄ could be used to scrub ethylene and not return it to the sample system.

Figure 12: Using conditioned air to replenish the fruit chamber by connecting the IN and the OUT (left); using ambient air to replenish the fruit chamber by disconnecting the OUT (right).

To sample a fruit:

• Open a data file to save the measurements to.
• Attach the chamber to the F-900 by screwing on the wand to the top of the chamber.
• Next, connect one of the tubes from the wand to the Intake port on the front of the F-900.
• Connect the black power chamber cable to the left of the display to power the fans in the fruit chamber.
• Place the fruit inside the chamber and close it.
• Observe and record the rate of change of ethylene over time with the F-900 Monitor Mode.