Leaf Photosynthesis & Respiration Lab Notes

Leaf Photosynthesis/Respiration Lab

Part 1:  Chamber covered in aluminum foil

1) Obtain leaves and put in Vernier BioChamber 250 with forceps
2) Obtain a piece of aluminum foil and wrap entirely around BioChamber 250 to block out light
3) Orient chamber like the image above (on its side)
4) Poke out hole for O2 sensor, which goes on top; CO2 probe goes on the side
5) Set up Lab Quest and sensor probes; Fit sensor probes into chamber
6) Calibrate according to directions below, if necessary.
7) Change units for both probes to “ppt” and change the “length” of recording to 900 seconds (15 minutes)
8) Press play to collect data; record starting and ending values and sketch graphs for both probes

Part 2:  Chamber exposed to bright light

1) Remove aluminum foil from container and PUT ON GOGGLES for safety purposes
2) Turn on lamp, then move BioChamber about 1 foot from the lamp
3) Fill 600ml beaker with tap water and place between lamp and BioChamber to block heat (but not light) from the leaves
4) Lamp should be on leaves for 5 minutes before beginning data collection
5) Set length of recording to 900 seconds again, press play, and collect data

Calibration steps:

1) CO2 should be around 350-400ppm; if not, use stylus to depress “CAL” button on probe until red light blinks and sensor       reads proper value
2) O2 should be around 20.5-21.0%; if not, calibrate by the following steps:
    a) Tap O2 box on Lab Quest and click “calibrate”; on next screen, click “Calibrate Now” in upper-left corner
    b) While another lab member depresses the “CAL” button on the O2 probe, enter “0” in first box and click “keep”
    c) Release O2 probe “CAL” button, then enter “20.9” in the right box and click “keep” and then “OK”