🌿 LI-COR LI-6800 Background Programs for leaf-level gas exchange measurement for photosynthesis model calibration

These LI-6800 Background Program scripts automate Dynamic Assimilation Technique (DAT) measurements across a series of light flux levels and temperatures, while ramping CO₂ and tagging each curve with a unique identifier (CurveID). It’s designed for efficient, high-resolution A–Ci curves to calibrate photosynthesis models.

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Key Features

• 🚀 DAT-Style A–Ci Curves: Continuous CO₂ ramping at varied lights and temperatures.
• 🤖 Fully Scripted Workflow: Minimal user input needed. Just start the script, and it handles light, temperature, and CO₂ changes dynamically.
• 📈 Model-Ready Output: Facilitates robust calibration of biochemical models of photosynthesis, including temperature and light dependencies.

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How to Use

1. 📥 Transfer the Scripts to the LI-COR

1. Download the .py script files (e.g., ACi_Light_Sweep.py) to your computer, and then to a USB thumbdrive.
2. Connect the head to the console and turn the LI-6800 on. Connect the USB thumbdrive to the LI-6800.
3. Use the LI-6800 file browser under Tools->Manage Files:. Select Copy files to LI-6800, and under the Copy to drop-down, select BP Directory. Find the protocol .py files, select them and press Copy to transfer the file to the device. Safely eject the USB with Eject.
4. Add user variables under the Constants -> User tab. Press Add followed by Edit and rename the variable CurveID. Make another variable and rename it Response.

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2. ⚙️ Run the Program and Set User Inputs

On the LI-COR LI-6800 console interface, navigate to the Programs tab, then to BP Builder and locate the programs downloaded in Step 1. Select the desired program and press Run.

📝 A dialog will appear to allow the editing of the following User inputs:

Variable	Label in UI	Description	Units	Example Default
begin_co2	Starting CO₂	Starting reference CO₂ for ramp	µmol mol⁻¹	10
init_wait	Pre ramp wait	Equilibration time before starting ramp	min	1
end_co2	Ending CO₂	Ending reference CO₂ for ramp	µmol mol⁻¹	2000
post_co2	Post-ramp CO₂	CO₂ setpoint after ramp	µmol m⁻² s⁻¹	400
ramp_rate	Ramp rate	Rate of CO₂ change during ramp	µmol mol⁻¹ min⁻¹	300
light_levels	Light levels	List of light intensities used per ramp	µmol m⁻² s⁻¹	[0,200,600,1200,1600,2000]
temperatures	Temperatures	List of air temperatures per light level	°C	[25,30,35,38,40,43]
log_int	Logging interval	Logging interval during CO₂ ramp	s	5
post_wait	Post ramp wait	Time to wait after ramp ends	min	0
pwlog	Log post ramp	Logging interval after ramp (if checked)	s (checkable)	Unchecked, value: 15

You only need to set these once. The script reads them at runtime.

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