Season and fluorescence


Fluorescence in evergreen plant in different seasons ( autumn, winter, spring, summer)


The One v3.0 (Phi2, NPQt, using Multi-Phase Flash)

The One Protocol to rule them all! Phi2, NPQt combined.

Changes from previous The One protocol: - Removed the Phi1 measurement, which was producing a lot of invalid data (removed by Dan and Frank) - Implemented the multi-phase flash protocol created by Tom Avenson

Chlorophyll content (SPAD) III

REQUIREMENTS: Firmware v0.41 or higher. Measures transmission at 940nm and 650nm in order to determine the 'greenness' of a leaf, an indicator of chlorophyll content and nitrogen content. The 940 is used to account for leaf thickness. Improvements over Chlorophyll content (SPAD): - performs 3 different spads at 3 intensities for thin and thick leaves - auto-chooses appropriate intensity - is calibrated to a Minolta SPAD device from factory.

Improvements over previous version -

  • Compatible with firmware v0.41 or higher.
Proton Motive Force via DIRK

Estimates the proton motive force through the ATP synthase, thereby estimating ATP production. The proton motive force is measured by measuring the electrochromic shift (ECS), the shift in the absorbance of chlorophyll at ~520nm in the thylakoid membrane due to a shift in the electric field. The electric field is created by the accumulation of hydrogen ions (H+) in the thylakoid, causing an electric field to be produced between the inside and outside of the thylakoid membrane. This measurement applies the ambient light level in the chamber to the sample, then shuts off the light, causing the intensity of the electric field to drop as the H+ ions drain from the thylakoid. This drop in electric field intensity is detected by the measuring light at 520nm. The method is called DIRK - Dark Induced Relaxation Kinetics. The size of the change in the electric field (and therefore 520 signal) is an indicator of the quantity of H+ ions which had accumulated in the thylakoid. The rate at which the electric field changes indicates the capacity of ATP synthase to release H+ from the thylakoid membrane.


  1. Leaf side (Multiple Choice)
  2. Season (Multiple Choice)
  3. What kind of plants? (Multiple Choice)
  4. Temperature (Short Answer)
  5. Time of day (Short Answer)




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