Compact Fluorometer for Long-term Monitoring of Photosynthesis

A MICRO-PAM system involves several light-weight chlorophyll fluorometers for field use. Being capable of multi-site monitoring of photosynthesis over weeks and months, the MICRO-PAM is tailored to study plant responses to environmental changes in nature and under controlled conditions. Due to its compact measuring heads, the MICRO-PAM is suited for smaller samples than those typically probed by the established MONITORING-PAM.

Originally, the MICRO-PAM has been developed to measure photosynthesis of lichens growing on rocks or in biological soil crusts. The actual field of application includes herbaceous plants, shrubs and trees. In addition to determining photosynthesis yield by the saturation pulse technique, the measuring heads record light intensity and temperature by external sensors, and humidity by an internal sensor.

• Compact measuring heads
• Energy-efficient design
• Chlorophyll fluorescence plus PAR, temperature, and humidity

The measuring heads of a MICRO-PAM system are denoted as MICRO-HEAD/3B where the “3” specifies the diameter in mm of the light guide and the "B" stands for the blue color of measuring and actinic light.

The MICRO-HEAD/3B possesses a blue power LED with maximum emission at 465 nm and a full width at half maximum of 22 nm. The maximum actinic light intensity at sample level is 3000 μmol m-2 s-1, the maximum saturation pulse intensity is 8000 μmol m^-2 s^-1.

The MICRO-HEAD/3B is equipped with a sample clip. A cosine-response PAR sensor is positioned parallel to the sample plane. A thermocouple touching the lower sample side measures temperature. Humidity is measured by a capacitive-type sensor located inside the fluorometer housing. On request, a special stand will be provided to mount the MICRO-HEAD/3B on solid surfaces.

MICRO-PAM systems can be operated in the ONLINE configuration in which up to four measuring heads can be connected via the MONI-IB4/LAN PC Interface Box to an USB port of a Windows computer running WinControl-3. In the OFFLINE configuration, measuring heads are connected directly or via the so-called MINI-HUB to a MONI-DA data acquisition system.