In the MODULAR version of PHYTO-PAM-II the multi-color-emitter and photomultiplier-detector units are separated from the control unit, mounted to a central optical unit holding a 10 x 10 x 45 mm cuvette.
The modular setup features flexibility in the choice of detector filters and constitutes an open optical system, providing two additional optical ports for connection of alternative light sources or detectors. Furthermore, it also allows to connect a miniature magnetic stirrer to the bottom of the cuvette and to insert a Peltier temperature control “finger” at the top.

The MODULAR version can be recommended primarily for basic research on photosynthesis of algae and cyanobacteria in dilute suspensions and/or natural phytoplankton samples. Therefor the MODULAR version is mainly designed for laboratory applications but as the Power-and-Control-Unit PHYTO-II-C is equipped with a battery, this PHYTO-PAM-II system may also be used in on-deck and field applications.


A basic system of the MODULAR version of the PHYTO-PAM-II consists of the following components:

  Power-and-Control-Unit PHYTO-II-C

  Multi-Color Emitter Unit PHYTO-II-E featuring Chip-On-Board (COB) LED arrays for pulse-modulated fluorescence excitation at 440, 480, 540, 590 and
625 nm, as well as actinic illumination (440, 480, 540, 590, 625 nm and white) in form of continuous light and Single- or Multiple Turnover light pulses; with far-red light source (740 nm) for selective excitation
of PS I

  Photomultiplier-Detector PHYTO-II-D featuring an automatic overload switch and special detector filter combination.

  Optical Unit ED-101US/MP with a 10 x 10 x 45 mm quartz-cuvette to be mounted on the delivered stand.

  Mini Quantum Sensor US-MQS/WB for calibration of the PAR lists of the measuring light, variously colored actinic light and multiple turnover pulses.

The system can be extended by the Temperature Control Unit US-T and the Miniature Magnetic Stirrer PHYTO-MS.

The Optical Unit as well as the Emitter-unit of the MODULAR version are almost identical to those of the MULTI-COLOR-PAM, rendering these two PAM measuring systems optically compatible. Major differences are the highly sensitive photomultiplier detector (PHYTO-PAM-II) versus the less sensitive photodiode detector (MULTI-COLOR-PAM), the quasi-simultaneous application of 5 measuring light colors for deconvolution of the responses of up to 4 different pigment types (PHYTO-PAM-II) versus one color at the time (MULTI-COLOR-PAM).
In general, the PHYTO-PAM-II is suited for differentiable analysis of mixed samples of phytoplankton, whereas the MULTI-COLOR-PAM can be recommended for basic research on wavelength-dependent properties of photosynthesis in leaves and mono cultured algae samples.

More differences are listed in the comparison table below.

Measuring light colors 5 5 + 400 nm
Measuring light intensity low and high 20 steps
Deconvolution of signal from population mixes Yes No
Signal Detection photomultiplier photodiode
Fast kinetics mode O-I1 rise, σII(λ) O-I1 rise, σII(λ) ,polyphasic rise, decay kinetics, freely programmable kinetics
Leaf clip No, only suspensions Yes
Pre-optimized Yes, algae flexible operation