The PAM-2500 chlorophyll fluorometers are successors of the well-known PAM-2000/2100 instruments which were introduced in the 1990s as the first portable PAM fluorometers. Since then they have been successfully applied worldwide by numerous scientists.
In the development of the PAM-2500, particular care was taken to maintain all properties appreciated by PAM-2000/2100 users and, at the same time, to integrate state-of-the-art technology.
PAM-2500 with first-generation 2030-B leaf clip and ultra-mobile PC connected by Bluetooth
Essentially, the hardware and optical system are thoroughly modernized. Also, while continuing basic elements of the graphical user interface, instrument operation is based on the newly-developed PamWin-3 software.
The program permits operation under Windows operating systems on normal personal computers, but also on ultra mobile touch screen computers (UMPC).
PAM-2500: Field measurement
Major Points of Progress of the PAM-2500
Saturation pulse as well as polyphasic rise analysis with time resolution down to 10 μs
Latest generation light-emitting diodes for all internal light sources
High sensitivity enabling high quality measurements with dilute suspensions of algae and cyanobacteria
The PAM-2500 chlorophyll fluorometer is an extremely compact and powerful measuring system. All optical and electronic components are located in a 23 cm x 10.5 cm x 10.5 cm housing. The light sources of the PAM-2500 are light-emitting diodes (LEDs) permitting quasi-rectangular light intensity changes.
The PAM-2500 employs measuring light of 630 nm consisting of 1 μs pulses given at frequencies from 10 Hz to 200 kHz. Strong red actinic light of 630 nm is provided by a Chip-On-Board LED array. The fluorometer also features a blue actinic light source having the peak emission at 455 nm. In addition, a far-red LED with peak at 750 nm permits selective excitation of PS I.
Measuring Principle & Quenching Analysis
The PAM-2500 chlorophyll fluorometers employs pulse-amplitude-modulated (PAM) measuring light to excite chlorophyll fluorescence. The intensity of the PAM excitation light can be sufficiently low for monitoring fluorescence yield without affecting the state of photosynthesis.
The resulting modulated chlorophyll fluorescence is detected with high sensitivity and selectivity, but the fluorometer is virtually insensitive to even strong unmodulated light like full sunlight or saturation pulses at up to 25,000 μmol m-2 s-1.
In addition to the current fluorescence yield in continuous light (Ft) and the maximum yield during saturation pulses (Fm or Fm') it is also possible to determine the minimum yield after dark-acclimation (Fo) or in illuminated state (Fo').
The PamWin-3 software calculates automatically four quenching coefficients (qP, qL, qN, and NPQ), the effective yield of PS II photochemistry (Y(II)=ΔF/Fm') and the complementary yields of non-photochemical energy dissipation (Y(NO) and Y(NPQ)) as well as the apparent electron transport rate (ETR).
Ultra Mobile Computer UMPC and Battery for Field Studies
Two add-ons convert the PAM-2500 chlorophyll fluorometer into a highly mobile field station, equipped with the options that a normal PC offers and working for hours independently of line current.
• A touch-screen ultra-mobile personal computer (UMPC; for instance the Acer Iconia W3) equipped with a high capacity battery. The UMPC is placed on top of the PAM-2500 fluorometer using a special metal box strapped to the fluorometer’s central unit.
• An external battery (12 V, 2.1 Ah) for the PAM-2500 chlorophyll fluorometer. An automatic charger for this battery is available.
All parts required for long-term battery-powered operation of the PAM-2500 chlorophyll fluorometer fit into the PAM-2500 carrying bag which is supplied with the basic system.
Light and Temperature-sensing
Leaf Clip 2030-B
Information on ambient light and temperature conditions is indispensable for field investigation. Therefore, we have devised the leaf-clip 2030-B which measures by a mini-quantum sensor the photosynthetically active radiation (PAR) impinging on the leaf under investigation. In addition, the 2030-B leaf-clip records the leaf temperature with a NiCr-Ni thermocouple.
To facilitate studies under field conditions, fluorescence measurements can be triggered by pushing the control button of the leaf-clip holder 2030-B. A tripod (ST-2101A) is available for positioning of the leaf-clip 2030-B but also the mini quantum/temperature-sensor 2060-M or the Arabidopsis leaf clip 2060-B.
Fiberoptics Holder for Surfaces 2060-A
The holder positions the PAM-2500 fiberoptics on bulky samples. Combinable with the 2060-M Mini Quantum/Temp.-Sensor, to measure temperature and impinging PAR of the surface area investigated.
Arabidopsis Leaf Clip 2060-B
Aluminum clip with small measuring area designed to position small leaves below the fiberoptics of the PAM-2500. When combined with the 2060-M Mini Quantum/Temp.-Sensor, PAR on sample level and lower leaf temperature is recorded.
Precise mini quantum and temperature sensors usable independently or in conjunction with the 2060-B Arabidopsis Leaf Clip or the 2060-A Fiberoptics Holder for Surfaces.
Leaf Clip DLC-8
The DLC-8 leaves clips permit dark-acclimation of small leaf areas in the field. The tip of the PAM-2500 fiber optics fits exactly in the DLC-8 port. With the fiber tip inserted, the sliding shutter of the DLC-8 can be opened so that F0 and FM level fluorescence can be measured without interference of ambient light.
Leaf Positioning Device DUAL-BA
For measurements of attached leaves with the fiber optics, we have developed the leaf positioning device, DUAL-BA. The device includes a fiber optics holder, a magnetic end piece for the fiber optics and a right-angled metal sheet that sticks to the end piece by magnetic force. The metal sheet positions the leaf in front of the fiber optics end.
Suspension Cuvette KS-2500
The suspension cuvette includes a 400 μl sample compartment made of stainless steel with PVC exterior. The cuvette is equipped with a 7 mm fiberoptics window adapter, an injection port for Hamilton syringes, and nozzles for connecting an external flow-through water-bath for temperature control.
The device is equipped with a specially modified stirrer plate to center and hold the KS-2500 suspension cuvette. The MKS-2500 stirrer comes with a Perspex base plate with stand bar for mounting fiberoptics on top of cuvette.
Fiberoptics Adapter 90º (2030-B90)
The fiberoptics adapter 90º can be attached to the leaf clips 2030-B and 2060-B to position the PAM-2500 fiberoptics at 90° angle relative to leaf plane.