Pulse-amplitude modulated (PAM) chlorophyll fluorometry in combination with saturating pulse analysis of fluorescence quenching is now a standard technique to assess plant photosynthesis.
In the 1990s, the Walz Teaching-PAM fluorometer (PAM-200) carried PAM fluorometry into university classrooms. Since then, there has been considerable progress in LED and PC technology, enabling the development of a powerful and versatile, and at the same time compact teaching fluorometer: the JUNIOR-PAM.
Optoelectronic Unit JUNIOR-PAM (BLUE Version)
|Modulated fluorescence excitation:||Blue LED (wavelength of maximum emission: 445 nm). Modulation frequencies 5 to 25 Hz adjustable in increments of 5 Hz, and 100 Hz. Fluorescence at wavelengths greater than 630 nm is measured.|
|Actinic light:||Same LED as used for modulated light. PAR at 1 mm distance from the tip of the 50 cm JUNIOR-PAM light guide: 25 to 1500 μmol m-2 s-1. Maximum PAR of saturation pulses, 7000 μmol m-2 s-1|
Optoelectronic Unit JUNIOR-PAM/W (WHITE Version)
|Modulated fluorescence excitation:||White LED (wavelengths of maximum emission: 445 and 545 nm). Modulation frequencies 5 to 25 Hz adjustable in increments of 5 Hz, and 100 Hz. Fluorescence at wavelengths greater than 650 nm is measured.|
|Actinic light:||Same LED as used for modulated light. PAR at 1 mm distance from the tip of the 50 cm JUNIOR-PAM light guide: between 25 and 1500 μmol m-2 s-1. Maximum PAR of saturation pulses, 4000 µmol m-2 s-1|
Optoelectronic Unit JUNIOR-PAM and JUNIOR-PAM/W
|Housing:||Aluminium housing with USB-B socket, M8 4-pole socket to connect the JUNIOR-PAM monitoring leaf clip (accessory), port for JUNIOR-PAM light guide, and swivel-mounted sample support|
|Far-red light:||LED with 745 nm maximum emission wavelength for selective excitation of photosystem I|
|Fluorescence detection:||PINphotodiode protected by long-pass filter. Selective window amplifier to measure pulse-amplitude modulated (PAM) fluorescence|
|Communication:||Standard USB communication via 1.2 m USB-cable type A-B|
|Power supply:||5 V DC supplied by the USB-cable type A-B used for communication|
|Power consumption:||100 mW at normal operation and 500 mW during saturation pulse|
|Dimensions:||11.5 cm x 6.5 cm x 3 cm (L x W x H)|
|Operating temperature:||0 to + 40°C|
|Operating humidity range:||35 to 85% RH (to avoid condensation)|
|Program:||WinControl-3 System Control and Data Acquisition Program (Windows XP/Vista, Windows 7+8) for operation of measuring system via PC, data acquisition and analysis|
|Saturation Pulse Analysis:||Measured: Ft, F0, FM, F, F0’ (also calculated), FM’. PAR, leaf temperature and relative humidity using Monitoring Leaf-Clip JUNIOR-BD. Calculated: F0’ (also measured), FV/FM and Y(II) (maximum and effective photochemical yield of PS II, respectively), qL, qP, qN, NPQ, Y(NPQ), Y(NO) and ETR (electron transport rate)|
|Fitting Routines:||Two routines for determination of the cardinal points α, Ik and ETRmax of light curves|
|Programmability:||Fully programmable using batch file language|
|Computer Requirements:||1 free USB socket. Processor, 1 GHz. RAM, 512 MB. Screen resolution, 1024 x 600 pixels. Interface, USB 2.0/3.0. Operating system: Microsoft Windows XP/Vista, Windows 7 and 8|
Miscellaneous items included
|Light guide:||50 cm x 1.5 mm (length x diameter) plastic fibre|
|Sample clips:||Open leaf clip (angle between incident radiation from JUNIOR-PAM and leaf surface, 60°) and magnetic leaf clip (angle between incident radiation from JUNIOR-PAM and leaf surface, 90°)|
|Fluorescence standard:||3 cm x 2 cm fluorescence foil|
|Polishing set:||set for fibre tips including various polishing pads|
|USB cable:||A-B USB cable|
|Software CD:||including latest WinControl-3 software|
|Transport Case JUNIOR-T:||Grey plastic box with handle. Interior: convoluted foam padding. Dimensions: 29 cm x 25 cm x 6 cm (L x W x H). Weight: 510 g|
Monitoring Leaf-Clip JUNIOR-BD
|Micro quantum sensor:||Selective PAR measurement, 0 to 2500 μmol m-2 s-1 PAR|
|Thermocouple:||Ni-CrNi, -20 to +60°C|
|Leaf temperature:||-20 to +60°C|
|Power supply:||JUNIOR-PAM special socket|
|Cable length:||100 cm|
|Dimensions:||13 cm x 2.5 cm (max.) x 5.5 cm (max.) (L x W x H)|
|Weight:||162 g (including cable)|
|Extra-long Light-Guide||100 cm x 1.5 mm (length x diameter) plastic fibre for difficult accessible samples or underwater measurements|
The JUNIOR-PAM fluorometer is a miniaturised instrument capable to carry out the full range of saturation pulse analysis of photosystem II. A small box of 11.5 x 6.5 x 3.0 cm contains all optical and electronic components. The fluorometer is connected to the sample via a 50 cm long single plastic fibre with 1.5 mm diameter.
The JUNIOR-PAM employs the same blue (460 nm) power LED for pulse modulated fluorescence excitation, actinic illumination and saturating pulses. Also, the fluorometer features a far-red LED for selective excitation of PS I and determination of the Fo’ level fluorescence.
Two different types of leaf-clips are provided, a 60° clip for measurements in ambient light and a magnetic leaf clip for Fo-Fm and Fv/Fm measurements.
An optional monitoring leaf-clip is available to measure ambient light intensity (PAR, µmol m-2 s-1) at leaf level and leaf temperature.