@article{KlughammerSchreiber2016,
  author    = {Klughammer, Christof and Schreiber, Ulrich},
  title     = {Deconvolution of ferredoxin, plastocyanin, and P700 transmittance changes in intact leaves with a new type of kinetic LED array spectrophotometer},
  series = {Photosynthesis Research},
  volume    = {128},
  journal   = {Photosynthesis Research},
  number    = {2},
  doi       = {10.1007/s11120-016-0219-0},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189050},
  pages     = {195-214},
  year      = {2016},
  abstract  = {A newly developed compact measuring system for assessment of transmittance changes in the near-infrared spectral region is described; it allows deconvolution of redox changes due to ferredoxin (Fd), P700, and plastocyanin (PC) in intact leaves. In addition, it can also simultaneously measure chlorophyll fluorescence. The major opto-electronic components as well as the principles of data acquisition and signal deconvolution are outlined. Four original pulse-modulated dual-wavelength difference signals are measured (785-840 nm, 810-870 nm, 870-970 nm, and 795-970 nm). Deconvolution is based on specific spectral information presented graphically in the form of 'Differential Model Plots' (DMP) of Fd, P700, and PC that are derived empirically from selective changes of these three components under appropriately chosen physiological conditions. Whereas information on maximal changes of Fd is obtained upon illumination after dark-acclimation, maximal changes of P700 and PC can be readily induced by saturating light pulses in the presence of far-red light. Using the information of DMP and maximal changes, the new measuring system enables on-line deconvolution of Fd, P700, and PC. The performance of the new device is demonstrated by some examples of practical applications, including fast measurements of flash relaxation kinetics and of the Fd, P700, and PC changes paralleling the polyphasic fluorescence rise upon application of a 300-ms pulse of saturating light.},
  language  = {en}
}
@article{KlughammerSiebkeSchreiber2013,
  author    = {Klughammer, Christof and Siebke, Katharina and Schreiber, Ulrich},
  title     = {Continuous ECS-indicated recording of the proton-motive charge flux in leaves},
  series = {Photosynthesis Research},
  volume    = {117},
  journal   = {Photosynthesis Research},
  doi       = {10.1007/s11120-013-9884-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132134},
  pages     = {471-487},
  year      = {2013},
  abstract  = {Technical features and examples of application of a special emitter-detector module for highly sensitive measurements of the electrochromic pigment absorbance shift (ECS) via dual-wavelength (550-520 nm) transmittance changes (P515) are described. This device, which has been introduced as an accessory of the standard, commercially available Dual-PAM-100 measuring system, not only allows steady-state assessment of the proton motive force (pmf) and its partitioning into ΔpH and ΔΨ components, but also continuous recording of the overall charge flux driven by photosynthetic light reactions. The new approach employs a double-modulation technique to derive a continuous signal from the light/dark modulation amplitude of the P515 signal. This new, continuously measured signal primarily reflects the rate of proton efflux via the ATP synthase, which under quasi-stationary conditions corresponds to the overall rate of proton influx driven by coupled electron transport. Simultaneous measurements of charge flux and \(CO_2\) uptake as a function of light intensity indicated a close to linear relationship in the light-limited range. A linear relationship between these two signals was also found for different internal \(CO_2\) concentrations, except for very low \(CO_2\), where the rate of charge flux distinctly exceeded the rate of CO2 uptake. Parallel oscillations in \(CO_2\) uptake and charge flux were induced by high \(CO_2\) and \(O_2\). The new device may contribute to the elucidation of complex regulatory mechanisms in intact leaves.},
  language  = {en}
}
@article{SchreiberKlughammerKolbowski2012,
  author    = {Schreiber, Ulrich and Klughammer, Christof and Kolbowski, J{\"o}rg},
  title     = {Assessment of wavelength-dependent parameters of photosynthetic electron transport with a new type of multi-color PAM chlorophyll fluorometer},
  series = {Photosynthesis Research},
  volume    = {113},
  journal   = {Photosynthesis Research},
  number    = {1},
  doi       = {10.1007/s11120-012-9758-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-127003},
  pages     = {127-144},
  year      = {2012},
  abstract  = {Technical features of a novel multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer as well as the applied methodology and some typical examples of its practical application with suspensions of Chlorella vulgaris and Synechocystis PCC 6803 are presented. The multi-color PAM provides six colors of pulse-modulated measuring light (peak-wavelengths at 400, 440, 480, 540, 590, and 625 nm) and six colors of actinic light (AL), peaking at 440, 480, 540, 590, 625 and 420-640 nm (white). The AL can be used for continuous illumination, maximal intensity single-turnover pulses, high intensity multiple-turnover pulses, and saturation pulses. In addition, far-red light (peaking at 725 nm) is provided for preferential excitation of PS I. Analysis of the fast fluorescence rise kinetics in saturating light allows determination of the wavelength- and sample-specific functional absorption cross section of PS II, Sigma(II)λ, with which the PS II turnover rate at a given incident photosynthetically active radiation (PAR) can be calculated. Sigma(II)λ is defined for a quasi-dark reference state, thus differing from σPSII used in limnology and oceanography. Vastly different light response curves for Chlorella are obtained with light of different colors, when the usual PAR-scale is used. Based on Sigma(II)λ the PAR, in units of μmol quanta/(m2 s), can be converted into PAR(II) (in units of PS II effective quanta/s) and a fluorescence-based electron transport rate ETR(II) = PAR(II) · Y(II)/Y(II)max can be defined. ETR(II) in contrast to rel.ETR qualifies for quantifying the absolute rate of electron transport in optically thin suspensions of unicellular algae and cyanobacteria. Plots of ETR(II) versus PAR(II) for Chlorella are almost identical using either 440 or 625 nm light. Photoinhibition data are presented suggesting that a lower value of ETR(II)max with 440 nm possibly reflects photodamage via absorption by the Mn-cluster of the oxygen-evolving complex.},
  language  = {en}
}