An improved method, using saturating light pulses, for the determination of photosystem I quantum yield via P700+-absorbance changes at 830 nm

ArabidopsisSTN7 Kinase Provides a Link between Short- and Long-Term Photosynthetic Acclimation

“…Actinic light (80 mmol m 22 s 21 ) was subsequently switched on, and a saturation pulse of red light (5000 mmol m 22 s 21 ) was applied to determine Pm9, the maximum P700 + absorption under illumination (Klughammer and Schreiber, 1994). The photochemical quantum yield of PSI, Y(I), defined as the fraction of total P700 that is reduced in a given state and is not limited by the acceptor side, was calculated as: Y(I) = 1 2 Y(ND) 2 Y(NA), where Y(ND) represents the fraction of total P700 that is oxidized in a given state (as a measure of donor side limitation), and Y(NA) is the fraction of total P700 that is not oxidized by a saturation pulse in a given state, calculated as (Pm 2 Pm')/Pm, which provides a measure of acceptor side limitation (Klughammer and Schreiber, 1994).…”

N-Terminal Structure of Maize Ferredoxin:NADP+ Reductase Determines Recruitment into Different Thylakoid Membrane Complexes

“…Chlorophyll fluorescence parameters were calculated basically according to Genty et al (1989) from dark-adapted maxima and measurements taken at saturating pulses, except that qP = (Fm9 2 F)/(Fm9 2 Fo9), where Fo9 was estimated according to Oxborough and Baker (1997), and NPQ was calculated according to Kramer et al (2004). ФI was calculated basically according to Klughammer and Schriebe (1994). ETRI and ETRII were calculated as µmol electrons/(m 2 $s) from the photosynthetically active radiation and either ФI or ФII, respectively, based on the assumptions that PSI and PSII absorbed equal quanta in all plants and that leaves of all plants absorbed 0.84 of quanta available.…”

Acrolein, an α,β-Unsaturated Carbonyl, Inhibits Both Growth and PSII Activity in the CyanobacteriumSynechocystissp. PCC 6803

“…In the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), the amount of P700 þ produced by an MT flash reflects the total amount of P700. 44) The steady-state amount of P700 þ in the absence of DCMU under FR light was the same that in the presence of DCMU (Fig. 5a).…”

“…The difference between the P700 amplitude obtained by the short saturating light pulse in the light and the far-red-induced amplitude determined in the dark-adapted state was attributed to A À . 44) Measurement of protein and chlorophyll (Chl) content. For protein quantification, cells were harvested and resuspended in 500 mL of extraction buffer (50 mM HEPES-KOH, pH 7.5, 1 mM MgCl 2 , 2 mM EDTA, 1 mM dithiothreitol, 2% w/v polyvinylpolypyroolidone, 1 mM phenylmethylsulfonyl fluoride, and 10 mM leupeptin).…”