Delayed light emission

The delayed light emission as observed from the Bolonian stone is now classified as phosphorescence. We know now that these stones contain barium sulfate with traces of bismuth and manganese, and that the corresponding reducing process concerns the transformation of sulfate into sulfur. It is now well known that alkaline earth metal sulfates emit phosphorescence that strongly increases when traces of heavy metals are present. The so-called inorganic multi-component compounds phosphor and crystallophosphor are in fact polycrystalline substances containing traces of some ionic activators of luminescence. 

Ap/t = p = rate of change of pressure, (Ap)max = maximum pressure increase, p ax maximum rate of change of pressure, = Induction period = time delay from admission of reactants to attainment of Pmax, AT = Reactant temperature excess, T = wall temperature, T) = Compressed gas temperature, T, = ignition delay, / = light emission intensity, Iw-ai = period of maximum rate of reaction given that (I20-60) = kp", Q = heat release rate. 

P Jursinic and Govindjee (1977) Temperature dependence of delayed light emission in the 6 to 340 microsecond range after a single flash in chloroplasts. Photochem Photobiol 26 617-628... 

In the oxidized sample, a prompt Chl-a fluorescence with a 0.42 ns lifetime is seen [Fig. 3 (A), trace (a)]. In the sample maintained at -450 mV and illuminated to photoaccumulate O ", the prompt fluorescence lifetime is 0.18 ns [trace (b)]. In the sample maintained at -450 mV but kept in the dark, the signal shows a prompt and a delayed fluorescence (or delayed light emission) with lifetimes of 1.06 ns and 4.3 ns, respectively [trace (c)]. Note that in the extended time region [panel (B)], only trace (c) still has a measurable emission tail. These results show that neither the sample in the oxidized state nor that with O" photoaccumulated show any delayed light emission. Only the sample in which Qa is pre-reduced shows the A3-ns luminescence. These results support the notion that the delayed emission is a recombination luminescence originating from the [P680 <1)"] state. 

BA Zilinskas and Govindjee (1975) Silicomolybdate andsilicomolybdate mediateddichlorophenylmethylurea-insensitive photosystem-ll reaction Electron flow, Chi a fluorescence and delayed light emission changes. Biochim Biophys Acta 387 306-319... 

Fig. 4. (A) Glow curves for spinach-leaf discs after a series of flashes (f-numbers). (B) Thermoluminescence intensity at 35 °C plotted as a function of flash number. Figure source Rutherford, Govindjee and Inoue (1984) Charge accumulation and photochemistry in leaves studied by thermoluminescence and delayed light emission. Proc Nat Acad Sci, USA 81 1109.

AW Rutherford, Govindjee and Y Inoue (1984) Charge accumulation and photochemistry in leaves studied by thermoiuminescence and delayed light emission. Proc Nat Acad Sci, USA 81 1107-1111... 

DE Fleischman and RK Clayton (1968) The effect of phosphorylation uncouplers and electron transport inhibitors upon spectral shifts and delayed light emission of photosynthetic bacteria. Photochem Photobiol 8 287-298... 

Wang CL, Xing D, Zeng LZ. Effect of artificial acid rain and S02 on characteristics of delayed light emission. Luminescence 2005 20 51-6. 

Fig. 19. Delayed light emission from a variety of biological materials.

Chloroplasts from 6-day-old wheat seedlings were used. The culture of wheat seedlings, the isolation of chloroplasts and the determination of CCKBP in chloroplasts were performed as described earlier [8]. The ATP content in detached wheat leaves was measured according to [12], and in vitro photophorphorylation was assayed according to [16]. Delayed light emission (DLE) of chloroplasts was measured as described by [20]. 

Fig. 4. Effects of the CCKBP and BA on delayed light emission. The procedures for chloroplast preparation were the same as noted in Table 1 and the extraction of the CCKBP was as noted in Fig. 2. Prepared chloroplasts were suspended in Tris buffer containing 10 mM NaCl, and then divided into aliquots (1 ml), to which 10 jul BA or water was added. After dark incubation in an ice bath for 20 min, 0.1 ml ofthe chloroplast suspension (ca. 0.18 mg chlorophyll per ml), plus 1 ml Tris buffer or Tris buffer containing the extracted crude CCKBP, was used for the DLE assay. The final BA concentration in these mixtures was 3 juM. Excitation light was 10 erg cm "-s when the sector was stopped. The intensity of DLE at 1.8 ms, after the cessation of 1 ms flash excitation, was measured as described in [20]. A control B 3 juM of BA C salt-washed chloroplasts with 3 juM of BA D salt-washed chloroplasts without BA E suspension of salt-washed chloroplasts mixed with CCKBP, but with no BA F Suspension of salt-washed chloroplasts mixed with CCKBP plus 3 juM of BA G CCKBP control solution H CCKBP solution + 3 fiM of BA...

Acknowledgements, We are grateful to the National Natural Science Foundation of China for the grant (No. 3861067) that supported this research. We are also grateful to Dr. D.Y. Li for his help in the measurement of the delayed light emission of chloroplasts. 

THE DYNAMICS OF MILLISECOND DELAYED LIGHT EMISSION AND ITS RELATION VH TH PHOTOPHOSPHORYLAH ON... 

Wraight CA, Crofts AR (1971) Delayed light emission and high energy state of chloroplasts, Eur. J. Biochem. 19 386-397. 

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