Advances on Photosystem II Investigation by Measurement of Delayed Chlorophyll Fluorescence by a Phosphoroscopic Method¶

Abstract

A method for data acquisition based on recording of light signal from a conventional phophoroscope fluorometer with high-speed digitalization is proposed to extract more information from a delayed chlorophyll a fluorescence (DF) signal. During the signal processing from all points registered by the fluorometer, we obtain simultaneously a large number of induction curves of DF decaying at different time ranges. In addition, it is possible to register a series of dark relaxation kinetics of DF, recorded at different moments during the induction period or at different temperatures. This allows the evaluation of the contribution of DF kinetic components during the induction period or at different temperatures and the comparison between DF signals registered with different phophoroscopes. With the phosphoroscope system used in this study, we have shown that the contribution of the millisecond components (with lifetimes 0.6 and 2-4 ms) predominates during the first second of the induction period. After 1 s of illumination, the amplitudes of the 0.6 ms and 2-4 ms components and of the slower one (with lifetime more than 10 ms) become approximately equal. The change in lifetime of the different components during the induction and during gradual heating is also observed. It is shown that all registered DF kinetic components have different temperature dependences.

Correlations between delayed fluorescence of chlorophyll, metabolism and yield of plants. II. Influence of moisture of leaf and temperature condition on delayed fluorescence of leaves

“…It was shown that the weakly associated polypeptides had fallen out of the chloroplast membrane also in case of increase in amount of mineral salts in suspension of chloroplast [25]. Last findings showed that in the leaf thermograms curve of DF, stationary level decline was observed starting from temperature at 35C, which was interpreted as a result of PSII oxygen-evolving system inhibition [26]. These results allow to suppose that the specific effect of both increased temperature and moisture loss could be stipulated by the PSII activity in consequence of disturbance in interaction between weakly associated polypeptides with chloroplast membrane.…”

Observation of nanosecond laser induced fluorescence of in vitro seawater phytoplankton

“…Light travel times cannot be the cause, since a 10 ns delay would represent some spatial gap of approxi mately 3 m, which is two to three times larger than the entire apparatus. Such a delay between pump and fluorescent emission has been seen in other work [20] and is common in photosynthetic systems [7,[21][22][23][24][25][26][27], being called delayed fluorescence (DF). It is noted that, with the exception of Ref.…”

MADS-Box Genes and Gibberellins Regulate Bolting in Lettuce (Lactuca sativa L.)

“…Chlorophyll was extracted with 25 ml 95% (v/v) ethanol, and the resultant supernatant was measured using a spectrophotometer (UV-2102C, YOUNIKE, China) at 649 nm (A 649 ), 665 nm (A665), and 470 nm (A 470 ) wavelengths, respectively. Contents of chlorophyll were calculated as described Zaharieva and Goltsev (2003).…”