Photosynthesis and Fast Changes in Light Emission by Green Plants

Govindjee, .; Jursinic, Paul A.

doi:10.1007/978-1-4684-3551-1_3

Cited by 43 publications

(27 citation statements)

References 265 publications

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“…The data on delayed fluorescence of photosynthetic organisms have been summarized in a number of detailed reviews (1,27,68,74,751. Recently, Lavorel et al [70] surveyed the problems raised by the recombination theory for delayed fluorescence in photosystem I1 (PS-II)* of algae and higher plants.…”

Section: Delay Edpuorescencementioning

confidence: 99%

Delayed Fluorescence and Phosphorescence of Plant Pigments

Krasnovsky

1982

Photochem & Photobiology

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Section: Delay Edpuorescencementioning

confidence: 99%

Delayed Fluorescence and Phosphorescence of Plant Pigments

Krasnovsky

1982

Photochem & Photobiology

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“…The increase in the yield (Table 1 area values; Fig. 2) upon NH2OH treatment is well known [25] and easily explained by a block in electron flow from Z to P~8o, thus increasing the latter's concentration, a component needed for DLE [15,26] P~8o under other conditions [2]. After NH2OH treatment in darkness, a block between Z and P68o is produced, and this block is partially overcome by added NH2OH (Figs.…”

Section: Discussionmentioning

confidence: 99%

Effects of hydroxylamine and silicomolybdate on the decay in delayed light emission in the 6?100 ?s range after a single 10 ns flash in pea thylakoids

Jursinic

1982

Photosynth Res

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Measurements are reported on μs delayed light emission, following a single 10 ns excitation flash, in Alaska pea thylakoids treated with hydroxylamine (NH2OH) or with silicomolybdate. 1. In thylakoids treated with 2 mM NH2OH in the light, or in the dark, the quantum yield of delayed light emission is considerably enhanced. A 10 μs lifetime component of delayed light emission is not significantly changed, whereas a 50-70 μs lifetime component is increased. MnCl2 and diphenylcarbazide are unable to reverse the above effects of NH2OH treatment. Thus Mn(2+) and diphenylcarbazide must not donate electrons directly to reaction center II but on the oxygen-evolution side of the NH2OH block. 2. When the closed form of photosystem II reaction centers (P680Q(-)), where P680 is the reaction center chlorophyll and Q is a 'stable' electron acceptor, is generated by preillumination of NH2OH-treated thylakoids with diuron present, the μs delayed light emission is inhibited, but a low level residual delayed light emission remains. Possible origins of this emission are discussed. It is believed that the best explanation for residual DLE is the existence of another acceptor besides Q that partakes in charge separation and rapid dissipative recombination when the reaction center is in the P680Q(-) state. 3. The quantum yield of delayed light emission from 'closed' reaction centers (P680 (+)Q(-)) that have all charge stabilization reactions (i.e., flow of electrons to P680 (+) and out of Q(-)) blocked by NH2OH treatment and addition of diuron is 1.1×10(-3) for components measured in a range from 6 to 400 μs and extrapolated to zero time. 4. The addition of silicomolybdate, which accepts electron from Q(-), causes delayed light emission in the μs range to be greatly inhibited.

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“…Thus, although most delayed light is due to a back reaction of PS II, detailed mechanisms are different for the fast and slower components. We refer the readers to reviews by Lavorel (1975) and by Govindjee and Jursinic (1979) that cover the literature and the ideas during that period.…”

Section: Major Discoveries and Contributions Of Govindjee In Understamentioning

confidence: 99%

Govindjee at 80: more than 50 years of free energy for photosynthesis

Eaton‐Rye

2013

Photosynth Res

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We provide here a glimpse of Govindjee and his pioneering contributions on the two light reactions and the two pigment systems, particularly on the waterplastoquinone oxido-reductase, Photosystem II. His focus has been on excitation energy transfer; primary photochemistry, and the role of bicarbonate in electron and proton transfer. His major tools have been kinetics and spectroscopy (absorption and fluorescence), and he has provided an understanding of both thermoluminescence and delayed light emission in plants and algae. He pioneered the use of lifetime of fluorescence measurements to study the phenomenon of photoprotection in plants and algae. He, however, is both a generalist and a specialist all at the same time. He communicates very effectively his passion for photosynthesis to the novice as well as professionals. He has been a prolific author, outstanding lecturer and an editor par excellence.

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Photosynthesis and Fast Changes in Light Emission by Green Plants

Cited by 43 publications

References 265 publications

Delayed Fluorescence and Phosphorescence of Plant Pigments

Delayed Fluorescence and Phosphorescence of Plant Pigments

Effects of hydroxylamine and silicomolybdate on the decay in delayed light emission in the 6?100 ?s range after a single 10 ns flash in pea thylakoids

Govindjee at 80: more than 50 years of free energy for photosynthesis

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