scholarly journals Influence of chloride salinity on primary photosynthetic processes in potato leaves

2020 ◽  
Author(s):  
E. D. Danilova ◽  
L. V. Коlomeichuk ◽  
M. V. Efimova
Keyword(s):  
Photosystem Ii ◽  
Photochemical Activity ◽  
Photosynthetic Parameters ◽  
Chloride Salinity

We investigated the effect of 125 mM NaCl on the potato leaves photosynthetic parameters (the content of chlorophylls a, b, and carotenoids; photochemical activity of photosystem II).

scholarly journals Subunit composition of CP43-less photosystem II complexes of Synechocystis sp. PCC 6803: implications for the assembly and repair of photosystem II

2012 ◽  
Vol 367 (1608) ◽  
pp. 3444-3454 ◽  
Author(s):  
M. Boehm ◽  
J. Yu ◽  
V. Reisinger ◽  
M. Beckova ◽  
L. A. Eichacker ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Gel Electrophoresis ◽  
Photochemical Activity ◽  
Subunit Composition ◽  
Null Mutant ◽  
Trap Potential ◽  
Native Gel ◽  
Oxygen Evolving ◽  
Pcc 6803

Photosystem II (PSII) mutants are useful experimental tools to trap potential intermediates involved in the assembly of the oxygen-evolving PSII complex. Here, we focus on the subunit composition of the RC47 assembly complex that accumulates in a psbC null mutant of the cyanobacterium Synechocystis sp. PCC 6803 unable to make the CP43 apopolypeptide. By using native gel electrophoresis, we showed that RC47 is heterogeneous and mainly found as a monomer of 220 kDa. RC47 complexes co-purify with small Cab-like proteins (ScpC and/or ScpD) and with Psb28 and its homologue Psb28-2. Analysis of isolated His-tagged RC47 indicated the presence of D1, D2, the CP47 apopolypeptide, plus nine of the 13 low-molecular-mass (LMM) subunits found in the PSII holoenzyme, including PsbL, PsbM and PsbT, which lie at the interface between the two momomers in the dimeric holoenzyme. Not detected were the LMM subunits (PsbK, PsbZ, Psb30 and PsbJ) located in the vicinity of CP43 in the holoenzyme. The photochemical activity of isolated RC47-His complexes, including the rate of reduction of P680 + , was similar to that of PSII complexes lacking the Mn 4 CaO 5 cluster. The implications of our results for the assembly and repair of PSII in vivo are discussed.

scholarly journals Alleviation of nickel toxicity in wheat (Triticum aestivum L.) seedlings by selenium supplementation

2013 ◽  
Vol 50 (2) ◽  
pp. 65-78 ◽  
Author(s):  
Ewa Gajewska ◽  
Daniel Drobik ◽  
Marzena Wielanek ◽  
Joanna Sekulska-Nalewajko ◽  
Jarosław Gocławski ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Chlorophyll A ◽  
Electrolyte Leakage ◽  
Growth Parameters ◽  
Photosynthetic Pigment ◽  
Triticum Aestivum L ◽  
Photochemical Activity ◽  
Wheat Seedlings ◽  
Chlorophyll A And B ◽  
Hydroponically Grown

Abstract Hydroponically grown wheat seedlings were treated with 50 μM N i and/or 15 μM Se. After a 7-day culture period, their growth parameters, N i, Se, F e, and M g contents, electrolyte leakage, photosynthetic pigment concentrations, and photochemical activity of photosystem II were determined. Exposure of wheat seedlings to N i alone resulted in reduction in the total shoot and root lengths, by 22% and 50%, respectively. Addition of Se to the N i-containing medium significantly improved the growth of these organs, compared to the seedlings subjected to N i alone. Application of Se decreased the accumulation of N i in shoots and roots and partially alleviated the N i-induced decrease in F e and M g concentations in shoots. Electrolyte leakage increased in response to N i stress, but in shoots it was diminished by Se supplementation. Exposure to N i led to a decrease in chlorophyll a and b contents and enhancement of chlorophyll a/b ratio, but did not influence the concentration of carotenoids. Enrichment of the N i-containing medium with Se significantly increased chlorophyll b content, compared to the seedlings treated with N i alone. Photochemical activity, estimated in terms of the maximum quantum yield of photosystem II , decreased in response to N i treatment but was significantly improved by simultaneous addition of Se. Results of our study suggest that alleviation of N i toxicity in wheat seedlings by Se supplementation may be related to limitation of N i uptake.

Effects of aging on chlorophyll fluorescence and photosystem II electron transport in isolated chloroplasts

1975 ◽  
Vol 53 (23) ◽  
pp. 2842-2845 ◽  
Author(s):  
M. Fragata
Keyword(s):  
Fatty Acids ◽  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Conformational Changes ◽  
Photochemical Activity ◽  
Photosynthetic Membrane ◽  
Fluorescence Characteristics ◽  
Protein Molecules ◽  
Effects Of Aging ◽  
Isolated Chloroplasts

The correlation between emission of energy and photochemical activity in isolated chloroplasts during aging was investigated. It was shown that aging hinders the intensity of chlorophyll-a fluorescence with a concomitant decrease of the photosystem II activity. In view of the parallelism between the action of exogenous fatty acids, especially C18-unsaturated acids, and the effects of aging, it is suggested that the thylakoid transformation during aging could result partly from conformational changes of the membrane polypeptides due to the presence of free fatty acids in the neighborhood of the protein molecules. It is possible that such a mechanism of fatty acid action may alter the fluorescence characteristics of chlorophyll as well as the tunneling of electrons in the photosynthetic membrane.

scholarly journals Evaluation of Copper Oxide Nanoparticles Toxicity Using Chlorophyll a Fluorescence Imaging in Lemna gibba

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
François Perreault ◽  
Abdallah Oukarroum ◽  
Laura Pirastru ◽  
Louka Sirois ◽  
William Gerson Matias ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Copper Oxide ◽  
Fluorescence Imaging ◽  
Copper Oxide Nanoparticles ◽  
Quantum Yields ◽  
Lemna Gibba ◽  
Photochemical Quenching ◽  
Oxide Nanoparticles ◽  
Photosynthetic Parameters ◽  
Cuo Nps

Copper oxide nanoparticles (CuO NPs), used in antifouling paints of boats, are released in the environment and can induce toxicity to aquatic organisms. In this report, we used chlorophyll a fluorescence imaging to evaluate CuO NPs toxicity in Lemna gibba. This approach allowed to evaluate the differential effect of CuO NPs on photosynthesis of whole L. gibba plants. Exposure to 0.1 to 0.4 g/L CuO NPs during 48h induced strong inhibition of photosynthetic processes resulting in a decrease of plant growth. By using fluorescence imaging, different photosynthetic parameters were evaluated simultaneously in microplate conditions. Imaging of FO fluorescence yield showed the decrease of leaf photosynthetic active surface for whole plants exposed to CuO NPs. This method showed that CuO NPs inhibited photosystem II maximal, photosystem II operational quantum yields, and photochemical quenching of fluorescence associated with electron transport. Nonphotochemical fluorescence quenching as an indicator of energy dissipation not used in photosynthesis was shown to be increased by the effect of CuO NPs. Such approach in microplate conditions provides synchronous high repetition measurements for numerous plants. This study may give a reliable methodological approach to evaluate toxicity risk of NPs in aquatic ecosystems.

A comparison of the photochemical activity of two forms of Photosystem II reaction centre isolated from sugar beet

1994 ◽  
Vol 1185 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Guillermo Montoya ◽  
Javier de las Rivas ◽  
Paula J. Booth ◽  
Linda B. Giorgi ◽  
David R. Klug ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Sugar Beet ◽  
Photochemical Activity ◽  
Reaction Centre
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