scholarly journals Polymer-Modified Single-Walled Carbon Nanotubes Affect Photosystem II Photochemistry, Intersystem Electron Transport Carriers and Photosystem I End Acceptors in Pea Plants

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 5958
Author(s):  
Nia Petrova ◽  
Momchil Paunov ◽  
Petar Petrov ◽  
Violeta Velikova ◽  
Vasilij Goltsev ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Photosystem I ◽  
Electron Transport Chain ◽  
Photosynthetic Electron Transport ◽  
Single Walled Carbon Nanotubes ◽  
Donor Side ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain ◽  
Walled Carbon Nanotubes

Single-walled carbon nanotubes (SWCNT) have recently been attracting the attention of plant biologists as a prospective tool for modulation of photosynthesis in higher plants. However, the exact mode of action of SWCNT on the photosynthetic electron transport chain remains unknown. In this work, we examined the effect of foliar application of polymer-grafted SWCNT on the donor side of photosystem II, the intersystem electron transfer chain and the acceptor side of photosystem I. Analysis of the induction curves of chlorophyll fluorescence via JIP test and construction of differential curves revealed that SWCNT concentrations up to 100 mg/L did not affect the photosynthetic electron transport chain. SWCNT concentration of 300 mg/L had no effect on the photosystem II donor side but provoked inactivation of photosystem II reaction centres and slowed down the reduction of the plastoquinone pool and the photosystem I end acceptors. Changes in the modulated reflection at 820 nm, too, indicated slower re-reduction of photosystem I reaction centres in SWCNT-treated leaves. We conclude that SWCNT are likely to be able to divert electrons from the photosynthetic electron transport chain at the level of photosystem I end acceptors and plastoquinone pool in vivo. Further research is needed to unequivocally prove if the observed effects are due to specific interaction between SWCNT and the photosynthetic apparatus.

Rewiring photosynthesis: a photosystem I-hydrogenase chimera that makes H2in vivo

2020 ◽  
Vol 13 (9) ◽  
pp. 2903-2914 ◽  
Author(s):  
Andrey Kanygin ◽  
Yuval Milrad ◽  
Chandrasekhar Thummala ◽  
Kiera Reifschneider ◽  
Patricia Baker ◽  
...  
Keyword(s):  
Electron Transport ◽  
Hydrogen Production ◽  
Photosystem I ◽  
Electron Transport Chain ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

Photosystem I-hydrogenase chimera intercepts electron flow directly from the photosynthetic electron transport chain and directs it to hydrogen production.

Stoichiometric Photophosphorylation in Thylakoids from the Blue-Green Alga, Anabaena variabilis

1980 ◽  
Vol 35 (1-2) ◽  
pp. 98-105 ◽  
Author(s):  
Erika Wax ◽  
Wolfgang Lockau
Keyword(s):  
Electron Transport ◽  
Green Alga ◽  
Photosystem I ◽  
Electron Transport Chain ◽  
Photosynthetic Electron Transport ◽  
Anabaena Variabilis ◽  
Blue Green Alga ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain ◽  
Photosynthetic Control

Abstract A method is described for the preparation of thylakoids from the blue-green alga Anabaena variabilis which exhibit photosynthetic control. The thylakoids can be stored in liquid N 2 with little loss in activity. P/e2 ratios (num ber of ATP molecules formed per pair of electrons transported) have been determined for partial reactions of the photosynthetic electron transport chain. Electron transport from water to an electron acceptor of photosystem I is coupled to phosphorylation with a P/e2 ratio of 0.9-1.2, from water to electron acceptors of photosystem II with ratios of 0.21-0.3 , and oxidations of hydrogen carriers by photosystem I with ratios of 0.3-0.35. Electron transport in these assay systems generates a proton gradient across the thylakoid membrane (acid inside), which is decreased by the substrates of phosphorylation and by uncouplers.

scholarly journals Effects of Different Planting Densities on Photosynthesis in Maize Determined via Prompt Fluorescence, Delayed Fluorescence and P700 Signals

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 276
Author(s):  
Wanying Chen ◽  
Bo Jia ◽  
Junyu Chen ◽  
Yujiao Feng ◽  
Yue Li ◽  
...  
Keyword(s):  
Electron Transport ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Electron Transport Chain ◽  
Plant Density ◽  
Photosynthetic Electron Transport ◽  
Planting Density ◽  
Strong Impact ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

The mutual shading among individual field-grown maize plants resulting from high planting density inevitably reduces leaf photosynthesis, while regulating the photosynthetic transport chain has a strong impact on photosynthesis. However, the effect of high planting density on the photosynthetic electron transport chain in maize currently remains unclear. In this study, we simultaneously measured prompt chlorophyll a fluorescence (PF), modulated 820 nm reflection (MR) and delayed chlorophyll a fluorescence (DF) in order to investigate the effect of high planting density on the photosynthetic electron transport chain in two maize hybrids widely grown in China. PF transients demonstrated a gradual reduction in their signal amplitude with increasing planting density. In addition, high planting density induced positive J-step and G-bands of the PF transients, reduced the values of PF parameters PIABS, RC/CSO, TRO/ABS, ETO/TRO and REO/ETO, and enhanced ABS/RC and N. MR kinetics showed an increase of their lowest point with increasing high planting density, and thus the values of MR parameters VPSI and VPSII-PSI were reduced. The shapes of DF induction and decay curves were changed by high planting density. In addition, high planting density reduced the values of DF parameters I1, I2, L1 and L2, and enhanced I2/I1. These results suggested that high planting density caused harm on multiple components of maize photosynthetic electron transport chain, including an inactivation of PSII RCs, a blocked electron transfer between QA and QB, a reduction in PSI oxidation and re-reduction activities, and an impaired PSI acceptor side. Moreover, a comparison between PSII and PSI activities demonstrated the greater effect of plant density on the former.

scholarly journals Impact of High Light on Reactive Oxygen Species Production within Photosynthetic Biological Membranes

2015 ◽  
Vol 6 (2) ◽  
pp. 50 ◽  
Author(s):  
Vetoshkina D. V. ◽  
Borisova-Mubarakshina M. M. ◽  
Naydov I. A. ◽  
Kozuleva M. A. ◽  
Ivanov B. N.
Keyword(s):  
Reactive Oxygen Species ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Reactive Oxygen ◽  
Photosynthetic Electron Transport ◽  
Lipid Phase ◽  
H2o2 Production ◽  
Oxygen Species ◽  
Photosynthetic Electron Transport Chain ◽  
Transport Chain

In this study we describe the mechanisms of reactive oxygen species (ROS) production in the photosynthetic electron transport chain of higher plants chloroplasts under illumination. We implement an improved method for the measurement of hydrogen peroxide (H2O2) production in lipid phase of photosynthetic membranes of chloroplasts. Total rate of H2O2 production and the production within the thylakoid membrane under operation of photosynthetic electron transport chain is evaluated. Obtained data show that even in the presence of an efficient electron acceptor, methyl viologen, an increase in light intensity leads to an increase in H2O2 production mainly within the thylakoid membranes. The role of H2O2 produced within the photosynthetic biological membrane is discussed.

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