Abstract
In this work, using the EPR and PAM-fluorometry methods, we have studied induction events of photosynthetic electron transport in Hibiscus rosa-sinensis leaves. The methods used are complementary, providing efficient tools for in situ monitoring of P700 redox transients and photochemical activity of photosystem II (PSII). The induction of P700+ in dark-adapted leaves is characterized by the multiphase kinetics with a lag-phase, which duration elongates with the dark-adaptation time. Analyzing effects of the uncoupler monensin and artificial electron carrier methylviologen (MV) on photooxidation of P700 and slow induction of chlorophyll a fluorescence (SIF), we could ascribe different phases of transient kinetics of electron transport processes in dark-adapted leaves to the following regulatory mechanisms: (i) acceleration of electron transfer on the acceptor side of PSI, (ii) pH-dependent modulation of the intersystem electron flow, and (iii) re-distribution of electron fluxes between alternative (linear, cyclic, and pseudocyclic) pathways. Monensin significantly decreases a level of P700+ and inhibits SIF. MV, which mediates electron flow from PSI to O2 with consequent formation of H2O2, promotes a rapid photooxidation of P700 without any lag-phase peculiar to untreated leaves. MV-mediated water-water cycle (H2O → PSII → PSI → MV → O2 → H2O2 → H2O) is accompanied by generation of ascorbate free radicals. This suggests that the ascorbate peroxidase system of defense against reactive oxygen species is active in chloroplasts of H. rosa-sinensis leaves. In DCMU-treated chloroplasts with inhibited PSII, the contribution of cyclic electron flow is insignificant as compared to linear electron flow. For analysis of induction events, we have simulated electron transport processes within the framework of our generalized mathematical model of oxygenic photosynthesis, which takes into account pH-dependent mechanisms of electron transport control and re-distribution of electron fluxes between alternative pathways. The model adequately describes the main peculiarities of P700+ induction and dynamics of the intersystem electron transport.
| Original language | English |
|---|---|
| Pages (from-to) | 400-415 |
| Number of pages | 16 |
| Journal | Journal of Photochemistry and Photobiology B: Biology |
| Volume | 152 |
| DOIs | |
| Publication status | Published - Nov 1 2015 |
| Externally published | Yes |
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Keywords
- Induction events
- Mathematical modeling
- Photooxidation of P
- Photosynthesis
- Regulation of photosynthetic electron transport
ASJC Scopus subject areas
- Radiation
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology
- Biophysics
Cite this
Short-term regulation and alternative pathways of photosynthetic electron transport in Hibiscus rosa-sinensis leaves. / Trubitsin, Boris V.; Vershubskii, Alexey V.; Priklonskii, Vladimir I.; Tikhonov, Alexander N.
In: Journal of Photochemistry and Photobiology B: Biology, Vol. 152, 01.11.2015, p. 400-415.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Short-term regulation and alternative pathways of photosynthetic electron transport in Hibiscus rosa-sinensis leaves
AU - Trubitsin, Boris V.
AU - Vershubskii, Alexey V.
AU - Priklonskii, Vladimir I.
AU - Tikhonov, Alexander N.
PY - 2015/11/1
Y1 - 2015/11/1
N2 - In this work, using the EPR and PAM-fluorometry methods, we have studied induction events of photosynthetic electron transport in Hibiscus rosa-sinensis leaves. The methods used are complementary, providing efficient tools for in situ monitoring of P700 redox transients and photochemical activity of photosystem II (PSII). The induction of P700+ in dark-adapted leaves is characterized by the multiphase kinetics with a lag-phase, which duration elongates with the dark-adaptation time. Analyzing effects of the uncoupler monensin and artificial electron carrier methylviologen (MV) on photooxidation of P700 and slow induction of chlorophyll a fluorescence (SIF), we could ascribe different phases of transient kinetics of electron transport processes in dark-adapted leaves to the following regulatory mechanisms: (i) acceleration of electron transfer on the acceptor side of PSI, (ii) pH-dependent modulation of the intersystem electron flow, and (iii) re-distribution of electron fluxes between alternative (linear, cyclic, and pseudocyclic) pathways. Monensin significantly decreases a level of P700+ and inhibits SIF. MV, which mediates electron flow from PSI to O2 with consequent formation of H2O2, promotes a rapid photooxidation of P700 without any lag-phase peculiar to untreated leaves. MV-mediated water-water cycle (H2O → PSII → PSI → MV → O2 → H2O2 → H2O) is accompanied by generation of ascorbate free radicals. This suggests that the ascorbate peroxidase system of defense against reactive oxygen species is active in chloroplasts of H. rosa-sinensis leaves. In DCMU-treated chloroplasts with inhibited PSII, the contribution of cyclic electron flow is insignificant as compared to linear electron flow. For analysis of induction events, we have simulated electron transport processes within the framework of our generalized mathematical model of oxygenic photosynthesis, which takes into account pH-dependent mechanisms of electron transport control and re-distribution of electron fluxes between alternative pathways. The model adequately describes the main peculiarities of P700+ induction and dynamics of the intersystem electron transport.
AB - In this work, using the EPR and PAM-fluorometry methods, we have studied induction events of photosynthetic electron transport in Hibiscus rosa-sinensis leaves. The methods used are complementary, providing efficient tools for in situ monitoring of P700 redox transients and photochemical activity of photosystem II (PSII). The induction of P700+ in dark-adapted leaves is characterized by the multiphase kinetics with a lag-phase, which duration elongates with the dark-adaptation time. Analyzing effects of the uncoupler monensin and artificial electron carrier methylviologen (MV) on photooxidation of P700 and slow induction of chlorophyll a fluorescence (SIF), we could ascribe different phases of transient kinetics of electron transport processes in dark-adapted leaves to the following regulatory mechanisms: (i) acceleration of electron transfer on the acceptor side of PSI, (ii) pH-dependent modulation of the intersystem electron flow, and (iii) re-distribution of electron fluxes between alternative (linear, cyclic, and pseudocyclic) pathways. Monensin significantly decreases a level of P700+ and inhibits SIF. MV, which mediates electron flow from PSI to O2 with consequent formation of H2O2, promotes a rapid photooxidation of P700 without any lag-phase peculiar to untreated leaves. MV-mediated water-water cycle (H2O → PSII → PSI → MV → O2 → H2O2 → H2O) is accompanied by generation of ascorbate free radicals. This suggests that the ascorbate peroxidase system of defense against reactive oxygen species is active in chloroplasts of H. rosa-sinensis leaves. In DCMU-treated chloroplasts with inhibited PSII, the contribution of cyclic electron flow is insignificant as compared to linear electron flow. For analysis of induction events, we have simulated electron transport processes within the framework of our generalized mathematical model of oxygenic photosynthesis, which takes into account pH-dependent mechanisms of electron transport control and re-distribution of electron fluxes between alternative pathways. The model adequately describes the main peculiarities of P700+ induction and dynamics of the intersystem electron transport.
KW - Induction events
KW - Mathematical modeling
KW - Photooxidation of P
KW - Photosynthesis
KW - Regulation of photosynthetic electron transport
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U2 - 10.1016/j.jphotobiol.2015.07.015
DO - 10.1016/j.jphotobiol.2015.07.015
M3 - Article
VL - 152
SP - 400
EP - 415
JO - Journal of Photochemistry and Photobiology B: Biology
JF - Journal of Photochemistry and Photobiology B: Biology
SN - 1011-1344
ER -