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Stefanov MA, Rashkov GD, Apostolova EL. Assessment of the Photosynthetic Apparatus Functions by Chlorophyll Fluorescence and P 700 Absorbance in C3 and C4 Plants under Physiological Conditions and under Salt Stress. Int J Mol Sci 2022; 23:3768. [PMID: 35409126 PMCID: PMC8998893 DOI: 10.3390/ijms23073768] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/26/2022] [Accepted: 03/27/2022] [Indexed: 11/18/2022] Open
Abstract
Functions of the photosynthetic apparatus of C3 (Pisum sativum L.) and C4 (Zea mays L.) plants under physiological conditions and after treatment with different NaCl concentrations (0-200 mM) were investigated using chlorophyll a fluorescence (pulse-amplitude-modulated (PAM) and JIP test) and P700 photooxidation measurement. Data revealed lower density of the photosynthetic structures (RC/CSo), larger relative size of the plastoquinone (PQ) pool (N) and higher electron transport capacity and photosynthetic rate (parameter RFd) in C4 than in C3 plants. Furthermore, the differences were observed between the two studied species in the parameters characterizing the possibility of reduction in the photosystem (PSI) end acceptors (REo/RC, REo/CSo and δRo). Data revealed that NaCl treatment caused a decrease in the density of the photosynthetic structures and relative size of the PQ pool as well as decrease in the electron transport to the PSI end electron acceptors and the probability of their reduction as well as an increase in the thermal dissipation. The effects were stronger in pea than in maize. The enhanced energy losses after high salt treatment in maize were mainly from the increase in the regulated energy losses (ΦNPQ), while in pea from the increase in non-regulated energy losses (ΦNO). The reduction in the electron transport from QA to the PSI end electron acceptors influenced PSI activity. Analysis of the P700 photooxidation and its decay kinetics revealed an influence of two PSI populations in pea after treatment with 150 mM and 200 mM NaCl, while in maize the negligible changes were registered only at 200 mM NaCl. The experimental results clearly show less salt tolerance of pea than maize.
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Affiliation(s)
| | | | - Emilia L. Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, 1113 Sofia, Bulgaria; (M.A.S.); (G.D.R.)
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Elshoky HA, Yotsova E, Farghali MA, Farroh KY, El-Sayed K, Elzorkany HE, Rashkov G, Dobrikova A, Borisova P, Stefanov M, Ali MA, Apostolova E. Impact of foliar spray of zinc oxide nanoparticles on the photosynthesis of Pisum sativum L. under salt stress. Plant Physiol Biochem 2021; 167:607-618. [PMID: 34464827 DOI: 10.1016/j.plaphy.2021.08.039] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 08/08/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
This study investigates the impacts of zinc oxide nanoparticles: bare (ZnO NPs) and ZnO NPs coated with silicon shell (ZnO-Si NPs), on Pisum sativum L. under physiological and salt stress conditions. The experimental results revealed that the foliar spray with ZnO-Si NPs and 200 mg/L ZnO NPs did not influence the stomata structure, the membrane integrity, and the functions of both photosystems under physiological conditions, while 400 mg/L ZnO-Si NPs had beneficial effects on the effective quantum yield of photosystem II (PSII) and the photochemistry of photosystem I (PSI). On the contrary, small phytotoxic effects were registered after spraying with 400 mg/L ZnO NPs accompanied by stimulation of the cyclic electron flow around PSI and an increase of the non-photochemical quenching (NPQ). The results also showed that both types of NPs (with exception of 400 mg/L ZnO NPs) decrease the negative effects of 100 mM NaCl on the photochemistry of PSI (P700 photooxidation) and PSII (qp, Fv/Fm, Fv/Fo, ΦPSII, Φexc), as well as on the pigment content, stomata closure and membrane integrity. The protective effect was stronger after spraying with ZnO-Si NPs in comparison to ZnO NPs, which could be due to the presence of Si coating shell. The role of Si shell is discussed.
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Affiliation(s)
- Hisham A Elshoky
- Nanotechnology and Advanced Materials Central Lab, Agricultural Research Center, Giza, Egypt; Regional Center for Food and Feed, Agricultural Research Center, Giza, Egypt
| | - Ekaterina Yotsova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Mohamed A Farghali
- Nanotechnology and Advanced Materials Central Lab, Agricultural Research Center, Giza, Egypt; Nanotechnology Research Center, British University in Egypt, Egypt
| | - Khaled Y Farroh
- Nanotechnology and Advanced Materials Central Lab, Agricultural Research Center, Giza, Egypt; Regional Center for Food and Feed, Agricultural Research Center, Giza, Egypt
| | - Kh El-Sayed
- Nanotechnology and Advanced Materials Central Lab, Agricultural Research Center, Giza, Egypt; Nanotechnology Research Center, British University in Egypt, Egypt
| | - Heba Elsayed Elzorkany
- Nanotechnology and Advanced Materials Central Lab, Agricultural Research Center, Giza, Egypt; Regional Center for Food and Feed, Agricultural Research Center, Giza, Egypt
| | - George Rashkov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Anelia Dobrikova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Preslava Borisova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Martin Stefanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - Maha Anwar Ali
- Biophysics Department, Faculty of Sciences, Cairo University, Giza, Egypt
| | - Emilia Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Sofia, Bulgaria.
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Stefanov MA, Rashkov GD, Yotsova EK, Borisova PB, Dobrikova AG, Apostolova EL. Different Sensitivity Levels of the Photosynthetic Apparatus in Zea mays L. and Sorghum bicolor L. under Salt Stress. Plants (Basel) 2021; 10:plants10071469. [PMID: 34371672 PMCID: PMC8309219 DOI: 10.3390/plants10071469] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 05/17/2023]
Abstract
The impacts of different NaCl concentrations (0-250 mM) on the photosynthesis of new hybrid lines of maize (Zea mays L. Kerala) and sorghum (Sorghum bicolor L. Shamal) were investigated. Salt-induced changes in the functions of photosynthetic apparatus were assessed using chlorophyll a fluorescence (PAM and OJIP test) and P700 photooxidation. Greater differences between the studied species in response to salinization were observed at 150 mM and 200 mM NaCl. The data revealed the stronger influence of maize in comparison to sorghum on the amount of closed PSII centers (1-qp) and their efficiency (Φexc), as well as on the effective quantum yield of the photochemical energy conversion of PSII (ΦPSII). Changes in the effective antenna size of PSII (ABS/RC), the electron flux per active reaction center (REo/RC) and the electron transport flux further QA (ETo/RC) were also registered. These changes in primary PSII photochemistry influenced the electron transport rate (ETR) and photosynthetic rate (parameter RFd), with the impacts being stronger in maize than sorghum. Moreover, the lowering of the electron transport rate from QA to the PSI end electron acceptors (REo/RC) and the probability of their reduction (φRo) altered the PSI photochemical activity, which influenced photooxidation of P700 and its decay kinetics. The pigment content and stress markers of oxidative damage were also determined. The data revealed a better salt tolerance of sorghum than maize, associated with the structural alterations in the photosynthetic membranes and the stimulation of the cyclic electron flow around PSI at higher NaCl concentrations. The relationships between the decreased pigment content, increased levels of stress markers and different inhibition levels of the function of both photosystems are discussed.
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Stefanov M, Yotsova E, Rashkov G, Ivanova K, Markovska Y, Apostolova EL. Effects of salinity on the photosynthetic apparatus of two Paulownia lines. Plant Physiol Biochem 2016; 101:54-59. [PMID: 26854407 DOI: 10.1016/j.plaphy.2016.01.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 05/25/2023]
Abstract
The effects of soil salinity on the functional activity of photosynthetic apparatus and pigment composition of two Paulownia lines (Paulownia tomentosa x fortunei and Paulownia elongata x elongata) were investigated. PAM chlorophyll fluorescence measurements revealed that salinity leads to: (i) an increase of the photochemical quenching coefficient (qP) and the linear electron transport rate (ETR) in both lines of Paulownia, while the maximum quantum yield of the primary photochemistry of PSII in the dark adapted state (Fv/Fm) was unaffected; (ii) improved the efficiency of the photochemical energy conversion (ФPSII); (iii) an impact on the chlorophyll fluorescence decrease ratio (RFd), which correlates to the net CO2 assimilation rate; (iv) an impact on [Formula: see text] reoxidation. The analysis of the kinetics of P700(+) reduction upon turning off far-red irradiation revealed that salinization lead to a delay of the cyclic electron transport around PSI in both studied lines as the effect on this process is more pronounced in P. tomentosa x fortunei than in (in comparison with) P. elongata x elongata. The present experimental results suggested high salt tolerance of the studied lines Paulownia, but P. tomentosa x fortunei is more tolerant to salinity than P. elongata x elongata. Molecular mechanisms involved in the Paulownia response to the soil salinity are discussed.
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Affiliation(s)
- Martin Stefanov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria
| | - Ekaterina Yotsova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria
| | - Georgi Rashkov
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria
| | - Katya Ivanova
- Faculty of Biology, University of Sofia, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria
| | - Yuliana Markovska
- Faculty of Biology, University of Sofia, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria
| | - Emilia L Apostolova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria.
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