title: Effects of salinity on the photosynthetic apparatus of two Paulownia lines.
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.
authors: Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria.
authors: Martin
authors: M
authors: Stefanov
authors: Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria.
authors: Ekaterina
authors: E
authors: Yotsova
authors: Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria.
authors: Georgi
authors: G
authors: Rashkov
authors: Faculty of Biology, University of Sofia, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria.
authors: Katya
authors: K
authors: Ivanova
authors: Faculty of Biology, University of Sofia, 8 Dragan Tsankov Blvd., 1164 Sofia, Bulgaria.
authors: Yuliana
authors: Y
authors: Markovska
authors: Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad.G. Bonchev Str. 21, Sofia 1113, Bulgaria. Electronic address: emya@bio21.bas.bg.
authors: Emilia L
authors: EL
authors: Apostolova
mesh_terms: D002734:Chlorophyll / Q000378:metabolism*; D019684:Magnoliopsida / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D054712:Salinity
chemical_list: D045332:Photosystem II Protein Complex; D002734:Chlorophyll
keywords: P700; PAM chlorophyll fluorescence; Paulownia; Pigment composition; Salinity