the changes of chl a fluorescence induction curve in response to different salinity levels in canola (barassica napus, l.) plants were investigated. the canola seedlings were exposed to salt stress (100 mm and 200 mm nacl) for 7 days and chl a fluorescence induction kinetics was analysed. by using the ojip-test, various parameters like vj, area, n, φpo, φeo, ψo, rc/abs and piabs were calculated...

With the aim to specifically study the molecular mechanisms behind photoinhibition of photosystem I, stacked spinach (Spinacia oleracea) thylakoids were irradiated at 4 degrees C with far-red light (>715 nm) exciting photosystem I, but not photosystem II. Selective excitation of photosystem I by far-red light for 130 min resulted in a 40% inactivation of photosystem I. It is surprising that thi...

Marine diatoms are photosynthetic, and thrive in environments where light fluctuates. Like all oxygenic photosynthetic organisms diatoms face a light-dependent inactivation of the Photosystem II complexes that photooxidize water to generate biosynthetic reductant. To maintain photosynthesis this photoinactivation must be countered by slow and metabolically expensive protein turnover, which is l...

Marine Synechococcus and Prochlorococcus are picocyanobacteria predominating in subtropical, oligotrophic marine environments, a niche predicted to expand with climate change. When grown under common low light conditions Synechococcus WH 8102 and Prochlorococcus MED 4 show similar Cytochrome b6f and Photosystem I contents normalized to Photosystem II content, while Prochlorococcus MIT 9313 has ...

The ability of photosystem (PS) II to catalyze the light-driven oxidation of water comes along with its vulnerability to oxidative damage, in particular of the D1 core subunit. Photodamaged PSII undergoes repair in a multi-step process involving (i) reversible phosphorylation of PSII core subunits; (ii) monomerization and lateral migration of the PSII core from grana to stroma thylakoids; (iii)...

The lipids of photosystem II particles, of chloroplasts and leaves are compared in the variegated tobacco mutant N C 95. The mutant differs from other N. tabacum mutants by the phenomenon that it has variegated leaves with green and with yellow-green leaf patches. Chloroplasts from the green leaf areas exhibit photosystem II and photosystem I reactions and have a normal lamellar system with gra...

We report simulations of the two-dimensional electronic spectroscopy of the Q(y) band of the D1-D2-Cyt b559 photosystem II reaction center at 77 K. We base the simulations on an existing Hamiltonian that was derived by simultaneous fitting to a wide range of linear spectroscopic measurements and described within modified Redfield theory. The model obtains reasonable agreement with most aspects ...

Photosystem II is a multisubunit membrane complex which performs the water oxidation process in the higher plants. Core dimers and monomers of photosystem II have been isolated from thylakoid membranes by sucrose density gradient centrifugation. Lipids extracted from different photosystem II-enriched fractions obtained from spinach thylakoids have been analysed by thin layer chromatography. Car...