photosystem

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photosystem

(ˈfəʊtəʊˌsɪstəm)
n
(Botany) botany either of two pigment-containing systems, photosystem I or II, in which the light-dependent chemical reactions of photosynthesis occur in the chloroplasts of plants
References in periodicals archive ?
Danish Khan told that a sewerage line from Landhi, Korangi linked to PS II was laid during 1960s and after passing half century it got under capacity.
Forty-three local wheat cultivars and breeding lines were exposed to a salt treatment (by adding 200 mM NaCl solution) for two weeks, and chlorophyll content and chlorophyll a fluorescence parameters, performance index (PI) and maximum quantum yield of PS II (Fv/Fm) were determined just after salt treatment.
In our study, Fv/Fm, qL and ETR were decreased under drought stress, indicating that drought stress inhibited the photochemical activity of PS II (Fig.
They describe the multiple roles of various reactive oxygen species in photosynthetic organisms, the structure and function of the water oxidation complex of PS II (water-plastoquinone oxido-reductase), the possible role of Mn-bicarbonate complex in the water oxidation complex, the structural and functional organization of the pigment-protein complexes, the structure and regulation of chloroplast ATP-synthase, the participation of molecular hydrogen in microalgae metabolism, concepts in the evolution and development of photosynthetic carbon metabolism, and the adaptive changes of photosynthesis at increased carbon dioxide concentrations, as well as the photosynthetic machinery response to low temperature stress.
During photosynthesis in normal conditions, a protein-pigment complex known as "Photosystem II" (PS II) must constantly be repaired to fix damage caused by sunlight and ultraviolet radiation.
Environmental factors such as salinity, which affect plant growth, have been investigated using measurements of quantum efficiency of photosystem II (PS II) (HAVAUX et al., 1988).
The first case was a 75-year-old man, ASA PS II, with a history of hypertension.
The results demonstrate: (1) conversion of excess excitation energy into heat, called thermal dissipation, limits energy flux through photosystem (PS) II during development of PS II, (2) following development of maximum electron-transport potential within PS II, thermal dissipation decreases allowing for increased photochemical utilization of excitation energy, and (3) changes of the magnitude of thermal dissipation help maintain an optimal, manageable energy flux through the photosystems during the development of photochemistry.
The PS II approach performs very poorly, relative to random sampling, across all three MLRAs.
Many studies have demonstrated abrupt decrease in PS II photochemistry above a threshold temperature (Terzaghi et al,.