27 Result(s)
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Olle Björkman
Plant Sciences
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Article
Letter from Olle Björkman
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Article
Photoprotection in a zeaxanthin- and lutein-deficient double mutant of Arabidopsis
When light absorption by a plant exceeds its capacity for light utilization, photosynthetic light harvesting is rapidly downregulated by photoprotective thermal dissipation, which is measured as nonphotochemic...
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Fluorescence quenching in four unicellular algae with different light-harvesting and xanthophyll-cycle pigments
We examined the relationship between non-photochemical quenching (NPQ) and xanthophyll de-epoxidation in the unicellular algae Euglena gracilis, Ochromonas danica, Phaeodactylum tricornutum, and Dunaliella ter...
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On the Respective Roles of the Various Xanthophylls During Seedling Development and High Light Stress in Arabidopsis
Six hundred different naturally occurring carotenoids have been identified to date and this diversity is reflected in the composition of the photosynthetic apparatus of different bacterial and algal classes. H...
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Xanthophylls and Excess-Energy Dissipation: A Genetic Dissection in Arabidopsis
Thermal dissipation of excess absorbed light energy is considered to play a key role in regulating light harvesting and electron transport, and to prevent photodamage to the photosynthetic apparatus (1, 2, 3)....
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Chapter
Non-photochemical quenching in four unicellular algae with different light-harvesting and xanthophyll-cycle pigments
Photosynthetic organisms have developed pathways to safely dissipate excessive energy as heat. In eukaryotic cells the major pathway of energy dissipation requires acidification of the thylakoid lumen and is t...
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Nigericin insensitive post-illumination reduction in fluorescence yield in Dunaliella tertiolecta (chlorophyte)
Cells of the green alga Dunaliella tertiolecta grown in a light/dark cycle were exposed to high light for about 15 min. In light, energy-dependent quenching reduced fluorescence emission and decreased PS II effic...
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Temperature-sensitive coupling and uncoupling of ATPase-mediated, nonradiative energy dissipation: Similarities between chloroplasts and leaves
The effects of temperature on the dark relaxation kinetics of nonradiative energy dissipation in photosystem II were compared in lettuce (Lactuca sativa L.) chloroplasts and leaves of Aegialitis annulata R. Br. A...
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Relationships among violaxanthin deepoxidation, thylakoid membrane conformation, and nonphotochemical chlorophyll fluorescence quenching in leaves of cotton (Gossypium hirsutum L.)
The kinetics and temperature dependencies of development and relaxation of light-induced absorbance changes caused by deepoxidation of violaxanthin to antheraxanthin and zeaxanthin (ΔZ; peak at 506 nm) and by ...
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Article
Adenine nucleotides and the xanthophyll cycle in leaves
The effects of varying the steady-state rate of non-cyclic photosynthetic electron transport on the leaf adenylate energy charge and the epoxidation state of the xanthophyll-cycle pigments were determined in l...
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Article
Adenine nucleotides and the xanthophyll cycle in leaves
The relationships among the leaf adenylate energy charge, the xanthophyll-cycle components, and photosystem II (PSII) fluorescence quenching were determined in leaves of cotton (Gossypium hirsutum L. cv. Acala) u...
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Carotenoid distribution and deepoxidation in thylakoid pigment-protein complexes from cotton leaves and bundle-sheath cells of maize
In response to excess light, the xanthophyll violaxanthin (V) is deepoxidized to zeaxanthin (Z) via antheraxanthin (A) and the degree of this deepoxidation is strongly correlated with dissipation of excess ene...
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Growth of cotton under continuous salinity stress: influence on allocation pattern, stomatal and non-stomatal components of photosynthesis and dissipation of excess light energy
Cotton (Gossypium hirsutum L.) plants were grown in flowing-culture solutions containing 0%, 26% and 55% natural seawater under controlled and otherwise identical conditions. Leaf Na+ content rose to 360 mM in 55...
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Chloroplast movements in leaves: Influence on chlorophyll fluorescence and measurements of light-induced absorbance changes related to ΔpH and zeaxanthin formation
Light-induced chloroplast movements were found to cause changes in chlorophyll fluorescence emission, closely matching those in leaf absorptance, both in terms of the kinetics and the maximum extent of the cha...
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Temperature dependence of violaxanthin de-epoxidation and non-photochemical fluorescence quenching in intact leaves of Gossypium hirsutum L. and Malva parviflora L.
The temperature dependence of the rate of de-epoxidation of violaxanthin to zeaxanthin was determined in leaves of chilling-sensitive Gossypium hirsutum L. (cotton) and chilling-resistant Malva parviflora L. by m...
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Role of the xanthophyll cycle in photoprotection elucidated by measurements of light-induced absorbance changes, fluorescence and photosynthesis in leaves of Hedera canariensis
The role of the xanthophyll cycle in regulating the energy flow to the PS II reaction centers and therefore in photoprotection was studied by measurements of light-induced absorbance changes, Chl fluorescence,...
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Leaf Xanthophyll content and composition in sun and shade determined by HPLC
As a part of our investigations to test the hypothesis that zeaxanthin formed by reversible de-epoxidation of violaxanthin serves to dissipate any excessive and potentially harmful excitation energy we determi...
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Relationship between efficiency of photosynthetic energy conversion and chlorophyll fluorescence quenching in upland cotton (Gossypium hirsutum L.)
The relationship between components of non-photochemical quenching of chlorophyll fluorescence yield (qNP) and dissipation of excessive excitation energy was determined in cotton leaves using concurrent measureme...
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Photoinhibition, 77K chlorophyll fluorescence quenching and phosphorylation of the light-harvesting chlorophyll-protein complex of photosystem II in soybean leaves
When the capacity of leaves for orderly dissipation of excitation energy in photosynthesis is exceeded, one mechanism by which the excess energy appears to be dissipated is through a nonradiative decay process...
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Comparison of the effect of excessive light on chlorophyll fluorescence (77K) and photon yield of O2 evolution in leaves of higher plants
High-light treatments (1750–2000 μmol photons m−2 · s−1) of leaves from a number of higher-plant species invariably resulted in quenching of the maximum 77K chlorophyll fluorescence at both 692 and 734 nm (F M, 6...
