Plants dissipate excess excitation energy as heat by non-photochemical quenching (NPQ). NPQ has been thought to resemble in vitro aggregation quenching of the major antenna complex, light harvesting complex of photosystem II (LHC-II). Both processes are widely believed to involve a conformational change that creates a quenching centre of two neighbouring pigments within the complex. Using recom...

The interactions of the xanthophylls zeaxanthin, antheraxanthin and violaxanthin with chlorophyll, which are relevant for the chlorophyll fluorescence quenching in the non-photochemical quenching (NPQ) process in green plants, are investigated by means of quantum chemical methods. In particular, we use a hybrid approach consisting of time-dependent density-functional theory (TDDFT) and configur...

Like most photosynthetic organisms, cyanobacteria are vulnerable to fluctuations in light intensity, which can damage their machinery. To protect against this, they use a photoprotective mechanism called non-photochemical quenching (NPQ), where excess absorbed photo-energy is dissipated as heat. In cyanobacteria, activation of Orange Carotenoid Protein (OCP) the critical first step NPQ response...

Isoprene-emitting plants are better protected against thermal and oxidative stresses. Isoprene may strengthen membranes avoiding their denaturation and may quench reactive oxygen and nitrogen species, achieving a similar protective effect. The physiological role of isoprene in unstressed plants, up to now, is not understood. It is shown here, by monitoring the non-photochemical quenching (NPQ) ...

There are multiple complementary and redundant mechanisms to provide protection against photo-oxidative damage, including non-photochemical quenching (NPQ). NPQ dissipates excess excitation energy as heat by using xanthophylls in combination with changes to the light-harvesting complex (LHC) antenna. The xanthophylls are oxygenated carotenoids that in addition to contributing to NPQ can quench ...

Abstract In this study, we investigated the physiological responses of maize with different amylose content at seedlings to drought stress. For waxy (WMS) and normal (NMS), decline photosynthesis under stress (DS) was due stomatal limitation. DS increased non-photochemical quenching coefficient (NPQ), whereas decreased activities peroxidase (POD) plant height (PH), compared plants irrigation. T...

The measurement of carbon isotope discrimination (∆) provides an integrated insight into theresponse of plants to environmental change. To investigate the potential use of ∆ for identifyingshade tolerance in rice, five rice varieties were selected and artificially shaded (53% lightreduction) during the grain-filling period in 2010 and 2011, in Sichuan, China. Shadingtreatment had a significant ...

Intensified water column stratification due to global warming has the potential to decrease nutrient availability while increasing excess light for the photosynthesis of phytoplankton in the euphotic zone, which together will increase the need for photoprotective strategies such as non-photochemical quenching (NPQ). We investigated whether NPQ is enhanced and how it is regulated molecularly und...

Photo-physiological variability of in vivo chlorophyll fluorescence (CF) per unit of chlorophyll concentration (CC) is analyzed using a biophysical model to improve the accuracy of CC assessments. Field measurements of CF and photosystem II (PSII) photochemical yield (PY) with the Advanced Laser Fluorometer (ALF) in the Delaware and Chesapeake Bays are analyzed vs. high-performance liquid chrom...

Nothofagus dombeyi (Mirb.) Blume and Nothofagus nitida (Phil.) Krasser, two evergreens in the South Chilean forest, regenerate in open habitats and under the canopy, respectively. Both overtop the forest canopy when they are in the adult stage, suggesting that their photoprotective mechanisms differ in ontogenetic dynamics. We postulated that N. nitida, a shade-tolerant species increases its ca...