The dynamics of non-photochemical quenching (NPQ) of chlorophyll fluorescence and the dynamics of xanthophyll conversion under different actinic light conditions were studied in intact leaves of Arabidopsis thaliana. NPQ induction was investigated during up to 180 min illumination at 450, 900, and 1,800 μmol photons m-2 s-1 (μE) and NPQ relaxation after 5, 30, 90, or 180 min of pre-illumination...

Absence of the Proton Gradient Regulation 5 (PGR5) protein from plant chloroplasts prevents the induction of strong trans-thylakoid proton gradient (ΔpH) and consequently also the thermal dissipation of excess energy (NPQ). The absence of the PSBS protein likewise prevents the formation of ΔpH-dependent NPQ. This component of NPQ is called qE, which is nearly exclusively responsible for inducti...

Photosynthetic organisms use various photoprotective mechanisms to dissipate excess photoexcitation as heat in a process called nonphotochemical quenching (NPQ). Regulation of NPQ allows for a rapid response to changes in light intensity and in vascular plants, is primarily triggered by a pH gradient across the thylakoid membrane (∆pH). The response is mediated by the PsbS protein and various x...

The aim of this study was to explore the role of the mitochondrial alternative oxidase (AOX) in the protection of photosynthesis during drought in wheat leaves. The relative water contents of water-replete and drought-exposed wheat plants were 97.2+/-0.3 and 75+/-2, respectively. Drought increased the amount of leaf AOX protein and also enhanced the rate of AOX-dependent O(2) uptake by the resp...

Plants must switch rapidly between light harvesting and photoprotection in response to environmental fluctuations in light intensity. This switch can lead to losses in absorbed energy usage, as photoprotective energy dissipation mechanisms can take minutes to hours to fully relax. One possible way to improve photosynthesis is to engineer these energy dissipation mechanisms (measured as non-phot...

INTRODUCTION The Neuropathic Pain Questionnaire-Short Form (NPQ-SF) is the shortest diagnostic tool for the assessment of neuropathic pain, designed with the goal to differentiate between neuropathic and nonneuropathic pain. The aim of this study was to translate, culturally adapt, and validate the NPQ-SF questionnaire in Arabic. METHODS A systematic translation process was used to translate ...

UNLABELLED The Neurophysiology of Pain Questionnaire (NPQ) was devised to assess how an individual conceptualizes the biological mechanisms that underpin his or her pain. Despite its widespread use, its psychometric properties have not been comprehensively interrogated. Rasch analysis was undertaken on NPQ data from a convenience sample of 300 spinal pain patients, and test-retest reliability w...

High light (beyond what is needed for maximum photosynthesis) is a major plant stress. Under extreme high-light conditions, the photosynthetic apparatus can be damaged irreversibly, but plants and algae have devised various strategies to protect themselves (photoprotection) (Björkman and Demmig-Adams, 1994). One of the strategies for survival in high light is to eliminate the excess absorbed en...