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...

Diatoms are a major group of primary producers ubiquitous in all aquatic ecosystems. To protect themselves from photooxidative damage in a fluctuating light climate potentially punctuated with regular excess light exposures, diatoms have developed several photoprotective mechanisms. The xanthophyll cycle (XC) dependent non-photochemical chlorophyll fluorescence quenching (NPQ) is one of the mos...

Background and Aims In photosynthetic organisms exposure to high light induces the production of reactive oxygen species (ROS), such as hydrogen peroxide (H2O2), which in part is prevented by non-photochemical quenching (NPQ). As one of the most stable and longest-lived ROS, H2O2 is involved in key signalling pathways in development and stress responses, although in excess it can induce damage....

NPQ (non-photochemical quenching) is a fundamental photosynthetic mechanism by which plants protect themselves against excess excitation energy and the resulting photodamage. A discussed molecular mechanism of the so-called feedback de-excitation component (qE) of NPQ involves the formation of a quenching complex. Recently, we have studied the influence of formation of a zeaxanthin-chlorophyll ...

OBJECTIVE To validate a Spanish version of the Northwick Park Neck Pain Questionnaire (NPQ) and to prove its usefulness in clinical practice. METHODS We studied 58 patients with non-inflammatory neck pain of more than 4 months duration. A blind back translation of the NPQ was made, and the resulting back-translation version was then compared with the original. The NPQ comprises 9 questions wi...

Long-lived shade leaves of avocado had extremely low rates of photosynthesis. Gas exchange measurements of photosynthesis were of limited use, so we resorted to Chl fluorescence imaging (CFI) and spot measurements to evaluate photosynthetic electron transport rates (ETRs) and non-photochemical quenching (NPQ). Imaging revealed a remarkable transient heterogeneity of NPQ during photosynthetic in...