The techniques utilized to extract chlorophyll from plant materials are destructive and based on methods that use organic solvents. This study proposes the non-destructive quantification of chlorophyll and nitrogen concentration using a portable chlorophyll meter (SPAD-502). Further, was possible to establish relationships between chlorophyll fluorescence and SPAD-502 values. This methodology c...

Transcript accumulation and translation of psbA as well as processing of the D1 precursor protein were investigated in relation to chlorophyll availability in vivo in cyanobacterial strains lacking photosystem I (PS I). The psbA transcript level was almost independent of chlorophyll availability and was approximately 3-fold lower in darkness than in continuous light (5 microE m-2 s-1). Upon ill...

This paper presents spectroscopic investigations of IsiA, a chlorophyll a-binding membrane protein produced by cyanobacteria grown in iron-deficient environments. IsiA, if associated with photosystem I, supports photosystem I in light harvesting by efficiently transferring excitation energy. However, if separated from photosystem I, IsiA exhibits considerable excitation quenching observed as a ...

The circadian clock, synchronized by daily cyclic environmental cues, regulates diverse aspects of plant growth and development and increases plant fitness. Even though much is known regarding the molecular mechanism of circadian clock, it remains challenging to quantify the temporal variation of major photosynthesis products as well as their metabolic output in higher plants in a real-time, no...

During leaf senescence, plants degrade chlorophyll to colorless linear tetrapyrroles that are stored in the vacuole of senescing cells. The early steps of chlorophyll breakdown occur in plastids. To date, five chlorophyll catabolic enzymes (CCEs), NONYELLOW COLORING1 (NYC1), NYC1-LIKE, pheophytinase, pheophorbide a oxygenase (PAO), and red chlorophyll catabolite reductase, have been identified;...

In an earlier paper (7) the chlorophyll composition of a number of chlorina mutants of barley obtained from D. W. Robertson (10) were described and it was then pointed out that one of the mutants appeared to be entirely lacking in chlorophyll b. Thus, it was of considerable interest to learn whether the chlorophyll b deficiency was affecting the photosynthetic activity of this mutant. Comparati...

[1] In the California Current System, strong mesoscale variability associated with eddies and meanders of the coastal jet play an important role in the biological productivity of the area. To assess the dominant timescales of variability, a wavelet analysis is applied to almost nine years (October 1997 to July 2006) of 1-km-resolution, 5-day-averaged, Seaviewing Wide Field-of-view Sensor (SeaWi...

The transfer of triplet excitation from chlorophyll to zeaxanthin in liposom es is a function o f temperature and pigment concentration. At 525 nm both chlorophyll and zeaxanthin triplet states are observed. The result is a biphasic increase in absorption. The rise time o f absorption by the chlorophyll triplet is much faster, than by the zeaxanthin triplet. With increasing temperature the cont...

Satellite and in situ chlorophyll concentration data collected as part of VALidation HYperspectral of a BIOgeochemical model (ValHyBio), a PNTS-sponsored project dedicated to satellite ocean-colour imaging of the Southwest Pacific, are analyzed to describe chlorophyll variability in the Coral Sea, a vast oligotrophic region characterized by a deep chlorophyll maximum and blue waters of high tra...

Chlorophyll is a key indicator of the physiological status of a forest canopy. However, its distribution may vary greatly in time and space, so that the estimation of chlorophyll content of canopies or branches by extrapolation from leaf values obtained by destructive sampling is labor intensive and potentially inaccurate. Chlorophyll content is related positively to the point of maximum slope ...