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 present investigation envisages the in vivo measured laser induced chlorophyll florescence spectra of EMS (Ethyl methane sulphonate) treated safflower leaves. Seeds of safflower were treated with 0.5% EMS for three treatment durations (3h, 5h and 7h) to raise the populations. The effect of EMS treatment on chlorophyll content in the leaves was assessed using laser induced chlorophyll fluore...

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 ...

The ch4 mutant of sweetclover (Melilotus alba) has previously been demonstrated to be partially deficient in chlorophyll and to have a higher ratio of chlorophyll a to b than normal plants. We were able to substantiate these findings when plants were grown at 23 degrees C and lower (permissive temperatures). However, when grown at 26 degrees C (nonpermissive temperature) the plants produced sma...

background: several concomitant disorders especially thyroid abnormalities have been reported in patients with myasthenia gravis (mg). we aimed to estimate the frequency and pattern of thyroid disorders in iranian patients with mg.all consecutive patients with mg referred to neurology clinic of rasool-e-akram hospital during 2006-2007 were enrolled. methods: all patients underwent clinical asse...