Chlorophyll-a plays a fundamental role in the solar energy conversion processes that occur in oxygen evolving organisms, such as plants algae and cyanobacteria. To study the chlorophyll-a species at the heart of these solar conversion processes FTIR difference spectroscopy has been a valuable tool. However, FTIR difference spectra are only partially understood. To gain a more detailed understan...

Sodium borohydride is a well known reducing agent. In methanol at room temperature formyl and keto groups are readily reduced to alcohol groups, while ester and carboxyl groups, carbon-carbon and carbon-nitrogen double bonds are only reduced with difficulty (2, 17). Of the groups present in chlorophyll b the C3 formyl and the C9 keto groups should be amenable to reduction, while the C2 vinyl an...

UNLABELLED The major photopigment of the cyanobacterium Acaryochloris marina is chlorophyll d, while its direct biosynthetic precursor, chlorophyll a, is also present in the cell. These pigments, along with the majority of chlorophylls utilized by oxygenic phototrophs, carry an ethyl group at the C-8 position of the molecule, having undergone reduction of a vinyl group during biosynthesis. Two ...

In plants, the formation of isopentenyl diphosphate and dimethylallyl diphosphate, the central intermediates in the biosynthesis of isoprenoids, is compartmentalized: the mevalonate (MVA) pathway, which is localized to the cytosol, is responsible for the synthesis of sterols, certain sesquiterpenes, and the side chain of ubiquinone; in contrast, the recently discovered MVA-independent pathway, ...

in recent years application of plant growth regulators especially growth retardants, has been significantly increased. trizols (paclobutrzol and trinexapac-ethyl) as the most effective and least harmful growth retardants, induce more dwarf and denser cover plants with both darker and thicker leaves.  therefore, an experiment based on completely randomized block design with 16 treatments and 3 r...

dust accumulation capacity of ficus carica l. and psidium guajava l. was investigated from eight different sites of multan, pakistan.  leaves of both plants were used for analyzing biometric (leaf area, fresh and dry weights) and biochemical attributes (chlorophyll contents, carotenoids and ascorbic acid).  maximum dust accumulation was occurred in the plants growing near road sites, while, min...

in order to study the effect of iron chelate (fe-eddha) on some biochemical characteristic of safflower (carthamus tinctorius l.) under two irrigation regimes, a field experiment was set up a split-plot based on randomized block design with four replication in 2011 in a research field of the faculty of agriculture at shahed university. in this study the main plots consisted of two levels of irr...

The fluorescence lifetime of chlorophyll a gives information about the primary photo-physical events in photosynthesis. Most of the light energy absorbed by chlorophylls is utilized for photochemistry. There are two main additional pathways competing for the absorbed light energy: fluorescence and radiationless internal conversion (heat). Only a few percent of the absorbed energy proceeds along...

Growth parameters and total pigment content (chlorophyll a+b and carotenoids) were investigated through postgermination, greening, natural senescence and subsequent rejuvenation of intact cotyledons of Cucurbita pepo L. (zucchini). Dark-induced senescence and recovery of the cotyledons after 2-day darkening of a whole plant were also studied. Results showed significant increase in the fresh wei...

Impact of the wheat stem sawßy, Cephus cinctus Norton (Hymenoptera: Cephidae), feeding injury on chlorophyll content and photosystem II (PSII) photochemistry in heads of wheat, TriticumaestivumL., at the grain-Þlling developmental stagewas evaluated by biochemically assessing the total chlorophyll, chlorophyll a (Chla), chlorophyll b (Chlb), chlorophyll a/b ratio (Chla/b), and carotenoid concen...