background:  stresses such as heat shock, starvation, or osmotic is essential to lead isolated microspores towards embryogenesis. despite the effectiveness of stresses in embryogenesis, they exert adverse effects on metabolism and growth of the regenerated plants.objectives: the effects of heat shock and 2,4-d treatment on total protein content of treated microspores, morphological and physiolo...

Toxic and bloom-forming cyanobacterium Microcystis aeruginosa was exposed to antialgal allelochemical gramine (0, 0.5, 1, 2, 4, 8 mg·L), The effects of gramine on photosynthetic pigments (lipid soluble: chlorophyll a and β-carotene; water soluble: phycocyanin, allophycocyanin, phycoerythrin, and total phycobilins) and absorption spectra were studied in order to identify the most sensitive pigme...

Photosynthetic action spectra of several cyanobacteria show a peak at about 650 nm, the height of which is correlated with allophycocyanin content in the strains examined. Allophycocyanin harvests light more efficiently than do phycocyanin and phycoerythrin. The contribution of chlorophyll a absorption to photosynthetic activity is barely detectable in cells of normal pigment composition. Chlor...

Different depths within a metalimnetic layer of Oscillatoria rubescens were sampled, and changes in biochemical composition and photosynthetic rate were analyzed. Although differences in pigment and protein content were found, the photosynthetic rates of the samples were not significantly different.

Evaluation of Photosynthetic Pigment, Antioxidant and Non-Antioxidant Activity some Morphological Traits Changes under Drought Stress in Castor Plant (Ricinus communis L.)

1. The relative absorption spectrum of the pigments in their natural state in the photosynthetic bacterium Spirillum rubrum is given from 400 to 900 mmicro. The position of the absorption maxima in the live bacteria due to each of the pigments is: green pigment, 420, 590, 880; red pigment, 490, 510, 550. 2. The relative absorption spectrum of the green pigment in methyl alcohol has been determi...

The nature of the initially excited state of the primary electron donor or special pair has been investigated by Stark effect spectroscopy for reaction centers from the photosynthetic bacteria Rhodopseudomonas viridis and Rhodobacter sphaeroides at 77 K. The data provide values for the magnitude of the difference in permanent dipole moment between the ground and excited state, [unk]Deltamu[unk]...

The delocalized, anticorrelated component of pigment vibrations can drive nonadiabatic electronic energy transfer in photosynthetic light-harvesting antennas. In femtosecond experiments, this energy transfer mechanism leads to excitation of delocalized, anticorrelated vibrational wavepackets on the ground electronic state that exhibit not only 2D spectroscopic signatures attributed to electroni...

In the last five year our research group have been starting to explore the unique and extremely different cyanobacteria world, a group of Gram-negative photosynthetic bacteria, able to inhabit any kind of water environment, such as coastal and inland waters. Their name derives from the capacity to produce, during their photosynthetic processes, a blue-green coloured pigment, called c-phycocyani...

Two-dimensional electronic spectroscopy of Light Harvesting Complex 4 from photosynthetic bacteria reveals excited state dynamics on two timescales and resolves exciton states with little to no oscillator strength. The results suggest a molecular structure in which the pigment dipole organization within the circular complex has more tangential than radial character.