Specimens of Pistia stratiotes were subjected to five concentrations of arsenic (As) for seven days. Growth, As absorption, malondialdehyde (MDA) content, photosynthetic pigments, enzymatic activities, amino acids content and anatomical changes were assessed. Plant arsenic accumulation increased with increasing metalloid in the solution, while growth rate and photosynthetic pigment content decr...

Harmful algal blooms occur all over the world, destroying aquatic ecosystems and threatening other organisms. The culture supernatant of the marine algicidal actinomycete BS01 was able to lysis dinoflagellate Alexandrium tamarense ATGD98-006. Physiological and biochemical responses to oxidative stress in A. tamarense were investigated to elucidate the mechanism involved in BS01 inhibition of alg...

Bacteriochlorophyll b (bchl b) has been isolated from the halophilic photosynthetic bacterium, Ectothiorhodospira halochloris. The pigment and a series of derivatives thereof are different from Bchl b from Rhodopseudomonas viriais by HPLC analysis, but similar by uv-vis spectroscopy. The chromatographic difference originates in different esterifying alcohols in the two pigments. The one from Rp...

The initial steps of photosynthesis require the absorption and subsequent transfer of energy through an intricate network of pigment–protein complexes. Held within the protein scaffold of these complexes, chromophore molecules are densely packed and fixed in specific geometries relative to one another resulting in Coulombic coupling. Excitation energy transfer through these systems can be accom...

The marine gastropod molluscs Tridachia crispata, Tridachiella diomedea, and Placobranchus ianthobapsus (Sacoglossa, Opisthobranchia) possess free functional chloroplasts within the cells of the digestive diverticula, as determined by observations on ultrastructure, pigment analyses, and experiments on photosynthetic capacity. In the light, the chloroplasts incorporate H(14)CO(3) (-)in situ. Re...

Spartina densiflora is a C(4) halophytic species that has proved to have a high invasive potential which derives from its clonal growth and its physiological plasticity to environmental factors, such as salinity. A greenhouse experiment was designed to investigate the synergic effect of 380 and 700 ppm CO(2) at 0, 171, and 510 mM NaCl on the growth and the photosynthetic apparatus of S. densifl...

Hermatypic-zooxanthellate corals track the diel patterns of the main environmental parameters - temperature, UV and visible light - by acclimation processes that include biochemical responses. The diel course of solar radiation is followed by photosynthesis rates and thereby elicits simultaneous changes in tissue oxygen tension due to the shift in photosynthesis/respiration balance. The recurre...

Spectral attenuance and photosynthetic performance over the range 300 to 700 nm were examined in red-tide populations of Prorocentrum micans and Gonyaulax polyedra collected off La Jolla, California, USA, in May 1969 and M a y June 1985; and in spring 1969, November 198t and AprilMay 1982, respectively. In the near ultraviolet (UV), high attenuance and diminished photosynthetic effectiveness we...

The photosynthetic and respiratory behaviors of two Dunaliella salina strains (IR-1 and Gh-U) were investigated at two temperature treatments and two assay temperatures. Net photosynthetic rate (P ), photonN saturated net photosynthetic rate (P ), irradiance required to Saturate Photosynthetic (SI), respiration and Nmax pigment changes in D. salina strains, containing different chlorophyll (Chl...

In common with many other higher plant species, Arabidopsis undergoes photosynthetic acclimation, altering the composition of the photosynthetic apparatus in response to fluctuations in its growth environment. The changes in photosynthetic function that result from acclimation can be detected in a noninvasive manner by monitoring chlorophyll (Chl) fluorescence. This technique has been used to d...