The freshwater chlorophyte Scenedesmus obliquus (Turpin) Kützing produces colonies as an inducible defence against herbivores. We investigated the dynamics of Scenedesmus colony formation and disintegration in response to the density of the herbivorous rotifer Brachionus calyciflorus in large-scale mesocosms. Additional bioassays were performed to investigate Scenedesmus colony disintegration u...

The effects of a commercially available anionic surfactant solution (FFD-6) on growth and morphology of a common green alga (Scenedesmus obliquus) and on survival and clearance rates of the water flea Daphnia magna were studied. The surfactant-solution elicited a morphological response (formation of colonies) in Scenedesmus at concentrations of 10-100 μl l(-1) that were far below the No Observe...

This study was conducted to elucidate the effect of pH on the toxicity of cadmium, cobalt and copper to the green alga Scenedesmus bijuga. The results revealed that the growth of Scenedesmus bijuga increased with increasing pH. However, the accumulation, the accumulation factor and the amount of free ionic forms of each metal decreased. Generally, it appears that the metals tested exert more to...

This work examines the effects of six pesticides on five green algae: Pseudokirchneriella subcapitata, Scenedesmus quadricauda, Scenedesmus obliquus, Chlorella vulgaris and Chlorella pyrenoidosa. The results indicate that the decreasing order of the average toxicity to five algae was: fluazinam > propineb > maneb > mancozeb > zineb > bromoxynil octanoate. however, according to sensitivity magni...

Toxicity of thorium by Monoraphidium sp. and Scenedesmus sp. was studied. Microalgal cultures were inoculated in ASM-1 medium in presence and absence of thorium. Its effect was monitored by direct counting on Fuchs-Rosenthal chamber and with software. The toxicity of thorium over the species was observed for concentrations over 50.0 mg/L. After 30 days, Monoraphidium cells decreased their conce...

Ab s t r a c t . The effect of organic-metallic compounds including lead, (C6H5)3PbCl, and tin, (C6H5)3SnCl, on cucumber leaves and green algae Scenedesmus quadricauda were studied. Both compounds, in concentration of 2 μmol dm, caused increased emission of ultra weak chemiluminescence (UCL) of cucumber leaf discs after 20 hours of treatment, and activity of tin triphenyl chloride was stronger ...

Z. Naturforsch. 43c, 438-442 (1988); received December 7, 1987/February 10, 1988 Cu Deficiency, Cytochrome Oxidase, Mitochondria, Pea Plants, Scenedesmus In Scenedesmus about half of N A D H oxidation proceeds via a cyanide-sensitive and the other half via a cyanide-insensitive respiratory pathway. In contrast, respiration is completely cyanide sensitive in pea indicating that the alternative r...

The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based ...

1. The kinetics of the inactivation of photosynthesis by 2537 A in Chlorella pyrenoidosa and Scenedesmus D(1) indicate that, while the destruction process is largely a first order effect, higher order effects also occur, which become evident at low exposures. In agreement with previous observations, endogenous respiration is insensitive to exposures which inactivate photosynthesis. 2. In Scened...