Toxicity of three herbicides to some nitrogen-fixing cyanobacteria

Effects of the Herbicide Molinate on Mixotrophic Growth, Photosynthetic Pigments, and Protein Content ofAnabaena sphaericaunder Different Light Conditions

“…It was found that benthiocarb at concentrations ranging from 6 to 8 g ml −1 was lethal to some species of Nostoc (Bhunia et al, 1991;Mishra and Pandey, 1989), and the IC 50 for butylate to Selenastrum capricornutum was 6.47 g ml −1 (Caux et al, 1996). The present studies with molinate indicate that A. sphaerica maintains a definite growth rate, even at concentrations up to 50 g ml −1 , which is much higher than the lethal doses of the above-mentioned carbamate pesticides.…”

“…The special metabolic characteristics make it able to degrade molinate to nontoxic metabolites, which decrease the sensitivity to molinate. Mishra and Pandey (1989) reported that A. doliolum was more resistant to benthiocarb than some species of Nostoc. Blanck et al (1984) reported that the sensitivities of different strains and geographical races of algae to a toxicant vary as much as 200-fold.…”

“…Soil algae, particularly nitrogen-fixing cyanobacteria, are important photosynthetic microorganisms because they contribute to soil fertility by fixing the atmospheric nitrogen (Watanabe, 1962) and are also quite sensitive to herbicides because they share characteristics with higher plants (ElSheekh et al, 1994). Many reports available indicate interaction between soil algae and herbicides, including effects of herbicides on algal growth, photosynthesis, nitrogen fixation, biochemical composition, and metabolic activities (Bhunia et al, 1991;Singh and Tiwari, 1988;El-Sheekh et al, 1994;Mishra and Pandey, 1989;Caux et al, 1996;Mattoo et al, 1984), as well as degradation and removal of herbicides by algae (Stratton, 1984). These studies, however, were conducted under standard phytotoxicity test conditions involving only the results of photoautotrophic growth of algae.…”

Toxicity of 40 Herbicides to the Green Alga Chlorella vulgaris

“…Little is known, however, about the toxicity of new herbicides to freshwater green algae (Fargasova, 1996). Up to now, the acute toxicity of only a few pesticides such as cypermethrin, trazine, prometyne, simetryn, and paraquat, to a few algal species has been studied (Megharaj et al, 1987;Mishra and Pondey, 1989;Fargasova and Kizlink, 1996;Kasai et al,1993;Yee, 1985;El-Sheekh, 1994;Marchini et al, 1988;Naessens et al, 2000;Samson and Popovic, 1988). The work reported here was done to examine the e!ect of 40 herbicides on the green alga Chlorella vulgaris.…”

Influence of bispyribac sodium on nitrogenase activity and growth of cyanobacteria isolated from paddy fields

“…However, bispyribac-sodium inhibits the synthesis of key aminoacids causing susceptible plants to stop growing and die within about two to three weeks (Slade et al, 2006). Many reports available indicate interaction between cyanobacteria and herbicides, including effects of herbicides on algal growth, photosynthesis, nitrogen fixation, biochemical composition and metabolic activities as well as degradation and removal of herbicides by algae and cyanobacteria (Lundqvist, 1970;Ibrahim, 1972;Singh, 1974;Dasilva et al, 1975;Tiwari et al, 1981;Maule and Wright, 1983;Stratton, 1984;Mattoo et al, 1984;El-Sawy et al, 1984;Singh et al, 1986;Goyal, 1986;Tandon and Lal, 1988;Singh and Tiwari, 1988;Mishra and Pandey, 1989a;Bhuniaa et al, 1991;Leganés and Fernández-Valiente, 1992;El Sheekh et al, 1994;Caux et al, 1996;Jeong-Dong and Choul-Gyun, 2006;).…”