CONSEQUENCES OF 2,4-D AND PENCYCURON TREATMENT ON THREE DIFFERENT CYANOBACTERIAL SPECIES - ANABAENA FERTILISSIMA RAO, AULOSIRA FERTILISSIMA GHOSE AND WESTIELLOPSIS PROLIFICA JANET

Three strains of filamentous-heterocystous cyanobacteria such as Anabaena fertilissima, Aulosira fertilissima and Westiellopsis prolifica were screened for their photosynthetic pigments, stress metabolites and enzymatic activities in response to 2,4-dichloro phenoxy acetic acid ethyl ester and 1-(4-chlorobenzyl)-1-cyclopentyl-3-phenylurea (Pencycuron). Amongst them, Westiellopsis prolifica grew maximally in BG11 medium amended with both the pesticides concentrations. In 2,4-D ethyl ester treated cultures the phycobilin pigments showed superior plummet as compared to chlorophyll-a and carotenoids in all three cyanobacterial species. Phycoerythrin showed highest reduction by 86% at 60 ppm in Anabaena fertilissima cells grown in medium amended with Pencycuron. After 4 days of inoculation slight raise in protein content at lower concentrations of 2,4-D was recorded in three species, whereas in Pencycuron treated cultures Anabaena fertilissima (10% at 60 ppm) and Aulosira fertilissima (7% at 60ppm) showed minor lapse, and W. prolifica was unaffected in all treated concentrations. However, carbohydrates and amino acids have shown inhibitor effect on the three species of cyanobacteria in response of the increasing concentration of both the pesticides, on the other hand, phenols exhibited the increasing trend. Activity of nitrate reductase, glutamine synthetase and succinate dehydrogenase were adversely affected in all three species when treated with the increasing concentrations of both the pesticides.