Effects of fungicide CM-75 on growth, biochemical composition and some enzymes of Nostoc ellipsosporum NDUPC002 was studied. The cyanbacterium Nostoc ellipsosporum NDUPC002 was isolated from agricultural fields of Varanasi, India and characterized by morphological as well molecular means. The organism was deposited at NAIMCC (NBAIM), Mau, India (Accession No. NAIMCC-C-000122). LC50 conc. of fungicide was 2ppm. 1ppm, 2ppm, and 4ppm were concentrations of treatments. All concentrations of CM-75 inhibited the growth of cyanobacteria, and maximum inhibition was observed in 4ppm treatment. All treatment concentrations of fungicide decreased the Chl.-a and carbohydrate content of cyanobacteria with maximum inhibition of 23.63% and 19.98% respectively in 4ppm treatment. Total protein content was slightly increased (1.57 %) in 1ppm treatment and decreased in other treatments with maximum inhibition of 15.47 % in 4 ppm treatment. All concentrations of fungicide inhibited the activity of Nitrate reductase and Glutamine synthetase with maximum inhibition of 58.93% and 41.15 % respectively in 4ppm. The findings of experiment suggested that even 1 ppm conc. of CM-75 was inhibiting the growth, biochemical composition and some of the enzymes (NR and GS) of Nostoc ellipsosporum NDUPC002.
