Fluometuron Induced Growth, Chemical And Photosynthetic Changes In Chlorella Vulgaris

Abstract

Presence of fluometuron at different concentrations in the culture medium of Chlorella vulgaris induced pronounced inhibition in the growth rate and dry weight of the alga throughout the experimental period. Furthermore, fluometuron variably reduced the photosynthetic pigment contents (chlorophyll a, chlorophyll b and carotenoids). At 1 and 2 ppm, fluometuron induced culture bleaching up to 3 and 5 days respectively. Thereafter, progressive marked increase in chlorophyll contents was observed accompanying culture regreening. Supplemental addition of fluometuron to the culture media reduced the level of reducing sugars, sucrose, polysaccharides and total sugars. The reductions in the different carbohydrate fractions were associated with marked increases in the different nitrogen components (amino-, protein - and total soluble -N). "COz - light fixation was significantly inhibited in the treated cultures. The incorporation of "COz into various photosynthetic intermediates was also, in general, markedly lowered below the control values and was found to vary with the concentration of fluometuron fed to the algal culture. The results are discussed in relation to the phytotoxicity of the herbicide used.