EN
Ultraweak luminescence (UL) within the visible range accompanies physiological processes taking place in Native non-stressed Nitellopsis Obtusa cells. Intensity of UL emission is several times higher than the intensity of an environmental medium. The influence of Humic acid (HA), diuron-urea herbicide (DCMU) and photosynthetic active radiation (PAR) on UL intensity and spectral composition for algae cells was investigated. Measurements were made both in neutral and reactive media. An artificial pond water (APW) served as a neutral medium. Algae cells in APW were used as the control samples. Concentrations of specific chemical agents were equal to 8·10-2mg·mL-1, 4.2·10-2 mmol·L-1 for HA and DCMU, respectively, whereas PAR intensity reached 900 µE·s-1·m-2. The influence of HA and light on UL intensity was studied.