Assessment of plant growth regulators affecting phytoplankton
and zooplankton in a small stream

Summary

The results of studying by biotesting plant growth regulators most widely used in agriculture in Russia and the CIS countries (Amitsid, Atlet, Geteroauksin, Tsirkon, Ethamon, Epin-extra) affecting phytoplankton (green alga Chlorella vulgaris) and zooplankton species (Daphnia magna Sr. cladoceran) are presented. As test parameters, the effect of suppression (inhibition) and stimulation of algal cell multiplication in water samples with plant growth regulators was used which was recorded by reducing or increasing the optical density of the algal cell suspension in the sample at 96-hour exposure and mortality of one-day daphnia youngsters at 96-hour exposure. For work commercial plant growth regulators in the concentration range of 10-9–10-3 mg/dm³ and water from the Ilevna small stream, the left tributary of the Oka River, were used. It was established that all studied plant growth regulators caused daphnia death. The toxic effect depended on the nature of the product, concentration and duration of exposure. Depending on the concentration, plant growth regulators either stimulated or inhibited the multiplication of green alga Chlorella vulgaris cells.

Key words

biotesting , plant growth regulators , cladocerans Daphnia magna Sr , green alga Chlorella vulgaris