Mozafar Sharifi - Associated Prof., Department of Biology, Faculty of Science ,Razi Unoversity of Kermanshah
Loghman Yousefizadeh - MSc. Student of Plant Ecology, Faculty of Science, Razi University of Kermanshah

In recent years, commercial glyphosate herbicide formulations have been widely used in agriculture to control aquatic weeds. These pesticides may result in disruption of ecological balance, causing damage to non-target organisms including fish, diatoms and other aqutice organisms. We assessed the effect of the commercial formulation Roundup® using artificial steram , An experiment was carried out using indoor experimental channels (artificial streams) to assess the long-term effect (20 days) of pesticide on periphyton communities exposed to low levels of Glyphosate (Roundap® formulation),The herbicide was added at four doses: a Control (without Roundup) and three treatments of 20,40 and 60 mg Lˉ¹ of the active ingredient (glyphosate). The effects of Glyphosate on community biomass were assessed by measuring dry mass, ash-free dry mass (AFDM), autotrophic index (AI) and chlorophyll a factors. In artificial streams with Roundup, there was a significant (p <0.05) reduction of chlorophyll a compared to controls. Roundup produced a clear delay in periphyton colonization in treated artificial stream and values of the periphyton mass variables (dry mass, ash-free dry mass (AFDM) and chlorophyll a ) were always higher in control channel Compared channeles with low and medium herbicide concentration.

Artificial stream, pesticide, Endosulfan, periphyton, Biomass, dry mass, Chlorophyll a , AFDM