Phytotoxic Effects of Dimeric Cationic Surfactant Gemini (16-2-16), (16-6-16) and (16-10-16)

In this study, the gemini surfactants of the alkanediyl- a-x-bis(alkyl dimethyl ammonium) dibromide type, with n-C16 alkyl groups and different spacers containing s carbon atoms, referred to as ''16-s-16'' (s = 2, 6, 10) were selected to examine their phytotoxic effects. These dimeric cationic gemini surfactants were synthesized in our laboratory. They were evaluated under laboratory conditions using onion (Allium cepa L.) as a test material. The phytotoxic effects on root were determined after 7th days. Surfactants used in study were tested at three different surfactant concentrations, 2.00, 1.00 and 0.5 g/L concentrations. The phytotoxicity results were based on the effective concentration that reduced root growth by 50 % (EC50). Some differences were observed between the effects of three types of gemini surfactants. Stimulatory effects only occurred in Gemini (16-2-16) at 0.5 g/L concentration, while inhibitory effects occured in Gemini (16-6-16) and Gemini (16-10-16) at all concentrations and in Gemini (16-2- 16) at 2.00 and 1.00 g/L concentration. It was observed that inhibitory effects increased with increasing concentrations of in Gemini (16-6-16) and Gemini (16-10-16).