The Interactions of Cu++ and CN− with Paraquat Phytotoxicity to a Chlorella

The interactions between copper (Cu++) and cyanide (CN−) with 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat) on phytotoxicity to Chlorella pyrenoidosa Chick, IAC 251, were determined by measuring chlorophyll absorbance at 434 and 670 mμ. Cu++ inhibited phytotoxicity and CN− accelerated paraquat activity with highly significant mutually antagonistic interactions occurring between Cu++ (2 ppm) and CN− (16 ppm) at paraquat levels to 2 ppm.