Phytotoxicity of Citronellol Against Amaranthus Viridis L.

Supriya Vaid

A study was undertaken to explore the phytotoxicity of citronellol, a volatile monoterpene found in Eucalyptus citriodora Hook. and many other aromatic plants, against the weed Amaranthus viridis L. in order to assess its herbicidal activity. Dose-response studies conducted under laboratory conditions revealed that citroellol (in concentrations ranging from 0.1µL to 2 µL) greatly suppresses the germination and seedling height of the test weed. At 2 µL concentration of citronellol, none of the seeds of the test weed germinated. At 1 µL concentration of citronellol, the radicle height of the test weed was reduced to a mere 28% and the plumule height was reduced to about 40% compared to control. Not only the germination and seedling growth, even the chlorophyll content and respiratory activity in the leaves of emerged seedlings of A. viridis were severely affected. The chlorophyll content and respiratory activity were reduced by about 30% and 60%, respectively, even at a very low concentration of 1 µL. These results indicated an adverse affect of citronellol on the photosynthetic efficiency and energy metabolism of the test weed. A strong negative correlation was observed between the concentration of citronellol and the observed effect. Based on the study, it can be concluded that citronellol possesses strong inhibitory potential against weeds that could be exploited for weed management.