BIOLOGIA PLANTARUM 35 (2): 293-297, 1993 BRIEF COMMUNICATION Autotoxic impact of essential oil extracted from Lantana camara L. R. K. ARORA and R. K. KOHLI* Allelopathy Research Laboratory, Department of Botany, Panjab University, Chandigarh 160 014, lndia Abstract The effect of crude volatile oils extracted from the young leaves of Lantana camara var. camara was studied on the parent plant itself. The contents of water and chlorophyll, of leaves apart from seed germination, seed vigour and length of seedlings of the parent plant were adversely affected with increasing concentration of the Lantana oils; this indicated autotoxic potential of the oil. The correlations between oil concentration and the studied parameters were rather strong and obeyed the concentration response relationship, typical of chemical bases. The cell respiration, however, increased with increasing concentration of the oil vapours. Compared to control, less than 13 % of the seeds of the parent plant exposed to 30 cm 3 m-3 of oil showed incipient germination with no growth of radicle beyond unmeasurable protuberance, and no plumule emergence. Lantana camara L. (Verbenaceae), a wild luxuriantly growing plant has encroached upon large areas of pasture and forests in tropical and subtropical parts of the world (Sharma 1988). Its prolification is attributed .to toxicity to grazing cattle, capacity to withstand adverse environmental conditions, and resistance to herbicides. In addition, strong allelopathic property of the plant against other plants enable this weed competitive advantage over other plants (Achhireddy and Singh 1984, Mersie and Singh 1987). In nature, it propagates sexually. However, its seeds either do not germinate or fail to establish seedlings in'the area of its colonization, probably due to autotoxic properties. Like any plant, the allelopathic chemicals of it may be released in nature by leaching from aerial or underground parts, after death and decay or through exuda- tion from roots, or volatilization of its oil. L. camara var. camara possesses Lantana Received 10 April 1992, accepted26 June 1992. *To whom correspondence should be sent. 293