MICROCOSM INVESTIGATION ON THE ALLELOCHEMIC POTENTIALOF AGERATUM CONYZOIDES ON SELECTED FOOD CROPRoger Bruce Syngkli, Sarah Lallianpuii and Prabhat Kumar Rai
Invasive alien plants like Ageratum conyzoidesinfluence the growth, yield, development, and productivityof food crops. The various allelochemicals present in A. conyzoides exert stimulatory or inhibitory effects onthe food crops. In this microcosm investigation through pot experiments, we evaluated the allelopathicpotential of A. conyzoides on the germination and seedling growth of a leafy vegetable of nutritional valuei.e., Lactuca sativa. The soil samples were collected from two different sites i.e., healthy forest soil and soilinvaded by A. conyzoides. The healthy forest soil was considered as control pot while A. conyzoides invadedsoil was selected for the experimental pot. The inhibitory effect of the invasive plant was observed on thetested crop of dietary value in human nutrition. The results revealed that the germination of the seeds isinhibited and suppressed by A. conyzoides. Microcosm studies demonstrated that out of the 15 seeds plantedon both pots, 13 seeds germinated and thrived on the experimental pot and 14 on the control pot. Theseedling height (32.1 cm), shoot length (27.65 cm), seedling biomass (1.866 g) and vigor index (6.829) wererecorded higher in the experimental pot. Whereas, the root length (4.8 cm), germination potential (0.93),germination percentage (93.33%), germination index (4.66) and germination rate index (434.91) were notedhigher in the control pot. A. conyzoides therefore showed both the inhibitory and stimulatory effects on L.sativa and thereby exhibited both positive and negative allelopathic effects. Further, bioassay experimentswith other bioassay crops can elucidate the chemical ecology and allelopathy potential of A. conyzoides.