ALLELOPATHIC EFFECTS OF AZADIRACHTA INDICA A. JUSS. AND MIKANIA MICRANTHA KUNTH LEAVES EXTRACTS ON SEED GERMINATION OF AMARANTHUS SPINOSUS L.

Allelopathic effects of aqueous leaf extracts of two selected plant species -Azadirachta indica A.Juss and Mikania micrantha Kunth on the seed germination of a common weed Amaranthus spinosus L. were studied. The experiments were conducted under laboratory conditions. Different test concentrations [5%, 10%, 15% and 20%] of aqueous extracts of both leaves were prepared separately. The receptor seeds were collected from Amaranthus spinosus. Seed germination tests were carried out in sterilized petri dishes. Effects of different concentrations of leaves extracts on the germination of seeds were studied and recorded for seven consecutive days. This data was compared with that of Control, i.e. Distilled water. Allelopathic inhibition of seed germination increased with increasing concentrations of leaves extracts for both donor plants. From the recorded results Germination potential and Germination rates were calculated. Germination potential was found to be the least in 15% and 20% concentration of both the leaves extracts. Germination rate was the lowest in 20% concentration of Mikania micrantha leaf extract. From the study, it was found out that both the plants show significant allelopathic effect against a common weed Amaranthus spinosus and this potential could be used to manage weeds. This work tries to point towards the possibility of developing bioherbicides from plants with such allelopathic activity, which could be used to control many weeds, an important problem faced in the agriculture fields. [ABSTRACT FROM AUTHOR]