Phytotoxicity Studies of Chromolaena odorata (L.) R.M. King and H. Robinson. Through Seed Germination Bioassays

Abstract

Invasive or alien weeds are those which are introduced to new areas intentionally or unintentionally. They are undesirable plants which affect crop production, their quality and quantity, other resource utilization and income generation activities of the humans. Chromolaena odorata is one such invasive or alien weed which has invaded Maval region in Pune district. Chromolaena odorata has shown gradual increase in its abundance and decrease in natural Phytodiversity and crop diversity over frequent field visits. The present study was therefore undertaken to investigate allelopathic potential of leachates of root, stem, and leaf of Chromolaena odorata on common legumes in Maval tehsil like Horsegram, Lentil, and Mothbean in seed germination bioassay experiment. Petri plate bioassay study revealed that lower concentrations of leachates promoted root length, shoot length, Vigour index but higher concentration (20%) of aqueous leachates reduced seed germination in Horsegram, Lentil, and Mothbeans significantly as compared to other concentrations (4%, 8%, 12%, 16% and control). Treatment with higher concentration caused a remarkable increase in the rate of inhibition. Phytochemical analysis showed the presence of Flavonoids, Saponins, Tannins, Alkaloids, Steroids and Terpenoids. The inhibitory effects on seed germination revealed allelopathic potential of weed Chromolaena odorata. Toxicity effect was more in 20% concentration of leaf leachates than in root and stem. This may be due to presence of more allelochemicals in leaf than in root and stem.