Allelopathic Influences of Artemisia Dubia Wall. Ex. Besser on Seed Germination of Parthenium Hysterophorus L.

Abstract

Screening plant produced phytotoxins (allelochemicals) through bioassay is an accepted strategic tool employed for the discovery of potential pesticides for weed management. The present laboratory based study was undertaken to serve the purpose of preliminary screening of phytotoxicity of Artemisia dubia against an invasive composite Parthenium hysterophorus. Allelopathic effect of aqueous (leachate and decomposed) extract, solvent extract (hexane, chloroform, methanol and water), soil amended extract with leaf, stem and root and essential oil of donor plant Artemisia dubia was studied on germination and seedling vigour of Parthenium hysterophorus. Extraction and quantification of different parts in different solvent was done by percolation method while hydro distillation method was followed for essential oil extraction. Bioassay was done by allowing P. hysterophorus seed to germinate in petri dishes (for solvent, aqueous and essential oil) and disposable plastic plates (for plant parts amended soil) in laboratory condition against varied concentrations of prepared extracts of Artemisia dubia. Yield of crude extract (solvent and aqueous) was high for leaf compared to stem and root. All the tested extract (aqueous, solvent, essential oil and soil amended with plant parts) from different plant parts significantly checked the germination of Parthenium hysterophorus in higher concentration with the effect being more pronounced due to leaf of Artemisia dubia. Linear growth of root and shoot also followed the same pattern. The order of allelopathic influence was leaf > stem > root in all the cases and it was concentration dependent. Length of root was retarded while stem length experienced no effect, sometime elongation (stem and root extract of leachate, stem extract of hexane and chloroform) and sometime retardation (aqueous decomposed extract of leaf, leaf amended soil and essential oil). Aqueous decomposed leaf extract, soil amended with leaf parts and essential oil were found to be most inhibitory. These results provide ample evidence that allelopathic potential exist in Artemisia dubia and this can be exploited for the control of Parthenium hysterophorus.