Allelopathic Potential of Parthenium hysterophorus: Is it Growth-stage Dependent?

Abstract

World’s one of the most invasive weeds Parthenium hysterophorus L. (Congress grass, family Asteraceae), native to South America, is the most aggressive alien weed in India. The present study aimed to determine the growth stage (early, intermediate and mature) of this weed which was most detrimental to the growth of adjoining crop plants. Impacts of leaf-leachate concentrations (0.5%, 1% and 2%) prepared from leaves at different growth stages of P. hysterophorus were investigated on seed germination and growth of crop Vigna unguiculata. The germination percentage, shoot length, number of leaves, pods, seeds and total biomass of the crop plants significantly declined with increasing concentration of the Parthenium leaf-leachate (maximum at 2%w/v) at all growth stages. However, the leaf-leachate from the leaves of P. hysterophorus at the early growth stage showed the highest detrimental impact on the crop V. unguiculata, followed by intermediate and mature growth stages. Total phenolic content, antioxidant activity and enzymatic were highest in leaves of P. hysterophorus at the early growth stage. In conclusion, the early growth stage of this noxious weed evidently being most detrimental to the growth of adjoining crop plants, suggests Parthenium’s early growth-centric management implication.