Population dynamics of parthenium hysterophorus (Asteraceae) and its biological suppression through Cassia occidentalis (Caesalpiniaceae)

Abstract

Phytosociological analysis performed over 2005 to 2009 revealed that Cassia occidentalis L. is a dominant species at 3 of 4 sites in Agra district, India, that were previously observed to be dominated by heavy populations of Parthenium hysterophorus L. In order to determine the role of biomolecular interaction, i.e. the allelopathic eff ect, if any, on this shift of fl oral pattern eff ects, aqueous shoot and root cold leachates were determined on seed germination, shoot cut bioassay, seedling bioassay, chlorophyll, nitrogen, and protein content of P. hysterophorus. A signifi cant reduction in germination percentage, shoot cut bioassay, seedling bioassay, and chlorophyll of P. hysterophorus was noticed at higher concentration of shoot leachates. Root leachates of 100% concentration of C. occidentalis obtained aft er 9 days were responsible for the maximum inhibition of nitrogen percentage and protein content of Parthenium, indicating that biomolecular interaction plays a signifi cant role in curbing the population dynamics of this obnoxious weed with enormous seed production potential. © tübi̇tak.