Comparative allelopathic effects of Eucalyptus tereticornis leaf extracts on germination and seedling growth of black turtle bean (Phaseolus vulgaris) and common purslane (Portulaca oleracea)

Over 14 days, germination, seedling growth, biomass, stem girth, and leaf count were measured. Analyses using ANOVA, Tukey’s HSD, and linear mixed models showed concentration‑dependent inhibition (p < 0.01).

Bean germination fell from 96.7% to 40.0%, with biomass reduced by ~50%. Purslane was more sensitive, with germination dropping from 90.0% to 13.3%, height reduced by over 60%, and fresh weight cut by 65%, though dry weight was unaffected. Significant Species × Concentration interactions highlighted differential susceptibility, confirming strong allelopathic effects relevant to bioherbicide potential and eucalyptus agroforestry design.