Autotoxicity of Celosia argentea and its allelopathic effects on other plants.
Objective: To demonstrate the autotoxicity and allelopathic potentials of Celosia argentea L. against other plants, discuss the adaptive mechanism of C. argentea as a common field weed and co-existence with the invasive plant Bidens pilosa. Method: Laboratory bioassay was used to evaluate allelopathic potentials of aqueous leachate of C. argentea fresh leaves on seed germination and seedling growth of four different plants, including C. argentea, B. pilosa, Brassica campestris and Raphanus sativus. Meanwhile, pot experiments were conducted to determine the effects of aqueous leachate and litter mulching of C. argentea fresh leaves on itself growth, and mutual allelopathic potentials of C. argentea and B. pilosa litter. Result: The aqueous leachate of C. argentea leaves displayed varying inhibitory effects on seed germination and seedling growth of four tested plants, and this inhibition increased with increasing concentrations. The aqueous leachate of C. argentea leaves at 0.2 500 g.mL-1 reduced itself root biomass by 37.5%. Litter mulching of C. argentea and B. pilosa significantly reduced the biomass of C. argentea after 40 days. Compared with the control, root biomass and total biomass of B. pilosa seedlings treated with litter mulching of B. pilosa decreased by 23.0% and 22.2% respectively. Conclusion: Not only C. argentea plant has autotoxicity, but also it has strong allelopathic effects on B. campestris and R. sativus. The large amount of C. argentea growth in field should be controlled, and monoculture and continuous cropping of C. argentea should be avoided. The mutual allelopathic inhibition was found between C. argentea and B. pilosa plants, and the co-existence of C. argentea with B. pilosa was conducted with the allelopathic effect.