Allelopathic effects of fruits of Phytolacca dioica L. on the germination and early growth of lettuce and beggartick

Plants produce substances through secondary metabolism. When these chemicals are released into the environment they can interfere in the germination and development of other plants. The objective of this research was to investigate the effects of allelopathic Phytolacca dioica L. on the germination and early growth of lettuce and beggartick, under laboratory conditions, using aqueous extracts of fruits of Phytolacca dioica at concentrations of 0, 1, 2, 4 and 8%. Phytochemical analysis of the fruit was performed; and pH and osmotic potential of extracts of fruit were tested. We analyzed the following germination parameters: percentage of germination (PG), speed of germination (VG) and speed of germination index (IVG), for the initial growth parameters examined are: length (root and shoot) and biomass (fresh and dry) of seedlings of lettuce and beggartick. The data were submitted to Tukey's test at 1% of probability. Parameters PG, VG and IVG were significantly affected, with increase in concentration of the extracts of fruits of Phytolacca dioica. The length (root and shoot) and biomass (fresh and dry) of seedlings of lettuce and beggartick were reduced significantly with increasing concentration of the aqueous extracts of fruits of Phytolacca dioica. The pH and osmotic potential of the extracts were maintained within appropriate standards and phytochemical analysis revealed the presence of flavonoids. The results showed that the fruits of Phytolacca dioica presented allelopathic effect on the lettuce and beggartick.