Potencial alelopático de Protium Amazonicum (Cuatrec.) Daly (Burseraceae)

Abstract

The objective of this work was to verify the interference of the allelopathic effect of the aqueous extracts of leaves of Protium amazonicum on seed germination and development of lettuce seedlings. Aqueous extracts were prepared with leaves of P. amazonicum added to distilled water at the concentrations of 2.5%, 5%, 7.5% and 10% (dry leaf mass / 100 mL distilled water). In the germination tests, five Petri dishes lined with two sheets of filter paper moistened with said extracts or distilled water (control) were used for each treatment. Ten seeds of lettuce were distributed on each plate. In this experiment the (GT) and (IVG) of the seeds were evaluated. In the growth experiment, the seeds were germinated (2 mm radicle) and then transferred to plastic pots lined with filter paper and moistened with the respective extracts or distilled water (control). Hypocotyl and radicle growth were evaluated. The experiments were kept at a constant temperature of 27ºC, with photoperiod of 12h. There was interference in morphological and / or physiological mechanisms that resulted in the increase of germination time. It was possible to observe that in the concentration 10% presented a stimulus of growth of 38% in relation to the average of the control. At concentrations of 2.5% and 10%, root mean values were significantly higher than control means, indicating a stimulus of 175% and 88% in radicle growth. Within the studied processes, aqueous extracts of leaves of P. amazonicum presented opposite results. In germination, severe inhibitory effects were observed. While, on growth, expressive stimulant effects were observed.