Allelopathic effect of aqueous extracts of annual sowthistle on green onion and cichory germination and radicle elongation.

Efectos alelopáticos de extractos acuosos de cerraja sobre la germinación y elongación radicular de achicoria y cebolla de verdeo.

p. 039-046

Della Penna, Angela B.; Batro, Alejandro y Estévez, Patricio.


The secondary metabolites that cultivated plants and weeds release into the environment can affect the growth and development of cultivated plants The allelopathic effect of aqueous extracts of annual sowthistle (Sonchus oleraceus L.) on the germination and radicle elongation of green onion (Allium schoenoprasum L.) and cichory (Cichorium intybus L.) was evaluated. Aqueous extracts were prepared at a 10% concentration, using dry ground leaves of sothwistle and distilled water (1:10 w/v), without maceration and with 48-hour maceration. These concentrated extracts (considered as 100%) were used to obtain dilutions at 50 and 20%. Fifty seeds of the species under study were placed on filter paper in each Petri dish –with 2 ml of distilled water in the controls, and 2 ml of each concentrated extract and their dilutions in the treatments. Electrical conductivity and pH of concentrated extracts were determined. The germination percentage at 48 and 96 hs and radicle elongation (mm) at 96 hs after the treatments were evaluated. The experimental design was completely randomized with three replicates. The data were submitted to ANOVA (P= 0.01) and mean values were compared by the Tukey test (P= 0.05) or by means of a t test (P= 0.05). S. oleraceus aqueous extracts reduced green onion and cichory germination and radicle elongation. The higher the concentration of the extract, the higher the inhibitory effect. The time of maceration influenced germination at medium concentrations, but had no effect on radicle elongation. The conductivity and the pH did not influence the results.

Key words:

Allelopathy, Allium schoenoprasum L.; concentration, Cichorium intybus L, Sonchus oleraceus L.