Efecto alelopático del extracto acuoso de los órganos aéreos de Baccharis notosergila griseb. (asteraceae) sobre la germinación, crecimiento inicial y morfología externa de plántulas de Lolium multiflorum L. (Poaceae)

The soil characteristics of the Salado Depression limited agricultural use, maintaining the entire area as natural grassland vegetation used for cattled feed. The high predominance of Baccharis notosergila (Asteraceae) in this region led to weed overgrowth, restricting the growth and establishment of the various forage species that make up the pasture. The leaves, stems and underground organs of B. notosergila contain tannins, lipid bodies and polyphenols suggesting that these secreted compounds may acts as allelopathic agents that inhibit the growth and establishment of other species in the areas. The objective was to determine whether aqueous extracts of B. notosergila have allelopathic effects on the germination and initial growth of Lolium multiflorum L. (Poaceae). Aqueous extracts (AE) of B. notosergila were obtained at different concentrations corresponding to the following treatments (T): T0 (Control); T1: 1%; T2: 5%; T3: 10%; T4: 25% and T5: 50%. Seeds of L. multiflorum were placed in Petri dishes with 5 ml of each T and germination and subsequent seedling growth were recorded. The AE had no effect on the germination of L. multiflorum, with T4 and T5 showing a decrease in the length of root and plumule 7 days after the start of the test. The presence of saponins in the extracts of 30 to 100% concentration was confirmed. These compounds secreted together with other secondary metabolites exert a suppressive effect on the initial growth of L. multiflorum seedlings, opening up management alternatives for the control of invasive species.