Abstract:
Biological invasion is currently one of the main causes of biodiversity loss and difficult
protection and recovery actions of ecosystems. Despite being an emerging area in plant ecology,
few studies investigate which are the mechanisms used by alien species that make them
successful in new habitats, like the release of secondary metabolism compounds that will act on
development and growth of others. In Brazil, Acacia mangium Willd threat the biodiversity even
in protected areas. Thus, the aim of this work was evaluated the allelopathic effect of A.
mangium Willd leave extract over L. sativa, L. leucocephala and U. brizantha seeds. Leaves
were collected from Parque Estadual de Itaúnas, ES, Brazil, macerated in ethyl alcohol for five
days and submitted to rotatory evaporation. Metabolites classes were identified by
phytochemical tests. For allelopathic bioassay, seeds of each plant tested were treated with water
or one of four concentration of the extract (1, 5, 10 and 50mg/mL). Phytochemicals tests
indicated the presence of triterpenos, saponins and tanins. As the allelopathic potential, the
extract not only reduced germination of L. sativain 5 and 10mg/mL but also affected the
germination speed index, germination mean speed, radicular length and radicles length speed
index. 50mg/mL took the full inhibition of germination. The invasive species L. leucocephala
and U. brizantha also were affected by extract, although U. brizantha has been more sensitive to
allelochemicals; this open a possibility of using an invasive species to control others and
demonstrate the resistance of L. leucocephala even under adverse conditions. |
