AÇÃO ALELOPÁTICA DE Holocalyx balansae Micheli SOBRE Ipomoea triloba L.

Abstract

Allelopathy constitutes a biochemical interaction, with a harmful or beneficial effect, between plants. This interaction occurs as a result of the release of allelochemicals from secondary metabolism. Holocalyx balansae Micheli is a tree species, from the Fabaceae family, in which phytochemical studies revealed the presence of flavonoids and cyanogenic glycosides in its leaflets. Thus, to evaluate the allelopathic action of H. balansae extracts on germination, Ipomoea triloba L. seeds were distributed in Petri dishes containing aqueous extract (treatment) and distilled water (control), and kept in a germination chamber at 30 °C, and after 48 hours the germination percentage was verified. In a greenhouse, I. triloba seeds were sown in pots containing sand and organic substrate and seedling emergence was observed, according to the treatment. In the control treatment the pots were irrigated with water, in the pre-emergence the pots received aqueous extract before the seedlings emerged and in the post-emergence treatment the extract was applied only after the seedlings emerged. To obtain the aqueous extract at a concentration of 10% (w/v), H. balansae leaflets were dried, weighed, crushed and diluted with distilled water. The aqueous extract inhibited the germination of I. triloba in laboratory bioassays and also affected emergence, when applied before seedling emergence, under greenhouse conditions. The results obtained demonstrate that H. balansae presents allelopathic activity on I. triloba, which may be related to the allelochemicals of the leaflets used to obtain the aqueous extracts.