Department of Hydraulics and Transport, Federal University of Mato Grosso do Sul, CxP 549, 79070-970, Campo Grande, MS, Brazil, E. Mail: marizeperes@hotmail.com.
1EMBRAPA Gado de Corte, 79002-970, Campo Grande, MS, Brazil.
In glasshouse pot culture we determined the bioactivity of crude ethanol extract (CEE) and semi-purified fractions (SFs) obtained with hexane (HF), ethyl acetate (EAF) and aqueous-ethanol (AEF) of Senna occidentalis shoots on the germination and growth of lettuce (Lactuca sativa L.) tomato (Lycopersicon esculentum Mill.), onion (Allium cepa L) and wheat (Triticum aestivum L.). Both CEE and the SFs of S. occidentalis inhibited 50% emergence of two dicotyledon test plants. While EAF inhibited the root growth in two monocotyledon test plants and shoot growth in tomatoes. The AEF inhibited the root and shoot growth of dicots and root growth of monocots. The low concentrations of extracts and fractions stimulated the onion growth and also increased the dry biomass in all test species. Thin-layer chromatography, detected the terpenes in HF and phenolic compounds and alkaloids in EAF. The spectrophotometer analyses found the highest total phenol and flavonoid content in EAF. The bioassays showed that aerial parts of S. occidentalis have allelopathic potential and may be useful in weed management programmes.
Allelochemicals, dry weight, natural herbicide, pot culture, root growth inhibition, seedling emergence, Senna occidentalis
