Allelochemical Potential of Alecrim-de-Campinas (Holocalyx balansae Micheli) on Germination and Growth of Species of Agro-Economic Interest

Abstract Herbicides selects resistant weed populations, such as morning glory (Ipomoea triloba L.) and sourgrass (Digitaria insularis (L.) Fedde). Natural compounds represent an alternative control method for weeds. Released into the environment, those metabolites can influence other organisms by allelochemical interactions. Alecrim-de-campinas (Holocalyx balansae Micheli) produces cyanogenic glycosides, which are toxic metabolites. Therefore, can crude extract, aqueous extracts, and H. balansae metabolites affect the germination and growth of morning glory, sourgrass, and lettuce? Crude extract (CE) and the ethyl acetate fraction (EAF) were obtained and their allelochemical potential evaluated by lettuce germination. Aqueous extracts (EAq) were tested on the germination and growth of lettuce, morning glory, and sourgrass. The HB-1 compound was isolated from EAF and its effect was tested on the growth of the weeds and on the germination and growth of lettuce. CE, EAF, and EAq reduced germination and inhibited growth, especially affecting root elongation. This study found no difference in lettuce germination under HB-1 solutions. The compound reduced seedling elongation, the bioassays caused the emergence of abnormal seedlings with root necrosis, yellowish and poorly expanded cotyledons and eophylls. The evaluated seedlings showed reduced growth and weight and morphological changes.