New perspectives on the allelopathic potential of Brazilian Atlantic Forest native trees

Secondary metabolites released into the environment by plants species can mediate interplant interactions, either positively or negatively affecting the growth and development of neighboring plants. The present work aims to evaluate the potential of aqueous extracts obtained from vegetative organs of saplings of six native tree species (Anadenanthera colubrina, Dalbergia nigra, Mimosa bimucronata, Piptadenia gonoacantha, Guarea guidonia and Moquiniastrum polymorphum), commonly used in the restoration of Atlantic Forest ecosystems, in controlling the growth of target plants. Seeds of the target species (Sesamum indicum) were distributed in Petri dishes containing the extracts. After seven days, the target seedlings were frozen and photographed for later measurements of their roots and shoots. The results showed a concentration-dependent relationship. Moreover, each donor species caused different responses in terms of phytotoxicity. The extracts that caused the greatest inhibition to the growth of the target species were obtained from G. guidonia roots and A. colubrina leaves, suggesting the occurrence of important inhibitory compounds regarding plant-growth control. Extracts from other species were found to stimulate shoot growth. Our findings indicate that plants may release allelochemicals since early stages of growth, suggesting that chemical traits in saplings planted for ecosystem restoration may affect the desired community assembly.