ABSTRACT:The interference of chemicals in the germination and growth of plant species, known as allelopathy, is one of the main ways of eliminating competition for resources through the release of allelochemicals. The aim of this study was to determine the presence of secondary metabolites in extracts prepared from leaves of Vochysia haenkeana, evaluating their allelopathic action on the germination and seedling growth of lettuce and tomato. The plant material was collected in the Taboco region, Mato Grosso do Sul state, and after drying and grinding, underwent extraction with the use of water and ethanol, concentration of 200.0 g L -1 . The method using an ultrasound bath was followed by maceration for 24 h in the refrigerator without the presence of light. The extracts were subjected to classical phytochemical analysis and the determination of pH, electrical conductivity, soluble solids and allelopathic tests. For bioassays, the extracts were diluted at concentrations of 25.0, 50.0, 100.0 and 150.0 g L -1 and the experimental design was completely randomized. There was a reduction in the percentage and speed of germination at concentrations of 25.0 and 50.0 g L -1 in both extracts. The seedling growth was also adversely affected, both in the germination chamber and in the greenhouse. These results are probably associated with the presence of different allelochemicals in the extracts, such as phenolic compounds and flavonoids, indicating that this species presented allelopathic action.

Knowledge of environmental conditions for seed germination and seedling formation of forest species is essential. The objective of this work is to evaluate the germination of Callisthene major seeds under laboratory conditions using six different temperatures (20, 25, 30, 35, 20-30 and 25-35 °C) and germitest paper (on and between paper). A completely randomized design was used with four replicates of 25 seeds per experimental unit. The variables evaluated were germination (%), germination speed index (GSI), average germination time (AGT) in days and normal seedlings. The results indicated that the species has a high germination index (above 94%) for all tested substrates and temperatures; however, the highest germination vigor (GSI and AGT) was obtained by alternating the temperature between 25-35 °C with the substrate on paper.