Tratamentos químicos de sementes de astronium urundeuva (M. Allemão) Engl.: aspectos sanitários e fisiológicos

Abstract

The growing concern for environmental preservation and recovery has highlighted the importance of native forest species, such as Aroeira (Astronium urundeuva), especially in the context of programs to recover degraded areas. The demand for quality seeds for these programs is growing, driven by legal requirements for regulating native forests and conserving ecosystems. Thus, the main objective of this research was to evaluate the efficiency of different chemical treatments on the sanitary and physiological quality of A. urundeuva seeds. First, the moisture content was evaluated and the weight of one thousand seeds was determined. To evaluate the sanitary and physiological quality, the following treatments were used: control, sodium hypochlorite (2%), captan, thiophanate-methyl and acibenzolar-S-methyl. The percentage of incidence of fungi was evaluated using the “blotter test” method; germination percentage; germination speed index, first count; normal and abnormal seedlings, dead seeds, length of the aerial part and root, stem diameter; dry mass of the aerial part, root and total. The experimental design used was completely randomized and the means were compared by the Tukey test (5%) using Assistat. The seeds presented moisture content and weight of a thousand seeds of 8.2% and 16.5 g, respectively. The fungal genera Aspergillus spp., Rhizopus spp. and Penicillium spp. were identified. The treatment of the seeds with the product captan proved to be efficient in reducing the incidence of fungi associated with the seeds of A. urundeuva, in addition to presenting higher germination and vigor rates compared to the other treatments evaluated in this study. The fungicide thiophanate-methyl did not provide effective phytosanitary control, but its use did not harm the physiological quality of A. urundeuva seeds, preserving their vigor and germination capacity. The use of sodium hypochlorite (2%) and the fungicide acibenzolar-S-methyl resulted in a significant reduction in the germination of mastic seeds, suggesting a possible phytotoxic effect of these treatments. Therefore, the use of the fungicide captan can be considered a viable alternative in the reduction of pathogens of mastic seeds.