Can pruning enhance the allelopathic effect? A study with Golden-Dewdrop

Abstract Golden-Dewdrop (Duranta erecta L.), known for its landscaping applications, undergoes successive pruning to maintain its ornamental structure, a practice known to induce numerous physiological and chemical responses in the plant. Therefore, this study aimed to evaluate the influence of pruning and different extraction methods on the allelopathic potential of Golden-Dewdrop on the germination and initial growth of lettuce. Leaf extracts were obtained by decoction (hot) and maceration (cold) at concentrations of 20%, 40%, 60%, 80%, and 100%, with distilled water as a negative control. Phytochemical screening of the extracts was performed for phenolic compounds, flavonoids, anthocyanidins, tannins, cardioactive heterosides, saponins, alkaloids, and terpenes. For the bioassay, germinative and morphological parameters were measured and characterized. The data were subjected to analysis of variance (ANOVA), and for quantitative data, regression models were adjusted, while for qualitative data, means were compared using the Scott-Knott test with 5% significance. Significant differences were observed between extraction methods and management practices, with the hot aqueous extract from pruned plants significantly reducing germination at higher concentrations. The initial growth of lettuce was severely affected, presenting numerous morphological abnormalities, with severe damage to the root system at all concentrations. This study suggests that pruning practices have a modulating effect on the allelopathic activity of Golden-Dewdrop, providing valuable information for landscaping projects and botanical studies considering its evaluation and production of phytotoxic phytochemicals. Resumo Pingo-de-ouro (Duranta erecta L.), conhecida por suas aplicações paisagísticas, é frequentemente submetida a sucessivas podas para manter sua estrutura ornamental, sabendo-se que essa prática gera inúmeras respostas fisiológicas e químicas na planta. Portanto, este estudo teve como objetivo avaliar a influência da poda e de diferentes métodos de extração sobre o potencial alelopático da Pingo-de-ouro na germinação e crescimento inicial da alface. Os extratos das folhas foram obtidos por decocção (quente) e maceração (frio) em concentrações de 20%, 40%, 60%, 80% e 100%, tendo água destilada como controle negativo. Foi realizada a triagem fitoquímica dos extratos para identificar compostos fenólicos, flavonoides, antocianidinas, taninos, heterosídeos cardiotônicos, saponinas