Allelopathy of aqueous Pachyrhizus erosus L. extracts on Euphorbia heterophylla and Bidens pilosa

Abstract

Allelopathy contributes to the sustainable management of weeds in growing areas, due to its ability to inhibit the development of weed species. This study aimed to evaluate the allelopathic effect of Pachyrhizus erosus extract on Euphorbia heterophylla and Bidens pilosa germination. The experiment was carried out in a completely randomized design, in a 2 x 2 x 4 factorial scheme, with four replications. The first factor corresponded to the plant portion (shoot and tuberous root), the second to the extract preparation method (water at room temperature and boiling) and the third to the extract concentrations (0 %, 25 %, 50 % and 100 %). Phytochemical analyses were performed to identify the presence of secondary metabolites. The variables germination percentage, germination rate index and dry biomass decreased with increasing aqueous extract concentrations for both E. heterophylla and B. pilosa. When applied a P. erosus crude shoot extract (boiling), decreases of 18 % and 92 % were observed in the E. heterophylla and B. pilosa germination, respectively, with a decrease of 91 % in the dry biomass of E. heterophylla seedlings. The tuberous root extract (boiling), on the other hand, reduced the germination percentages for E. heterophylla and B. pilosa in 18 % and 80 %, respectively. The phytochemical evaluation indicated the presence of flavonoids, coumarins and saponins in the shoot and tuberous root extracts, while tannins were only observed in the shoot extract. Thus, it can be concluded that P. erosus extracts display an allelopathic effect on the weed species evaluated.

Levantamento fitossociológico de plantas daninhas em cultivo de couve-folha em consorciação com quiabeiro em sistema de produção orgânico

“…A alelopatia representa um mecanismo pelo qual determinadas plantas interferem no desenvolvimento de outras, alterando seu padrão e densidade (Smith, 1989). O controle de B. pilosa, E. heterophylla, entre outras espécies são descritos com resultados satisfatórios na literatura (Barbosa et al, 2018;Bernardes et al, 2020;Paula et al, 2020). A campo, há relatos de redução de 59% na densidade populacional de plantas daninhas através de estratégias alelopáticas (Arif et al, 2015).…”

Bioatividade de óleos essenciais na germinação e no vigor em sementes de tomate

“…O efeito alelopático de óleos essenciais e de extratos de plantas já foi comprovado em alguns estudos e indica as potencialidades do uso dos metabólitos secundários presentes nas diversas espécies vegetais, tais como S. trilobata em tomate, cebola, rabanete e repolho (HERNÁNDEZ-ARO et al, 2016); Araucaria angustifolia em alface (SILVEIRA et al, 2014); Plectranthus barbatus em Amaranthus delexus (LESSA et al, 2017); Pachyrhizus erosus L. em Euphorbia heterophylla e Bidens pilosa (BARBOSA et al, 2018); Anacardium occidentale em tomate e alface (MATIAS et al, 2017); picão preto (Bidens pilosa L.) em feijão comum (Phaseolos vulgaris L.) (COELHO et al, 2014).…”

A nanoemulsion of Rosmarinus officinalis L. essential oil with allelopathic effect against Lactuca sativa L. seeds / Uma nanoemulsão a partir do óleo essencial de Rosmarinus officinalis L com efeito alelopático em sementes de Lactuca sativa L

“…They play an essential role in plant defense and their interaction with the environment (Campolo et al, 2020). Among such interactions, the allelopathic effect is the direct interference that can stimulate and/or inhibit the development of other plant species Brazilian Journal of Development, Curitiba, v.7, n.9, p. 86752-86771 sep. 2021 (Almeida et al, 2019;Barbosa et al, 2018;Campolo et al, 2020;Karalija et al, 2020;Matias et al, 2017;Mirmostafaee, Azizi and Fujii, 2020;Salomão, Ferro and Ruas, 2020;Schandry and Becker, 2020;Takao, Imatomi and Gualtieri, 2015;Zucareli et al, 2019).…”