<b>Phytotoxic effects of aqueous leaf extracts of four Myrtaceae species on three weeds

Abstract

Research on allelopathic interactions can be useful in the search for phytotoxins produced by plants that may be employed as natural herbicides. The aim of this study was to assess the phytotoxic action of aqueous leaf extract of Blepharocalyx salicifolius, Myrcia multiflora, Myrcia splendens and Myrcia tomentosa on the germination and development of three weeds. The working hypothesis was that leaf extracts of Myrtaceae may negatively influence the development of weed species. Aqueous leaf extracts at 5 and 10% (g mL -1 ) were tested on the germination and growth of Euphorbia heterophylla, Echinochloa crus-galli and Ipomoea grandifolia and compared with the herbicide oxyfluorfen and distilled water (control). The most extracts caused pronounced delays in seed germination and inhibited the growth of seedlings of E. heterophylla; I. grandifolia and E. crus-galli, with the last target species had no growth shoot inhibited by the extracts. In this study, the potential and efficiency of the tested aqueous leaf extracts were evident because they were more phytotoxic to the weeds than the herbicide. Thus, the aqueous extracts of leaves from Myrtaceae species show potential for the isolation of active compounds that can be used for the production of natural herbicides in the future.Efeito fitotóxico de extrato foliar aquoso de quatro espécies de Myrtaceae sobre três espécies infestantes de cultura RESUMO. Estudos relacionados à interações alelopáticas podem ser úteis na busca por fitotoxinas produzidas por plantas que podem ser empregadas como herbicidas naturais. O objetivo deste trabalho foi avaliar a atividade fitotóxica de extratos aquosos de folhas de Blepharocalyx salicifolius, Myrcia multiflora, Myrcia splendens e Myrcia tomentosa sobre a germinação e o desenvolvimento de três plantas infestantes de culturas agrícolas. A hipótese testada neste trabalho foi que extratos foliares de Myrtaceae podem influenciar negativamente sobre o desenvolvimento de espécies infestantes de cultura. Foram testados os extratos foliares aquosos a 5 e 10% (g mL -1 ) sobre a germinação e crescimento de três espécies infestantes de cultura e comparados com o herbicida oxyfluorfen e água destilada (controle). A maioria dos extratos promoveram atrasos acentuados na germinação de sementes e inibiram o crescimento de plântulas de E. heterophylla; I. grandifolia e E. crus-galli, apenas esta última espécie alvo não apresentou inibição no crescimento de sua parte aérea pelos extratos. O presente estudo comprovou o potencial e a eficiência dos extratos, uma vez que foram mais fitotóxicos às espécies infestantes que o herbicida. Assim, extratos foliares aquosos de espécies de Myrtaceae apresentam potencial para isolamento de compostos que poderão ser usados para produção de herbicidas naturais no futuro.Palavras-chave: alelopatia, germinação, crescimento, herbicida. 242Imatomi et al.

Allelopathic Effects of Aqueous Extracts of Alternanthera philoxeroides on the Growth of Zoysia matrella

“…The results show that the effect of ethyl propionate on the SOD and CAT activities of Z. matrella's growth also ranged from slightly stimulatory (≤0.5 mmol) to highly The data are the mean values (n = 3) ± standard error of the mean; different letters in the same column denote significant differences at p<0.05. inhibitory (≥1 mmol) in a similar fashion to the effects of A. philoxeroides extracts on Z. matrella (Table 3 and Table 4). In addition, ethyl propionate was found to have the strongest inhibition of root length in Z. matrella, which accords with the results of Imatomi et al [38], who found that the order of the inhibitory effect of allelopathic sensitivity (RI) of Codonopsis pilosula followed the sequence root dry weight > root volume > root length > height > seedling dry weight in treatments with high concentrations of ferulic acid (that is, ferulic acid has stronger inhibitory effects on the roots of Codonopsis pilosula than on the aboveground parts). The strongest inhibition of extracts of Solidago canadensis L. on the germination of rapeseed was also attributed to the presence of phenolic compounds in all treatments [39].…”

<b>Allelopathic bioactivity of fresh and infused aqueous extracts of Brazilian cherry (<i>Eugenia uniflora</i> L.) on lettuce and maize

“…This effect appears to be common in allelopathic studies, supported by the results obtained by Capobianco, Vestena, and Bitencourt (2009) and Al-Sherif, Hegazy, Gomaa, and Hassan (2013) all of which demonstrated that the allelopathic effects vary according to the exposed part of the plant. Imatomi et al (2015) suggested that this differential effect may be due to higher extract exposure of the roots, however, this does not apply in the current study as the shoots and roots were exposed to the extracts at the same intensity. In general, treatment with Brazilian cherry extracts affected the target species in some way, but the phytotoxicity of the fresh extract was greater than the infused extract.…”

“…Comparable effects on the root development of maize have also been observed for Azadirachta indica A. Juss (Rickli, Fortes, Silva, Pilatti, & Hutt, 2011) and Lupinus angustifolius L. (Gomes, Fortes, Silva, Bonamigo, & Pinto, 2013), at all concentrations tested. Imatomi et al (2015) evaluated the allelopathic potential of extracts of 15 Brazilian Myrtaceae species, all of which had phytotoxic effects on root development of the target species.…”

“…The release of these compounds can affect the development of other surrounding plants either a beneficial or harmful way, a phenomenon known as allelopathy (Inderjit, Wardle, Karban, & Callaway, 2011). This ecological characteristic is common in other Myrtaceae species, including Myrcia guianensis (Souza Filho et al, 2006), Eugenia involucrata, Acca sellowiana (Sausen, Lowe, Figueiredo, & Buzzarro, 2009), Blepharocalyx salicifolius, Myrcia multiflora, Myrcia splendens and Myrcia tomentosa (Imatomi et al, 2013;Imatomi, Novaes, Miranda, & Gualtieri, 2015).…”

The Effect of Young Coconut Husk on the Quality of Goat Manure-Chicken Excreta Bioculture

“…Tests were carried out in Petri disks on washed sand media covered with cotton on the bottom. Bioculture was dissolved with destiled water in 10 mL of solution with concentrations of 0, 5 and 10% (Imatomi et al, 2015), applied daily and observed after watering for 3 days. Data on liquid fertilizer contents and germination tests were analyzed using one way ANOVA.…”