Doutorado em Genética e Melhoramento

URI Permanente para esta coleção

http://repositorio.ufes.br/handle/10/17475

Nível: Doutorado
Ano de início: 2013
Conceito atual na CAPES: 5
Ato normativo: Homologado pelo CNE/CES Parecer nº 250/2014, portaria nº 187 de 06/03/2015, publicado no DOU de 09/03/2015 seção 1, página 11
Periodicidade de seleção: Semestral
Área(s) de concentração: Genética e Melhoramento
Url do curso: https://geneticaemelhoramento.ufes.br/pt-br/pos-graduacao/PPGGM/detalhes-do-curso?id=1416

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Navegando Doutorado em Genética e Melhoramento por Autor "Alves, Thammyres de Assis"

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    Eco-friendly herbicide potencial of different Psidium species: mechanisms of action, phytotoxicity and cytogeno-toxic approaches
    (Universidade Federal do Espírito Santo, 2021-02-26) Alves, Thammyres de Assis; Fontes, Milene Miranda Praca; https://orcid.org/0000000177389518; http://lattes.cnpq.br/1372644511398549; https://orcid.org/0000000311484832; http://lattes.cnpq.br/2518493606370352; Oliveira, Stéfanie Cristina de; https://orcid.org/0000-0001-8350-2601; http://lattes.cnpq.br/6404885772178652; Carrijo, Tatiana Tavares; https://orcid.org/0000000283660738; http://lattes.cnpq.br/0479854777557016; Vieira, Larissa Fonseca Andrade; https://orcid.org/0000-0002-7947-7498; http://lattes.cnpq.br/8814776095228940
    Since the beginning of agronomic activities, diseases, pests, and weeds started to appear. Thus, development of agrochemicals was especially important for increasing agricultural productivity, resulting in lower costs and increased efficiency of production. However, research has shown that agrochemicals have been damaging human health and the environment. In this way, environmentally friendly agrochemicals have gained the attention of researchers. For the evaluation of such potential, bioassays with model systems are used, with emphasis on plant bioassays, which are overly sensitive to toxic agents, allowing different analyzes simultaneously (phyto-cyto-genotoxicity), in addition to having a high correlation with other organisms including mammals. Thus, the present research evaluated and compared the toxicity of the aqueous and ethanolic leaf extracts of the species Psidium cattleyanum, as well as of the essential oils of Psidium acidum and Psidium cauliflorum, investigating their potential bioherbicides and their cellular mechanisms of action through plant toxicity bioassay, using the plants model Lactuca sativa and Sorghum bicolor. For this, the essential oils were extracted, the extracts prepared, and the chemicals compounds were characterized. For the biological tests, seeds of the model plants were treated with the essential oils of the two species in the concentrations of 3000, 1500, 750, 375 and 187.5 mg mL-1 and with the extracts in the concentrations of 100, 50, 25 and 12.5 mg mL-1 , distilled water, dichloromethane and glyphosate were applied as controls. The variables: germination percentage (GP), germination speed index (GSI), root growth (RG), aerial growth (AG), mitotic index (MI), chromosomal changes (CA) and nuclear changes (NA) were evaluated. Flavonoids, flavonoids, flavones, flavonoids, alkaloids, resins, xanthones and anthraquinone glycoside were identified in the ethanolic extract. Both extracts evaluated, in the highest concentration, inhibited the initial development of the both plants used as models. In addition, all extracts caused changes in the mitotic phases and inhibited the MI. In addition, the treatments promoted an increase in CA and NA. The mechanism of action presented was aneugenic, clastogenic and determined in epigenetic changes. The ethanolic extract was more cytotoxic since it had a more expressive effect at a lower concentration. Despite the cytotoxicity of the extracts under study, they promoted changes at lower levels than the glyphosate positive control. Thus, both extracts have less cytotoxicity than the commercial herbicide glyphosate. Regarding the essential oils evaluated, both were shown to be phyto-cytotoxic. The essential oil of P. acidum inhibited the sorghum RG and the lettuce AG. While P. cauliflorum reduced the GP, GSI, RG and AG of both models, being, therefore, more phytotoxic than P. acidum and non-selective. The cytotoxic investigation indicated that oil from both species inhibited the MI of the model plant. It was observed, through the CA, that the essential oil of P. cauliflorum has mechanisms of aneugenic and clastogenic action and that both oils determined in epigenetic changes observed by the increase of the chromosomal adherence. The results indicate the bioherbicidal potential of the essential oil of P. cauliflorum, which, in addition to being non-selective and demonstrating an inhibition rate like glyphosate, presented a lower NA rate than the commercial herbicide.