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Allelopathic activity of aqueous extracts of Aristolochia esperanzae O. Ktze in the germination and growth of Lactuca sativa L. and Raphanus sativus L.

By Ana Beatriz Gatti

Abstract

O objetivo deste trabalho foi analisar os efeitos de extratos aquosos de diferentes órgãos de Aristolochia esperanzae na germinação e crescimento de alface e rabanete. Todos os extratos preparados obedeceram à proporção de 100g de material vegetal para 300 mL de água destilada, que produziu o extrato considerado 100% concentrado. A partir deste, foram feitas diluições com água destilada para 75, 50 e 25%. Nos testes de germinação foram avaliados os efeitos dos extratos obtidos de folha, caule, raiz, fruto e flor a 100, 75, 50 e 25% Para o teste de crescimento foram utilizados extratos de folha, caule e raiz na concentração de 100 e 50%. Nos testes de germinação foram utilizadas quatro repetições de 30 sementes distribuídas em placas de Petri forradas com duas folhas de papel de filtro umedecidas com 5 mL dos referidos extratos, secas durante 12 horas e reumedecidas com 4,5 mL de água destilada. No primeiro teste avaliou-se a porcentagem e velocidade de germinação das sementes. No teste de crescimento, as sementes foram previamente germinadas (2-4 mm de radícula) e depois transferidas para caixas plásticas contendo os substratos papel de filtro e fibra de coco umedecidos com os respectivos extratos. Avaliou-se a altura das plântulas, o comprimento radicular, a massa seca das plântulas, e a presença de anormalidades nas plântulas. Os testes foram mantidos a temperatura constante de 27C. Através dos resultados obtidos pode-se concluir que os extratos de folha foram os que mais afetaram a porcentagem de germinação e que todos os extratos e as diferentes concentrações retardaram a germinação de sementes de alface e de rabanete. Quanto ao teste de crescimento pode-se verificar que os extratos de caule e raiz causaram anormalidades nas plântulas. As plântulas crescidas no substrato papel de filtro apresentaram maior inibição do crescimento, em relação àquelas crescidas no substrato fibra de coco. A concentração dos extratos foi a principal responsável pelo estímulo ou inibição causada no crescimento das plântulas de alface e rabanete.The objective of this work was analyze the effects of aqueous extracts of Aristolochia esperanzae organs in the germination and early growth of lettuce and radish. All the prepared extracts obeyed the ratio of 100g of plant material + 300 mL of distilled water to produce an extract 100% concentrated. This extract was diluted with distilled water to produce final concentrations of 75, 50 and 25%. In the germination tests the extracts of leaf, stem, root, fruit and flower, with concentration of 100, 75, 50, 25% were evaluated. In the seedlings growth, extracts of leaf, stem and root were used in the concentration of 100 and 50%. In the germination tests, four replicates of 30 seeds were distributed in Petri dishes with two filter paper moistened with 5 mL of the extracts, dried during 12 hours and moistened again with 4,5 mL of distilled water. In the first test, the rate and germination percentage was evaluated. In the growth test, the seeds were previously germinated (2-4mm root length) and transferred to plastic boxes containing the filter paper or coconut fiber, moistened with the extracts. The aerial part height, root length, dry mass and the presence of abnormalities in the seedlings were evaluated. Both tests were maintained at constant temperature (27C). The obtained results showed that the leaf extracts affected strongly the germination percentage and all the extracts, in different concentrations, delayed the germination of lettuce and radish seeds. In the growth test could be verified that the stem and root extracts caused abnormalities in the seedlings. The seedlings grown in filter paper presented bigger growth inhibition in relation to seedlings from coconut fiber. The extract concentration was the main responsible for the incentive or inhibition caused on lettuce and radish seedlings growth

Topics: FISIOLOGIA VEGETAL, Fisiologia vegetal, Alelopatia, Germinação, Crescimento, Análise cromatográfica, Allelopathy, Aristolochia, Lettuce, Radish, FISIOLOGIA VEGETAL
Publisher: Universidade Federal de São Carlos
Year: 2003
OAI identifier: oai:agregador.ibict.br.BDTD_UFSCAR:oai:ufscar.br:652
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