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Objetivou-se com este estudo avaliar o potencial alelopático de extratos metanólicos de folhas, flores e raízes de capuchinha (Tropaeolum majus L.) sobre a germinação de sementes e o crescimento inicial de plântulas de picão-preto. O extrato metanólico com melhor potencial de inibição foi submetido a particionamento, resultando nas frações hexânica, clorofórmica, acetato de etila e hidrometanólica e posterior caracterização pelo espectro de absorção na região do infravermelho (IV). O efeito alelopático foi avaliado sobre as sementes de picão-preto, as quais foram distribuídas sobre papel germitest umedecido com 2mL dos extratos e mantidas em germinador do tipo B.O.D. regulado a temperatura de 25°C e luz branca constante, sendo que as sementes imersas diretamente em água constituíram o tratamento controle. A avaliação da qualidade da semente foi realizada pelos testes de germinação e vigor (primeira contagem e comprimento de raiz primária e de hipocótilo das plântulas), em delineamento inteiramente ao acaso. O potencial alelopático das folhas de capuchinha foi maior em relação às demais partes da planta sobre a germinação das sementes, comprimento de hipocótilo e de raiz das plântulas de picão-preto. Estes efeitos podem estar associados à presença de grupos químicos polares, pois à medida que se aumentou a polaridade dos solventes detectou-se maior efeito inibitório sobre a germinação e o crescimento inicial de plântulas de picão-preto.This research aimed to evaluate the metanolic extracts allelopathic potential from leaves, flowers and roots of capuchinha (Tropaeolum majus L.) on picão-preto seeds germination and initial seedling growth. The best inhibitor metanolic extract was fractioned, in hexanic, cloroformic, etil acetate and hidrometanolic fractions and it was characterized through absorption spectrum using mid-infrared. To evaluate the allelopathic effect of metanolic extracts and the fractions aftereffect; it was used picão-preto seeds distributed on 2ml extracts moistured paper maintained in B.O.D. germinator at 25°C and white constant light. Seeds sowed directly in water moistured germitest paper constituted the control. The allelopathic potential extracts were evaluated through the first count, final germination percentage, seedlings primary root and hypocotyl length (cm). The experiment was carried out DIC with three replications of 25 seeds. The capuchinha leaves showed allelopathic potential on picão-preto seeds germination, hypocotyl and seedlings primary root length. It was suggested that such effects are associated to the presence of polar chemical groups because the increase in the solvents polarity detected the major picão-preto germination and seedlings growth inhibition effect.

This research aimed to evaluate the metanolic extracts allelopathic potential from leaves, flowers and roots of capuchinha (Tropaeolum majus L.) on picão-preto seeds germination and initial seedling growth. The best inhibitor metanolic extract was fractioned, in hexanic, cloroformic, etil acetate and hidrometanolic fractions and it was characterized through absorption spectrum using mid-infrared. To evaluate the allelopathic effect of metanolic extracts and the fractions aftereffect; it was used picão-preto seeds distributed on 2ml extracts moistured paper maintained in B.O.D. germinator at 25°C and white constant light. Seeds sowed directly in water moistured germitest paper constituted the control. The allelopathic potential extracts were evaluated through the first count, final germination percentage, seedlings primary root and hypocotyl length (cm). The experiment was carried out DIC with three replications of 25 seeds. The capuchinha leaves showed allelopathic potential on picão-preto seeds germination, hypocotyl and seedlings primary root length. It was suggested that such effects are associated to the presence of polar chemical groups because the increase in the solvents polarity detected the major picão-preto germination and seedlings growth inhibition effect. [ABSTRACT FROM AUTHOR]