ResumoA família Meliaceae foi identificada como um dos grupos mais promissores para o controle biológico, pois a maioria das espécies possui compostos biologicamente ativos. Dentre as espécies, o Nim (Azadirachta indica A. Juss.) é a que mais se destaca pela sua alta eficiência e baixa toxidade, empregada no controle de insetos, fungos e nematóides. O objetivo deste trabalho foi verificar o potencial alelopático do extrato aquoso de folhas frescas de Nim sobre a germinação de alface, soja, milho, feijão e picão-preto, como forma de controle dessa invasora. O extrato foi obtido através da trituração de 200 g/L de folhas frescas de Nim, considerado extrato 100%, e diluído em água destilada nas concentrações de 80, 60, 40 e 20%, além da testemunha com apenas água. As sementes foram mantidas em câmara de germinação à temperatura de 25°C, com fotoperíodo de 12 h de luz. O extrato aquoso prejudicou a porcentagem de germinação e comprimento médio de raiz de alface, que tiveram valores de 1% e 0,1cm respectivamente. Para soja, o extrato afetou negativamente o tempo médio de germinação e velocidade media de germinação. Houve redução drástica do comprimento médio de raiz à medida que aumentou a concentração para soja, milho e feijão. Para Bidens pilosa todos os parâmetros analisados foram afetados negativamente, demonstrando sensibilidade ao extrato. O bioensaio realizado em laboratório demonstrou que o extrato aquoso de folhas frescas de Azadirachta indica possui efeito alelopático sobre todas as espécies estudadas. Palavras-chave: Alelopatia. Nim. Plantas cultivadas. Invasora. The family Meliaceae has been identified as one of the most promising for biological control, as most species have biologically active compounds. Among the species, the Neem (Azadirachta indica A. Juss) is that stands out most for its efficiency and low toxicity, and it is utilized to control insects, fungi and nematodes. The aim of this work was to verify the allelopathic potential of aqueous extract of fresh leaves of Neem on germination of lettuce, soybeans, maize, beans and Bidens pilosa, as a way to control this weed. The extract was obtained by grinding 200g/L of fresh leaves of the Neem (considered extract 100%) and diluting in distilled water at concentrations of 80, 60, 40, and 20%, and a control with only AbstractRecebido para publicação 30
Atividade alelopática do exsudato radicular de Jatropha curcas L. sobre plântulas de Brassica napus L., Glycine max L., Zea mays L. e Helianthus annuus L.
The expression of chemical compounds by individual plants of the same species in different locations may be affected by abiotic factors resulting in differences in the production of allelopathic compounds. The objective of this study was to compare the phytochemical profiles of plant species from two different forest formations in the state of Paraná, Brazil. The forest formations were Seasonal Semideciduous Forest (SSF) and Lowland Ombrophilous Dense Forest (LODF), and the five study species were Jacaranda micrantha, Cecropia pachystachya, Mimosa bimucronata, Schinus terebinthifolius and Cedrela fissilis. Secondary metabolites were extracted by exhaustive extraction with methanol, and the crude extract was fractionated using column chromatography. The fractions were used to calculate the retention factor of the main compounds using thin layer chromatography and phytochemical tests. The classes of compounds identified were practically the same among the analyzed species, however, at different levels of concentration. The type of tannins found in S. terebinthifolius differed between the two forest formations.
O manguezal é um ecossistema de transição entre os ambientes terrestre e marinho e representa um importante indicador ecológico pelos serviços ecossistêmicos fornecidos. No entanto, apesar da relevância ecológica, ainda sofre pressões antrópicas e vem perdendo em extensão e qualidade ambiental. No Brasil e, especificamente, no município de Paranaguá, uma mescla de uso antrópico tem causado pressões significativas sobre os manguezais. Neste sentido, o objetivo deste estudo é avaliar o grau de antropização dos manguezais urbanos do município de Paranaguá (PR), através da utilização de imagens de altíssima resolução espacial, obtidas através de Aeronave Remotamente Pilotada a fim de subsidiar políticas municipais de ordenamento territorial. Do ponto de vista metodológico, a partir de campanhas de campo, foram produzidos mapas com auxílio do software QGIS 3.10, a partir da fotointerpretação de ortomosaicos . A legenda das classes de antropização abrangeu: deposição de lixo domiciliar (i), entulhos (ii), lançamento de efluentes domésticos sem tratamento (iii) e manilhas (iv). Os resultados apontaram um total de 475 pontos de pressão antrópica sobre as 22 manchas de manguezal analisadas. A classe de maior destaque foi a de lixo domiciliar, seguida respectivamente de lançamento de efluentes domésticos sem tratamento, entulhos (material de construção) e, por fim, manilha. Como conclusão, o uso de ortomosaicos de alta resolução mostrou ser uma ferramenta importante e eficaz na análise da antropização dos manguezais urbanos, destacando assim , as áreas com maior pressão e, contribuindo para um monitoramento contínuo. Os produtos desta pesquisa podem auxiliar na elaboração de de instrumentos de ordenamento territorial do município, destacando a necessidade da construção de um olhar holístico em prol da conservação dos manguezais.
ABSTRACT:The development of researches about vigor provides greater insight about the physiological behavior of seeds over storage periods. The aim of this study was to evaluate the biochemical changes which occurred in beans stored for 360 days. Analyses were performed at 0, 30, 90, 180, 270, and 360 days after receiving the seeds (S1 and S2) and grains (G1 and G2) of BRS Splendor. The following tests were conducted: water content, electrical conductivity, and chemical composition of the soaking solution, where sugars and ions Fe 2+ , Zn, Ca 2+ , Mg 2+ and K + were quantified. The experimental design was completely randomized split-plot and means were compared through Tukey test (p>0.05). Water content decreased after 90 days, and after 180 days reached an average of 16%. The electrical conductivity showed the greatest loss of solute after 90 days. Larger amounts of soluble sugars were found in S1 and G1. The quantities of potassium and calcium decreased after 360 days, while magnesium increased after 90 days of storage. The electrical conductivity test showed no direct relation to the quantification of the investigated ions. The amount and behavior of amino acids and studied ions did not showed relation to the decrease in vigor of beans.
*Autor para correspondência. Agência financiadora: Fundação Araucária.Este artigo é de Acesso Livre, disponibilizado sob os termos da Creative Commons Attribution 3.0 Unported License (http://creativecommons.org/licenses/by/3.0/) que permite uso não-comercial, distribuição e reprodução em qualquer meio, desde que este trabalho original seja devidamente citado. specie has great nutritional value because of its high protein content, and contain important minerals for alimentation. Consequently, the cultive of this cereal is extremely important, the consortium system is a way to guarantee the introduction of this species in the region cultivation. The objective was to know the allelopathic effects in consortium simulation of amaranth-soybean and amaranth-corn, besides the interaction between the invader beggarticks and the amaranth. For the exudate preparation, 50 amaranth seeds were germinated under moistened filter paper with 5mL of destilated water in Petri dishes, that were stored in germination chambers at 25ºC, with photoperiod of 12 hours of light. After five days, the seedings were removed and the same substrate was used to germinate the species studied. Also, the contrary was made, in which the germinated seeds of the agricultural species gave place to the amaranth seeds. The experimental design was entirely casualized, and the data was submitted to variance analysis and the means compared by the Tukey test (p<0,05). None of the agricultural species showed sensitive to the amaranth effects, in the same conditions however, the beggarticks raised increased the length of the shoot. Only the corn exudate offers negative effects on the amaranth initial development. Therefore those consortium simulations must be field analyzed to prove such effects.
This study aimed to analyse the allelopathic bioactivity of fresh and infused aqueous extracts of Brazilian cherry leaves on the germination of lettuce and the initial development of maize. Brazilian cherry leaves were used to prepare a fresh aqueous extract (200 g L-1) and an infused extract (100 g L-1), which were diluted to concentrations of 0.4, 0.8, 1.2, 1.6 or 2.0% w/v. The variables evaluated in lettuce were the germination rate (GR), germination time index (GTI), germination speed index (GSI) and root length (RL). To determine the effect on the initial development of maize, we measured the shoot (SL) and root (RL) length. The experimental design included a factorial 2 × 5 design (two extracts and five concentrations), in addition to a control treatment (no extract). In general, the allelopathic bioactivity differed between the fresh and infused extracts. The fresh extract was more phytotoxic for the GR and RL of lettuce. Some beneficial results were observed for the infused extract, including an increase in the RL of lettuce and SL of maize. These effects were dependent on the extract concentration. Thus, there is evidence that Brazilian cherry extracts have allelopathic bioactivity.
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