%0 Journal Article
%T Allelopathic effect of black mustard tissues and root exudates on some crops and weeds Efeito alelop芍tico de tecidos de mostarda-preta e exsudatos da raiz de algumas culturas e plantas daninhas
%A E Al-Sherif
%A A.K. Hegazy
%A N.H. Gomaa
%A M.O. Hassan
%J Planta Daninha
%D 2013
%I Sociedade Brasileira da Ci那ncia das Plantas Daninhas
%R 10.1590/s0100-83582013000100002
%X Laboratory and greenhouse experiments were conducted to evaluate the phytotoxic effect of black mustard extracts and root exudates on two crops: Trifolium alexandrinum and Triticum aestivum, and two weeds: Phalaris paradoxa and Sisymbrium irio. The seeds were treated with aqueous and ethanolic extracts and chloroform for eight days, or subjected to root exudates of just harvested mustard in a greenhouse for five weeks. High-performance liquid chromatography (HPLC) was used to quantify phytotoxins from plant tissues. Seed germination of P. paradoxa was reduced with the lowest concentration of the different extracts. However, the aqueous extract at 4% completely curtailed the germination of all the target species. In general, plant extracts had a concentration-dependent reduction of seedling growth of the target species. However, the ethanolic extract, at the lowest concentration, has stimulated the shoot length of both T. alexandrinum and T. aestivum, and the root length of the former. Mustard root exudates inhibited emergence and growth of the target species throughout the experiment. Ferulic and syringic acids were the dominant allelochemicals found when HPLC was used. Experimentos de laborat車rio e estufa foram realizados para avaliar o efeito fitot車xico dos extratos de mostarda-preta e exsudatos de raiz de duas culturas: Trifolium alexandrinum e Triticum aestivum, bem como de duas plantas daninhas: Phalaris paradoxa e Sisymbrium irio. As sementes foram tratadas com extratos aquosos, etan車licos e clorof車rmio por oito dias, ou submetidas a exsudatos de raiz de mostarda rec谷m-colhidaem estufa durante cinco semanas. A cromatografia l赤quida de alto desempenho (HPLC) foi usada para a quantifica  o de fitotoxinas a partir de tecidos de plantas. Sementes de P. paradoxa apresentam germina  o reduzida com a menor concentra  o dos diferentes extratos. No entanto, o extrato aquoso a 4% restringiu completamente a germina  o de todas as esp谷cies-alvo. Em geral, os extratos de plantas tiveram uma redu  o, dependendo da concentra  o do crescimento de mudas das esp谷cies-alvo. No entanto, o extrato etan車lico, na concentra  o mais baixa, tem estimulado o comprimento dos ramos de T. alexandrinum e T. aestivum e o comprimento da raiz da primeira. Exsudatos de raiz de mostarda inibiram o surgimento e crescimento das esp谷cies-alvo durante todo o experimento. Os 芍cidos fer迆lico e siringico foram os aleloqu赤micos dominantes encontrados utilizando HPLC.
%K alelopatia
%K Brassica nigra
%K extratos vegetais
%K isotiocianatos (ITCs)
%K 芍cidos fen車licos
%K allelopathy
%K Brassica nigra
%K plant extracts
%K isothiocyanates (ITCs)
%K phenolic acids
%U http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582013000100002