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No dia 29 de abril de 2025, \u00e0s 14 horas, Yasmin Tavares Cavalcanti, defendeu sua disserta\u00e7\u00e3o de mestrado intitulada \u201cAutocontrole de germina\u00e7\u00e3o em sementes de Eugenia\u201d no programa de p\u00f3s-gradua\u00e7\u00e3o em Biodiversidade Vegetal e Meio Ambiente do Instituto de Pesquisas Ambientais (IPA). A banca da defesa foi formada pelos pesquisadores: Dr. Claudio Jos\u00e9 Barbedo, Dr. Danilo da Cruz Centeno e a Dra. Carolina Coelho.<\/p>\n
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Sementes de esp\u00e9cies de Eugenia L. (Myrtaceae) s\u00e3o recalcitrantes e apresentam capacidade de regenera\u00e7\u00e3o da germina\u00e7\u00e3o quando o eixo embrion\u00e1rio \u00e9 perdido. Contudo, o in\u00edcio da germina\u00e7\u00e3o aparentemente resulta na produ\u00e7\u00e3o de inibidores uma vez que n\u00e3o se verificam germina\u00e7\u00f5es simult\u00e2neas, indicando processos de autocontrole da germina\u00e7\u00e3o nessas sementes. Estudos recentes demonstraram significativa rela\u00e7\u00e3o entre o in\u00edcio da germina\u00e7\u00e3o e o aumento da produ\u00e7\u00e3o de \u00e1cido g\u00e1lico, um \u00e1cido fen\u00f3lico com diversas a\u00e7\u00f5es biol\u00f3gicas, dentre as quais a inibi\u00e7\u00e3o da germina\u00e7\u00e3o de sementes e esporos. \u00c9 poss\u00edvel, portanto, que este composto esteja envolvido no autocontrole da germina\u00e7\u00e3o em sementes de esp\u00e9cies de Eugenia. Este trabalho teve como objetivos: 1) verificar, pela aplica\u00e7\u00e3o direta de \u00e1cido g\u00e1lico nas sementes de Eugenia brasiliensis Lam., por pr\u00e9-embebi\u00e7\u00e3o ou por Umedecimento do substrato de germina\u00e7\u00e3o, a a\u00e7\u00e3o do \u00e1cido g\u00e1lico como inibidor da germina\u00e7\u00e3o. Para tanto, solu\u00e7\u00f5es aquosas de \u00e1cido g\u00e1lico em quatro concentra\u00e7\u00f5es (5g\/L, 10g\/L, 20g\/L e 40g\/L) foram aplicadas diretamente no substrato (vermiculita) ou utilizadas para pr\u00e9-embebi\u00e7\u00e3o das sementes. Em ambos os casos, foram utilizadas sementes inteiras e sementes fracionadas ao meio; 2) verificar a extens\u00e3o temporal do autocontrole da germina\u00e7\u00e3o, desde a germina\u00e7\u00e3o at\u00e9 diferentes fases de desenvolvimento da pl\u00e2ntula. Quando as pl\u00e2ntulas, crescidas em ambiente com luz cont\u00ednua ou no escuro cont\u00ednuo, atingiram diferentes comprimentos de parte a\u00e9rea (\u2264 5 cm, 6\u00a01cm, 8\u00a01 cm, 12 \u00a01,5 cm e \u2265 13,5 cm), as ra\u00edzes e partes a\u00e9reas foram removidas e a semente foi novamente semeada em substrato umedecido com \u00e1gua para nova germina\u00e7\u00e3o. Os resultados da aplica\u00e7\u00e3o de \u00e1cido g\u00e1lico confirmaram seu efeito inibidor da germina\u00e7\u00e3o, principalmente nas concentra\u00e7\u00f5es de 20g\/L e 40g\/L. J\u00e1 os de regenera\u00e7\u00e3o ap\u00f3s desenvolvimento de pl\u00e2ntulas demonstraram que a capacidade regenerativa das sementes se estende at\u00e9 que as pl\u00e2ntulas atinjam at\u00e9 ao menos 11 cm para as cultivadas no escuro e 8 cm para as cultivadas no claro. Portanto, ficou demonstrado que as sementes de Eugenia apresentam potencial de se manterem no solo por longos per\u00edodos em condi\u00e7\u00f5es de produzir novas plantas ainda que as condi\u00e7\u00f5es do meio sejam desfavor\u00e1veis ap\u00f3s as primeiras germina\u00e7\u00f5es destas sementes.<\/p>\n
Palavras-chave:<\/strong> \u00e1cido g\u00e1lico, esgotamento de reserva energ\u00e9tica, longa perpetua\u00e7\u00e3o, regenera\u00e7\u00e3o, sementes de Eugenia brasiliensis Lam.<\/p>\n ABSTRACT<\/strong><\/p>\n Seeds of Eugenia L. (Myrtaceae) species are recalcitrant and have the capacity to regenerate germination after the embryonic axis is lost. However, the onset of germination apparently results in the production of inhibitors since there are no simultaneous germinations, indicating processes of self-control of germination in these seeds. Recent studies have demonstrated a significant relationship between the onset of germination and the increase in the production of gallic acid, a phenolic acid with several biological actions, among which is the inhibition of seed and spore germination. It is possible, therefore, that this compound is involved in the self-control of germination in seeds of Eugenia species. This study aimed to: 1) to verify, by direct application of gallic acid to Eugenia brasiliensis Lam. seeds, by pre-soaking or by soaking the germination substrate, the action of gallic acid as a germination inhibitor. For this purpose, aqueous solutions of gallic acid in 4 concentrations (5 g\/L, 10 g\/L, 20 g\/L and 40 g\/L) were applied directly to the substrate (vermiculite) or used for pre-soaking the seeds. In both cases, whole seeds and seeds split in half were used; 2) to verify the temporal extension of germination self-control, from germination to different stages of seedling development. When the seedlings, grown in an environment with continuous light or in continuous darkness, reached different shoot lengths (\u2264 5 cm, 6,0\u00a01,0 cm, 8,0\u00a01,0 cm, 12,0 \u00a01,5 cm and \u2265 13,5 cm), the roots and shoots were removed and the seed was sown again in a substrate moistened with water for new germination. The results of the application of gallic acid confirmed its inhibitory effect on germination, mainly at concentrations of 20 g\/L and 40 g\/L. The results of regeneration after seedling development demonstrated that the regenerative capacity of the seeds extends until the seedlings reach at least 11 cm for those grown in the dark and 8 cm for those grown in the light. Therefore, it was demonstrated that Eugenia seeds have the potential to remain in the soil for long periods in conditions to produce new plants even if the environmental conditions are unfavorable after the first germinations of these seeds.<\/p>\n Key words:<\/strong> gallic acid, depletion of energy reserves, long perpetuation, regeneration, Eugenia brasiliensis Lam. seeds.<\/p>\n
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<\/a>Yasmin Tavares Cavalcanti<\/strong><\/a>
\nAutocontrole de germina\u00e7\u00e3o em sementes de Eugenia<\/em><\/a><\/p>\n
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