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Em 18 de agosto de 2023, a aluna Maria Gessi Teixeira do Programa de P\u00f3s-Gradua\u00e7\u00e3o em Biodiversidade Vegetal e Meio Ambiente do Instituto de Pesquisas Ambientais (IPA) defendeu a tese de doutorado intitulada \u201cMicropropaga\u00e7\u00e3o de Nidularium minutum<\/em> Mez (Bromeliaceae): influ\u00eancia de reguladores de crescimento e atividades do sistema antioxidante na brota\u00e7\u00e3o.<\/p>\n Micropropagation is a technique that has been used for the conservation of bromeliad species, as it allows the production of a large quantity of plants in a short space of time, destined to supply the ornamental market or for use in reforestation programs. Nidularium minutum<\/em> is an endemic and vulnerable bromeliad that has ornamental potential, which makes the development of micropropagation protocols aimed at its conservation important. Plant growth regulators (PGR) and nitrogen sources, as well as variations in temperature and light, have been associated with the induction of in vitro multiplication. However, no relationship has been established between activation of the antioxidant system and the factors that induce bromeliad sprouting, which could indicate that the process of cellular differentiation of plants subjected to in vitro multiplication would activate stress responses. The objectives of this study were to investigate the possible influence of in vitro multiplication growth regulators on the enzymatic activities of the antioxidant system during the process of obtaining clones of N. minutum<\/em>, as well as the anatomy of this bromeliad during shooting. Multiplication-inducing media containing different concentrations of PGR were tested. Shoot numbers, biometric parameters, photosynthetic pigments and survival after acclimatization were evaluated. Anatomical analyzes were carried out during the budding phases. The activities of antioxidant system enzymes were analyzed in plants from treatments in which sprouting was induced and compared with plants that did not sprout. The results showed that in vitro shooting of N. minutum<\/em> is asynchronous and enhanced by BAP. The formation of shoots in 100% of the plants occurred only after 240 days of cultivation in medium with cytokinin. A small portion of plants tend to sprout even in a medium free of PGR and there is a difference in sprouting capacity between different individuals. The plants originating from the shoots were successfully acclimatized to all treatments. The formation of sprouts is accompanied by adjustments in the activity of enzymes of the antioxidant system that vary during the differentiation of tissues from buds to sprouts, evidenced by anatomical analyses. Lipid peroxidation (LPO) levels vary depending on the amount of buds or tissue already differentiated, and in plants that sprouted these were lower compared to plants that did not have sprouts. Anatomical analyzes revealed the presence of trichomes (colleters) in the apical region of the stem, undescribed for the species. This work contributed to deepening knowledge about the endogenous factors that control the organogenesis process of N. minutum<\/em>, creating support for studies on the induction of plant production via in vitro sprouting.<\/p>\n Keyword<\/strong>s: Anatomy; Antioxidant enzymes; bromeliad; Endangered species; In vitro plant culture; Lipid peroxidation; Ornamental plant, Reactive oxygen species.<\/p>\n A micropropaga\u00e7\u00e3o \u00e9 uma t\u00e9cnica que tem sido utilizada para a conserva\u00e7\u00e3o de esp\u00e9cies de brom\u00e9lias, pois possibilita a produ\u00e7\u00e3o de grande quantidade de plantas em curto espa\u00e7o de tempo, destinadas ao abastecimento do mercado de ornamentais ou para uso em programas de reflorestamento. Nidularium minutum<\/em> \u00e9 uma brom\u00e9lia end\u00eamica e vulner\u00e1vel que possui potencial ornamental, o que torna importante o desenvolvimento de protocolos de micropropaga\u00e7\u00e3o visando sua conserva\u00e7\u00e3o. Reguladores de crescimento de plantas (PGR) e fontes nitrogenadas, bem como varia\u00e7\u00f5es na temperatura e luz, t\u00eam sido associados \u00e0 indu\u00e7\u00e3o da multiplica\u00e7\u00e3o in vitro<\/em>. Entretanto, n\u00e3o foi estabelecida rela\u00e7\u00e3o entre ativa\u00e7\u00e3o do sistema antioxidante e os fatores indutores da brota\u00e7\u00e3o de brom\u00e9lias, o que poderia indicar que o processo de diferencia\u00e7\u00e3o celular das plantas submetidas \u00e0 multiplica\u00e7\u00e3o in vitro<\/em> ativaria respostas de estresse. Os objetivos deste estudo foram investigar a poss\u00edvel influ\u00eancia dos reguladores de crescimento da multiplica\u00e7\u00e3o in vitro<\/em> sobre as atividades enzim\u00e1ticas do sistema antioxidante durante o processo de obten\u00e7\u00e3o de clones de N. minutum<\/em>, bem como a anatomia desta brom\u00e9lia durante a brota\u00e7\u00e3o. Foram testados meios indutores de multiplica\u00e7\u00e3o que continham diferentes concentra\u00e7\u00f5es de reguladores de crescimento. N\u00fameros de brotos, par\u00e2metros biom\u00e9tricos, pigmentos fotossint\u00e9ticos e sobreviv\u00eancia ap\u00f3s aclimatiza\u00e7\u00e3o foram avaliados. An\u00e1lises anat\u00f4micas foram realizadas durante as fases da brota\u00e7\u00e3o. As atividades de enzimas do sistema antioxidante foram analisadas nas plantas dos tratamentos nos quais a brota\u00e7\u00e3o foi induzida e comparadas com as plantas que n\u00e3o brotaram. Os resultados mostraram que a brota\u00e7\u00e3o in vitro de\u00a0 N. minutum<\/em> \u00e9 assincr\u00f4nica e intensificada pelo BAP. A forma\u00e7\u00e3o de brotos em 100% das plantas ocorreu somente ap\u00f3s 240 dias de cultivo em meio com a citocinina. Uma pequena parcela das plantas tem tend\u00eancia a brotar mesmo em meio livre de PGR e h\u00e1 diferen\u00e7a na capacidade de brota\u00e7\u00e3o entre os diferentes indiv\u00edduos. As plantas origin\u00e1rias dos brotos foram aclimatizadas com sucesso para todos os tratamentos. A forma\u00e7\u00e3o de brotos \u00e9 acompanhada de ajustes na atividade das enzimas do sistema antioxidante que variam durante a diferencia\u00e7\u00e3o dos tecidos de gemas para brotos, evidenciados pelas an\u00e1lises anat\u00f4micas. Os n\u00edveis de peroxida\u00e7\u00e3o lip\u00eddica (LPO) variam dependendo da quantidade de gemas ou tecido j\u00e1 diferenciado, sendo que nas plantas que brotaram estes foram menores em rela\u00e7\u00e3o \u00e0s plantas que n\u00e3o apresentavam brotos. As an\u00e1lises anat\u00f4micas revelaram a presen\u00e7a de tricomas (col\u00e9teres) na regi\u00e3o apical do caule n\u00e3o descritos para a esp\u00e9cie. Este trabalho contribuiu para aprofundar o conhecimento sobre dos fatores end\u00f3genos que controlam o processo de organog\u00eanese de N. minutum<\/em>, criando subs\u00eddios para estudos da indu\u00e7\u00e3o da produ\u00e7\u00e3o de mudas via brota\u00e7\u00f5es in vitro<\/em>.<\/p>\n Palavras-chave<\/strong>: Anatomia; Brom\u00e9lia; Cultivo in vitro; <\/em>Enzimas antioxidantes; Esp\u00e9cies amea\u00e7adas; Esp\u00e9cies reativas de oxig\u00eanio; Planta ornamental; Peroxida\u00e7\u00e3o lip\u00eddica.<\/p>\n![\"\"](\"https:\/\/smastr16.blob.core.windows.net\/pgibt\/sites\/242\/2023\/10\/maria_gessi_teixeira_dr.jpg\")
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 A banca examinadora foi presidida pela orientadora, Dra. Catarina Carvalho Nievola, e foi composta pela Dra. Mar\u00edlia Gaspar (Instituto de Pesquisas Ambientais), Dra. Juliana Aparecida Fernando (Universidade Federal de Pelotas), Dr. Breno R\u00e9gis Santos (Universidade Federal de Alfenas) e Dr. Evandro Alves Vieira (Instituto Tecnol\u00f3gico VALE).<\/p>\n
\nMicropropaga\u00e7\u00e3o de Nidularium minutum<\/em> Mez (Bromeliaceae): influ\u00eancia de reguladores de crescimento e atividades do sistema antioxidante na brota\u00e7\u00e3o<\/h3>\n
\nABSTRACT<\/strong><\/h4>\n
RESUMO<\/strong><\/h4>\n
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<\/a>Maria Gessi Teixeira<\/strong><\/a>
\nMicropropaga\u00e7\u00e3o de Nidularium minutum<\/em> Mez (Bromeliaceae): influ\u00eancia de reguladores de crescimento e atividades do sistema antioxidante na brota\u00e7\u00e3o<\/a><\/p>\n
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