Aspectos subcelulares e influência de fatores exógenos nos espaços secretores de resina de Protium heptaphyllum (aubl.) marchand. (burseraceae)
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Data
2018-02-23
Autores
Palermo, Fernanda Helena [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Espécies de Burseraceae são conhecidas pela produção de resina utilizada na produção de incensos, repelentes, impermeabilizantes, medicamentos e cosméticos, além de conferir às plantas proteção contra herbívoros e patógenos. Protium heptaphyllum é uma espécie arbórea produtora de resina aromática com comprovada ação medicinal no tratamento de doenças respiratórias e do trato digestivo, dentre outras. Apresenta grande plasticidade quanto aos ambientes de ocorrência, estando presente em ecossistemas com características contrastantes em diferentes regiões do Brasil. Espaços secretores de resina ocorrem associados ao floema de raiz, caule e folhas, podendo formar uma rede anastomosada no caule. Esse trabalho teve como objetivo analisar os aspectos subcelulares envolvidos na origem, desenvolvimento e funcionamento dos espaços secretores de resina em P. heptaphyllum, além de avaliar a influência do etileno no desenvolvimento do sistema secretor. Amostras de caule jovem foram processadas para análise convencional e citoquímica em microscopia eletrônica de transmissão. Plantas jovens foram mantidas em casa de vegetação e submetidas a diferentes concentrações de Ethephon: 6g L-1 (T1), 12g L-1 (T2), 18g L-1 (T3) e 24g L-1 (T4); amostras de suas folhas e caule foram processadas segundo técnicas usuais em anatomia vegetal. Os canais secretores se originam por esquizogênese e se desenvolvem por esquizolisogênese. As células epiteliais apresentam população de organelas consistente com secreção de lipídios, polissacarídeos e proteínas. Canais maduros podem se alongar, ramificar e fundir por processo que envolve separação e morte de células. Pectinase e celulase foram detectadas e estão associadas ao processo de expansão do sistema secretor e liberação da secreção. Folhas de plantas tratadas com Ethephon mostraram aumento na área do lume dos ES, o que pode estar relacionado à ação do etileno em processos de degradação da parede celular. No caule primário, plantas do T2 e T3 apresentaram diminuição na área do lume em comparação com o grupo controle e T1. No caule em crescimento secundário, plantas do T4 apresentaram maior densidade de ES; entretanto, nessa região caulinar, plantas do T2 e T4 apresentaram ES com menor área do lume. A resposta diferencial do sistema secretor em órgãos em estrutura primária e secundária pode estar relacionada à atuação distinta do hormônio nos diferentes meristemas. Nossos resultados podem fornecer subsídios para o estabelecimento de técnicas mais sustentáveis e eficientes de extração de resina dessa espécie.
Burseraceae species are known for resin production used in the yield of incense, repellent, waterproofing, drugs and cosmetics, and also protect plants against herbivores and pathogens. Protium heptaphyllum is a tree producer of aromatic resin with medicinal action in respiratory and digestive diseases, among others. It occurs in many environments, being present in ecosystems with contrasting characteristics in different regions of Brazil. Resin secretory spaces (SS) occur associated with phloem in root, stem and leaves, and form an anastomosed network in the stem. We aimed to analyze the subcellular aspects involved in the origin, development and functioning of the resin secretory spaces in P. heptaphyllum, besides to evaluate the influence of ethylene on the development of the secretory system. Young stem samples were processed for conventional analysis and cytochemistry in transmission electron microscopy. Young plants were kept in greenhouse and treated with different concentrations of Ethephon: 6g L-1 (T1), 12g L-1 (T2), 18g L-1 (T3) e 24g L-1 (T4); leaf and stem samples were processed according to usual techniques in plant anatomy. Secretory canals in the phloem originated by schizogenesis and developed by schyzolysigenesis. Epithelial cells presented organelles consistent with lipid, polysaccharides and proteins secretion. Mature canals can elongate, ramify and fuse, resulting in a complex structure. Pectinase and cellulase were detected and are associated with expansion and processes of secretion release of the secretory system. Leaves from plants treated with Ethephon showed wider SS; this can be associated with the ethylene action in degradation processes of cell walls. In the primary stem, plants under T2 and T3 presented narrower lumen area in comparison to control group and T1. In secondary stem, plants under T4 exhibited higher density of SS; however, in this stem region, plants under T2 and T4 showed SS with narrower lumen. The differential answering of the secretory system between organs under primary and secondary growth can be associated with the distinctive action of ethylene on the different meristems. Our results can provide subsidies to the establishment of more sustainable and efficient techniques of resin extraction in this species.
Burseraceae species are known for resin production used in the yield of incense, repellent, waterproofing, drugs and cosmetics, and also protect plants against herbivores and pathogens. Protium heptaphyllum is a tree producer of aromatic resin with medicinal action in respiratory and digestive diseases, among others. It occurs in many environments, being present in ecosystems with contrasting characteristics in different regions of Brazil. Resin secretory spaces (SS) occur associated with phloem in root, stem and leaves, and form an anastomosed network in the stem. We aimed to analyze the subcellular aspects involved in the origin, development and functioning of the resin secretory spaces in P. heptaphyllum, besides to evaluate the influence of ethylene on the development of the secretory system. Young stem samples were processed for conventional analysis and cytochemistry in transmission electron microscopy. Young plants were kept in greenhouse and treated with different concentrations of Ethephon: 6g L-1 (T1), 12g L-1 (T2), 18g L-1 (T3) e 24g L-1 (T4); leaf and stem samples were processed according to usual techniques in plant anatomy. Secretory canals in the phloem originated by schizogenesis and developed by schyzolysigenesis. Epithelial cells presented organelles consistent with lipid, polysaccharides and proteins secretion. Mature canals can elongate, ramify and fuse, resulting in a complex structure. Pectinase and cellulase were detected and are associated with expansion and processes of secretion release of the secretory system. Leaves from plants treated with Ethephon showed wider SS; this can be associated with the ethylene action in degradation processes of cell walls. In the primary stem, plants under T2 and T3 presented narrower lumen area in comparison to control group and T1. In secondary stem, plants under T4 exhibited higher density of SS; however, in this stem region, plants under T2 and T4 showed SS with narrower lumen. The differential answering of the secretory system between organs under primary and secondary growth can be associated with the distinctive action of ethylene on the different meristems. Our results can provide subsidies to the establishment of more sustainable and efficient techniques of resin extraction in this species.
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Palavras-chave
breu-branco, canais secretores, desenvolvimento, etileno, resina, ultraestrutura, secretory canals, development, ethylene, resin, ultrastructure