Glandular trichomes in Connarus suberosus (Connaraceae): distribution, structural organization and probable functions

Autor(es)

Denardi, Joao Donizete ^[1] ; Trombert Oliveira, Denise Maria ^[2] ; Sousa Paiva, Elder Antonio ^[2]

Afiliação do(s) autor(es)

^[1] Univ Estadual Mato Grosso do Sul, Unidade Univ Coxim, BR-79400000 Coxim, MS - Brazil

^[2] Univ Fed Minas Gerais, Inst Ciencias Biol, Dept Bot, BR-31270901 Belo Horizonte, MG - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Revista de Biología Tropical; v. 60, n. 1, p. 505-513, MAR 2012.
• Citações Web of Science: 6

Resumo

Connarus suberosus is a typical species of the Brazilian Cerrado biome, and its inflorescences and young vegetative branches are densely covered by dendritic trichomes. The objective of this study was to report the occurrence of a previously undescribed glandular trichome of this species. The localization, origin and structure of these trichomes were investigated under light, transmission and scanning electron microscopy. Collections were made throughout the year, from five adult specimens of Connarus suberosus near Botucatu, Sao Paulo, Brazil, including vegetative and reproductive apices, leaves and fruits in different developmental stages, as well as floral buds and flowers at anthesis. Glandular trichomes (GTs) occurred on vegetative and reproductive organs during their juvenile stages. The GTs consisted of a uniseriate, multicellular peduncle, whose cells contain phenolic compounds, as well as a multicellular glandular portion that accumulates lipids. The glandular cell has thin wall, dense cytoplasm (with many mitochondria, plastids and dictyosomes), and a large nucleus,with a visible nucleolus. The starch present in the plastids was hydrolyzed during the synthesis phase, reducing the density of the plastid stroma. Some plastids were fused to vacuoles, and some evidence suggested the conversion of plastids into vacuoles. During the final activity stages of the GTs, a darkening of the protoplasm was observed in some of the glandular cells, as a programmed cell death; afterwards, became caducous. The GTs in C. suberosus had a temporal restriction, being limited to the juvenile phase of the organs. Their presence on the exposed surfaces of developing organs and the chemical nature of the reserve products, suggest that these structures are food bodies. Field observations and detailed studies of plant-environment interactions, as well as chemical analysis of the reserve compounds, are still necessary to confirm the role of these GTs as feeding rewards. Rev. Biol. Trop. 60 (1): 505-513. Epub 2012 March 01. (AU)

• Processo FAPESP: 00/12469-3 - Estudos morfológicos, anatômicos, histoquímicos e ultra-estruturais em plantas do Cerrado (Senso lato) do estado de São Paulo
• Beneficiário: Silvia Rodrigues Machado
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático