Abstract
Colleters are secretory structures, with a protective function, that occur in different organs and in many Angiospermae families. The aim of this work was to describe the anatomy and micromorphology of colleters present in Psychotria nuda (Cham. & Schltdl.) Wawra as well as analyze the structure and composition of crystals from the central axis of the structure under study. The material was collected at the Tinguá Biological Reserve and processed according to usual techniques for light and scanning electron microscopy. The colleters are of the lachrymiform type, with an elongated central axis, formed by fundamental parenchyma, sheathed by a palisade layer, responsible for the secretion. Raphid crystals were observed in the central axis of the colleters. By X-ray microanalysis it was possible to show calcium predominance in these structures.
Highlights
Psychotria L. is a pantropical genus in the tribe Psychotrieae (Robbrecht 1988)
Even though colleters have been cited for some species of Psychotria (Whitmoyer & Horner 1970; Da Cunha & Vieira 1993/97) they have never been described for Psychotria nuda
Colleters are secretory structures comprised of an elongated central axis formed by fundamental parenchyma that is surrounded by an epidermal palisade layer (Da Cunha & Vieira 1993/97) made of secretory cells (Thomas 1991)
Summary
Psychotria L. is a pantropical genus in the tribe Psychotrieae (Robbrecht 1988). Psychotria nuda (Cham. & Schltdl.) Wawra is a widely distributed shrub that can be 1 to 5 meters tall and is commonly called sonhos-de-ouro (golden dreams) (EMBRAPA 1994). & Schltdl.) Wawra is a widely distributed shrub that can be 1 to 5 meters tall and is commonly called sonhos-de-ouro (golden dreams) (EMBRAPA 1994) This species is found throughout the Atlantic Forest along the eastern coast of Brazil. The function of colleters is still under debate but it is believed that they protect the shoot apex and the lateral buds by a physical or chemical mechanism. This type of structure has been described under various names (Ramayya & Bahadur 1968; Van Hove & Kagoyre 1974; Dave & Patel 1975; Curtis & Lersten 1980), making it complicated to morphologically classify
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