New registers of colleters in species of Myrtaceae from Brazilian Cerrado

Abstract

Colleters are secretory structures that produce a sticky substance, consisting of a mixture of mucilage, proteins, terpenes, pectic substances and even alkaloids, which lubricates and protects the shoot apical meristem. Several colleter types have been described and have taxonomic value in many botanical families. In Myrtaceae, the colleters description is recent and presents three new morphological types (conic, euryform and petaloid) that differ those already described for other eudicots. In this work, we report the colleters morphological types in six species of three genera belonging to the Myrteae tribe of Myrtoideae from the Brazilian Cerrado. The samples were fixed for light and scanning electron microscopy. Histochemical tests were carried out on the fresh and methacrylate-embedded material. The conic and euryform colleters from Myrtoideae species of the Cerrado did not differ either morphologically nor as to the secretion nature from those described for Myrtoideae species from others biomes, which may indicate their potential use for taxonomic purposes. Considering the hypothesis that the multiple fleshy-fruit lineages have evolved independently in Myrteae tribe, our results indicate the relevance of additional studies in order to recognize the pattern of distribution of colleters in Myrtaceae.

Sistema subterrâneo e proteção das gemas aéreas de >i<Psidium grandifolium>/i< Mart. Ex Dc. ocorrentes em área de Cerrado natural e Cerrado em regeneração

“…Coléteres estavam presentes protegendo os ápices caulinares de todas as gemas aéreas da espécie estudada. Em Mrytaceae, coléteres já foram descritos nos ápices vegetativos e na base das axilas foliares em diferentes gêneros da família, sendo a morfologia cônica a mais recorrente entre as espécies (Costa et al, 2020;Da Silva et al, 2012;Silva et al, 2019;. Os coléteres de P. grandifolium analisados nas plantas das suas áreas são cônicos, não-vascularizados, sésseis, de base ampla e desprovidos de epiderme em paliçada como descritos por Silva e colaboradores (2019).…”