Colleters in Chamaecrista (L.) Moench sect. Chamaecrista and sect. Caliciopsis (Leguminosae-Caesalpinioideae): anatomy and taxonomic implications

Abstract

Th e genus Chamaecrista contains ca. 330 species organized into six sections, of which section Chamaecrista is the second largest (ca.75 species) distributed among six series, while the section Caliciopsis contains only two species. Colleters have been described in the genus Chamaecrista and they show potential taxonomic and phylogenetic signifi cance. Th ey are associated with lubrication, desiccation prevention and protection from microbial attacks of young developing organs. Although six types of colleters have been described for the genus Chamaecrista, there have been no studies focusing on the diversity of colleters in the sections Chamaecrista and Caliciopsis. Samples from developing leaves and fl owers of both sections were obtained from herbarium and fi eld collections and subjected to standard methodologies for both light and scanning electron microscopy. Histochemical tests were also performed to determine the nature of the exudates. Five types of non-vascularized colleters were found: short digitiform, long digitiform, club-shaped, pyriform and short bottle-shaped. Polysaccharides, pectins, lipids and proteins were detected in the exudates of all types of colleters. Among the fi ve types of colleters observed, pyriform is a novelty for Chamaecrista, reinforcing the signifi cant morphological diversity of these secretory structures in this genus.

Structures related to resprouting potential of two Myrtaceae species from Cerrado: morpho-anatomical and chemical studies

“…These characteristics are also observed in the parenchyma cells throughout the colleter axis, except on the peduncle when present. This homogeneous pattern of cells observed in colleters of Eugenia in this study and in Silva et al (2012) has also been described in Fabaceae colleters (Paiva and Machado 2006, Coutinho et al 2015, Silva et al 2017.…”

“…These authors found pectic compounds in intercellular spaces and in the cytosol in all the parenchyma cells of colleter axis, as described in this paper. Colleters are not vascularized, as verified in other species (Martins et al 2010b, Silva et al 2017, Ribeiro et al 2017. Secretion in colleters in E. dysenterica and E. punicifolia is released through spaces that form between the epidermal cells.…”

“…The exudate of colleters of the analyzed species reacts positively to detection of polysaccharides, commonly found in these structures (Silva et al 2017, Ribeiro et al 2017, which confirms its mucilaginous nature, responsible for its main function, which is to protect the meristem (Ribeiro et al 2017). In addition to meristem protection, the presence of secretion and location of the colleters highlight the importance of these structures for protection of buds against excessive sunlight and high transpiration levels, reducing water loss (Oliveira et al 2017), proliferation of fungi (Ribeiro et al 2017), as well as can be considered as an adaptive factor in Myrtoideae (Silva et al 2012).…”

Estruturas relacionadas ao potencial de rebrotamento de duas espécies de Myrtaceae do Cerrado: análises morfoanatômicas e químicas

“…Nos coléteres de Apocynaceae (Appezzato-da-Glória & Estelita, 2000a;Martins et al, 2010b) e Rubiaceae (Coelho et al, 2013) (Paiva & Machado, 2006;Coutinho et al, 2015;Silva et al, 2017). (Silva et al, 2017;Ribeiro et al, 2017;Martins et al, 2010b) e pode indicar que o transporte nessas estruturas seja feito via simplasto (Silva et al, 2012). A secreção nos coléteres em E. dysenterica e E. punicifolia é liberada através de espaços que se formam entre as células epidérmicas.…”

“…A secreção observada nos coléteres das espécies analisadas reage positivamente para detecção de polissacarídeos. Este tipo de secreção é uma característica geralmente encontrada em coléteres (Silva et al, 2017;Ribeiro et al, 2017), confirmando a sua natureza mucilaginosa, responsável pela função principal dos coléteres, que é proteger os meristemas (Ribeiro et al, 2017). A presença de secreção e a localização dos coléteres evidencia a importância dessas estruturas para a proteção de gemas contra a luz solar excessiva e altos níveis de transpiração, reduzindo o dessecamento (Oliveira et al, 2017), proliferação de fungos (Ribeiro et al, 2017) e pode ser considerada como um fator adaptativo na subfamília…”