Portal de Periódicos da CAPES

Artigo Acesso aberto Produção Nacional Revisado por pares

BIBTEX RIS

Foliar colleters in Macrocarpaea obtusifolia (Gentianaceae): anatomy, ontogeny, and secretion

2013; Canadian Science Publishing; Volume: 92; Issue: 1 Linguagem: Inglês

10.1139/cjb-2013-0203

1916-2804

Valdnéa Casagrande Dalvi, Lucas Siqueira Cardinelli, Renata Maria Strozi Alves Meira, Aristéa Alves Azevedo,

Plant and animal studies

Colleters are secretory structures located in reproductive and (or) vegetative organs of many eudicots. In Gentianaceae Juss., the presence of foliar colleters has been neglected, and anatomical and histochemical studies are scarce. The objectives of this study were to investigate the anatomy, ontogeny, and chemical nature of the secretion found in Macrocarpaea obtusifolia (Griseb.) Gilg colleters to establish a relationship between their structure and function and check whether these structures are similar to those described for other genera of the Gentianaceae and other families of the Gentianales. Samples of leaves at different developmental stages were collected and processed for anatomical and histochemical analysis using light microscopy and scanning electron microscopy. Colleters in M. obtusifolia have a protodermal origin, are of standard type, and are not vascularized. Young colleters are translucent and produce an abundant amount of sticky secretion. Later, they turn yellowish with a blackened region at the apex of the head, and the secretion, composed of polysaccharides and proteins, becomes less abundant and brownish. During senescence, the process begins with complete degradation and cell collapse of the secretory portion. The colleters of the standard type in M. obtusifolia have been observed for the first time in the Gentianaceae and represent additional evidence that reinforces how common this type of colleter is in the Gentianales. Such results provide new information on the anatomy, ontogeny, histochemistry, and colleter types of Gentianaceae.