Loading…

Leaf and sepal colleters in Calolisianthus speciosus Gilg (Gentianaceae): a morphoanatomical comparative analysis and mechanisms of exudation

ABSTRACT Calolisianthus speciosus, an endemic species of cerrado and campos rupestres in Brazil, bears colleters in both the leaf base and sepal. These colleters (leaf and sepal) were anatomically compared to identify differences in their structure and secretion mechanism. Samples of sepals and leav...

Full description

Saved in:
Bibliographic Details
Published in:Acta Botânica Brasílica 2021-09, Vol.35 (3), p.445-455
Main Authors: Zanotti, Analu, Fernandes, Valéria Ferreira, Azevedo, Aristéa Alves, Meira, Renata Maria Strozi Alves
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:ABSTRACT Calolisianthus speciosus, an endemic species of cerrado and campos rupestres in Brazil, bears colleters in both the leaf base and sepal. These colleters (leaf and sepal) were anatomically compared to identify differences in their structure and secretion mechanism. Samples of sepals and leaves in different development stages were collected and processed according to standard methodologies for anatomical and ultrastructural studies. Sepal and leaf colleters were anatomically similar, being non-vascularized, sessile or short-stalked and composed of a multicellular secretory head with large intercellular spaces where secretion, with a predominance of protein and polysaccharides, is accumulated. The secretory cells have thin walls, dense cytoplasm with granular endoplasmic reticulum, numerous dictyosomes and mitochondria. The ultrastructural characters are in agreement with the production of mucilaginous/protein secretion. The large secretion-filled vacuole merges with the plasma membrane releasing its contents to the periplasmic space where it remains until release outside of the cell wall, where it is accumulated in intercellular spaces formed by schizogeny. This accumulation generates pressure that promotes the passage of secretion through the external wall and the cuticle of superficial secretory cells of the head of the colleter.
ISSN:0102-3306
1677-941X
DOI:10.1590/0102-33062020abb0424