ESTRUTURAS SECRETORAS ASSOCIADAS AOS DENTES FOLIARES DE MONTEVERDIA GONOCLADA (MART.) BIRAL (CELASTRACEAE): CARACTERIZAÇÃO MORFOANATÔMICA, MICROMORFOLÓGICA E HISTOQUÍMICA

Abstract

Glands are composed of cells and/or tissues capable of producing secretions that can be released or stored within the plant body. In leaves, colleters, hydathodes, and nectaries are examples of external secretory structures that may occur along the leaf margin. In Celastraceae, leaf margins can be entire, serrate, crenate, or dentate, and glandular structures are sometimes associated with these margins. This study aimed to investigate the anatomical, micromorphological, and histochemical characteristics of the leaf teeth of Monteverdia gonoclada to determine the nature of these glands. Young and mature leaves were collected, fixed in FAA 50, and analyzed using light microscopy (clearing, paradermal and cross-sections, and histochemical tests) and scanning electron microscopy. The leaf margins of M. gonoclada are crenate, with dark-colored glands visible under a stereomicroscope. These glands correspond to colleters, commonly present in young leaves and deciduous in mature leaves. Histochemical tests with ruthenium red and PAS revealed polysaccharides in the secretion, indicating a protective role against desiccation and pathogen entry. Our findings contribute to the anatomical knowledge of secretory structures in Celastraceae, a family with scarce studies on colleters. Additionally, this research highlights the importance of analyzing both young and mature leaves and demonstrates the potential of anatomical studies for advancing knowledge within the family.