Data/hora: 21/06/2024 03:51:33

Biblioteca(s): | Embrapa Florestas.
Data corrente: | 15/09/2008
Data da última atualização: | 15/09/2008
Autoria: | MÉNDEZ, J.; ALVAREZ-OTERO, R.; BRIONES, M. J. I.
Título: | Morphological and structural aspects of the earthworm calciferous gland and its calcareous secretion.
Ano de publicação: | 2008
Fonte/Imprenta: | In: INTERNATIONAL COLLOQUIUM ON SOIL ZOOLOGY, 15; INTERNATIONAL COLLOQUIUM ON APTERYGOTA, 12., 2008, Curitiba. Biodiversity, conservation and sustainabele management of soil animal: abstracts. Colombo: Embrapa Florestas. Editors: George Gardner Brown; Klaus Dieter Sautter; Renato Marques; Amarildo Pasini. 1 CD-ROM.
Idioma: | Inglês

Conteúdo:

The oesophageal glands of earthworms are commonly referred as calciferous glands and they
are present in all species of the family Lumbricidae. Most studies have mainly focused on the
well-known Lumbricus terrestris, however many structural aspects are still unknown for the
majority of the species included in the family and the significance of their secretions remains
uncertain. In this study we provide new insights into the morphology and ultraestructure of several
earthworm species belonging to three genera (Allolobophora, Dendrobaena and Octolasion)
collected from different locations in Europe. Earthworms were hand-sorted in the field and taken
back to the laboratory for removal of the glands by dissection. The morphological studies of the
mineral phases involved in the calcareous secretions were analysed by field emission scanning
electron microscopy (FE-SEM) of the air dried frozen sections. Results showed that the anatomy
of the glands of these three genera falls into three types: (i) pouches and oesophageal
enlargements present (Octolasion), pouches present but no enlargements (Allolobophora),
pouches absent but enlargements present (Dendrobaena). Calcium secretion usually appears
initially to be a ?milky fluid? and in those species with pouches the calcium carbonate crystals
aggregate resulting in bigger concretions of different sizes. The morphological characterisation
of the mineral secreetion using FE-SEM showed that the glandular segments contained
spherulites usually packing the interlamellae spaces. These spherulithic deposits mainly consisted
of ovoid to spherical particles varying in size. In contrast, all the morphologies detected in the
solid concretions stored in the pouches could be classified into spherulithic, mulberry-like
aggregates and rhombohedral crystals. Coalescence between two or more spheres was
occasionally observed leading to the formation of larger aggregates, and possibly to the ultimate
formation of rhombohedral calcite crystals. These results evidence that the differences in the
anatomy of the gland determine the morphology of the calcareous secretion among different
species.

Categoria do assunto: | --
Registro original: | Embrapa Florestas (CNPF)
Exemplares: | CNPF - (43560-1) - UPE - PL - -- - CD0305 -  -  - DIS