In:
Botany, Canadian Science Publishing, Vol. 91, No. 6 ( 2013-06), p. 403-413
Abstract:
Colleters are secretory structures of taxonomic relevance that are characterized by the production of a mucilaginous substance in the shoot apices and the development of organs that act against dehydration, herbivores, and pathogens. However, no studies have investigated the senescence and programmed cell death processes of colleters. The goal of this study was to describe the structure of Alseis pickelii Pilger et Shmale (Cinchonoideae) colleters and to characterize the process of senescence. Colleters in the early development stage have a smooth surface and turgid epidermal cells with dense cytoplasm. Subsequently, the epidermal cells exhibit one of the first signs of cell death described for colleters, cytoplasm retraction. Colleters at the intermediate stage show a wrinkled surface as a consequence of their secretory process. During the secretory phase, colleter cells show a hypertrophic endoplasmic reticulum and Golgi apparatus, suggesting high synthesis activity. Senescent colleters have a widened aspect, have disorganized epidermal cells, and are collapsed, making it difficult to see their structure. Histochemical tests showed the same reaction with Schiff's and Ruthenium Red reagents for all three stages, indicating the mucilaginous character of the secretion. Lipids and proteins were also observed throughout colleter development. DNA fragmentation, a typical symptom of cells undergoing processes of programmed cell death, was observed by TUNEL and quantified by a Cell Death Detection ELISA assay.
Type of Medium:
Online Resource
ISSN:
1916-2790
,
1916-2804
DOI:
10.1139/cjb-2012-0249
Language:
English
Publisher:
Canadian Science Publishing
Publication Date:
2013
detail.hit.zdb_id:
2467208-7
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