Occurrence and characterisation of calcium oxalate crystals in stems and fruits of Hylocereus costaricensis and Selenicereus megalanthus (Cactaceae: Hylocereeae)
Fecha
2016-10
Tipo
artículo original
Autores
Viñas Meneses, María
Jiménez García, Víctor
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Resumen
Detailed description about occurrence of calcium oxalate (CaOx) crystals in the edible vine cactus species Hylocereus costaricensis and Selenicereus megalanthus is scarce. Therefore, we evaluated and characterized the presence, morphology and composition of CaOx crystals in both species. Crystals were isolated from
greenhouse and in vitro vegetative stems, and from ripe fruit peels and pulp by enzymatic digestion
and density centrifugation and quantified with a haemocytometer. Morphologies were studied using
scanning electron microscopy, elemental composition with energy-dispersive X-ray spectroscopy and
salt composition with X-ray powder diffraction. Analyses conducted confirmed that isolated crystals were
exclusively composed by CaOx, both mono- and dihydrated. Highest crystal contents were measured in
greenhouse stems, followed by the fruit peels. While very few crystals were quantified in in vitro plants,
they were not detected in the fruit pulp at all, which is of advantage for its human consumption and
could be linked to mechanisms of seed dispersal through animals. Different crystal morphologies were
observed, sometimes varying between genotypes and tissues analysed. This is the first work known to
the authors with a detailed characterization of CaOx crystals in vine cacti.
Descripción
Palabras clave
Calcium oxalate crystal, Elemental composition, Energy-dispersive, X-ray spectroscopy, Pitahaya Scanning electron microscopy, X-ray powder diffraction