Journal Article

Cellular Ultrastructure and Crystal Development in <i>Amorphophallus</i> (Araceae)

Christina J. Prychid, Rachel Schmidt Jabaily and Paula J. Rudall

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 101, issue 7, pages 983-995
Published in print May 2008 | ISSN: 0305-7364
Published online February 2008 | e-ISSN: 1095-8290 | DOI:
Cellular Ultrastructure and Crystal Development in Amorphophallus (Araceae)

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  • Ecology and Conservation
  • Evolutionary Biology
  • Plant Sciences and Forestry


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Background and Aims

Species of Araceae accumulate calcium oxalate in the form of characteristically grooved needle-shaped raphide crystals and multi-crystal druses. This study focuses on the distribution and development of raphides and druses during leaf growth in ten species of Amorphophallus (Araceae) in order to determine the crystal macropatterns and the underlying ultrastructural features associated with formation of the unusual raphide groove.


Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and both bright-field and polarized-light microscopy were used to study a range of developmental stages.

Key Results

Raphide crystals are initiated very early in plant development. They are consistently present in most species and have a fairly uniform distribution within mature tissues. Individual raphides may be formed by calcium oxalate deposition within individual crystal chambers in the vacuole of an idioblast. Druse crystals form later in the true leaves, and are absent from some species. Distribution of druses within leaves is more variable. Druses initially develop at leaf tips and then increase basipetally as the leaf ages. Druse development may also be initiated in crystal chambers.


The unusual grooved raphides in Amorphophallus species probably result from an unusual crystal chamber morphology. There are multiple systems of transport and biomineralization of calcium into the vacuole of the idioblast. Differences between raphide and druse idioblasts indicate different levels of cellular regulation. The relatively early development of raphides provides a defensive function in soft, growing tissues, and restricts build-up of dangerously high levels of calcium in tissues that lack the ability to adequately regulate calcium. The later development of druses could be primarily for calcium sequestration.

Keywords: Amorphophallus; Araceae; calcium oxalate; crystals; development; druses; raphides; ultrastructure

Journal Article.  6207 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

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