Premium
Plant Cystoliths: A Complex Functional Biocomposite of Four Distinct Silica and Amorphous Calcium Carbonate Phases
Author(s) -
Gal Assaf,
Hirsch Anna,
Siegel Stefan,
Li Chenghao,
Aichmayer Barbara,
Politi Yael,
Fratzl Peter,
Weiner Steve,
Addadi Lia
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201201111
Subject(s) - amorphous calcium carbonate , amorphous silica , biocomposite , phase (matter) , stalk , calcium carbonate , mineral , chemical engineering , materials science , chemistry , component (thermodynamics) , mineralogy , organic chemistry , composite number , composite material , biology , physics , horticulture , engineering , thermodynamics
Abstract Plant cystoliths are mineralized objects that are formed by specialized cells in the leaves of certain plants. The main mineral component of cystoliths by volume is amorphous calcium carbonate (ACC) and the minor component is silica. We show that the silica stalk is formed first and is essential for ACC formation. Furthermore, the cystolith is shown to be composed of four distinct mineral phases with different chemical properties: an almost pure silica phase grades into a Mg‐rich silica phase. This Mg‐rich silica is overlaid by a relatively stable ACC phase. A bulky and less stable ACC phase encapsulates the first ACC phase. This architecture poses interesting questions about the role of Mg in the silica phase and suggests a strategy for ACC stabilization that takes advantage of a precise regulation of the mineral‐growth microenvironment.