Insolubilization of Potassium Chloride Crystals in Tradescantia pallida.

1. BRIZUELA, M. , MONTENEGRO,T; CARJUZAA, P.; MALDONADO, S.

PROTOPLASMA

Año: 2008 vol. 231 p. 145 - 149

0033-183X

Summary   Calcium oxalate crystals are by far the most prevalent and widely distributed mineral deposits in higher plants. In Tradescantia pallida, an evergreen perennial plant widely used as an ornamental plant, calcium oxalate crystals occur in the parenchyma tissues of stem, leaf and root as well as in flower organs in the form of either raphides or tetragonal prismatic crystals, or both. Energy dispersive X-ray analysis revealed that C, O and Ca were the main elements and K, Cl, and Si the minor elements. Infrared and X-ray analyses of crystals collected from these tissues detected the coexistence of two calcium oxalate chemical forms i.e., whewellite and weddellite, as well as calcite, opal and sylvite. Here, we show for the first time the occurrence of epitaxy in mineral crystals of plants. Epitaxy, which involves the oriented overgrowth of one crystal onto a second crystalline substrate, might explain how potassium chloride (sylvite) -one of the most water-soluble salts- stays insoluble in crystal form when coated by a calcium oxalate epilayer. The results point out to the potential role of crystals regulating ionic equilibrium of both calcium and potassium ions.