Inorganic Composition of Cystoliths Isolated from Leaves of Higher Plants

Abstract

Cystoliths are well known as intracellular mineralized inclusions which are formed in specialized cells called lithocysts in leaves. They occur in the following five families; Urticaceae, Moraceae, Ulmaceae, Cucurbitaceae and Acanthaceae [1–3]. In these plants, a remarkable number of cystoliths are contained in their leaves and reaches several thousands per square centimeter in the leaves [4, 5]. Thus, cystolith formation is the most prominent calcium carbonate deposition in higher plants [3]. Hiltz and Pobeguin [6] studied the inorganic composition of cystoliths of Ficus elastica and found amorphous calcium carbonate as a main component of cystolith together with small amounts of silicon and magnesium with traces of titanium, aluminum and iron. At the same time, they showed a restricted distribution of silicon in the stalk of cystolith by microincineration technique and suggested the silicification of the stalk. Arnott [3] and Setoguchi et al. [5] reported small amounts of vaterite in the amorphous calcium carbonate in Morus alba and M. bombycis. In the present work, we isolated cystoliths from the leaves of F. retusa and Ceitis sinensis and studied their major inorganic components with their distribution in cystolith.