Silicification of Betula Woody Tissue in vitro

Pieces of Betula twigs were placed in solutions of sodium metasilicate (5,000 to 10,000 parts per million) and allowed to remain for 12 to 24 hours, after which they were washed and wet-ashed with chromic acid. Opaline silica was deposited on inner surfaces of cell walls so that silica replicas of the various types of cell lumens were produced. Entire twigs were not replicated intact, but macroscopic replicas of cell aggregates were common. Carbon replicas of the silica replicas provide an unusual view of cellular spaces in woody tissue. The pits were viewed as projections from cells rather than holes in cell walls. This technique offers a new way of examining woody tissue and a method for deliberate petrification in a relatively short period of time under laboratory conditions.