The ability of diatoms to make silica-based cell walls has been the subject of fascination for centuries. It started with a microscopic observation by an anonymous English country nobleman in 1703, who observed an object that looked like a chain of regular parallelograms and debated whether it was just crystals of salt, or a plant.Anonymous (1702). "Two letters from a Gentleman in the Country, relating to Mr. Leeuwenhoek's Letter in Transaction, no. 283.", Philos. Trans. R. Soc. Lond. B, 23: 1494–1501. The viewer decided that it was a plant because the parallelograms didn't separate upon agitation, nor did they vary in appearance when dried or subjected to warm water (in an attempt to dissolve the "salt"). Unknowingly, the viewer's confusion captured the essence of diatoms—mineral utilizing plants. It is not clear when it was determined that diatom cell walls are made of silica, but in 1939 a seminal reference characterized the material as silicic acid in a "subcolloidal" stateRogall, E. (1939). "Ueber den feinbau der kieselmembran der diatomeen", Planta: 279-291. Identification of the main chemical component of the cell wall spurred investigations into how it was made. These investigations have involved, and been propelled by, diverse approaches including, microscopy, chemistry, biochemistry, material characterisation, molecular biology, 'omics, and transgenic approaches. The results from this work have given a better understanding of cell wall formation processes, establishing fundamental knowledge which can be used to create models that contextualise current findings and clarify how the process works. Modified material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License.
