Biological Silification

horsetail silica

Silicon is not considered an essential element as its presence is not required for plants to survive; however it has a significant positive effect on plant growth and resistance to environmental stresses, and silicon deposition even increases the strength of cell walls. We have begun investigating biosilification in plants such as horsetail and rice.

The image to the right is a figure taken from Law & Exley (2011). It shows PDMPO-labelled silica deposition in horsetail. a. Rhizome; b. Basal stem, arrows (main and insert) indicate punctate deposits of silica associated with cell walls; c. Basal stem, arrow (insert) indicates silica deposition at cell plate between dividing cells; d. Basal stem, arrow (insert) indicates punctate deposits of silica associated with highly invaginated cell walls; e. Distal stem, showing (main and insert) rosette-like silica structures and heavily silicified stomata; f. Node, showing high density of silicified structures including doughnut-like pore (insert); g. Node, showing jagged appearance of silica-rich cell walls; h. Leaf, showing high densities of rosette-like silica structures; i. Leaf, demonstrating the intimate association of silica with stomata (insert); j. Spores, showing heavily silicified spores including (insert) punctate deposits of silica on the spore surfaces. Scale bars; 100 μm - d,e,f,g,h,i; 200 μm - a,b,c,j.

Relevant Publications

  1. Exley C, Tollervey A, Gray G, Roberts S & Birchall JD (1993) Silicon, aluminium and the biological availability of phosphorus in algae. Proceedings of the Royal Society of London Series B 253, 93-99. 
  2. Exley C (1998) Silicon in life: A bioinorganic solution to bioorganic essentiality. Journal of Inorganic Biochemistry 69, 139-144. 
  3. Exley C (2009) Silicon and bone. Bone 44, 1018.
  4. Exley C (2009) Silicon in Life: Whither Biological Silicifcation? In; Biosilica in Evolution, Morphogenesis, and Nanobiotechnology (Eds. WEG Müller, MA Grachev), Progress in Molecular and Subcellular Biology, Marine Molecular Biotechnology, 47, p 173-184.
  5. Exley C (2009) Darwin, natural selection and the biological essentiality of aluminium and silicon. Trends in Biochemical Sciences 34, 589-593. 
  6. Law C and Exley C (2011) New insight into silica deposition in horsetail (Equisetum arvense). BMC Plant Biology 11, 112.