Thursday, March 26, 2015

Microscopic silica structures in plant tissue: phytoliths and their other names

Phytoliths develop in the tissue of various plant species after take-up of monosilicic-acid-containing groundwater from soil. Silicon dioxide (silica) concretions are then deposited in those plant structures—both intracellular and extracellular structures—through which the water circulates. These plant stones are commonly called phytoliths, but are known under other names as well [1]:
The term is Greek (phyto means plant, lith means stone). Other names that have been used in the past include opaline silica, plant opal, and opal phytoliths, but the most common is simply phytoliths.
Silica phytoliths are a subgroup of biogenic opal [2]. This explains why some synonyms associate phytoliths with opal, a hydrated amorphous form of silica. Phytoliths are composed of mainly noncrystalline silica, enriched in terrigenous metals and other chemical elements such as carbon permitting radiometric dating.

Arguably, the most interesting aspect of phytolithic mineral secretions is their long-time persistence as siliceous plant remains, such as the brown-colored fine dust that Charles Darwin observed at Porto Praya during his voyage on the Beagle [1].

Phytoliths are now systematically studied by multidisciplinary research communities [3-6]. Forensics, archaeology and paleobotany are disciplines naturally interested in the phytolithic fingerprint structures to identify the past occurrences and associations of plant species. Phytolith analysis, including phytolith dating, helps to reconstruct past macro- end microenvironments. The understanding of agricultural development and evolving human dietary patterns based on phytolith tracking is shaping current decisions in health care and nutrition.

Phytolith properties such as mechanical strength, heat absorbability and fungal defense activity makes the broadly accessible phytoliths promising constituents for micro- and nanotechnology applications.

Keyterms: inorganic biochemistry, archaeobotany, biogenic silicaecofact, microfossil, plant opal, opaline silica, [SiOx(OH)4-2x]n.

References and more to explore
[1] Thomas C. Hart: Phytoliths: The Storytelling Stones Inside Plants. American Scientist March April 2015103 (2), pp. 136-143 [].
[2] J. Kamenik, J. Mizera and Z. Řanda: Chemical composition of plant silica phytoliths. Environmental Chemistry Letters 2013. 11 (2), pp. 189-195. doi.: 10.1007/10311-012-0396-9.
[3] Irwin Rovner: Plant Opal Phytolith Analysis: Major Advances in Archaeobotanical Research. Advances in Archaeological Method and Theory 1983, 6, pp. 225-266.
[4] C.A.E. Strömberg et al.: Decoupling the spread of grassland from the evolution of grazer-type herbivores in South America. Nature Communications 2012, 4, article number: 1478. doi: 10.1038/ncomms2508.
[5] Soumya Jain: Biogenic Silica: An Inspiration to Nanotechnology. December 30, 2013 [].
[6] J. Mazumdar and R. Mukhopadhyay: Phytoliths of fern IV: In some aquatic ferns and Chinese Brake fern. Bioresearch Bulletin 2013, 2 (2) [].

No comments:

Post a Comment