Phytolith

Phytoliths strengthen the plant against abiotic stressors such as salt runoff, metal toxicity, and extreme temperatures.

In many cases, phytoliths appear to lend structure and support to the plant,[4] much like the spicules in sponges and leather corals.

Experimental studies have shown that the silicon dioxide in phytoliths may help to alleviate the damaging effects of toxic heavy metals, such as aluminum.

Cacti use these as a reserve for photosynthesis during the day when they close their pores to avoid water loss; baobabs use this property to make their trunks more flame-resistant[citation not found].

[2][6] Soluble silica, also called monosilicic or orthosilicic acid with a chemical formula of (Si(OH)4), is taken up from the soil when plant roots absorb groundwater.

By an unknown mechanism, which appears to be linked to genetics and metabolism, some of the silica is then laid down in the plant as silicon dioxide.

Such immobilised elements, in particular carbon, are valuable in that they permit radiometric dating in reconstructing past vegetation patterns.

Silica is bioactive, meaning it is able to change the expression of certain plant genes to jumpstart a defensive response against these stressors.

In terms of fungal infections, the deposition of silica has been shown to create a physical barrier between invading fungi and the plant.

[8] In 2009, researchers at the Rock Springs Agricultural Experiment Station at The Pennsylvania State University investigated the effects of pathogenic viruses on phytolith production in Cucurbita pepo var.

Contrastingly, plants affected with bacterial wilt disease resulted in much larger phytoliths but they were abnormally shaped.

Because they are made of the inorganic substances silica or calcium oxalate, phytoliths don't decay with the rest of the plant and can survive in conditions that would destroy organic residues.

[9] Phytoliths may be extracted from residue on many sources: dental calculus (buildup on teeth); food preparation tools like rocks, grinders, and scrapers; cooking or storage containers; ritual offerings; and garden areas.

Current liquids used include zinc bromide, hydrochloric acid, or sodium polytungstate which are added to the sample.

The sample should be placed in a mounting media on the slide which can be Canada Balsam, Benzyl Benzoate, silicon oil, glycerin, or water.

The target phytolith count is dependent on the objectives, research design, and conditions of the archaeological site from which they were obtained.

[20] Robustness of phytoliths make them available to be found in various remains including sedimentary deposits, coprolites, and dental calculus from diverse environmental conditions.

Findings such as these reveal useful information about the diet of these extinct animals, and also shed light on the evolutionary history of many different types of plants.

[33] Freshwater oases and related landscape changes that could have affected plant-human interactions were reconstructed through synthesizing phytolith, pollen, and paleoenvironmental data in the well-known early hominin site of Olduvai Gorge in Tanzania.

While this yields phytoliths as an important area of study regarding carbon sequestration, not all plant species produce analogous results.

[40] While carbon sequestration is a potentially important way to limit atmospheric greenhouse gas concentrations in the long term, the use of phytoliths to achieve this must be balanced against other uses that might be made of the same biomass carbon (or land for producing biomass) to reduce Greenhouse gas emissions (GHG) by other means including, for example, the production of bioenergy to offset fossil fuel emissions.