Stokes, Ian (2016) Biosilicification in Oryza sativa and other plants. Doctoral thesis, Keele University.

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Abstract

Rice (Oryza sativa) is well known as a biosilicifier though the mechanisms which underlie the silica
deposition in them are still relatively unknown. Silica deposits in rice were imaged through various complementary techniques including PDMPO staining and fluorescence microscopy, scanning electron microscopy, micro-particle induced X-ray emission and low-energy X-ray fluorescence. These techniques showed silica deposition throughout all expected sites of silica deposition, as well as revealing novel areas of silica deposition in the xylem, a region not usually considered to be a zone of silicification despite its known role in transporting silicic acid.

Silicon was found to be co-localised with aluminium at the silica cells through the use of low-energy X-ray fluorescence. This is, to the best of our knowledge, the first evidence of silicon/aluminium colocalisation
in rice leaves.

The link between the hemicellulose callose and silicification was investigated, with aniline blue and
immunofluorescence staining revealing numerous sites of callose deposition in rice leaf tissue, all of which matched with known areas of silica deposition.

It was demonstrated that silicic acid uptake in rice does occur at a rate which would require active transport through the use of a simple experiment where the silicic acid content of solutions with rice plants growing in them were measured over time.

Silicification was studied in developing rice seedlings using PDMPO staining and fluorescence microscopy to image structures from different developmental stages of seedlings. Silicification was found to occur at all stages of development, with evidence of silicification of precursor leaf tissue inside ungerminated seeds.

The implications of these findings were discussed and the possibility that silicon may be maintained in a form other than solid silica in certain areas of rice plants was put forward.

Item Type: Thesis (Doctoral)
Subjects: Q Science > QK Botany
Divisions: Faculty of Natural Sciences > School of Life Sciences
Depositing User: Lisa Bailey
Date Deposited: 10 Nov 2016 09:28
Last Modified: 10 Nov 2016 09:28
URI: http://eprints.keele.ac.uk/id/eprint/2456

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