Phytoliths and other Indicators:
Diagnostic Indicators for reconstructing rice ecology:
- Most commonly microscopic one celled algae organisms encased in a silica shell which allows them to be preserved in the archaeological record usually layered within seabeds or other strata to form part of the record for geological activity and environment in prehistory.
- Diatoms are present in any water bearing environment, in particular soil, and can show the environmental behaviour of
- Microscopic silica body within a plant’s structure that archaeologists can use to reconstruct plant profiles. The inorganic remains survive in the archaeological record and are diagnostic to plants, and parts of plants.
- Phytoliths are prepared from plant remains that have been charred to leave the phytolith isolated for analysis. This can also be done through chemically dissolving the surrounding soil, or by bleaching.
- Seeds will inform archaeologists about what plants were present at a site and in what quantity. This is a comparative analysis that will demonstrate the prevalence of rice at archaeological sites, and what weeds were present.
- An assemblage is the larger context of the archaeological record. Diatoms, phytoliths and seeds are the micro-remains which are individual components which make up the larger site, such as a padi field or terrace, which is known in the archaeological record as an ‘assemblage’.
The Early Rice Project is looking at assemblages in three ways:
- Creating a record of assemblages from modern day traditional rice farming in Asia
- Analysing micro-remains from prehistoric rice assemblages
- Comparing the two records to reconstruct a model of rice agriculture
- Indica vs. Japonica - these two variations of the rice plant were domesticated through distinct events.
Cultivation vs. Domestication (after Fuller, Harvey and Qin 2006) – the first implies human activity, and the second changes in the plant structure. The overlap of the two lasted between 1-2 millennia, and can be measured against diagnostic morphological changes from wild to domesticated rice such as:
- Decrease in hairs designed to help the rice spikelet grip soil. This was to help rice plants naturally disperse, which was made redundant with humans doing this for it.
- Increase in grain size and weight (this can be seen through the phytolithic record)
- Non shattering spikelet base so that plants could be harvested without damage. In addition, this meant that rice plants maintained all grains at maturity rather than scattering.
Examples of wild (left) and domesticated (right) rice spikelet bases
Page last modified on 09 nov 10 17:32