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IDENTIFICATION OF PHYTOLITHS AND THEIR APPLICATION TO
RESEARCH ON RICE ORIGIN AND SPREAD (abstract)
Baozhang CHEN, Institute of Regional Development, Xuzhou Teachers College, Xuzhou 221009
(Agricultural Archaeology 1998:401. Translated by Yu Chen; edited by B. Gordon)
While it was by looking for grain traces in Chinese sites that ancient rice was
first detected, there has been no agreement on its origin. Poor preservation of leaves,
stems, grain, etc., in archaeological sites lost precious data, but tiny plentiful and
resistant phytoliths were preserved in stratified sites for a long time. Hence, phytolith
analysis has become the preferred technique for the study of ancient grain.
The problem is recognizing phytolith species and subspecies in archaeological
samples. Oryza sativa belongs to O. Oryzeae of the grass family. Presently, the two
main identifiable Oryzeae (including Oryza, Leersia and Zizannia, etc.) are:
(1) so-called 'special dumbbell' shaped phytoliths in leaf and stem cuticles, with
special sequencing and conformation of a 'short handle'. Subovate phytoliths are
thick and short, and concave or spoon-shaped on both edges; they are parallel to the
cuticle and their axes are perpendicular to the leaf axis.
(2) so-called fan-shaped (mobile bubble cells) on the blade with scaly stripes on the
very slick semicircular fan arc.
Identifiable traits of Oryza are glume and fan-shaped phytolith parameters, the
glume comprising lemma and palea. Long siliceous cells in its skin have special
shape and range, described by Watanabe as ‘a hollow ridge with sharp edge and
undulated margin’. Besides early-harvested bamboo, reed, broomcorn barley, etc., all
species in the grass family produce fan-shaped phytoliths. Hence, it is an important
for researchers to identify them in archaeological samples based on their traits.
Houyuan Lu et al. 1996 selected more than 30 plants from different subfamilies for
phytolith analysis and measurement of their fan-shape for discriminant analysis.
To evaluate phytolith meaning in botanical classification and its use in rice
origin research, it seems particularly important to clarify phytolith traits, including
those in wild rice, indica and japonica. Fujiwara Hiroshi and Sato et al. studied many
fan-shaped phytoliths, differentiating between indica and japonica via preliminary
discriminant analysis. The Jiangsu Agricultural Academy et al. also studied many
wild and cultivated fan-shaped rice phytoliths, with formation parameters differing in
diverse wild rice and cultivated species. In Jiahu site research, glume phytoliths were
studied in detail by Baozhang Chen et al., identifying wild rice, indica and japonica.
In conclusion, phytolith analysis can solve the problem of poor plant
preservation. It can play a significant role in the research of rice origin and
propagation.