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Phytoliths analysis for the discrimination of Foxtail millet (Setaria italica) and Common millet (Panicum miliaceum).

Lu H, Zhang J, Wu N, Liu KB, Xu D, Li Q - PLoS ONE (2009)

Bottom Line: Our research shows that five key diagnostic characteristics in phytolith morphology can be used to distinguish Foxtail millet from Common millet based on the presence of cross-shaped type, regularly arranged papillae, Omega-undulated type, endings structures of epidermal long cell, and surface ridgy line sculpture in the former species.We have established identification criteria that, when used together, give the only reliable way of distinguishing between Foxtail millet and Common millet species based on their phytoliths characteristics, thus making a methodological contribution to phytolith research.Our findings also have important implications in the fields of plant taxonomy, agricultural archaeology, and the culture history of ancient civilizations.

View Article: PubMed Central - PubMed

Affiliation: Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China. houyuanlu@mail.iggcas.ac.cn

ABSTRACT
Foxtail millet (Setaria italica) and Common millet (Panicum miliaceum) are the oldest domesticated dry farming crops in Eurasia. Identifying these two millets in the archaeobotanical remains are still problematic, especially because the millet grains preserve only when charred. Phytoliths analysis provides a viable method for identifying this important crop. However, to date, the identification of millet phytoliths has been questionable, because very little study has been done on their morphometry and taxonomy. Particularly, no clear diagnostic feature has been used to distinguish between Foxtail millet and Common millet. Here we examined the anatomy and silicon structure patterns in the glumes, lemmas, and paleas from the inflorescence bracts in 27 modern plants of Foxtail millet, Common millet, and closely related grasses, using light microscopy with phase-contrast and microscopic interferometer. Our research shows that five key diagnostic characteristics in phytolith morphology can be used to distinguish Foxtail millet from Common millet based on the presence of cross-shaped type, regularly arranged papillae, Omega-undulated type, endings structures of epidermal long cell, and surface ridgy line sculpture in the former species. We have established identification criteria that, when used together, give the only reliable way of distinguishing between Foxtail millet and Common millet species based on their phytoliths characteristics, thus making a methodological contribution to phytolith research. Our findings also have important implications in the fields of plant taxonomy, agricultural archaeology, and the culture history of ancient civilizations.

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Comparison of the endings structures of epidermal long cells in the upper lemma and palea for the two millet species.(A) Cross wavy type of Foxtail millet. (B) Cross finger type of Common millet.
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pone-0004448-g009: Comparison of the endings structures of epidermal long cells in the upper lemma and palea for the two millet species.(A) Cross wavy type of Foxtail millet. (B) Cross finger type of Common millet.

Mentions: Based on our observation and statistics of endings structures of epidermal long cells, we found that three important parameters can be used to characterize the morphological variations of structures of epidermal long cells in the upper lemma and palea (Figure 9): (1) W = width of endings interdigitation of dendriform epidermal long cells. (2) H = undulation amplitude of dendriform epidermal long cell walls. (3) R = ratio of width of endings interdigitation to undulation amplitude, R = W/((H1+H2)/2) (Figure 9). These three parameters are relatively stable among different millet samples.


Phytoliths analysis for the discrimination of Foxtail millet (Setaria italica) and Common millet (Panicum miliaceum).

Lu H, Zhang J, Wu N, Liu KB, Xu D, Li Q - PLoS ONE (2009)

Comparison of the endings structures of epidermal long cells in the upper lemma and palea for the two millet species.(A) Cross wavy type of Foxtail millet. (B) Cross finger type of Common millet.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2636886&req=5

pone-0004448-g009: Comparison of the endings structures of epidermal long cells in the upper lemma and palea for the two millet species.(A) Cross wavy type of Foxtail millet. (B) Cross finger type of Common millet.
Mentions: Based on our observation and statistics of endings structures of epidermal long cells, we found that three important parameters can be used to characterize the morphological variations of structures of epidermal long cells in the upper lemma and palea (Figure 9): (1) W = width of endings interdigitation of dendriform epidermal long cells. (2) H = undulation amplitude of dendriform epidermal long cell walls. (3) R = ratio of width of endings interdigitation to undulation amplitude, R = W/((H1+H2)/2) (Figure 9). These three parameters are relatively stable among different millet samples.

Bottom Line: Our research shows that five key diagnostic characteristics in phytolith morphology can be used to distinguish Foxtail millet from Common millet based on the presence of cross-shaped type, regularly arranged papillae, Omega-undulated type, endings structures of epidermal long cell, and surface ridgy line sculpture in the former species.We have established identification criteria that, when used together, give the only reliable way of distinguishing between Foxtail millet and Common millet species based on their phytoliths characteristics, thus making a methodological contribution to phytolith research.Our findings also have important implications in the fields of plant taxonomy, agricultural archaeology, and the culture history of ancient civilizations.

View Article: PubMed Central - PubMed

Affiliation: Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China. houyuanlu@mail.iggcas.ac.cn

ABSTRACT
Foxtail millet (Setaria italica) and Common millet (Panicum miliaceum) are the oldest domesticated dry farming crops in Eurasia. Identifying these two millets in the archaeobotanical remains are still problematic, especially because the millet grains preserve only when charred. Phytoliths analysis provides a viable method for identifying this important crop. However, to date, the identification of millet phytoliths has been questionable, because very little study has been done on their morphometry and taxonomy. Particularly, no clear diagnostic feature has been used to distinguish between Foxtail millet and Common millet. Here we examined the anatomy and silicon structure patterns in the glumes, lemmas, and paleas from the inflorescence bracts in 27 modern plants of Foxtail millet, Common millet, and closely related grasses, using light microscopy with phase-contrast and microscopic interferometer. Our research shows that five key diagnostic characteristics in phytolith morphology can be used to distinguish Foxtail millet from Common millet based on the presence of cross-shaped type, regularly arranged papillae, Omega-undulated type, endings structures of epidermal long cell, and surface ridgy line sculpture in the former species. We have established identification criteria that, when used together, give the only reliable way of distinguishing between Foxtail millet and Common millet species based on their phytoliths characteristics, thus making a methodological contribution to phytolith research. Our findings also have important implications in the fields of plant taxonomy, agricultural archaeology, and the culture history of ancient civilizations.

Show MeSH