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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.

Show MeSH
Diverse silicon deposits occur at different cell layers in epidermal long cell of the upper lemma from Common millet.(A) Transection of lemma and palea of P. miliaceum showing the following: es: extracellular sheet (keratose layer), oe: outer epidermis, hf: hypoderm fibres, vb: vascular bundle, sm: spongy mesophyll, and ie: inner epidermis. (B) Surface spotted sculpture with adnate silicon extracellular sheet and outer epidermis. (C) Surface saw-toothed sculpture with adnate silicon outer epidermis and hypoderm fibres.
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pone-0004448-g012: Diverse silicon deposits occur at different cell layers in epidermal long cell of the upper lemma from Common millet.(A) Transection of lemma and palea of P. miliaceum showing the following: es: extracellular sheet (keratose layer), oe: outer epidermis, hf: hypoderm fibres, vb: vascular bundle, sm: spongy mesophyll, and ie: inner epidermis. (B) Surface spotted sculpture with adnate silicon extracellular sheet and outer epidermis. (C) Surface saw-toothed sculpture with adnate silicon outer epidermis and hypoderm fibres.

Mentions: P. miliaceum have a smooth spotted sculpture with adnate silicon extracellular sheet and outer epidermis, or a surface saw-toothed sculpture with adnate silicon outer epidermis and hypoderm fibres. This is a reliable feature in distinguishing them from S. italica (Figure 12).


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)

Diverse silicon deposits occur at different cell layers in epidermal long cell of the upper lemma from Common millet.(A) Transection of lemma and palea of P. miliaceum showing the following: es: extracellular sheet (keratose layer), oe: outer epidermis, hf: hypoderm fibres, vb: vascular bundle, sm: spongy mesophyll, and ie: inner epidermis. (B) Surface spotted sculpture with adnate silicon extracellular sheet and outer epidermis. (C) Surface saw-toothed sculpture with adnate silicon outer epidermis and hypoderm fibres.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0004448-g012: Diverse silicon deposits occur at different cell layers in epidermal long cell of the upper lemma from Common millet.(A) Transection of lemma and palea of P. miliaceum showing the following: es: extracellular sheet (keratose layer), oe: outer epidermis, hf: hypoderm fibres, vb: vascular bundle, sm: spongy mesophyll, and ie: inner epidermis. (B) Surface spotted sculpture with adnate silicon extracellular sheet and outer epidermis. (C) Surface saw-toothed sculpture with adnate silicon outer epidermis and hypoderm fibres.
Mentions: P. miliaceum have a smooth spotted sculpture with adnate silicon extracellular sheet and outer epidermis, or a surface saw-toothed sculpture with adnate silicon outer epidermis and hypoderm fibres. This is a reliable feature in distinguishing them from S. italica (Figure 12).

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