2006) showed that in the model organism Arabidopsis, a member of the mustard family, silicon application alleviated stress caused by pathogens. Phytoliths usually differ morphologically within a species, depending on which part of the plant produces them. All parts of the Cucúrbita plant produce large amounts of phytoliths, but the most useful ones, diagnostic of the genus and sometimes the species, come from the fruit rind (Fig. 1) (Pipemo 2006a).
This arrangement protects the fruit from herbivores and pathogenic fungi and is the natural state in all wild members of the genus. As in Cucúrbita, the tissue and cellular characteristics of fruit rinds used to identify macroscopic remains are used to identify their phytoliths. Also in contrast to Cucúrbita, phytoliths in gourds are hemispherical because solid silica is not deposited in the hypodermis of the crust.
By referring to other discussions in the 1988 phytolith book and presentation/discussions of the same data in Piperno. Every specimen of Balsas teosinte, the wild ancestor of maize, examined in blind and other studies, has dominant tent shape proportions. Thus, a genetic locus responsible for a number of crucial phenotypic changes during maize domestication also encoded several types of phytoliths in maize and its wild ancestor, creating the basis for archaeobotanical identifications of the phytoliths.
The scalloped phytoliths in the peel were closely similar in size and shape to those typically found in modern specimens of the plant.
Archaeological Results
This is expected given the age of the ears, by which time the genetic loci responsible for teosinte transformation in maize, including the gene that controls phytolith formation in each, tgal, had long been selected by human selection. The latter allows the generation of two independent lines of empirical data, providing evidence - often from the same stone tool factory or ceramic cookware• for the presence of two different parts of the same, worn plant structure , its cores and hulls. (glumes/cupules) (see Dickau et al., 2007; Iriarte et al. 2004; Perry et al Pearsall et al. Pipemo et al. 2000). In southwestern Ecuador, Las Vegas is a well-known and important Preceramic (Early to early Middle Holocene B.P.) occupation of the coastal region by tropical foragers and horticulturalists that has been studied by Karen Stothert and colleagues, including the author (Stothert 1985; Stothert et al 2003).
The well-accepted radiocarbon sequence for the Vegas culture provided a good opportunity for a detailed, comparative carbon-14 study of the cytoplasmic carbon found within phytoliths derived from the plant cells in which phytolith formation occurred. The stratigraphic integrity of the dates further indicated that any movement and mixing of phytoliths downward through the soil columns was insignificant. In addition, the author recently found the characteristic rhizome phytoliths of laren just described for Vegas occurring at the Aguadulce rockshelter in some of the same stratigraphic levels as the seed phytoliths, dating to ca.
Interestingly, cassabanana (Sicana odorifera), another domesticated member of the Cucurbitaceae with high amounts of diagnostic phytoliths, has so far not been recovered from pre-Columbian contexts. The same results were obtained when the data values were used with the prediction formula of the author's earlier discriminant function (Pipemo 1988), indicating the robustness of the results. Using the other identification criteria, also discussed above, which are applied independently of the discriminant function analysis (such as how many cruciforms of all sizes are Variant 1 and how many large-sized cruciforms (> 16 microns wide) are Variant Is, and other characteristics), phytoliths that are corn has been identified, contains all the characteristics of corn.
The average size of the crossed forms is fully consistent with the size in modern corn breeds. Furthermore, the interbody types and other phytolith types used to estimate the presence of maize do not match any of the hundreds of non-Zea cruciform-producing wild grasses against which phytoliths from modern maize races were compared ( see Pipemo 2006a). Another interesting feature of the Aguadulce Rock Shelter phytolith record should be discussed in relation to the presence of maize.
It has been conclusively shown that what is preserved in phytoliths is some of the carbon that was present in the plant cells where phytolith formation occurred. Some of the first botanists who conducted dedicated phytolith research during the last century noted these often visible inclusions and suggested that they were remnants of cellular organic matter. These beliefs were later confirmed by a number of investigators, who also analyzed the composition of the sealed carbon in detail (see Pipemo, 2006a: 125-132 for a detailed discussion).
Summary
Dating fossil opal phytoliths from Garua Island, West New Britain to determine phytolith assemblage chronology. Anthropological Papers of the American Museum of Natural History, v. Chandler-Ezell, C, Pearsall, D.M., and Zeidler, J.A. 2006) Root and tuber phytoliths and starch grains document cassava {Manihot esculenta), arrowroot {Maranta arundinacea) and Ueren {Calathea sp.) at the Real Alto site, Ecuador. Oxford: Proceedings of the 44th International Congress of the Americanists, British Archaeological Reports, International Series Resource Use, Crop Dispersals, and the Transition to Agriculture in Prehistoric Panama: Evidence from Starch Grains and Macroremains.
2003b) Assessing the feasibility of maize identification through analysis of cruciform size and three-dimensional morphology of phytoliths in grasslands of southeastern South America. Evidence for cultivar adoption and emergent complexity during the Mid-Holocene in the La Plata Basin, Uruguay. 2006) Experimental demonstration of antiherbivore effects of silica in grasses: impacts on leaf digestibility and vole growth rates.
Plant food sources of the Ecuadorian Formative: review and comparison with the central Andes. Archeology of Formative Ecuador, p. 1990) The ancient period of maize cultivation in Ecuador: a summary and reappraisal of the evidence. Zeidler (2004) Maize in Ancient Ecuador: Results from the Analysis of Stone Tool Remains from the Real Alto Site. 2004).
Starch analyzes reveal the relationship between tool type and function: An example from the Orinoco Valley of Venezuela. Occurrence of phytoliths in reproductive structures of selected tropical angiosperms and their significance in tropical paleoecology, paleoethnobotany and systematics. 1993) Phytoliths in Maize and Teosinte Reproductive Structures: Implications for the Study of Maize Evolution.
Stothert (2000a) Phytoliths in Cucúrbita and other Neotropical Cucurbitaceae and their occurrence in early archaeological sites from the lowland American tropics. Weiland (1985) Preceramic maize in Central Panama: phytolith and pollen evidence. 2007) Pre-Columbian maize distribution in the Neotropics. Phytolith assemblages containing corn leaf phytoliths from 2-7 cm AD. above date) were directly dated to 4250 ± 60 B.P., and phytolith assemblages from underlying Preceramic levels containing corncob phytoliths yielded internally consistent dates of 6207 ± 60 B.P. B.P., and 7061 ± 81 B.P. Wavy top roundels were not searched for in Sitio Sierra phytolith assemblages.
A phytolith from bottle gourd showing how the irregular pattern of the stone cells can be observed on the phytolith surface. In contrast to teosinte, phytolith assemblages under the control of the maize allele of Tga1. A phytolith from a fruit peel of Cucúrbita moschata, recovered from Huaca Prieta, Peru. It resembles that found in modern fruits of the crop.
Center, a phytolith from the rhizome of Calathea allouia taken from a preceramic level of Vegas Site 80.
