Scanning Microscopy


Solid deposits of SiO2 (phytoliths) accumulate in many plants in specific intracellular and extracellular locations. Phytoliths have morphological characteristics unique to some taxa and therefore have taxonomic significance. Phytoliths persist and maintain their morphological integrity long after a plant has died, thus becoming a microfossil of the plant that produced them. Development of phytolith sytematics for microfossil phytoliths has traditionally followed a typological approach based on simple verbal descriptions of shape. A new method for use in phytolith sytematics is the morphometric approach which employs computer-based Image Analysis Systems to make quantified measurements of morphological parameters (size, shape, texture, etc.) which can be used as discriminators between taxa. These parameters, called morphometrics, or morphometries, are potentially important for improved phytolith sytematics. This study evaluates the effect of varying environmental conditions on 18 different phytolith morphometries relative to shape and size as a prerequisite to the further development of a morphometric based phytolith taxonomy. Results indicate that environmental conditions do indeed effect phytolith morphometries for the silica cell phytoliths produced by the two grass species considered in this study. However, the effects are not usually significant (p ≤ 0.05). Moreover, results of discriminant analyses using the morphometric data obtained indicate that the varying environmental conditions did not hinder the potential of phytolith morphometries to discriminate between plant taxa.

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