RESUMEN
Enterolobium cyclocarpum and Piscidia piscipula are two important tree Fabaceae species distributed from the Yucatan Peninsula, Mexico. Our aims were focused on the E. cyclocarpum and P. piscipula seeds for: (1) to examine the seed permeability and imbibition rate, (2) to evaluate the effect of seed pre-germinative treatments, and (3) to characterize the structures involved on the presence of physical dormancy (PY). We used fresh seeds to determine seed permeability and imbibition rate, seed viability by means of tetrazolium test, furthermore, we applied mechanical scarification and boiler shocks for 5 s, 10 s and 15 s treatments. Morphological characterization of the seed coat was by Scanning Electron Microscope (SEM). Seed viability in E. cyclocarpum and P. piscipula were 100% and 96%, respectively. Seed permeability and imbibition rate in E. cyclocarpum were low. The highest germination in E. cyclocarpum was in the mechanical scarification (92%), while in P. piscipula, this parameter was in the 10 s boiling water treatment (76.0%). The presence of PY was confirmed in both species because they showed low seed permeability, and imbibition rate; furthermore, exhibited macrosclereids cells. The present research seeks to promote the sustainable use of E. cyclocarpum and P. piscipula.
RESUMEN
A burial and a rich offering were found under Room 2 in the Murals Building, Bonampak, a Mayan archaeological site situated in Chiapas, Mexico. This burial may be related with the creation of the famous mural paintings. A rich set of jewelry made of green stones was among the different objects found. Green stones have great importance in Mesoamerican cultures, those composed of jadeite being the most appreciated. To characterize the green stones, different spectroscopic techniques were used in a complementary way: Raman and infrared spectroscopies (FT-IR) were used for global mineralogical analysis, while X-ray diffraction (XRD) and X-ray fluorescence (XRF) were applied simultaneously in situ on the artifacts that were not successfully identified by these molecular techniques. In addition, XRF was used to contrasts the elemental information from pieces composed of pyroxenes that may be related to the raw sources of jade in Guatemala. The main minerals identified within the beads and earrings were jadeite with omphacite and jadeite with albite; to a minor extent, quartz, and serpentine. In this paper, the main features of the molecular and X-ray techniques are compared in order to determine the advantages and limitations of these spectroscopies for mineral identification. With this combination of techniques, it was possible to undertake a suitable characterization of the analyzed objects. This paper focuses on the XRD-XRF combined analysis for in situ noninvasive characterization.
RESUMEN
Jadeite was greatly appreciated by pre-Hispanic cultures in Mesoamerica. Despite its importance, knowledge of its mining sources was lost after the Spanish conquest. In the 1950s the only confirmed jadeite deposits in Mesoamerica were found in the Motagua River Fault (MRF), Guatemala. The aim of this study is to present a methodology that is appropriate for the study of archeological jadeite objects using non-destructive spectroscopic and micro-ion beam analysis techniques. This methodology has been applied to perform mineral, elemental, and luminescence characterization of five jadeite samples from the MRF, with white, lilac, and green colors. Fourier-transformed infrared spectroscopy and X-ray diffraction analysis confirmed the presence of jadeite, albite, and omphacite as the main mineral phases in the samples. Elemental maps using particle-induced X-ray emission (PIXE) with a nuclear microprobe and elemental concentration analysis from individual mineral grains using micro-PIXE coupled with micro-ionoluminescence (IL) allowed the detection of minor feldspar, titanite, and grossular mineral contents. Distinctive features from the mineral, elemental, and luminescence characterization have been found that allow the identification of these five jadeite samples.