Laboratory

Vegetal Analysis

Vegetal Analysis


Group members: Dr. Frida Piper, Dr. Alex Fajardo.  Within the line of research, Terrestrial Ecosystems of the CIEP, diverse analyses are done associated with the research projects.  The processing and analysis of vegetative matter demands effort and time.  The process, from the moment the plants are gathered in the field to when they are converted into data with statistical value, requires a high investment in specialized human capital. For this reason, and because these are contextualized in projects of scientific research, the vegetal analyses done at the CIEP provide an opportunity to develop theses for masters degrees and PhDs.  The aforementioned analyses are not offered as services.

Entry and processing of vegetative material.  The plants or vegetal tissues are generally collected in the field, rarely coming from controlled conditions (nurseries, greenhouses).  The first step consists of drying the material, then weighing it, and finally grinding it. For this purpose, the laboratory has a stove with forced circulated air used exclusively for vegetal specimens, precision analytic scales, and diverse small grinders to grind the material before the analyses.  After processing, the material is stored in dry, cool conditions until it is analyzed.

Analysis of foliar phosphorus.  This analysis had its beginnings in the framework of the project, DID S-2010-66.  Some vegetal species, such as those belonging to the family Proteaceae (ex. Ciruelillo: Embothrium coccineum) or the lupines, present special root adaptations called PROTEOID (or cluster) ROOTS. These roots exude organic compounds that solubilize phosphorus not available in the soil.  Within the project, the relationship of the fertility of the soil, the formation of proteoid roots, and the nutritional state of the plant is studied. The analysis of phosphorus is done by means of digestion of the dried and ground tissue in acetic acid 2% (V/V) and later colorimetric determination adapted from Murpy and Riley. 

Analysis of Non-structural Carbohydrates (NSC). The NSCs are comprised of total soluble sugars and the starch.  The method for quantifying the NSC is based upon the determination of each component separately. The NSCs are the principal form of carbon reserves and energy in the plants, and their quantification is of high interest in studies of nutrition, food quality, ecology and vegetal physiology. The extraction of total soluble sugars is done through digestion in ethanol 80% (V/V) in a thermo-regulated bath at 80°C and colorimetric determination with Resorcinol. The tissue pellet resulting from the previous stage is dissolved in perchloric acid at 35% for the extraction of starch, the determination of which is done, also, by the method of Resorcinol.  Because the acid extraction inevitably removes some structural components, the enzymatic extraction of starch is recommended. At present, a new method of determining NSC is being implemented, based on the enzymatic extraction of the starch and colorimetric determination with O-toluidine. The Dendrochronology analysis consists in measuring with precision the width of growth rings of trees by means of a sliding bar (Valmex Inc. USA) fitted with a dendrochronometer (Accurite system) and a stereoscope (Olympus).  The determination of the width of the growth rings permits the obtaining of growth rates of trees and the association of these patterns of growth to physiographic and climate aspects.