A preliminary study of chemical properties in temperate forest fire of the Chilean Andean range for planning of ecosystems restoration

Despite vegetation in fire-prone landscapes having different fire adaptations, a change in the worldwide fire regime could affect all ecosystem processes and systems. In this sense, soil systems play a key role in ecosystems, not only providing inorganic nutrients to plants, but also serve as filter water and carbon storage. The aim of this research was to identify the effects of wildfire on the chemical properties of young volcanic soils over the medium-term in two natural protected areas of Andean Mountain range. A comparative statistical analysis was performed to identify significant differences in different soil parameters between forty-eight unburned and burned soil samples. Therefore, significant differences were identified between evaluated samples in organic matter, macronutrients, micronutrients, and cation exchange capacity. Whilst organic soil matter and potassium content substantially increased due to incomplete vegetation combustion; the presence of calcium content and cation exchange capacity decreased with the occurrence of fire. Our findings showed that there were significant differences between unburned soils or a soil that had been burned once and soil that had been burned twice in thirteen years. These findings should support decision making, improving the selection of passive or active restoration actions and thus efficiency in forest management

Characterization of the Cell Wall Component through Thermogravimetric Analysis and Its Relationship with an Expansin-like Protein in Deschampsia antarctica

Deschampsia antarctica Desv. (Poaceae) is one of the two vascular plants that have colonized the Antarctic Peninsula, which is usually exposed to extreme environmental conditions. To support these conditions, the plant carries out modifications in its morphology and metabolism, such as modifications to the cell wall. Thus, we performed a comparative study of the changes in the physiological properties of the cell-wall-associated polysaccharide contents of aerial and root tissues of the D. antarctica via thermogravimetric analysis (TGA) combined with a computational approach. The result showed that the thermal stability was lower in aerial tissues with respect to the root samples, while the DTG curve describes four maximum peaks of degradation, which occurred between 282 and 358 °C. The carbohydrate polymers present in the cell wall have been depolymerized showing mainly cellulose and hemicellulose fragments. Additionally, a differentially expressed sequence encoding for an expansin-like (DaEXLA2), which is characterized by possessing cell wall remodeling function, was found in D. antarctica. To gain deep insight into a probable mechanism of action of the expansin protein identified, a comparative model of the structure was carried out. DaEXLA2 protein model displayed two domains with an open groove in the center. Finally, using a cell wall polymer component as a ligand, the protein–ligand interaction was evaluated by molecular dynamic (MD) simulation. The MD simulations showed that DaEXLA2 could interact with cellulose and XXXGXXXG polymers. Finally, the cell wall component description provides the basis for a model for understanding the changes in the cell wall polymers in response to extreme environmental conditions