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This study estimated the severity of Nilahue-Barahona and Las Máquinas wildfires, occurred in central Chile during the summer of 2016-17, by an empirical-statistical modelling based on pre- and post-fire arithmetic differences of spectral indices sensitive to vigor, turgor and calcination states of vegetation. By doing this, map of damages were created to aid the efficient management and ecological restoration of disturbed forestry ecosystems. The index differences were calculated from Sentinel-2 satellite images, acquired anually in the summers spanning from 2016 to 2019. The resulting nine index-derived differences were used as predictors of burn severity, field-measured during the summer of 2019 using the CBI (composite burn index) method, into a linear stepwise regression that allowed for selecting those with the highest predictability. CBI yielded low correlations as its calculation includes low vegetation strata largely recovered at the time of the field data collection. However, when overstory field data were used alone, correlations increased (70 % of the data = 0.80, P < 0.05). This was because this stratum was still appreciably damaged during the field campaign, along with its best representation from the image planimetry. The burn severity of both wildfires was mapped using the overstory data as regressand in a model based on NDWIex-ante-2019, NDWIex-ante-2018, NBRex-ante-2018 and NBRex-ante-2017 differences (R² ad = 0.77, RMSE = 0.35). [ABSTRACT FROM AUTHOR]

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This work was carried out with the objective of determining the answer to plant growth and water relations of two rice varieties (Oryza sativa L.) when being exposed to different NaCl levels. Plants were developed in a growth chamber under hydroponic conditions. Evaluations were carried out at the beginning of the experiment, at seven and 14 days of having applied treatments and after seven days of recovery. Evaluations consisted of the biomass expressed as fresh and dry matter from roots and the air part, stomatal conductance, transpiration as well as leaf, osmotic, pressure and osmotic potentials at full turgor. The analysis of plant behavior indicated that they modified growth as much as water relations when exposed to saline conditions. It was also appreciated that under these conditions, plants developed the osmotic adjustment mechanism. [ABSTRACT FROM AUTHOR]