Infra-red spectroscopy reveals chemical interactions driving water availability for enzyme activities in litters of typical Mediterranean tree species

Abstract

Rebufa. Infra-red spectroscopy reveals chemical interactions driving water availability for enzyme activities in litters of typical Mediterranean tree species. Soil Biology and Biochemistry, Elsevier, 2017, 114, pp.72-81. 10 In Mediterranean ecosystems, water is one of the main drivers of the microbial activities that support organic matter turnover in soils or litters. In addition to drought stress, coastal areas are subject to osmotic stress linked to sea spray exposure. Here we explored i) how water availability, characterized by water activity a w , is impacted by adding NaCI to litter, ii) the chemical interactions between water, NaCl and the litter matrix and iii) whether microbial activities (using lipase as a model) are affected under these conditions. Litters of two vegetal species typical of the Mediterranean area (Quercus pubescens and Pinus halepensis) were subjected to FTIR-ATR (Fourier-Transformed Infra-Red e Attenuated Total Reflectance) spectroscopy for chemical characterization. Q. pubescens and P. halepensis litters were characterized by cutin and aromatics respectively. Sorption isotherms were identical for both species litters; when NaCl was added, a shift in isotherm shape was observed at a w ranging from 0.75 to 1. FTIR also discriminated samples with and without added NaCl and revealed that cellulose is probably the polymer in interactions with ions. Very interestingly, no differences were found between lipase hydrolytic activities with and without added NaCl: salt addition had no effect on these activities.

AComDim, a multivariate tool to highlighting impact of agroclimatic factors on Moringa oleifera Lam. leaf’s composition from their FTIR-ATR profiles

“…Before each analysis, the powder samples were lyophilized for 48 h to remove the available water. The water presence modifies the appearance of the leaf spectral fingerprint by the overlapping of its IR bands with the characteristic bands of leaf metabolites [22].…”

The contributions of soil biochemical characteristics and soil organic carbon (SOC) structure to SOC mineralization rate during forest succession on the Loess Plateau, China

“…Soil samples were ground through a 0.05 mm sieve with an agate mortar and measured using a Fourier transformation infrared spectrometer (FTIR‐ATR) (Nicolet iS10, Thermo Fisher Scientific) following the method of Farnet‐Da Silva et al (2017). An average of 32 scans were recorded over the spectral range of 4000–500 cm −1 .…”

“…Therefore, when determining the relationship between microorganisms and soil carbon mineralization, it is necessary to link them with SOC structures. Especially in the forest succession process, the mechanisms underpinning SOC mineralization require investigation as they are of great significance in terms of SOC sequestration (Farnet‐Da Silva et al, 2017; Pisani et al, 2015).…”

Integrated biomarker responses of the submerged macrophyte Vallisneria spiralis via hydrological processes from Lake Poyang, China

“…To adapt the negative effects of high water stress and eliminate the free radicals under anaerobic active oxygen, the vegetation has formed a set of complex antioxidant systems in the evolutionary process. Among those antioxidant systems, antioxidant enzyme activities of vegetation are essential to maintain normal growth and development under the stress from high water levels [11]. The three most effective antioxidant enzymes are the superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and lipid degradation product (thiobarbituric acid, TBARS), which have been studied for a long time and widely used for field assessments [12,13].…”