Diversity of mycorrhizal fungi and soil indicative species in coastal plantations of northeast Brazil

The aim of this work was to evaluate arbuscular mycorrhizal(AM)fungi as soil indicators and the mycorrhization of native and exotic tree species planted in the Acaraúbasin,a transition area from the coast to the Brazilian semiarid region.Plots with 6-year-old trees of four native and three non-native species as well as one non-forested area were evaluated in terms of the diversity of AM fungi in the mycorrhizosphere and the root colonization by AM and ectomycorrhizal(EcM)fungi.Twenty-four AM fungi were identified;Claroideoglomus etunicatum,Glomus sinuosum,Paraglomus albidum,Acaulospora laevis,and Acaulospora brasiliensis were abundant in the forest soil.Diversity,dominance,evenness and richness indices of AM fungi were higher in plots with native trees.All root samples were colonized by AM fungi and only A nadenanthera colubrina,Acacia mangium,Casuarina equisetifolia and Eucalyptus urophylla formed associations with EcM fungi.Acaulospora morphotypes served as soil indicators for coverings with the native species Astronium fraxinifolium and Colubrina glandulosa.Exotic species may favor the proliferation of rarer AM fungi.These fungi–plant relationships may be important in the management of forest systems,and the evidence with mycorrhizal associations allows the inclusion of Brazilian species in tropical reforestation.

Influence of Environmental and Microclimate Factors on the Coffee Beans Quality (C. canephora): Correlation between Chemical Analysis and Stable Free Radicals

The present study reports a physicochemical comparison of shade-grown and sun-grown coffee beans, under unripe, rip and roasted-ripe conditions, using electrical conductivity measurements, electron paramagnetic resonance (EPR), infrared spectroscopy (FTIR), and high performance liquid chromatography (HPLC). Moreover, the assessed physicochemical parameters were compared with organoleptic evaluations based on the Coffee Quality Institute protocol. The values found for electrical conductivity, leached potassium, and stable free radicals were respectively 29%, 31%, and 350% higher for shade-grown coffee beans, whereas polyphenol oxidase enzymatic activity was 23% lower. By contrast, FTIR and HPLC measurements identified higher chlorogenic acid and lipid contents in sun-grown coffee beans. Importantly, the sensorial grade attributed to roasted-ripe grains was 12% higher for sun-grown coffee. Our findings suggest that shade-grown coffee beans have undergone microorganismal activity and undesired fermentation during cultivation, which resulted in lower coffee quality. A correlation between a set of selected physicochemical properties and organoleptic properties was robustly established and could be used in the development of future coffee bean quality control protocols.

^(222)Rn calibration procedure for water analyses by liquid scintillation counting

Purpose Among the several methods to measure ^(222)Rn in water,the liquid scintillation counting(LSC)technique is one of the most sensitive and widely used when analysing non-saline waters by liquid extraction,providing excellent accuracy,precision and low-level detection limits.When using the liquid scintillation counter Tri-Carb 3170 TR/SL(Perkin-Elmer)it is not possible to make an automatic determination of the alpha/beta discrimination parameter,being necessary to evaluate the pulse decay discriminator(PDD)value manually to the ^(222)Rn determination.In this work,we describe the steps to perform the calibration of that type of equipment.Methods The method consists in the preparation of standard samples from a ^(226)Ra certified standard solution and the adjustment of the PDD value by hand until the percentage of alpha events reaches a plateau of a near-constant fraction of total events.The process consists in taking several measures between PDD 80 and 200 with 15 min counting time each.Within the plateau,the alpha/beta ratio was used to determine the plateau final range as well as the optimum PDD value.After that,the calibration standards and blanks were measured and the region of interest(ROI)was established by finding the maximum value for the figure of merit(FOM)in the upper and lower limits.Results The optimal PDD value of 148 was established by the alpha/beta ratio,and after that,it was possible to measure ^(226)Ra standards to perform the calibration.An efficiency of(9.758±0.035)×1^(0-1) was obtained.In routine measurements,a detection limit of about 0.50 Bq L^(-1) is achieved for a 120 min counting time.To evaluate the uncertainty budget,the uncertainties of the net count rate,the efficiency,the sample amount and the decay correction factor were considered.Conclusions A method was developed for the calibration of LSC Tri-Carb 3170 TR/SL with the optimization of the PDD using a ^(226)Ra standard solution.The acquisition to obtain the plot of the variation of the events fraction in each window(alpha and beta)in function of PDD allowed to evaluate a plateau where the fraction of events was at a minimum.Afterwards,it was possible to measure the set of ^(226)Ra standards after the equilibrium with ^(222)Rn and determine the efficiency for ^(222)Rn with a detection limit of about 0.50 Bq L^(-1) in routine analyses.

NiWO4 powders prepared via polymeric precursor method for application as ceramic luminescent pigments

Ni WO4 was prepared using the polymeric precursor method and studied in terms of physical and chemical properties to verify its stability for industrial applications as pigments.The characterization was accomplished using thermal analyses,X-ray diffraction(XRD),scanning electron microscopy(SEM),photoluminescence(PL)and UV–Vis spectroscopies,colorimetric coordinates,and Raman spectra.Increasing the temperature,successive exothermic reactions were observed and they are related with thermal decomposition of the organic compound.The stability was reached at^700℃.The material is verified to become completely free of second phase at^800℃.The end Ni WO4 powders showed an intense charge transfer(CT)-related tail centered in the ultraviolet region,resulting in a yellow product.In addition,the powders exhibited broad excitation band and broad deep blue–green emission band,which were enhanced with increasing powders’crystallinity.