Chemical characterization of lignin and lipid fractions in industrial hemp bast fibers used for manufacturing high-quality paper pulps

The chemical composition of lignin and lipids of bast fibers from industrial hemp (Cannabis sativa) used for high-quality paper pulp production was studied. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) of fibers showed a lignin with a p-hydroxyphenyl:guaiacyl:syringyl unit (H:G:S) molar proportion of 13:53:34 (S/G ratio of 0.64). p-Hydroxycinnamic acids, namely, p-coumaric and ferulic acids, were found in only trace amounts. Among the lipids, the main compounds identified by GC/MS of the hemp fibers extracts were series of n-alkanes, free and esterified sterols and triterpenols, waxes, and long-chain n-fatty acids. Other compounds such as n-aldehydes, n-fatty alcohols, steroid hydrocarbons, and steroid and triterpenoid ketones as well as steryl glycosides were also found.     

Protected wading bird species threaten relict centenarian cork oaks in a Mediterranean Biosphere Reserve: A conservation management conflict

Conservation management conflicts frequently arise when an overpopulation of a protected organism has negative effects on other valuable elements in the same ecosystem. We studied the interactions between a colony of protected tree-nesting wading birds and a remnant population of centenarian cork oaks that was part of the formerly dominant forests in the Doñana Biological Reserve (SW Spain). A significant increase in the tree mortality rates has been recorded in areas that are yearly influenced by the bird colony.We analysed a cohort of surviving trees using a gradient of nesting bird influence. Tree-nesting history, bird isotopic signature (δ¹⁵N), tree health-related parameters (defoliation, δ¹³C and leaf surface coverage by faeces) and several soil variables were evaluated. Bird influence was related to increased soil salinity. This increase correlated to increased water-use efficiency for the leaves and to crown defoliation, suggesting that the heavily occupied trees are under higher stress and in poorer health condition than the unoccupied ones. We tested structural equations models (SEM) that were based on hypothesised bird effects on the health of the trees. Soil-mediated effects of the nesting birds best explained the symptoms of the declining health of the trees, whereas the percent of leaves’ surface that was covered by faeces did not improve the fitted SEM model.For the reserve’s managers, a challenging trade-off exists between preserving the relict trees, which have a high genetic diversity and a key ecological role in these savannah-like ecosystems, and maintaining the current nesting area for these protected, but expanding, wading birds.     

Behavior of monosaccharides, phenolic compounds, and color of red wines aged in used oak barrels and in the bottle

A red wine with appropriate basic quality characteristics for aging was stored in oak barrels for 12 months and then bottled and aged for a further 6 months. The same ambient conditions of temperature and humidity were maintained throughout the entire aging process. The barrels used were made from three different species of oak by four different cooperages and had been used for at least two years. Analysis of variance and principal component analysis were run on the values for hexoses, pentoses, total anthocyanins, ortho-diphenols, low- and high-polymer polyphenols, and color parameters to study the behavior of the monosaccharides and polyphenols in response to the factors of aging time, the oak variety employed, and the source cooperage where the barrels had been made. Time trends for all the phenolic components were directly related to aging time, with low-polymeric polyphenols (LPPs) being the most affected by wood type and source cooperage. Wine color was defined by a basic red color which decreased with aging time in the barrel and was altered by yellowish pigment components differing for each of the barrels in which oxidative aging took place and by increased stability of the blue copigments. Principal component analysis showed that samples of the same source wine aged in different barrels tended to be grouped together according to each of the aging intervals considered.     

Spatial variability of short-term effect of tillage on soil penetration resistance

The effect of tillage on soil properties varies within field due to spatial variability of soils. Mapping changes of soil penetration resistance (PR) would be useful to understand and assess tillage practices to alleviate soil compaction. The objectives were to model the short-term effect of tillage on PR and its spatial structure, and to delineate homogeneous zones based on soil response in a Typic Argiudoll previously managed under no-till. A grid sampling for PR and soil water content (SWC) were performed before and after chiselling. Spatial analysis was performed on the effect of tillage on PR data by 10 cm layers and homogeneous zones were delineated by k-means cluster analysis. The effect of tillage was ?0.33 MPa in 10–20 and 20–30 cm layer. No differences of PR were found at 0–10 cm. Short range (5–7 m) spatial structure on the horizontal plane was observed in all layers. Only 45% of the field showed a marked effect of tillage on PR. Mapping the effect of tillage on PR would be a useful approach for evaluating the global and local response of soil to tillage, as well as for delineating of areas within field for site-specific tillage practices.     

Establishment of Retama sphaerocarpa L. seedlings on a degraded semiarid soil as influenced by mycorrhizal inoculation and sewage‐sludge amendment

A field experiment was carried out to evaluate the effectiveness of mycorrhizal inoculation with three arbuscular mycorrhizal (AM) fungi (Glomus intraradices Schenck & Smith, Glomus deserticola (Trappe, Bloss. & Menge), and Glomus mosseae (Nicol & Gerd.) Gerd. & Trappe) and the addition of composted sewage sludge (SS) with respect to the establishment of Retama sphaerocarpa L. seedlings, in a semiarid Mediterranean area. Associated changes in soil chemical (nutrient content and labile carbon fractions), biochemical (enzyme activities), and physical (aggregate stability) parameters were observed. Six months after planting, both the addition of composted SS and the mycorrhizal‐inoculation treatments had increased total N content, available‐P content, and aggregate stability of the soil. Values of water‐soluble C and water‐soluble carbohydrates were increased only in the mycorrhizal‐inoculation treatments. Rhizosphere soil from the mycorrhizal‐inoculation treatments had significantly higher enzyme activities (dehydrogenase, protease‐BAA, acid phosphatase, and β‐glucosidase) than the control soil. In the short‐term, mycorrhizal inoculation with AM fungi was the most effective treatment for enhancement of shoot biomass, particularly with G. mosseae (about 146% higher with respect to control plants). The addition of the composted SS alone was sufficient to restore soil structural stability but was not effective with respect to improving the performance of R. sphaerocarpa plants.     

Evaluation of preflooding effects on iron extractability and phytoavailability in highly calcareous soil in containers

Previous pot cropping and laboratory incubation experiments were consistent with field observations showing that temporary flooding before cropping can increase the availability of soil Fe to plants. To study the effect of temporary flooding on changes in soil Fe phytoavailability we used 24 highly calcareous, Fe chlorosis–inducing soils to carry out a pot experiment where peanut and chickpea were successively grown after flooding for 30 d. At the end of the cropping experiment, the preflooded soil samples exhibited higher concentrations of acid oxalate‐, citrate/ascorbate‐ and diethylenetriaminepentacetic acid (DTPA)–extractable Fe (Fe_ox, Fe_ca, and Fe_DTPA, respectively) than the control (nonflooded) samples. Also, Fe_ox and Fe_ca exhibited no change by effect of reflooding of the cropped soils or three wetting–drying cycles in freeze‐dried slurries of soils previously incubated anaerobically for several weeks. Leaf chlorophyll concentration (LCC) in both peanut and chickpea was greatly increased by preflooding. The best predictor for LCC was Fe_ox, followed by Fe_ca and Fe_DTPA. The LCC–soil Fe relationships found suggest that the Fe species extracted by oxalate and citrate/ascorbate from preflooded soils were more phytoavailable than those extracted from control soils. However, the increased phytoavailability of extractable Fe forms was seemingly limited to the first crop (peanut). Flooding dramatically increased Fe_DTPA; however, high Fe_DTPA levels did not result in high LCC values, particularly in the second crop. Therefore, this test is a poor predictor of the severity of Fe chlorosis in preflooded soils.     

Multiple domestications of the Mesoamerican gene pool of lima bean (Phaseolus lunatus L.): evidence from chloroplast DNA sequences

The Mesoamerican (MA) gene pool of lima bean (Phaseolus lunatus L.) is widely distributed from northern Mexico to northern Argentina in its wild forms and from the southern United States to the east coast of Brazil in its domesticated forms. This broad distribution and lack of wild accessions of the MA gene pool in many areas of its natural distribution has impeded determining its center of domestication and establishing whether it has a single or multiple centers. To answer these questions, we evaluated 262 accessions of P. lunatus using two intergenic spacers of chloroplast DNA: atpB-rbcL and trnL-trnF. The data were analyzed using a maximum likelihood tree (ML), a haplotype network and two estimators of genetic differentiation (N _ST and G _ST). Nucleotide diversity (π) and haplotype (Hd) were quantified to estimate the percentage of reduction in genetic diversity (%r) as a founder effect. The ML tree and haplotype network indicated the existence of three groups (AI, MI and MII), which was supported by the high values of N _ST (0.61–0.80). Values for %r were high (58.67–60.83 %). Existence of Mesoamerican and Andean gene pools was confirmed, with two genetically and geographically distinct groups (MI and MII) within the MA gene pool. We present the first evidence for multiple origins of domestication for the MA gene pool. For MI, we propose western central Mexico as the domestication area and between Guatemala and Costa Rica for MII. We observed a founder effect in the MA gene pool as a result of domestication.     

A General Approach to Model Movement in (Highly) Fragmented Patch Networks

Landscape heterogeneity can often be represented as a series of discrete habitat or resource patches surrounded by a matrix of non-habitat. Understanding how animals move in such networks of patches is important for many theoretical and applied questions. The probability of going from one patch to another is affected in a non-trivial way by the characteristics and location of other patches in the network. Nearby patches can compete as possible destinations, and a particular patch can be shadowed by neighboring patches. We present a way to account for the effects of the spatial configuration of patches in models of space use where individuals alternate between spending time in a patch and moving to other patches in the network. The approach is based on the original derivation of Ovaskainen and Cornell (J Appl Probab 40:557–580, 2003) for a diffusion model that considered all possible ways in which an individual leaving a particular patch can eventually reach another patch before dying or leaving the patch network. By replacing the theoretical results of Ovaskainen and Cornell by other appropriate functions, we provide generality and thus make their approach useful in contexts where diffusion is not a good approximation of movement. Furthermore, we provide ways to estimate time spent in the non-habitat matrix when going from patch to patch and implement a method to incorporate the effect of the history of previous visits on future patch use. We present an MCMC way to fit these models to data and illustrate the approach with both simulated data and data from sheep moving among seasonally flooded meadows in northern Patagonia.Supplementary materials accompanying this paper appear online.     

Heterogeneity in soil hydrological response from different land cover types in southern Spain

This paper reports results from the analysis of the soil hydrological response to simulated rainfall in a cork oak forest in Los Alcornocales Natural Park (SW Spain). Four different soil/vegetation units were selected for the field experiments: [1] cork oak woodland, [2] heathland, [3] grassland, and [4] cork oak/olive tree mixed forest. Rainfall simulations tests were performed on circular plots of 1256.6 cm² at an intensity of 56.5 mm h^− 1 for 30 min.Marked differences in the hydrological behavior of the studied vegetation types were observed after the rainfall simulations. The soils under woodland showed low runoff rates and coefficients. The highest runoff rates were measured on the heath and grass-covered parts of the hillslope. Water repellency of the soil, measured from water drop penetration tests, reduced infiltration (especially under the heathland), and seems to be the cause of fast ponding and runoff generation during the first stages of rainstorms.The mosaic of different patterns of hydrological response to rainfall, such as runoff generation or infiltration, is governed by the spatial distribution of vegetation and its influence on the soil surface.     

Online RPLC-GC via TOTAD method to isolate (+)-methyl epijasmonate from lemon (Citrus limon Burm.)

Pure (+)-methyl epijasmonate was isolated from lemon ( Citrus limon Burm.) for the first time. To that aim, two commercial essential oils and one homemade extract were included in the present paper. First, a study on the appropriate chromatographic conditions to avoid the epimerization from methyl epijasmonate to the more stable methyl jasmonate was accomplished. The results obtained are discussed. The presence of (+)-methyl epijasmonate in the three samples studied was initially established through the direct injection into GC-MS. However, the overlapping of (+)-methyl epijasmonate with other matrix components made it necessary to employ a multidimensional technique. RPLC-GC analysis via through-oven transfer adsorption-desorption (TOTAD) provided the selectivity and sensitivity required, reflecting that the homemade lemon extract was an adequate natural source to obtain pure (+)-methyl epijasmonate by means of the collection of the corresponding RPLC fraction.