Biomass production by two-year-old poplar clones on floodplain sites in the Lower Midwest, USA

Four Populus clones were grown for two years at 1×1 m spacing for study of total biomass production and carbon sequestration capacity on floodplain sites previously in forage grasses under climatic conditions of the lower Midwest, U.S.A. Total biomass (above-and below-ground) in the first year ranged from 3.9 Mg ha^–1 in a Populus deltoides x P. nigra clone (I45/51) to 1.9 Mg ha^–1 for a local-source Populus deltoides clone (2059). Second year total biomass production was substantially higher, ranging from 13.9 Mg ha^–1 in I45/51 to 7.4 Mg ha^–1 in P. deltoides clone 26C6R51. Second-year leaf area index (LAI) values for I45/51 plants reached 4 during mid-season, indicating essentially complete canopy closure in this clone by the second year after planting. In contrast, maximum mid-season, second-year LAI was significantly lower in P. deltoides clones ( 2.4). There was some evidence for differential allocation to roots and shoots among Populus clones, with 26C6R51 showing relatively more allocation to root biomass than other clones. Second-year growth in Populus deltoides clone 2059 accelerated substantially, and this genotype exhibited two-year biomass accumulation nearly equal to that of I45/51 despite having less leaf area. This result suggested a higher photosynthetic capacity or assimilation efficiency in the former. This revised version was published online in August 2006 with corrections to the Cover Date.     

Refugial forests of the southern Appalachians: photosynthesis and survival in current-year Abies fraseri seedlings

Fraser fir (Abies fraseri (Pursh) Poiret) is an endemic, high-elevation conifer confined to six relict mountaintop communities in the southern Appalachian Mountains, USA. High adult mortality has occurred over the past 50 years, possibly the result of an introduced insect (Adelges piceae Ratzeburg), air pollution, or both. Knowledge of the mechanisms of and limitations to seedling establishment may allow reestablisment and perpetuation of this unique community type, notwithstanding global climate change. We monitored seedling emergence and mortality in relation to photosynthetic performance and water relations in microsites differing in canopy openness (sunlight exposure) over the summer of 2004. Abundance of cotyledonous seedlings in early summer was 2.3 times greater (849 versus 366 seedlings m(-2)) in microsites with lower sky exposure (greater canopy closure) than in microsites with greater sky exposure (greater canopy openness). In contrast, late-season abundance and survival were greater in areas beneath more open canopies than in areas beneath less open canopies (3.3 times and 11.7 times greater, respectively). However, newly emerged seedling survival in a completely open site (no overhead canopy) was zero, despite an initial density of 124 seedlings m(-2). Seedling water status was similar in open- and closed-canopy sites (-0.52 and -0.74 MPa, respectively). Photosynthetic carbon gain was higher in newly emerged seedlings at open canopy than at closed canopy sites, especially during early morning. Based on photosynthetic light response curves and measured sunlight regimes, seedlings in open canopy sites were estimated to assimilate 3.3-4.5 times more carbon than seedlings at closed sites. Reductions in carbon gain of closed-site seedlings, primarily a result of limited sunlight, corresponded to substantial increases in seedling mortality (98 versus 79% in open canopy sites). Thus, sunlight exposure, which reflects overstory canopy structure, appears to be an important factor influencing newly emerged seedling survival and distribution.     

Conservation Effects on Soil Quality and Climate Change Adaptability of Ethiopian Watersheds

This study analyzes effects of soil and water conservation (SWC) on soil quality and implications to climate change adaptation and mitigation in the Upper Blue Nile River Basin of Ethiopia by using the Anjeni watershed as a case study site. Disturbed and undisturbed soil samples were collected from two sub‐watersheds of Anjeni: the Minchet sub‐watershed (with SWC measures) and the Zikrie sub‐watershed (without SWC measures). Soil samples were taken from 30‐cm depth from five representative landscape positions and analyzed following the standard soil lab analysis procedures. The results show that soils from the conserved sub‐watershed had improved quality indicators compared with those from the non‐conserved site. Significant improvement due to SWC measures was observed in the soil hydrological [total moisture content (+5·43%), field capacity (+5·35%), and available water capacity (+4·18%)] and chemical [cation exchange capacity (+4·40 cmol(+) kg⁻¹), Mg²⁺ (+1·90 cmol(+) kg⁻¹), Na⁺ (+0·10 cmol(+) kg⁻¹)] properties. SWC interventions significantly reduced soil erosion by 57–81% and surface runoff by 19–50% in the conserved sub‐watershed. Reduction in soil erosion can maintain the soil organic carbon stock, reduce the land degradation risks, and enhance the C sequestration potential of soils. Therefore, adoption of SWC measures can increase farmers' ability to offset emissions and adapt to climate change. However, SWC measures that are both protective and sufficiently productive have not yet been implemented in the conserved sub‐watershed. Therefore, it is important that SWC structures be supplemented with other biological and agronomic measures in conjunction with soil fertility amendments appropriate to site‐specific conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

The application of polyamines by pressure or immersion as a tool to maintain functional properties in stored pomegranate arils

Pomegranate fruits were treated with putrescine (Put) or spermidine (Spd) at 1 mM either by pressure infiltration or by immersion and then were stored at 2 degrees C for 60 days. Samples were taken biweekly and were further stored 3 days at 20 degrees C for shelf life study. The treatments were effective on maintaining the concentration of ascorbic acid, total phenolic compounds, and total anthocyanins in arils at higher levels than in control samples. In addition, the two ways of polyamine application increased the levels of total antioxidant activity (TAA) during storage, especially when polyamines were applied by pressure infiltration. Moreover, Spd showed the best results on increasing TAA through maintenance of total phenolic compounds.     

Acculturation, economics and food insecurity among refugees resettled in the USA: a case study of West African refugees

OBJECTIVES: To assess the occurrence and severity of food insecurity, and examine associations between food insecurity and measures of socio-economic status and indicators of acculturation. DESIGN: Structured interviews among a non-probability sample of West African refugees at baseline and 6 months' follow-up.Setting Mid-sized city in north-eastern USA. SUBJECTS: One hundred and one caregivers with children under the age of 5 years and who have been living the USA for fewer than 4 years. RESULTS: Food insecurity was indicated in approximately half of households (53%). The occurrence of food insecurity was associated with measures of socio-economic status such as income, employment status and participation in the Food Stamp Program (P < 0.05). Measures of acculturation such as difficulty in the shopping environment and language difficulty were also associated with the occurrence and severity of food insecurity, as was time lived in the USA (P < 0.05). Among households who had been in the USA for 1 year or less, food insecurity was indicated in 73%, whereas among households who had been in the USA for at least 3 years food insecurity was indicted in 33%. CONCLUSIONS: Refugees are a potentially vulnerable group and our results echo others in suggesting a need for more thorough monitoring of the health and well-being of recently resettled refugees. These results also suggest that reliance on employment as the sole indicator of success in the resettlement process may be too narrow an indicator. Future research should focus on a wider range of measures of health and well-being.     

Geographical classification of honey samples by near-infrared spectroscopy: a feasibility study

The potential of near-infrared (NIR) spectroscopy to determine the geographical origin of honey samples was evaluated. In total, 167 unfiltered honey samples (88 Irish, 54 Mexican, and 25 Spanish) and 125 filtered honey samples (25 Irish, 25 Argentinean, 50 Czech, and 25 Hungarian) were collected. Spectra were recorded in transflectance mode. Following preliminary examination by principal component analysis (PCA), modeling methods applied to the spectral data set were partial least-squares (PLS) regression and soft independent modeling of class analogy (SIMCA); various pretreatments were investigated. For unfiltered honey, best SIMCA models gave correct classification rates of 95.5, 94.4, and 96% for the Irish, Mexican, and Spanish samples, respectively; PLS2 discriminant analysis produced a 100% correct classification for each of these honey classes. In the case of filtered honey, best SIMCA models produced correct classification rates of 91.7, 100, 100, and 96% for the Argentinean, Czech, Hungarian, and Irish samples, respectively, using the standard normal variate (SNV) data pretreatment. PLS2 discriminant analysis produced 96, 100, 100, and 100% correct classifications for the Argentinean, Czech, Hungarian, and Irish honey samples, respectively, using a second-derivative data pretreatment. Overall, while both SIMCA and PLS gave encouraging results, better correct classification rates were found using PLS regression.     

Effect of pyriproxyfen on developing stages and embryogenesis of California red scale (CRS), Aonidiella aurantii

During the past decade, the insect growth regulator pyriproxyfen has been the most used insecticide for controlling the California red scale (CRS), Aonidiella aurantii (Maskell), an important pest in citrus groves worldwide. The aim of the present research was to develop bioassays for determining the effect of pyriproxyfen on developing stages and embryogenesis of CRS that can serve as baselines for monitoring resistance. Pyriproxyfen was very effective against first- and second-instar nymphs of a susceptible strain of CRS; 0.1 and 0.2 mg AI L(-1), resulting in 80 and 100% mortality of first-instar nymphs, and in 62.5 and 91.7% mortality of second-instar nymphs respectively. According to probit analysis, the LC(50) and LC(90) values of pyriproxyfen for first-instar nymphs were 0.03 and 0.15 mg AI L(-1), and for second-instar nymphs they were 0.05 and 0.25 mg AI L(-1) respectively. Pyriproxyfen was quite effective on first-instar nymphs of a CRS field strain originating from a citrus grove where two successive applications of the compound had been applied. Mortality rates were 86 and 100% at concentrations of 0.2 and 0.4 mg AI L(-1) respectively. Pyriproxyfen suppressed embryogenesis when CRS females were treated with pyriproxyfen. Young CRS females treated with 1.0 and 5.0 mg AI L(-1) pyriproxyfen produced 6.6 N(1)/F and 2.4 N(1)/F as compared with 10.9 N(1)/F in untreated control.     

Identification of new, odor-active thiocarbamates in cress extracts and structure-activity studies on synthesized homologues

New, odorant nitrogen- and sulfur-containing compounds are identified in cress extracts. Cress belongs to the botanical order Brassicales and produces glucosinolates, which are important precursors of nitrogen- and sulfur-containing compounds. Those compounds often present low perception thresholds and various olfactive notes and are thus of interest to the flavor and fragrance chemistry. When the study of organonitrogen and organosulfur compounds is undertaken, Brassicale extracts are one of the matrices of choice. Cress extracts were studied by analytical (GC-MS, GC-FPD) and chemical (fractionation) means to identify new interesting odorant compounds. Two compounds that have never been reported in cress extracts, containing both nitrogen and sulfur, were discovered: N-benzyl O-ethyl thiocarbamate and N-phenethyl O-ethyl thiocarbamate. These two molecules being of organoleptic interest, their homologues were synthesized and submitted to organoleptic tests (static and GC-sniffing). Their odors evolve from garlic and onion over green, mushroom- and cress-like to fresh, spearmint-like. This paper presents the origin, chemical synthesis, and organoleptic properties of a series of O-alkyl thiocarbamates.     

Immune response to Sarcocystis neurona infection in naturally infected horses with equine protozoal myeloencephalitis

Equine protozoal myeloencephalitis (EPM) is one of the most common neurologic diseases of horses in the United States. The primary etiologic agent is Sarcocystis neurona. Currently, there is limited knowledge regarding the protective or pathophysiologic immune response to S. neurona infection or the subsequent development of EPM. The objectives of this study were to determine whether S. neurona infected horses with clinical signs of EPM had altered or suppressed immune responses compared to neurologically normal horses and if blood sample storage would influence these findings. Twenty clinically normal horses and 22 horses with EPM, diagnosed by the presence of S. neurona specific antibodies in the serum and/or cerebrospinal (CSF) and clinical signs, were evaluated for differences in the immune cell subsets and function. Our results demonstrated that naturally infected horses had significantly (P<0.05) higher percentages of CD4 T-lymphocytes and neutrophils (PMN) in separated peripheral blood leukocytes than clinically normal horses. Leukocytes from naturally infected EPM horses had significantly lower proliferation responses, as measured by thymidine incorporation, to a non-antigen specific mitogen than did clinically normal horses (P<0.05). Currently, studies are in progress to determine the role of CD4 T cells in disease and protection against S. neurona in horses, as well as to determine the mechanism associated with suppressed in vitro proliferation responses. Finally, overnight storage of blood samples appears to alter T lymphocyte phenotypes and viability among leukocytes.