Effects of forest-fuel harvesting on the amount of deadwood on clear-cuts

Forest residue left after clear-cutting is increasingly being used as biofuel in Sweden. Deadwood is an important habitat for many species and a crucial resource for forest biodiversity. On eight clear-cuts in eastern central Sweden, the amount of Picea abies (L.) Karst. deadwood left on the ground was compared with the amount collected in piles for fuelwood extraction. It was found that 65% of the volume, 77% of the surface area and 84% of the pieces of slash were to be extracted. In another study on 23 clear-cuts in the same region, it was found that 36% of the logs left outside piles after clear-cutting were later removed. These studies indicate that a considerable amount of potential substrate is lost during slash extraction.     

Fine earth soil bulk density at 0.2 m depth from Land Use and Coverage Area Frame Survey (LUCAS) soil 2018

Soil Bulk Density (BD) is an extremely important variable because it is an important site characterization parameter, and it is highly relevant for policy development because it is mandatory for calculating soil nutrient stocks. BD can influence soil chemical properties, land-use planning and agronomic management. The 2018 Land Use and Coverage Area Frame Survey (LUCAS) saw the unprecedented collection of BD core analysis in a subset of the locations in Europe and the United Kingdom where soil physical and chemical properties were analysed in the 2009 and the 2015 sampling campaigns. Here, we integrated the LUCAS 2018 BD sampling campaign with the mass fraction of coarse fragments previously determined in LUCAS 2009–2015 in order to provide a dataset of the volume fraction of coarse fragments and the BD of the fine earth and improve soil organic carbon (SOC) stock estimation accuracy for topsoil. BD data sampled at 0–10 and 10–20 cm were averaged to harmonize the BD with the mass fraction of coarse fragments measured in 2009, 2012 and 2015. Samples were from cropland, grassland and woodland soils, which accounted for 41%, 21% and 30%, respectively, of the total number of selected sites (n = 6059); ‘bareland’, and ‘shrubland’ accounted for 3% of the sites each, whereas ‘artificial land’ accounted for <1%. Only six samples were classified as ‘wetland’. The dataset was produced assuming the mass density of the coarse fraction to be constant across all LUCAS soil samples. We also estimated the SOC stocks associated with LUCAS 2018 BD and SOC content measurements and showed that correcting the BD by the coarse mass fraction instead of the coarse volume fraction generates SOC stock underestimation. We found the highest deviations in woodlands and shrublands. We showed that, when SOC stock is computed with coarse mass fraction, the error compared with the computation by volume may vary depending on the SOC and coarse mass fraction. This may imply a SOC stock underestimation for European soils. This dataset fits into the big framework of LUCAS soil properties monitoring and contributes both to soil awareness and soil research and assessments, which are two important objectives of the Soil Strategy and the European Soil Observatory (EUSO).     

Retained Woody Structure in 1- to 2-Year-Old Loblolly Pine (Pinus taeda L.) Plantations in Mississippi,Louisiana, and Arkansas: Implications for Wildlife Conservation

Information regarding how site preparation techniques affect residual woody structure is lacking for the southern United States in spite of the importance of such structure for many wildlife species. Therefore, we documented retained structure in young loblolly pine (Pinus taeda L.) plantations established using four common site preparation regimes: mechanical only, chemical only, chemical + mechanical, or chemical + prescribed burning. Herbicides reduced live tree density and increased snag density relative to mechanical methods. Prescribed burning reduced density of coarse woody debris (CWD) along with density and volume of piled CWD relative to chemical and mechanical methods. Our results provide a baseline for further studies of wildlife and retained structure in southern pine forests.     

Local airborne particulate concentration is associated with visible tracheal mucus in Thoroughbred racehorses

Reason for performing study: Accumulations of tracheal mucus assessed by endoscopic examination are associated with poor performance in racehorses. The air quality in horses' stalls may contribute to this visible tracheal mucus. Objectives: To determine whether the concentration and number of airborne particulates in stalls are associated with visible accumulations of tracheal mucus and with the number of inflammatory cells in tracheal aspirates. Methods: We studied 107 racehorses from 3 stables, in 3 different months, and measured airborne particulate matter 3 times daily in each of the stalls. On each monthly visit, horse airways were examined endoscopically and assigned a mucus score, and tracheal lavage was performed. Bivariate procedures, general estimating equations and linear mixed models were applied to estimate the association between PM and the presence of accumulations of mucus and number of inflammatory cells. Results: Stable, stall, month and PM were all significantly associated with the presence of accumulations of tracheal mucus, which had an overall prevalence of 67%. The odds of horses having visible accumulation of mucus were increased when horses occupied enclosed stables or stalls with higher particulate concentrations, and when concentrations of larger particles (≤10 µm in diameter) were elevated. Sixty‐eight percent of tracheal wash samples contained more than 20% neutrophils. Increased numbers of neutrophils were associated with the concentration of smaller particles (≤2.5 µm in diameter). Potential relevance: Careful consideration of stable construction and management practices focused on maintaining the lowest possible dust concentrations throughout the day should reduce the prevalence of visible accumulations of tracheal mucus, potentially improving racing performance.     

No “Gadgil effect”: Temperate tree roots and soil lithology are effective predictors of wood decomposition

The “Gadgil effect” hypothesizes that root associations may slow down decomposition through pre‐emptive competition. In the context of recalcitrant litter decomposition, specifically coarse wood debris, it is uncertain as to what is the relative importance of soil communities associated with living roots when compared to those without roots. Here, it is hypothesized that the presence of live roots and active photosynthates will enhance wood decomposition. To test this hypothesis, the presence or absence of temperate tree roots was used in this study. Sugar maple (Acer saccharum) and white oak (Quercus alba) roots were manipulated at three sites of either limestone or shale parent rock residuum. At each site, wood substrate was placed in soils beneath the canopy of either A. saccharum or Q. alba, while in the presence of roots (root⁺). At the same time, wood substrate was placed in the same soil community, but live root exposure was eliminated by trenching (root^?). This eliminated active photosynthate supply to the soil microbial community. Results determined that live root exposure promoted faster decomposition and greater mycelial colonization of wood substrate. Also, sites of shale parent rock residuum had higher rates of decomposition in comparison with limestone parent rock residuum. Although additional work is needed to determine the extent in which roots and lithology can facilitate wood decomposition, these findings suggest that living roots impact decomposers and provide a pathway towards humus and soil organic matter formation.     

杂粮重金属污染及其风险评价方法

杂粮品种多样,营养丰富,具有较好的发展前景。然而,重金属污染影响杂粮的食用安全,进而影响杂粮产业的发展。列举了杂粮中常见的重金属污染问题及危害,梳理了国内外的研究现状,同时总结了重金属污染风险的评估方法,以期为相关科研人员提供更多的研究思路,为杂粮产业的发展提供参考依据。     

麦二叉蚜唾液蛋白基因Sg1655时空表达谱及其抑制小麦防御反应的功能

为进一步明确麦二叉蚜Schizaphis graminum唾液蛋白Sg1655在调控小麦防御反应中的作用,基于麦二叉蚜唾液腺转录组数据,利用PCR技术克隆获取Sg1655开放阅读框,利用生物信息学软件对其序列进行分析;通过实时荧光定量PCR（real-time quantitative PCR,RT-qPCR）技术检测Sg1655在麦二叉蚜不同组织及不同龄期中的表达;利用细菌III型分泌系统将Sg1655导入到小麦叶片内,检测其瞬时表达对小麦胼胝质积累的影响。结果表明,Sg1655开放阅读框全长375 bp,编码125个氨基酸残基,N端1~21位为信号肽序列,预测蛋白分子量为14.90 kD。麦二叉蚜Sg1655氨基酸序列与玉米蚜Rhopalosiphum maidis同源序列相致性最高,为89.52%;麦二叉蚜Sg1655与玉米蚜同源序列聚为一个分支,亲缘关系最近。Sg1655在麦二叉蚜各组织中均有表达,其中在唾液腺中表达量最高,Sg1655在麦二叉蚜各个龄期均有表达,且在不同龄期之间无显著差异。小麦叶片内Sg1655瞬时表达可显著抑制小麦胼胝质积累,表明该蛋白可作为潜在效应子参与抑制小麦防御反应。     

新疆伊犁地区马疱疹病毒1型ORF30基因序列分析

为研究马疱疹病毒1型（EHV-1-XJ2015）新疆伊犁分离株致病基因型,评估新疆EHV-1-XJ2015的潜在风险因素,本试验设计特异性引物,应用PCR技术扩增EHV-1-XJ2015分离株ORF30基因相应区域,连接至克隆载体,成功构建重组质粒pMD19-T-ORF30。测序结果表明,EHV-1-XJ2015毒株ORF30基因2 254 bp处为A,且编码天冬酰胺（N）,分析证明EHV-1-XJ2015基因型为非神经型毒株,毒力倾向表现为流产型毒株;遗传进化显示,EHV-1-XJ2015毒株与日本分离株90c16、00c19、HH1、NY03为同一分支,氨基酸同源性最高为100%。本研究结果为开展EHV-1分子流行病学调查研究及为新疆地区现有诊断方法和防控措施的评估提供理论依据。     

粗酶制剂和维生素C对肉鸡生长性能的影响

选取３日龄艾维菌健康雏鸡４００只,随机分为４组。Ｉ组为对照组,Ⅱ组添加维生素Ｃ,Ⅲ组添加粗酶制剂,Ⅳ组添加粗酶制剂与维生素Ｃ,饲养３５ｄ,结果表明：１０日龄时,Ⅱ,Ⅲ,Ⅳ组体增重显著高于Ｉ组,１７日龄和３５日龄时,各组间体增重差异不显著,Ⅰ,Ⅱ,Ⅲ,Ⅳ组的３５日龄全程料肉质量比分别为２．０９８、１．９９５,１．９９７,１．９０４。说明在肉鸡生长早期（１４ｄ前）添加粗酶制剂和维生素Ｃ能显著促进生长,     

新型马铃薯低酒度饮品的研制

研究了发酵型马铃薯饮料的加工工艺和最佳配方。实验结果表明,最佳糖化工艺:95℃,pH为600,耐高温α淀粉酶添加量为15μ·g-1,液化60min后,降温60℃,pH值调整为450,添加糖化酶150μ·g-1,糖化40h。利用中性蛋白酶分解,添加05%酵母25℃发酵120h,经过滤或不经过滤调配后,制得营养丰富的低酒精度饮品。