抗菌肽粗提物对肉鸡生长性能、粪便微生物菌群结构及经济效益的影响

为分析抗菌肽粗提物对肉鸡生长性能、粪便微生物菌群结构及经济效益的影响,试验选择体重相近的21日龄白羽肉鸡600只,随机分成4组,每组15个重复,每个重复10只,1组为空白对照组饲喂基础日粮,试验2、3、4组在基础日粮中分别添加1.0％、1.5％、2.0％的抗菌肽粗提物,试验期为21 d.结果表明:(1)试验2、3、4组...     

白茎盐生草幼苗对干旱胁迫的响应研究

采用盆栽试验对白茎盐生草幼苗进行为期0d、5d、10d、15d、20d、25d的自然失水胁迫,通过生理生长指标和叶片微观结构研究白茎盐生草幼苗对干旱胁迫的响应,为干旱半干旱区水土保持和生态恢复提供理论基础.研究表明:随干旱程度的加深,土壤含水率、白茎盐生草叶片肉质化程度、叶片相对含水量明显下降,而根冠比、质膜相对透性、...     

白斑综合征病毒与凡纳滨对虾肠道菌群区系之间关系的初步研究

比较了同一养殖池中的感染白斑综合征病毒(WSSV)和未感染WSSV的凡纳滨对虾的肠道菌群,旨在探讨对虾肠道菌群与机体健康状态之间的关系。感染WSSV对虾肠道的细菌总数为1.06×106CFU/尾,显著高于未感染WSSV的对虾(1.78×105CFU/尾;P<0.05),且其肠道中的细菌分别属于弧菌属、气单胞菌属、海水球菌属、盐水球菌属和乳酸杆菌属;染WSSV的对虾(P<0.05),气单胞菌的比例显著的低于感染WSSV的对虾(P<0.05);盐球菌所占的比例两者之间差异不显著。结果显示,两种对虾在肠道菌群组成和细菌组成和细菌数量上存在显著的差异,初步表明对虾肠道菌群区系和机体的健康状态密切相关。     

Feasibility analysis of NIR for detecting sweet corn seeds vigor

This paper explores the feasibility of particle-based detection and grading of seed vigor based on a self-built seed single-granulation device using near infrared spectroscopy (NIRS). Sweet corn with uniform kernel size was used for this study. The seed samples were divided into three types, they were normal seeds, artificially aged seeds and heat-damaged seeds. A 2-part spectral acquisition of each seed were performed, one for the collection of seeds that fall into the detection zone within the separation pipe, another was on the static platform, whose collection was performed on 5 faces of each seed. Partial least squares discriminant analysis (PLS-DA) was used to classify the original data of the seeds. In the 2 parts, the discriminant results of the unprocessed normal seeds and the artificial accelerated aging seeds, the untreated normal seeds and the heat-damaged seeds showed that classification accuracy was higher than 98%. The research indicates that the spectral data of different positions of seeds can reflect their activity information, and it is feasible to detect and classify seeds in real time in the detection area of the separation pipeline.     

天然生胶杂质含量测量结果不确定度评定

根据GB/T 8086—2008规定的测定方法,分析了测定过程中的随机效应与系统效应,计算这两种效应对测定过程导致的不确定度和,最终对本方法所产生的不确定度给予综合评定。     

Sewage sludge processing determines its impact on soil microbial community structure and function

Composting and thermal drying are amongst the most commonly used post-digestion processes for allowing sanitation and biological stabilization of sewage sludge from municipal treatment plants, and making it suitable as soil conditioner for use in agriculture. To assess the impact of sludge-derived materials on soil microbial properties, fresh (LAF), composted (LAC) and thermally dried (LAT) sludge fractions, each resulting from a different post-treatment process of a same aerobically digested sewage sludge, were added at 1% (w/w) application rate on two contrasting (a loam and a loamy sand) soils and incubated under laboratory conditions for 28 days. Soil respiration, microbial ATP content, hydrolytic activities and arginine ammonification rate were monitored throughout the incubation period. Results showed that soil biochemical variables, including the metabolic quotient (qCO₂), were markedly stimulated after sludge application, and the magnitude of this stimulatory effect was dependent on sludge type (precisely LAT > LAF > LAC), but not on soil type. This effect was related to the content of stable organic matter, which was lower in LAT. Genetic fingerprinting by PCR–DGGE revealed that compositional shifts of soil bacterial and, at greater extent, actinobacterial communities were responsive to the amendment with a differing sludge fraction. The observed time-dependent changes in the DGGE profiles of amended soils reflected the microbial turnover dependent on the sludge nutrient input, whereas no indications of adverse effects of sludge-borne contaminants were noted. Our findings indicate that composting rather thermal drying can represent a more appropriate post-digestion process to make sewage sludge suitable for use as soil conditioner in agriculture.     

炭化条件对竹原纤维炭孔隙结构的影响分析

为研究炭化竹原纤维的特性,进一步提升竹原纤维的使用性能,拓宽竹原纤维的应用领域,采用可控电炉制备了不同炭化温度和不同保温时间条件下的炭化竹原纤维,利用全自动比表面积及孔隙度分析仪测试了炭化竹原纤维的比表面积、比孔容及平均孔径,探讨了炭化条件对其性能的影响。结果表明：随炭化温度的升高和保温时间的延长,炭化竹原纤维的比表面积、比孔容和孔径分布先增大后减小,在较优的工艺条件下,炭化竹原纤维的比表面积和比孔容最大值分别可达819.35m2/g和0.7358cm3/g,平均孔径最小可达2.0836nm。     

Contrasting development of soil microbial community structure under no-tilled perennial and tilled cropping during early pedogenesis of a Mollisol

A range of agricultural practices influence soil microbial communities, such as tillage and organic C inputs, however such effects are largely unknown at the initial stage of soil formation. Using an eight-year field experiment established on exposed parent material (PM) of a Mollisol, our objectives were to: (1) to determine the effects of field management and soil depth on soil microbial community structure; (2) to elucidate shifts in microbial community structure in relation to PM, compared to an arable Mollisol (MO) without organic amendment; and (3) to identify the controlling factors of such changes in microbial community structure. The treatments included two no-tilled soils supporting perennial crops, and four tilled soils under the same cropping system, with or without chemical fertilization and crop residue amendment. Principal component (PC) analysis of phospholipid fatty acid (PLFA) profiles demonstrated that microbial community structures were affected by tillage and/or organic and inorganic inputs via PC1 and by land use and/or soil depth via PC2. All the field treatments were separated by PM into two groups via PC1, the tilled and the no-tilled soils, with the tilled soils more developed towards MO. The tilled soils were separated with respect to MO via PC1 associated with the differences in mineral fertilization and the quality of organic amendments, with the soils without organic amendment being more similar to MO. The separations via PC1 were principally driven by bacteria and associated with soil pH and soil C, N and P. The separations via PC2 were driven by fungi, actinomycetes and Gram (−) bacteria, and associated with soil bulk density. The separations via both PC1 and PC2 were associated with soil aggregate stability and exchangeable K, indicating the effects of weathering and soil aggregation. The results suggest that in spite of the importance of mineral fertilization and organic amendments, tillage and land-use type play a significant role in determining the nature of the development of associated soil microbial community structures at the initial stages of soil formation.     

低效林的近自然经营技术

探讨了低效林的概念与类型,分析了低效林的成因及其改造方法,并针对我国长江上游大面积低效林的现状,试图通过引进近自然经营技术理念,为大面积地改造低效林,实现森林的可持续经营提供指导.