北方农户多元有机垃圾混合厌氧发酵研究

为从源头上解决农村有机垃圾排放污染和实现资源化利用,以北方典型农户为研究对象,开展问卷评估和沼气化利用混配试验研究.结果表明,农村家庭有机垃圾主要由厨余垃圾和人类粪便组成,日平均总产量3.71～4.96 kg(以每户3～4人计);将厨余垃圾、粪便和玉米秸秆按照干物质23??44??9比例混合可获得最大TS产气率330 mL·g-1.经测算,若将每户产出有机垃圾全部用以厌氧转化,每天产沼气1.5 m3以上,可满足3～4人普通家庭日常饮食.研究对改善农村环境和调整生活用能结构提出新思路.     

氮磷钾配施对青麻叶产量及肥料利用率的影响

采取田间小区试验,研究氮磷钾配施对青麻叶肥料利用率及产量的影响,探索NPK肥料在青麻叶上的利用效率,以期为青麻叶科学施肥提供科技支撑.结果表明:N肥对青麻叶生物产量、经济产量影响最大,P肥、K肥次之,N、P、K肥料配合施用是提高青麻叶产量的关键措施;N、P、K肥料配合施用能显著提高肥料利用率,在试验条件下,N、P、K肥料配合施用青麻叶的N、P、K肥利用率分别为49.5％、27.4％、58.1％.     

Uterine Expression of WNT7A and β-catenin After Induction of Oestrus in Sheep

WNT7A and β-catenin localisations and roles in regulating periimplantation ovine conceptus development under natural estrous conditions have been elaborated.However,their locations and expression patterns have not been reported under induction of oestrus.The localisation,expression and function of WNT7A and β-catenin in the uterine tissues of the early pregnant and non-pregnant sheep on days 10,12,14,16 and 18 following artificial induction of oestrus were investigated by means of in situ hybridisation,real-time RT-PCR,immuno-histochemistry and western blotting methods.WNT7A and β-catenin mRNA and protein were both restricted to the apical surfaces of the uterine luminal epithelium (LE) and glandular epithelium (GE).In pregnant sheep,protein localisation of WNT7A and β-catenin was observed both in the endometrial LE and GE.Their staining presented on day 10,increased between day 12 and day 16,and decreased on day 18.WNT7A and β-catenin mRNA and protein expression increased initially and then decreased from day 10 to day 18,peaking on day 16,and β-catenin reaching a peak on day 18 in the uterine tissues of pregnant sheep (p0.05).By contrast,no significant changes in WNT7A and β-catenin mRNA and protein expression levels were observed from day 10 to day 18 of the oestrus cycle in the uterine tissues of non-pregnant sheep (p0.05).Additionally,WNT7A and β-catenin mRNA and protein expression levels in the uterine tissues of the early pregnant sheep were significantly higher than those of non-pregnant sheep (p0.05).Treatment of endometrial epithelial cells with WNT7A increased the mRNA expressions of β-catenin,c-myc and Cyclin D1.These results provided an underlying mechanism of periimplantation ovine conceptus development under induction of oestrus.     

不同基质配比对盆栽香菜生长及品质的影响

以“大叶香菜”为试验材料,设置T1（草炭∶蛭石∶珍珠岩=3∶1∶1）、T2（草炭∶蛭石∶珍珠岩∶有机肥=6∶1∶1∶2）、T3（草炭∶蛭石∶有机肥=3∶1∶1）、T4（草炭∶蛭石∶珍珠岩∶有机肥=2∶1∶1∶1）、T5（草炭∶蛭石∶珍珠岩∶有机肥=1∶1∶1∶1）和T6（草炭∶蛭石∶有机肥=2∶1∶1）共6种基质配比种植盆栽香菜,研究不同基质配比对盆栽香菜生长及品质的影响。结果表明,T4处理的盆栽香菜茎粗、根长和根体积等生长指标优于其他处理,全株鲜质量相对较大,为2.854 g,全株干质量具有最大值,为0.384 g。T4处理的品质指标可溶性蛋白含量、维生素C含量和叶绿素含量也相对较高,分别为37.78、0.20和2.02 mg/g。因此,建议使用草炭∶蛭石∶珍珠岩∶有机肥=2∶1∶1∶1的基质配比进行盆栽香菜的种植。      

经济政策不确定性对中国粮食安全的影响

为探究经济政策不确定性对中国粮食安全的影响,基于2000—2018年中国31个省(市、自治区,统计数据未含港澳台地区)的面板数据,采用PVAR模型,研究经济政策不确定性对中国粮食供给安全、获取安全、稳定性安全和资源安全的影响及区域差异。结果表明:1)总体上,经济政策不确定性对中国粮食安全具有负向影响。2)分区域看,粮食主产区的供给安全受经济政策不确定性负向影响最大,粮食主销区的获取安全受经济政策不确定性冲击最为明显,经济政策不确定性对粮食产销平衡区的冲击最小。3)从粮食安全衡量维度看,经济政策不确定性对供给安全、获取安全和资源安全具有抑制影响,对稳定性安全呈现正向冲击作用。为确保粮食安全,中国应继续加强对粮食生产政策支持、稳定国内粮食价格和健全保障粮食安全的制度机制。     

气相色谱-串联质谱法测定柑橘中苯醚甲环唑的不确定度评定

[目的] 对气相色谱-串联质谱法测定柑橘中苯醚甲环唑农药残留进行不确定度评定。[方法] 运用气相色谱-串联质谱法对柑橘中苯醚甲环唑残留量进行测定,建立数学模型, 分析测定过程的主要不确定度来源, 对各个分量进行评估。[结果] 测量不确定度主要来源于前处理方法提取和净化产生的回收率差异、标准溶液配制和目标物色谱峰面积测定误差。当苯醚甲环唑的残留量为 0.047 mg/kg 时, 扩展不确定度为 0.003 mg/kg (P=95%, k=2)。[结论] 该方法适用于气相色谱-串联质谱法测定苯醚甲环唑残留量的不确定度分析, 可为农药残留测量结果的准确性提供科学可靠的依据。     

木质生物炭对厌氧发酵产甲烷性能的影响

为研究木质生物炭对厌氧发酵产甲烷性能的影响,以玉米秸秆、牛粪作为发酵底物,以灌木生物炭、杨木生物炭、混合木屑生物炭作为添加剂,通过控制生物炭的种类、粒径以及灰分含量等关键因素,进行了批式厌氧发酵强化试验。结果表明：生物炭对厌氧发酵系统有重要影响,且粒径越小,产气能力越强。其中,杨木生物炭对厌氧发酵系统影响最大,不仅提升了厌氧发酵系统的甲烷累积产量（4.9%）、最大甲烷日产率（15.0%）以及水解速率（15.6%）,也缩短了发酵延滞期。此外,杨木生物炭的灰分含量对厌氧发酵也有重要影响。当灰分含量为2.6 g·L^-1时,对厌氧发酵系统影响最大,在提升厌氧发酵系统的缓冲能力、最大甲烷日产率（14.4%）的同时,也缩短了延滞期（11.8%）,灰分含量过高或过低均不利于系统产甲烷。     

Safe conservation and utilization of peanut germplasm resources in the Oil Crops Middle-term Genebank of China

Peanut(Arachis hypogaea L.)is an important oil and cash crop in the world.Peanut germplasm collected in China are abundant,which provides important material gua...     

南沙群岛重点岛礁潟湖微型浮游动物的群落结构与摄食

潟湖是岛礁生物多样性演变的重要环境场,在岛礁水生态系统的物质循环和能量流动中发挥重要作用,而微型浮游动物的生态功能研究是解析南沙群岛岛礁水域潟湖生态系统初级生产力组成、流向、能量流动效率的重要研究内容之一。实验通过对南沙群岛重点岛礁渚碧礁、美济礁与永暑礁潟湖表层水域中微型浮游动物与生态环境调查,研究了其群落结构及其与环境因子的关系,并通过稀释培养实验研究了微型浮游动物的摄食压力。结果显示,调查水域共发现微型浮游动物20种,总丰度的范围为320～1 460个/L,以无壳纤毛虫丰度最高。无壳纤毛虫在渚碧礁潟湖西部水域（ZB-1）丰度最高,砂壳纤毛虫峰值则出现在永暑礁潟湖中部水域（YS-3）,桡足类幼体丰度最大值出现在美济礁潟湖北部水域（MJ-2）。聚类分析结果显示,3个岛礁潟湖中部区域的微型浮游动物群落相似度较高,溶解氧是影响群落结构的最重要因素,特别是对MJ-3站位影响最为突出。摄食实验结果显示,3个岛礁潟湖水域浮游植物生长率为0.22～1.36 d^-1;微型浮游动物摄食率范围为0.22～0.60 d^-1,微型浮游动物每天约摄食浮游植物现存量的...     

Effects of entrance design on catch efficiency of arabesque greenling traps: a field experiment in Matsumae, Hokkaido

ABSTRACT:   A field experiment was conducted in the Matsumae area of Hokkaido, Japan, during June and July 2002, to investigate the effects of different entrance designs on the catch efficiency of fish traps by fishing with commercial traps (entrance inclination angle [α] = 37°; funnel length of entrance [ L _f ] = 22 cm) and experimental traps. The experimental traps were of the same size and similar design as commercial traps, with different entrance inclination angles (trap E1: α = 46°; E2: α = 27°; E3: α = 0°; all L _f  = 22 cm) or funnel lengths (E4: α = 37°, L _f  = 8 cm). In total, 2200 fish during 200 trap hauls were captured. The catch was significantly higher using both traps E2 and the commercial trap than with trap E3 ( P  < 0.05), and the catch of trap E2 was higher than that of the commercial trap. There were no significant differences in mean fish body length or the frequency distributions of body length among trap types (E1, E2, E3 and commercial). The funnel length of the entrance also affected the catch of traps. Trap E4 had significantly higher catches than the commercial trap ( P  = 0.04) when traps were deployed for a 1-day soak time. Fish body length frequency distributions did not differ between trap E4 and the commercial trap. The results showed that catch can be greatly affected by trap entrance designs.