饲用酸化剂中甲酸、乙酸、丙酸、乳酸、柠檬酸的同步测定

实验建立利用高效液相色谱同时测定饲用酸化剂中甲酸、乙酸、丙酸、乳酸、柠檬酸含量的方法。采用Grom-Sil org acid柱(250 mm×2.1 mm,5μm)进行分析。流动相为pH值2.5磷酸水溶液;流速为1.0 ml/min;检测波长为210 nm;柱温为30℃。在此色谱条件下,5种有机酸分离良好。平均回收率均大于85%,RSD小于10.0%。对实际样品的检测结果表明:该方法操作简便易行,准确可靠。     

锦园、锦花黄桃的引种表现及栽培技术要点

2012年从上海市农业科学院林木果树研究所引进锦园、锦花两个黄桃品种苗木至泰安试栽。经多年栽培观察,两个品种树体健壮,果肉黄色,汁液多,口感甜,综合品质优良,经济价值高,适于泰安及周边地区推广,简述了栽培技术要点。     

Effect of subcutaneously administered diclazuril on the output of Eimeria species oocysts by experimentally infected rabbits

The effect of subcutaneously injected diclazuril on the output of Eimeria species oocysts was studied in experimentally infected rabbits. Diclazuril was administered either prophylactically at 0.5, 1 or 2 mg/kg bodyweight two days before each rabbit was inoculated with 20,000 oocysts of a mixed-species field isolate of Eimeria or therapeutically at 1, 2 or 4 mg/kg bodyweight five days after they were inoculated. The prophylactic treatments significantly reduced (P<0.05) the output of oocysts in faeces and the numbers in the rabbits' livers at all doses. The therapeutic treatment at 4 mg/kg also caused a significant reduction (P<0.05) in oocyst shedding, but the lower doses resulted in only a moderate reduction. The shedding of the pathogenic species Eimeria stiedae, Eimeria magna, Eimeria irresidua, Eimeria flavescens, Eimeria piriformis and Eimeria intestinalis was significantly reduced (P<0.05) in all the treated groups. The burden of oocysts in the livers of the therapeutic groups (4000 to 9000) were significantly lower (P<0.05) than in the inoculated but untreated control group (23,000), but higher than in the prophylactic groups (around 1000).     

Efficacy of decoquinate against drug sensitive laboratory strains of Eimeria tenella and field isolates of Eimeria spp. in broiler chickens in China

The efficacy of decoquinate against Eimeria infections in broiler chickens was evaluated using two drug sensitive laboratory strains of Eimeria tenella and 20 field isolates of Eimeria spp. collected from farms in China where various anticoccidials (including maduramicin) had been used. Decoquinate (20-40 ppm in feed) and maduramicin (5 ppm) were efficacious against E. tenella laboratory strains, but decoquinate more so than maduramicin. Body weight gains of E. tenella infected chickens were significantly improved, and caecal lesions were prevented, by feeding either decoquinate or maduramicin. Decoquinate also prevented oocyst production, but maduramicin did not. Most (18/20) Eimeria field isolates were resistant to maduramicin, judged by oocyst production; decoquinate at > or =20 ppm completely controlled all 20 field isolates. Decoquinate has potential value as a broiler anticoccidial in China and other countries where it has not been previously used.     

兔非特异性免疫力抗长角血蜱幼虫感染能力的研究

本实验以卡介苗作为免疫增强剂和以地塞米松与雷公藤擦剂作为免疫抑制剂,以此改变兔非特异性免疫功能,观察免疫力不同的动物抗长角血蜱幼虫感染的能力.结果发现非特异性免疫增强组兔对蜱抵抗力较强,而非特异性免疫抑制组相对较弱,提示在蜱活动季节灭蜱时,应该考虑动物体况,加强动物营养,对种用动物以免疫增强剂进行接种,减少疾病的发生。蜱作为多种病原体的生物性媒介和自身作为病原体对人和动物危害严重。通常采用的灭蜱措施主要有药物防治、生物防治等,但对不同体况动物自身抗蜱能力的研究尚缺,本实验对此进行了研究。     

盐胁迫对牧草种子萌发及其恢复的影响

观察了７种牧草种子在８个ＮａＣｌ浓度;０（０Ｍｐａ）,２１－９－０．１Ｍｐａ）,６６（－０．３Ｍｐａ）,１１ｐ（－０．５Ｍｐａ）,１５０（－０．７０Ｍｐａ）,２００（－０．９Ｍｐａ）,２６７（－１．２Ｍｐａ）,３３４（－１．９５Ｍｐａ）,４４５（－２．６０３Ｍｐａ）ｍｍｏｌ／Ｌ下的发芽率及胚根和胚芽的生长,将盐胁迫下未萌发种子移入营养液中,观测它们在解除发芽率呈下降趋势,但长穗偃麦草的发芽率几乎不     

基于虚拟仪器技术的温室监控系统

利用LabVIEW开发平台设计了基于虚拟仪器的温室监控系统,其基本思想是将传统的硬件仪器监控系统通过虚拟仪器技术来实现。为此,介绍了温室监控系统的组成及工作原理。该系统可完成温室内的温度、湿度、光照和CO2等参数的采集。通过监视温室历史与实时环境参数,对温室环境的调节进行必要的人为控制,实现温室环境参数优化管理。该系统具有分析效果好、投入成本低和功能易扩展等优点。     

Relationships between soil macroaggregation and humic carbon in a sandy loam soil following conservation tillage

Purpose

Humic substances are recalcitrant and might act as persistent binding agents to form macroaggregates. The focus of this study is in investigating the contribution of humic carbon (HC) to soil aggregation in response to various tillage and residue managements.

Materials and methods

Arable soils following 8-year contrasting managements were collected to determine aggregate size distribution and stability and HC fractions including humic acid (HA) and fulvic acid (FA). The contribution of HC to aggregation was divided into three special effects including positive effect (PE), negative effect (NE), and combined effect (CE), and these effects were measured using aggregate fractionation techniques.

Results and discussion

As well as to promote structural stability, HC bounds predominantly with the silt + clay fraction and secondarily with microaggregates to form larger aggregates. The PE increased with increasing aggregate size, whereas the NE followed the opposite pattern. A positive CE was observed for large and small macroaggregates, whereas the CE for microaggregates and the silt + clay fraction was negative. Compared to continuous tillage, reduced- and no-tillage decreased the PE for large and small macroaggregates by 1.58–30.98% at the 0–20 cm depth, and straw returning also slightly decreased the corresponding PE relative to straw removing. By contrast, a significantly higher NE for small macroaggregates at the 0–10 cm depth while 6.33–81.11% decreases in CE for large and small macroaggregates at the 0–10 cm depth as well as for large macroaggregates at the 10–20 cm depth, were observed under reduced- and no-tillage. The extraction of HC significantly reduced the aggregate stability and reduced- and no-tillage effectively limited its decrease magnitude. Small macroaggregates and microaggregates made larger contributions to soil HC accumulation than did other fractions. An averagely increased contribution from large or small macroaggregates was observed under both reduced-/no-tillage and straw returning at the 0–20 cm depth. A significant and positive relationship was found between the mass proportion of macroaggregates and the HC accumulation in 0–20 cm soil. Large macroaggregates had significantly higher HA/FA ratios than small macroaggregates, and reduced- and no-tillage significantly increased these ratios both in large and in small macroaggregates. The CE for large or small macroaggregates was also significantly negatively correlated with their HA/FA ratios.

Conclusions

Overall, the HC accumulation in soil is likely to play a key role in macroaggregation, but conservation tillage might decrease the contribution magnitude of HC to large or small macroaggregation through increasing the corresponding HA/FA ratios.

     

水稻矮秆多分蘖突变体mz3的遗传分析和基因定位

通过EMS诱变粳稻品种中花11获得一个稳定遗传的矮秆多分蘖突变体mz3。遗传分析表明该突变性状受一对隐性基因控制,并利用mz3与籼稻品种南京11杂交建立的F2群体,将该基因定位在水稻第6染色体长臂上的SSR标记RM19353与RM510之间约747kb范围内。由于该区间包含控制水稻株高和分蘖的D3基因,结合表型分析,推测突变基因与D3可能为一对等位基因。设计7对引物分别对中花11与突变体mz3的基因进行测序,结果显示,与中花11相比,D3基因在mz3中第636位核苷酸由G突变为A,使得编码色氨酸的密码子TGG突变为终止密码子TGA,导致翻译提前终止。进一步对定位群体中10个隐性极端个体测序,结果显示所有极端个体都带有该突变位点。亚细胞定位结果表明,突变体编码的D3蛋白与野生型一样定位在细胞核中,荧光双分子互补试验结果表明,突变体D3蛋白不能与D14蛋白发生互作,推测突变体编码的D3截短蛋白缺少了与D14互作的氨基酸序列,从而阻碍了独脚金内酯信号传递。因此,mz3表型很可能由D3基因突变引起。     

Simulating in situ ammonia volatilization losses in the North China Plain using a dynamic soil‐crop model

Ammonia (NH₃) volatilization is an important N loss pathway in intensive agriculture of the North China Plain (NCP). Simulation models can help to assess complex N and water processes of agricultural soil–crop systems. Four variations (Var) of a sub‐module for the deterministic, process‐based HERMES model were implemented ranging from simple empirical functions (Var 3 and 4) to process‐oriented approaches (Var 1 and 2) including the main processes of NH₃ volatilization, urea hydrolysis, nitrification from ammonium‐based N fertilizer, and changes in soil solution pH. Ammonia volatilization, plant growth, and changes in ammonium and nitrate pools in the soil over several winter wheat–summer maize double‐crop rotations at three locations in the NCP were simulated. Results were calibrated with two data sets (Dongbeiwang 1, Shunyi) and validated using two data sets (Dongbeiwang 2, Quzhou). They showed that the ammonia volatilization sub‐module of the HERMES model worked well under the climatic and soil conditions of N China. Although the simpler equations, Var 3 and 4, showed lower deviations to observed volatilization across all sites and treatments with a mean absolute error (MAE) of 1.8 and 1.4 in % of applied N, respectively, compared to process‐oriented approaches, Var 1 and 2, with a MAE of 2.2 and 1.9 in % of applied N, respectively. Environmental conditions were reflected better by the process‐oriented approaches. Generally, simulation results were satisfying but simulated changes in topsoil pH need further verification with measurements.