半垄式根域限制栽培在南方设施葡萄上的应用

针对南方地下水位高、土壤板结等原因造成的设施栽培葡萄果实品质不佳问题,对“藤稔”、“巨峰”、“夏黑”和“金手指”4个葡萄品种进行半垄式根城限制栽培试验研究.结果表明:利用地表以下15～20 cm板结的高容重土壤代替人工制品作为自然隔离带,能起到很好的根城限制作用,提高了4种葡萄果实的糖酸比,改善了果实的内在品质;提高了“藤稔”、“巨峰”和“夏黑”的花青苷和总酚含量,从而改善了其外观和营养品质;根域限制栽培降低了“藤稔”葡萄的单粒果实质量,但对其余3种葡萄影响不显著.该试验结果对南方葡萄设施栽培技术的提升具有积极意义.     

限根栽培对番茄生长和品质的影响

以番茄(Lycopersicon esculentum)粉果E756为试验材料,采用不同栽培体积及基质,研究限根栽培对粉果E756生长和品质的影响。结果表明,随着限根体积的减小,粉果E756株高、茎粗及叶面积差异明显,处理组的株高、茎粗明显低于对照组,同时,粉果E756植株的光合能力下降,产量降低,但番茄果实的品质有所改善,与对照相比,栽培体积为0.3 m×0.3 m×36 m的种植方式,总糖含量高1.27个百分点,VC含量高4.72 mg/kg,可溶性固形物含量高0.63个百分点。     

Phosphate Solubilizing Ability and Phylogenetic Diversity of Bacteria from P-Rich Soils Around Dianchi Lake Drainage Area of China

The phylogenetic diversity of phosphate solubilizing bacteria(PSB)distributed in P-rich soils in the Dianchi Lake drainage area of China was characterized,and the tricalcium phosphate(TCP)solubilizing activities of isolated PSB were determined.Among 1 328 bacteria isolated from 100 P-rich soil samples,377 isolates(28.39%of the total)that exhibited TCP solubilization activity were taken as PSB.These PSB showed different abilities to solubilize TCP,with the concentrations of solubilized P in bacterial cultures varying from 33.48 to 69.63 mg L^-1.A total of 123 PSB isolates,with relatively high TCP solubilization activity(>54.00 mg L^-1),were submitted for restriction fragment length polymorphism(RFLP)analysis,which revealed 32 unique RFLP patterns.Based on these patterns,62 representative isolates,one to three from each RFLP pattern,were seffected for 16S rRNA sequencing.Phylogenetic analysis placed the 123 PSB into three bacterial phyla,namely Proteobacteria,Actinobacteria and Firmicutes.Members of Proteobacteria were the dominant PSB,where 107 isolates represented by 26 RFLP patterns were associated with the genera of Burkholderia,Pseudomonas,Acinetobacter,Enterobacter,Pantoea,Serratia,Klebsiella,Leclercia,Raoultella and Cedecea.Firmicutes were the subdominant group,in which 13 isolates were affiliated with the genera of Bacillus and Brevibacterium.The remaining 3 isolates were identified as three species of the genus Arthrobacter.This research extends the knowledge on PSB in P-rich soils and broadens the spectrum of PSB for the development of environmentally friendly biophosphate fertilizers.     

Water intake in domestic rabbits (Oryctolagus cuniculus) from open dishes and nipple drinkers under different water and feeding regimes

Rabbits (Oryctolagus cuniculus) are often presented suffering from urolithiasis. A high water intake is important in the prophylaxis of uroliths. We investigated the influence factors for water intake using 12 rabbits subjected to different feed and water regimes with practical relevance: Hay, fresh parsley, a seed mix and two different pelleted feed were offered in diverse combinations. Water was provided either by open dish or nipple drinker. Water was accessible ad libitum except for four treatments with 6 h or 12 h water access. Under the different feeding regimes, the drinker had no influence on water intake, but faecal dry matter content was significantly higher with nipple drinkers [60.0 ± 2.1 vs. 57.2 ± 2.1% of wet weight (mean ± 95% confidence interval), p = 0.003]. Dry food led to a higher drinking water intake but total water intake was still lower than with addition of 'fresh' food. With restricted water access, rabbits exhibited a significantly higher water intake with open dishes compared with nipple drinkers (54.9 ± 9.8 vs. 48.1 ± 8.2 g/kg(0.75) /day (mean ± 95% confidence interval), p = 0.04). High proportions of fresh parsley or hay in the diet enhanced total water intake and urine output, and led to lower urinary dry matter content and lower urinary calcium concentrations. Restricted access to drinkers led to a decreased total daily water intake and increased dry matter content of urine and faeces. For optimal water provision and urolith prophylaxis, we recommend a diet with a high 'fresh food' proportion as well as additionally hay ad libitum with free water access, offered in an open bowl.     

Imprecision when using measuring cups to weigh out extruded dry kibbled food

Many pet cats and dogs are fed dry extruded kibbled food by measuring cup, yet the precision and accuracy of this feeding strategy is not known. Over 12 studies, we assessed precision and accuracy of weighing out food portions, of various dry kibbled foods, by measuring cup. Poor precision was noted in all studies, with intra- and inter-subject coefficients of variation ranging from 2 to 13% and 2 to 28% respectively. Variable accuracy was also noted, which ranged from an 18% under-estimate to an 80% over-estimate in portion size. No specific factors were associated with imprecision, but the degree of inaccuracy was negatively associated with portion size (R = -0.67, p = 0.022), and positively associated with the number of subjects participating in the study (R = 0.60, p = 0.048). This is the first study to document imprecision and inaccuracy of using measuring cups to estimate portions of extruded dry kibbled food. Over time, such errors could contribute to insidious weight gain in companion animals, potentially contributing to the development of obesity. Imprecision in measuring food portions could also contribute to failure of weight management programmes for obese animals.     

中国部分地区绵羊肺炎支原体的基因多态性分析

为了解绵羊肺炎支原体(Mycoplasma ovi pneumoniae,Mo)在我国部分地区的流行病学特征,采用随机扩增多态性DNA(RAPD)及限制性片段长度多态性(RFLP)方法对26株Mo基因多态性进行了研究,并利用NTsys2.10e软件对获得的多态性图谱进行了聚类分析.结果在相似系数为0.70时,26株Mo可分成6个RAPD群或6个RFLP群;相似系数为0.90时,分成18个RAPD群或18个RFLP群;相似系数为1.00时,分成25个RAPD群或26个RFLP群.结果表明,我国Mo存在高度的基因多态性,这种多态性与地域差异相关,与宿主来源也具有一定的相关性.研究结果为了解我国Mo的分子流行病学特征打下了基础,也为建立有效的Mo诊断方法和疫苗研制提供了参考依据.     

限饲对绒山羊生长性能和屠宰性能的影响

本研究通过饲养试验与屠宰试验来探讨限饲对绒山羊生产性能和屠宰性能的影响。将20只育成羊随机分成4组,即分别为自由采食组(AL)及自由采食组采食量的90%(IR90%)、80%(IR80%)和70%(IR70%)。正式试验期为90 d。结果表明:AL的日增重比IR90%组I、R80%组显著高出91.21%和194.92%(P<0.05),但IR90%和IR80%之间无显著差异(P>0.05),另外IR70%组的日增重为-6.3 g/d。宰前活体重、空体重、胴体重和屠宰率随着营养水平的降低有所减少(P<0.05)。随着营养水平的降低,肾周脂肪、系网膜脂肪占空体重的比例显著减少(P<0.05)。随着限饲强度的增加,日增重逐渐下降,体内脂肪沉积也随之减少。综合分析显示,绒山羊的限饲的阈值为IR80%。     

我国西北地区的水资源约束与农业结构的战略性调整

在分析我国西北地区农业发展制约因素的基础上，充分考虑西部大开发中的生态建设的宏观目标，结合西北地区农业水环境的特点和我国进入WTO的大背景，提出西北农业结构战略性调整的基本思路与对策措施。     

牛场肥水灌溉对土壤氨氧化微生物的影响

以不同牛场肥水灌溉制度下河北省徐水县梁家营长期定位施肥试验田为研究对象,通过构建氨氧化细菌和氨氧化古菌的amoA 基因克隆文库,利用T-RFLP方法研究了5种施肥处理(CK:不施肥;CF:300 kg N·hm^-2,120 kg P₂O·hm^-2,75 kg K₂O·hm^-2;T4:105 kg N·hm^-2,39 kg P₂O₅·hm^-2;T5:210 kg N·hm^-2,78 kg P₂O₅·hm^-2; T11:317 kg N·hm^-2,117 kg P₂O₅·hm^-2)下土壤中氨氧化细菌及氨氧化古菌的多样性及其群落结构演变。氨氧化细菌T-RFLP结果显示,T5 处理土壤中氨氧化细菌的 Shannon-Wiener指数(H')和 Pielou指数(E)均最高, T11处理最低,表明T5处理增加了土壤中氨氧化细菌的多样性和丰富度,T11处理一定程度上降低了氨氧化细菌的多样性和丰富度。基于amoA基因建立的系统进化树显示,土壤中氨氧化细菌主要属于Nitrosospira 和Nitrosomanas。氨氧化古菌T-RFLP结果显示,T11处理氨氧化古菌Shannon-Wiener指数(H')、Simpson 指数(Ds)和Pielou指数(E)均最高,表明T11处理增加了土壤中氨氧化古菌的多样性和丰富度。氨氧化古菌的系统发育树显示大部分氨氧化古菌amoA序列与 Cluster S 聚为一类,且占主导地位,少数序列为Unclassified-Archaea(未分类古菌)。最大优势菌与来自中国荷斯坦奶牛瘤胃样品的氨氧化古菌Clone属于同种,推测牛场肥水灌溉增加了土壤的氨氧化古菌的群落多样性。     

Resistance of bacterial communities in the potato rhizosphere to disturbance and its application to agroecology

Soil bacteria have the ability to increase agricultural sustainability through the production of biopesticides and biofertilizers. Application of bacteria to field crops often results in sporadic colonization and unpredictable crop performance. This research sought to understand the colonization of the potato (Solanum tuberosum L.) rhizosphere using reciprocal transplants. Plants were grown in a forest or an agricultural soil and then transplanted into either the same soil or the opposite soil. Bacterial communities were profiled using terminal restriction fragment length polymorphism (TRFLP) and analyzed using pairwise comparisons. The results revealed that the bacterial community that colonized the rhizosphere in the first soil remained mostly intact for 30 days after the plants were transplanted into another soil in which the soil bacteria community differed from that found in the original soil. The concept that it may be possible to establish a functional microbiota and to deliver it to an agricultural environment was tested. A nitrogen-fixing bacterial community was established on plants grown under tissue culture conditions and the plants were transplanted into a field soil. Plants inoculated with eight separate nitrogen-fixing communities showed an average fivefold increase in dry biomass when compared to mock-inoculated plants and the microbial profiles remained distinct at 30 days after transplantation. These results demonstrate that the plant rhizosphere is a resistant community and that the first bacterial community that becomes established on the root remains with the plant even when the plant is placed into soil with a vastly different microbiota.