隐性白肉鸡羽速自别雌雄系的选育(1)

本研究根据现代遗传学基因测交理论,共用32只表型慢羽公鸡与245只快羽母鸡组成测交试验.结果表明,所测的32只公鸡无一只为纯合慢羽基因型.但发现测交后代的快慢羽分布比例与孟德尔遗传上的分离定律完全吻合.同时通过混合精液输精,实施扩群繁育,其中选留慢羽种母雏1460只,表型慢羽种公雏150只,从而为建立隐性白鸡慢羽系奠定了基础.     

北京油鸡胚胎成纤维细胞系建立与生物学特性研究

采取组织块直接培养法，对北京油鸡胚胎组织进行原代和继代培养，成功地建立了成纤维细胞系。并对培养细胞进行了形态学、细胞生长动力学观察，以及核型和乳酸脱氢酶、苹果酸脱氢酶的同工酶分析。结果表明，该细胞系的群体倍增时间(PDT)为24h；细胞染色体中二倍体占主体，为76％～88％；乳酸脱氢酶、苹果酸脱氢酶同工酶电泳图谱与本室其它细胞系有明显差别；细菌、真菌、病毒、支原体检测呈阴性。该细胞系的建立，使北京油鸡这一国家重要种质资源在细胞水平上保存下来，也为基因组文库和体细胞克隆等研究提供了理想的生物材料。     

不同施肥模式对玉米各器官碳氮累积和分配的影响

以长期定位试验为依托,选取:1)不施肥(CK);2)农民习惯施肥(FP);3)推荐施肥(OP);4)有机肥氮替代100%化肥氮(OM);5)有机肥氮替代50%化肥氮(MF)5个处理,研究不同施肥模式对玉米植株及各器官碳氮含量、碳氮分配比例及C/N的影响,为西南紫色土地区合理施肥、作物增产提供科学依据。结果表明,与FP处理相比,MF处理显著增加了玉米植株生物量,达26.2%。相比OM和OP处理,MF处理显著增加玉米苞叶和根茬中碳浓度,分别增加5.4、4.2 g·kg^-1和7.4、21.3 g·kg^-1,同时增加玉米苞叶、根茬、穗轴和籽粒中的碳储量,玉米茎秆和籽粒中的氮储量也有增加。此外,相比FP处理,MF处理能显著增加玉米整株的碳储量和氮储量,达29.1%和16.9%。等氮水平下,MF、OP处理均能增加玉米苞叶和籽粒中碳同化物的分配比例,MF处理玉米籽粒中氮素的分配比例较OP和OM处理分别增加1.7%和3.6%,同时MF处理能使玉米维持较高的C/N。综上,有机肥氮替代50%化肥氮能增加玉米植株的生物量,同时提高玉米对氮素的吸收和碳素的累积,增加玉米籽粒中碳同化物和氮素的分配比例,同时,有机肥氮替代50%化肥氮能使玉米植株维持较高的C/N,有利于产量的形成,该施肥方式不仅能够促进氮素的高效利用,减少化肥的投入,还能够减少化肥损失,降低氮素损失引发的环境风险。     

Fine structure of the canal neuromasts of the lateral line system in the adult zebrafish

The mechanosensory lateral line system of fish is responsible for several functions such as balance, hearing, and orientation in water flow and is formed by neuromast receptor organs distributed on head, trunk and tail. Superficial and canal neuromasts can be distinguished for localization and morphological differences. Several information is present regarding the superficial neuromasts of zebrafish and other teleosts especially during larval and juvenile stages, while not as numerous data are so far available about the ultrastructural characteristics of the canal neuromasts in adult zebrafish. Therefore, the aim of this study was to investigate by transmission electron microscopy the ultrastructural aspects of cells present in the canal neuromasts. Besides the typical cellular aspects of the neuromast, different cellular types of hair cells were observed that could be identified as developing hair cells during the physiological turnover. The knowledge of the observed cellular types of the canal neuromasts and their origin could give a contribution to studies carried out on adult zebrafish used as model in neurological and non‐neurological damages, such as deafness and vestibular disorders.     

Processing traits and digestibility of extruded dog foods with soy protein concentrate

Soya bean protein concentrate (SPC) with two particle sizes were evaluated on extrusion parameters, kibble formation, digestibility and palatability of dog foods. Eight diets were extruded: PBM—control diet based on poultry by‐product meal (PBM); GM—a diet in which corn gluten meal (GM) replaced 45% of the diet protein; cSPC15%, cSPC30% and cSPC45%—diets in which SPC of coarse particle size (600 μm) replaced 15%, 30% and 45% of the diet protein; and sSPC15%, sSPC30% and sSPC45%—diets in which SPC of small particle size (200 μm) replaced 15%, 30% and 45% of the diet protein. The digestibility of nutrients was evaluated for the PBM, GM, cSPC45% and sSPC45% diets, using six dogs per food. The PBM, GM and cSPC45% diets were compared for palatability. Data were submitted for analysis of variance, and the means were compared by polynomial contrasts or Tukey's test (p < .05). The cSPC increased the specific mechanical energy (SME) application, extrusion temperature and pressure linearly, resulting in lower kibble density and higher expansion and starch gelatinization (SG) (p < .01). When comparing the PBM, GM, cSPC45% and sSPC45% diets, higher SME, extrusion temperature and pressure, SG and kibble expansion were verified for the cSPC45% diet (p < .05). The DM, fat and crude protein digestibility were similar among diets. Faecal pH, ammonia and lactate did not differ, demonstrating that the removal of oligosaccharides and soluble non‐starch polysaccharides of SPC produces an ingredient with mostly non‐fermentable fibre. Dogs preferred the PBM to the GM diet (p < .05), but consumed the PBM and cSPC45% foods equally. In conclusion, SPC exhibited good extrusion functionality, favouring kibble expansion and SG, with high digestibility, similar to that of PBM. The removal of soluble compounds from soya beans resulted in an ingredient with low fermentable fibre content, which did not alter faecal formation or characteristics.     

Response of labile organic C and N pools to plastic film removal from semiarid farmland soil

To examine the effects of plastic film removal on grain yield and soil organic matter (SOM), a spring maize (Zea may L.) field experiment was conducted for 5 yr at Changwu Agricultural and Ecological Experimental Station of Northwest China. Compared with traditional plastic film mulching during entire growing stages (FM), plastic film removal at the silking stage (RM) resulted in a 6.3% higher average maize yield. Under the RM treatment, soil organic carbon and total nitrogen significantly increased after the 5‐yr cultivation in the 0‐ to 20‐cm layer. Significant increases in extractable organic C (EOC), KMnO₄‐oxidizable C (KMnO₄‐C) and C management index (CMI) in the 0‐ to 20‐cm layer, and light fraction organic C and EOC in the 20‐ to 40‐cm layer were observed in response to plastic film removal after the 1‐yr treatment; the responses were more significant after 5 yr. Under the RM treatment, significant increases in microbial biomass C, light fraction organic N, extractable organic N, KMnO₄‐C and CMI were also observed after five years in the 20‐ to 40‐cm layer. Moreover, KMnO₄‐C and EOC were much more sensitive than other labile SOM fractions to the application of RM, even after only 1 yr of cultivation. Therefore, compared with mulching for the whole growing season, plastic film removal at the maize silking stage is an effective option for increasing yields and enhancing SOM concentration and soil sustainability in the regions with semiarid monsoon climates that have sufficient rainfall during maize reproductive stages.     

浅谈二种生活用具在棉花自交与杂交中的应用

棉花在栽培过程中,为了获得好性状的棉珠,利用自交与杂交技术进行育种,本文论述小铁夹和吸汽水管方法的精髓及注意事项。     

宁夏玉米营养成分近红外分析模型建立与应用

研究采集宁夏区内各市县(固原、海原、同心、中卫、中宁、永宁、平罗)抽取玉米样品120批,用近红外分析仪扫描定标样品集获得玉米近红外光谱图,利用偏最小二乘法建立模型,并分别经过无预处理、均值中心化、标准正态变量转换、一阶导数、标准正态变量转换结合去趋势校正(SNV+D)预处理光谱,获得水分、粗蛋白、粗脂肪、粗纤维预测模型,分别是经过MC、SNV+D、SNV+D、SNV+D光谱预处理后效果最好。预测决定系数R² _p分别为0.951、0.976、0.728、0.897,相对分析误差RPD除粗脂肪为2.62外,其他均大于3的近红外预测模型,通过预测模型验证集验证后,并对模型预测值与实测值进行U检验,结果为差异不显著(P>0.05)。该近红外预测模型对玉米中水分、粗蛋白、粗纤维具有较佳预测效果,粗脂肪的预测精度有待进一步提高。     

东北地区春玉米临界氮浓度稀释曲线的建立和验证

过量施氮是目前玉米栽培中存在的普遍现象,基于临界氮浓度稀释曲线计算得出的氮营养指数是诊断氮营养丰缺的重要手段。基于东北地区4个生态点的试验数据,构建了东北地区春玉米临界氮稀释曲线,并在此基础上建立了氮营养指数模型和需氮量模型,结果表明,东北地区春玉米地上部临界氮浓度与生物量符合幂函数关系。利用独立试验资料对建立的临界氮浓度稀释曲线进行检验,发现基于临界氮浓度稀释模型计算的氮营养指数可以准确诊断玉米植株的氮营养状况,并计算出实时的氮素需求量。该研究建立的东北地区春玉米临界氮稀释模型可以为该地区春玉米的氮营养诊断和动态调控提供较好的理论和技术指导。     

覆膜滴灌玉米产量和农艺性状相关性分析

为明确在覆膜滴灌条件下玉米品系(种)主要农艺性状与产量的关系,应用DPS软件对15个玉米杂交品系(种)的主要农艺性状和产量性状进行相关性、灰色关联度等分析,结果表明:籽粒重、穗重、产量的变异系数较大;玉米产量与生育期、籽粒水分含量、穗重、籽粒重呈显著正相关关系;聚类分析可将参试的15个品系(种)划分为3类,第Ⅲ类表现良好,值得进行推广种植。灰色关联度分析表明,玉米籽粒重、穗重、生育期、籽粒水分含量等性状是影响玉米产量的主导因素,在玉米高产育种中,应以其为主攻目标,提高玉米后代的有效选择,加速高产育种进程。