陕北黄土高原区日光温室蔬菜产业发展的几点思考

阐述了陕北黄土高原区日光温室蔬菜产业发展的优势和现状,通过深入到陕北蔬菜生产和销售的第一线就其日光温室蔬菜生产等方面的问题进行了调查研究,综合分析陕北黄土高原区日光温室蔬菜产业发展的制约因素。结果认为,主要存在着无公害蔬菜标准化生产和消费的社会意识和氛围不浓,产品质量和生产效益相对较低;蔬菜“优质优价”的市场机制还未建立,蔬菜质量监督检测机构尚未形成;日光温室蔬菜无公害标准化生产的推广服务体系尚未建立,产业化组织机制发育不健全;日光温室蔬菜生产规模小,品牌产品缺乏;农民文化水平偏低等五个方面的制约因素。并就陕北日光温室蔬菜产业可持续发展提出了相应的对策,包括充分发挥气候资源优势,合理规划设施布局;实施品牌战略,推行无公害生产;增强科技意识,提高市场竞争力;科学管理,提高生产水平;加强组织领导,走产业化之路等几个方面。     

Campylobacter jejuni strains of human and chicken origin are invasive in chickens after oral challenge

The aim of the study was to evaluate the colonizing ability and the invasive capacity of selected Campylobacter jejuni strains of importance for the epidemiology of C jejuni in Danish broiler chickens. Four C. jejuni strains were selected for experimental colonization studies in day-old and 14-day-old chickens hatched from specific pathogen free (SPF) eggs. Of the four C. jejuni strains tested, three were Penner heat-stable serotype 2, flaA type 1/1, the most common type found among broilers and human cases in Denmark. The fourth strain was Penner heat-stable serotype 19, which has been shown to be associated with the Guillain Barré Syndrome (GBS) in humans. The minimum dose for establishing colonization in the day-old chickens was approximately 2 cfu, whereas two- to threefold higher doses were required for establishing colonization in the 14-day-old chickens. Two of the C. jejuni strains were shown to be invasive in orally challenged chickens as well as in three different human epithelial cell lines.     

巴西橡胶树HbAPXs基因家族6个成员的染色体物理定位

抗坏血酸过氧化物酶(ascorbate peroxidase,APX)是活性氧清除系统的重要成员之一,会对细胞的结构以及功能产生危害.为了揭示HbAPXs基因家族中的6个成员位于巴西橡胶树的细胞核染色体上的具体位置,展现HbAPXs家族基因6个成员之间的分布情况.本研究采用荧光原位杂交技术(fluorescence in situ hybridization,FISH),对HbAPXs基因家族6个成员(HbAPX1,HbAPX3,HbAPX4,HbAPX5,HbAPX6,HbAPX7)进行了物理定位分析.实验结果表明:HbAPX1定位于4号染色体的短臂,其信号的位点到染色体的着丝粒之间的百分比距离为12.51;而HbAPX3、HbAPX4、HbAPX5、HbAPX6和HbAPX7定位在7、1、2、9和3号染色体上,均为长臂,其基因信号的位点到相对应的染色体的着丝粒之间的百分比距离分别为80.27、24.72、87.19、13.69和57.63,并讨论了其与已完成定位基因之间的位置关系.HbAPXs基因家族中的6个成员互为独立的基因,均分布在不同的染色体上.本研究通过物理定位确定这些基因在染色体上的具体位置和相互关系,可为橡胶树育种及基因组学的研究提供细胞遗传学依据.     

奶牛瘤胃和肠道微生态系统中乳酸菌的种类及益生机理

奶牛瘤胃和肠道中微生态菌群的构成对奶牛的健康具有重要的作用。随着人们对奶牛胃肠道中乳酸菌的分离鉴定及其益生特性的研究,乳酸菌在奶牛健康养殖中的有益作用逐渐引起人们的重视。本文主要对奶牛瘤胃及肠道中乳酸菌种类和益生机理进行总结,旨在为奶牛的健康养殖提供一定的理论基础。     

野生细叶百合组织培养体系的建立

以细叶百合为试材,采用组织培养的方法,研究细叶百合不同部位、不同激素配比及不同发生途径对获得细叶百合再生植株的影响。结果表明:以鳞茎为外植体,通过器官发生途径获得再生植株,其最佳分化及增殖培养基为MS+6-BA 1.0mg/L+NAA 0.1mg/L;以花器官、幼嫩叶片为外植体通过体细胞发生途径获得再生植株,其愈伤组织诱导培养基为MS+2,4-D2.0mg/L+NAA 1.5mg/L,不定芽诱导培养基为MS+6-BA 1.0mg/L+IAA 0.1mg/L,最佳增殖培养基为MS+6-BA 0.5mg/L+NAA 0.1mg/L,生根培养基为1/2MS+NAA 0.1mg/L。     

间歇入渗减渗机理浅析

该文从理论上分析了间歇入渗减渗的内在机理,以大田实测资料验证了致密层形成与发展的客观性,对间歇入渗条件下水力传导度减小的机理进行了分析,可为进行间歇灌溉灌水技术的研究者和用水管理者提供有益的参考。     

区域蒸发量的遥感研究现状及发展趋势

遥感手段是解决区域蒸发量分布问题的重要方法。随着遥感和GIS技术的发展,定量遥感模型从大叶模型发展到两层、多层或多源模型,参数反演是其核心内涵,出现了比较系统的参数反演公式,但在参数反演时一般都需要风速、温度等参数,这些参数用遥感手段比较难以获得,这就限制了定量遥感模型的广泛应用,因此研究仅依靠遥感信息反演地表通量的定量模型是今后定量遥感模型的主要发展趋势。     

Effects of phosphate on trace element accumulation in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.): a 5-year phosphate application study

Purpose

Phosphate (P) fertilizers are being widely used to increase crop yield, especially in P-deficient soils. However, repeated applications of P could influence trace element bioaccumulation in crops. The effects of 5-year P enrichment on trace element (Cu, Zn, Cd, Pb, As, and Hg) accumulation in Oryza sativa L. were thus examined.

Materials and methods

Two paddy soils with different initial P availabilities were amended with and without P fertilizer from 2009 to 2013. Trace elements and P levels in rice and soils were analyzed.

Results and discussion

In soil initially with limited P, P amendment enhanced grain Pb, As, and Hg concentrations by 1.8, 1.5, and 1.4-fold, respectively, but tended to decrease the grain Cd level by 0.73-fold, as compared to the control. However, in soil initially with sufficient P, P amendment tended to reduce accumulation of all examined elements in rice grain.

Conclusions

Phosphate amendment in initially P-limited and P-sufficient soils had different effects on trace element availability in soil (as reflected by extractable element) and plant physiology (growth and metal translocation), resulting in contrasting patterns of trace element accumulation in rice between the two types of soils. Our study emphasized the necessity to consider the promoting effects of P on Pb, As, and Hg accumulation in grain in initial P-deprived soil.

     

旱塬特大干旱年冬小麦肥效的异常性分析

该通过对比分析表明：特大干旱年份，磷肥肥效显，氮肥肥效受抑。与一般年份截然相反。造成这种异常的原因，与氮、磷的生理特性及吸收机理密切相关。     

The effects of road transportation with or without homeopathic remedy supplementation on growth performance,apparent nutrient digestibility,fecal microbiota,and serum cortisol and superoxide dismutase levels in growing pigs

The specialization of swine production and the market demand for pigs at different growth stages makes road transportation inevitable. However, road transportation usually causes a stress response in pigs. It is reported that homeopathic remedies supplementation could alleviate the stress response in pigs. This study investigated the effects of road transportation with or without homeopathic remedy (Convermax) supplementation on growth performance, nutrient digestibility, fecal microbiota, and serum cortisol and superoxide dismutase (SOD) concentrations in growing pigs. A total of 180 crossbred 49-d-old growing pigs [(Yorkshire × Landrace) × Duroc] with an initial body weight of 13.17 ± 0.02 kg were randomly allotted to 2 groups based on the initial body weight, containing 18 replicates with 5 pigs (mixed sex) in each. The pigs were fed dietary supplementation of a homeopathic remedy (Convermax) (0 or 200 mg/kg of feed, as-fed) for 35 d. On day 21, 45 pigs (70-d old; 25.25 ± 0.37 kg) were randomly selected from each group and assigned to either 2 hr of road transportation or no road transportation, resulting in a 2 × 2 factorial design. We found that road transportation led to an increase in the fecal coliform bacteria counts (P = 0.023) and serum cortisol concentration (P = 0.039) and a decrease in the serum SOD concentration (P < 0.001). However, supplementing homeopathic remedy (Convermax) to the diet of growing pigs increased gain to feed ratio (P = 0.042), apparent nitrogen digestibility (P = 0.019), and serum SOD concentration (P = 0.007), whereas decreased serum cortisol concentration (P = 0.022). In brief, road transportation induced stress response for growing pigs and increased harmful bacteria counts in their intestines. Dietary supplementation of homeopathic remedy (Convermax) alleviated stress response, improved apparent nitrogen digestibility, and increased gain to feed ratio. However, no significant interactive effects between road transportation with or without dietary homeopathic remedy (Convermax) levels were observed on the detected parameters in growing pigs.