基于高分三号卫星数据与Η/Α/α-分解特征参数的农作物分类研究

利用高分三号(GF-3)卫星的全极化C波段多极化合成孔径雷达数据,基于Η/Α/ \stackrel{-}{\alpha }极化分解提取香农熵(SE)及其强度分量(SE_I)和极化分量(SE_P)、单次反射特征值相对差异度(SERD)、二次反射特征值相对差异度(DERD)、极化比(PF)、基准高度(PH)、极化不对称性(PA)和雷达植被指数(RVI)共9个特征参数,将其应用于农作物分类研究中,以支持向量机(SVM)和随机森林(RF)算法为例,初步探索了基于Η/Α/ \stackrel{-}{\alpha }分解提取的这9个特征参数在GF-3数据支持下的农作物分类潜力。结果显示:单独将SERD、PH、PF、RVI和SE_P参数用于2种分类方法时,分类精度较高,在82%~92%;但单独运用PA、DERD、SE和SE_I的分类精度均低于80%。将分类精度较低的4个参数组合后,分类精度明显提高,在SVM和RF下的总体分类精度分别达到93.02%和92.05%,Kappa系数均大于0.8。结果表明,基于全极化GF-3数据和Η/Α/ \stackrel{-}{\alpha }极化分解方法提取的9个特征参数,能很好地表征农作物的散射特征,可用于农作物分类研究。     

芝麻栽培种与野生种(Sesamum indicatum)杂种F_1的获得及特性鉴定

【目的】通过远缘杂交获得芝麻栽培种与野生种的杂交后代,改良芝麻栽培种对茎点枯病的抗性。【方法】对野芝3号(S.indicatum)(P_3)和芝麻栽培种中芝14(P_1)、中芝14同源四倍体(P_2)进行正反种间杂交,通过幼胚培养技术获得杂种F1植株。首先利用SSR分子标记、细胞学、形态学方法进行后代真实性鉴定,筛选出真杂种。后对种间杂交的3个亲本(野芝3号、中芝14及其同源四倍体)以及杂种后代F1株系进行茎点枯病人工接种鉴定。【结果】种间正反交组合后代的幼胚成苗率有明显差异,在接种的773个幼胚中,有155个幼胚发育成苗,平均幼胚成苗率为20.05%。种间正交组合(P_3×P_1、P_3×P_2分别为32.75%和21.11%),高于反交组合(P_1×P_3、P_2×P_3分别为8.84%和13.41%)。说明亲本的基因型在很大程度上影响远缘杂交的成苗率。P_3×P_1、P_1×P_3组合F1植株染色体数目为42条;P_3×P_2、P_2×P_3组合F1染色体数目为55条,正反交杂种F1株系大部分花粉粒形态独特,形状规则但多无内含物,为高度不育类型;部分F1株系有少量的可育花粉,为部分不育型。选用多态性较好的HS142引物在亲本中芝14中能清晰的扩增出2条特异性条带(约460和500 bp),在野芝3号则扩增出1条特异性条带(约380 bp)。然后对12个后代进行鉴定,其中有10个杂种F1植株同时具有3条父、母本特异条带,另2株仅出现母本或父本带为假杂种。以高抗种质野芝3号为母本的种间杂交P_3×P_1、P_3×P_2后代染病的病斑长度分别为9.35和6.65 cm,反交组合后代的病斑长度分别为9.90和8.90 cm;所有杂交组合的后代对茎点枯病抗性均高于其栽培种亲本(P_1 14.30 cm和P_2 11.46 cm),但低于野生种亲本(P_3 4.80 cm)。【结论】通过种间杂交结合幼胚培养可以筛选出茎点枯病抗性明显高于芝麻栽培亲本的新种质。     

Identifying Potential Within-Field Management Zones from Cotton-Yield Estimates

Remotely-sensed cotton yield estimates, collected mid-season over the past 11 years, were investigated to identify the degree of temporal stability exhibited in two irrigated fields on Colly Central farm, Collarenabri, NSW, Australia. In particular, the aims of the investigation were: (1) to develop stable yield zones from multi-year yield estimates derived from 11 consecutive years' mid-season Landsat TM imagery; (2) to discover the number of consecutive years of yield estimates required to give similar stable estimates of yield zones to those derived from all 11 years of available data. Results of the investigation indicate that the fields described in the study exhibit a strong degree of temporal stability. Additionally, where an assumption is made that 11 years worth of yield estimates will cluster to generate the most temporally stable regions of similarity, the mapping of clusters generated using 5 or more years will generate comparable regions of similarity with high confidence that the regions will indeed closely match those of the temporally stable 11 year estimates.     

转LOS5玉米的大田抗旱性鉴定

【目的】培育转基因抗旱玉米新品种是解决玉米生产问题的重要途径。通过鉴定和分析拟南芥LOS5转入玉米后对玉米田间抗旱性的影响,筛选抗旱性突出的转LOS5的玉米株系用于抗旱育种。【方法】在150、225、300、375、450和600 mm(CK)梯度灌水胁迫处理条件下,大田鉴定8个转LOS5玉米株系及其受体郑58的抗旱性,测定产量和其他农艺性状的变化,明确LOS5在提高玉米抗旱性方面的主要田间表现形式,同时筛选抗旱性显著优于受体的转基因株系。【结果】随着累计灌水量600—150 mm逐渐降低,9个试验材料的产量和抗旱性均相应下降。8个转基因玉米株系的产量在225—450 mm灌水范围内均显著高于受体郑58,且在正常灌水600 mm的一半处理(300 mm)时差异最大化。300 mm灌水处理中,8个转基因株系的抗旱性指数为0.56—0.70,显著高于受体郑58(0.5),抗旱性提高12%—40%。抗旱性从强到弱的材料顺序是T8920B6、T8920B2、T8920B7、T8920B5、T8020B1、T8920B4、T8920B3、T8920B8和受体郑58。营养体生长和发育方面,在灌水150—225 mm处理中,8个转基因材料灌浆末期的叶色SPAD值38.4—42.4,均极显著高于受体郑58(28.7—37.5),但地上部生物重量、株高和穗位高没有显著差异;果穗发育方面,在灌水150—225 mm处理中,8个转基因株系的穗重为42.3—61.6 g,穗长为10.9—13.1 cm,均极显著高于受体(36.4—40.7 g和8.5—11.8 cm),但轴重和穗粗的差异不显著;籽粒发育方面,8个转基因株系的穗粒数为86.6—182.6,行粒数为8.4—15.6,也显著高于受体的穗粒数57.3—83.2和行粒数4.9—7.1,但穗行数和百粒重差异不显著。【结论】LOS5转入受体郑58后,对转基因玉米开花前营养生长的影响较小,但在开花之后维持受旱玉米的穗长、行粒数和灌浆后期叶色等方面发挥了积极作用,使受旱玉米的穗重、穗粒数和产量保持在相对较高的水平,从而提高了玉米的抗旱性;LOS5转基因玉米株系的抗旱性均高于受体郑58,但抗旱性提高程度有显著差异,对不同转化株系进行大田抗旱性鉴定和筛选是十分必要的;正常灌水量一半的胁迫强度能最大化玉米抗旱性的差异,有利于鉴定和筛选出有利用价值的转基因材料。     

Genetic Diversity of <Emphasis Type="Italic">E. coli O157:H7</Emphasis> Isolated from Some Leafy Greens,Irrigated by Aleppo River,Using Random Amplified Polymorphic DNA (RAPD) Marker

In recent years, fresh fruits and vegetables have been linked to numerous foodborne illness outbreaks in different regions of the world. In Syria, there is not a lot of research that study E. coli and its serotypes by PCR technology. In this study, we have fulfilled a total count of bacteria, the census total coliform group, and Escherichia coli, as well as the serotype E. coli O157:H7 on some leafy greens (Spinacia oleracea, Beta vulgaris) irrigated by Aleppo River. The molecular characterization was done for ten strains of E. coli isolated from collected samples. The samples were inoculated on blood agar and suspicious colonies, then transferred to EMB and MacConkey agar using a primer (COL 1) in RAPD technic. Molecular characterization also performed ten strains of serotype E. coli O157:H7 isolated in medium (Sorbitol-MacCONKEY Agar), then by primers (OPA-03, OPA-13 OPC-12, OPE-20) in RAPD technic. The results showed significant differences between collected samples. The total count of bacteria in the first site (Handarat) for spinach and chard were the lowest, but in the fourth site (Jezraya) it was the highest among all samples. The results showed also the existence of E. coli in all sites except the first one in riverbed Handarat, and E. coli O157:H7 was found only in Jezraya village. Extracted DNA from samples was amplified by RAPD. after electrophoresis in the gel agarose, eleven different bands were detected from isolated strains of E. coli. These results refer to the great genetic diversity of Escherichia coli. For serotype E. coli O157:H7 thirty-four different bands were detected. RAPD analysis had the high discriminatory capacity for typing E. coli isolates. Because of its simplicity and rapidity, RAPD analysis appears to be a highly valuable tool for studying E. coli molecular epidemiology.     

油菜抗倒伏测试风洞关键部件仿真与试验

为解决现有油菜抗倒伏品种选育周期长、难度大等问题，依托计算流体力学软件Fluent建立油菜抗倒伏测试风洞模型，对风洞扩散段、稳定段、收缩段等关键部位进行参数设计及仿真试验，分析该模型对风洞流场品质的影响，最终通过正交试验选择最佳设计方案。结果显示，单因素试验中，收缩段长度Lc增加，风洞出口风速变异系数增加，气流品质下降；随稳定段长度Lw增加，风洞出口风速变异系数先减小后增加，稳定段长度1 000 mm时，风速变异系数最低，气流品质最佳；阻尼网距稳定段出口长度增加，风洞出口风速变异系数先降低后增加，阻尼网距稳定段出口0.65Lw时，风速变异系数最小。正交试验结果显示，收缩段长度600 mm、稳定段800 mm、阻尼网距风洞出口0.65Lw时，对应风洞试验区风速平均变异系数为0.139，风速较其他方案更稳定，气流品质最佳。实测验证发现，与仿真结果相比，实测风速大小无明显差别，且实测结果中各截面风速变异系数略优于仿真值，整体仿真结果与实测效果拟合较好。     

稻粒黑粉病病株田间格局及抽样技术研究

采用聚集度指数（Ｉ、Ｃ、Ｍ＾＊、ＣＡ、Ｋ、Ｉδ）和Ｉｗａｏ及Ｔａｙｌｏｒ法,研究了稻粒黑粉病病株在稻田的空间分布型。结果表明,稻粒黑粉病病株在稻田的空间分布型呈聚集分布。在此分布型的基础上,通过调查病株密度,比较了平行线、单对角线、棋盘式及“Ｚ”字型抽样法,最后肯定平行线抽样法最好。理论抽样数量通过Ｉｗａｏ法计算公式得出不同发病率（Ｘ）所需最大的抽样稻丛数为：ｎ＝３．４６／Ｘ＋０．７１。     

增氧水输入对壤土土壤氮的影响

【目的】研究不同溶解氧含量的增氧水对壤土土壤矿化作用和硝化作用的影响,分析增氧水输入提高土壤的供氮能力的作用机制。【方法】以壤土为供试土壤,采用室内土壤培养方法,选取常规水(RCK)、自然空气供氧曝气增氧(RD₁)、33％增氧供氧曝气增氧(RD₂)和90％增氧供氧曝气增氧(RD₃)4个不同浓度增氧水输入,测定不同培养时间下不同浓度增氧水输入下壤土土壤的 {\mathrm{NH}}_{\mathrm{４}}^{＋}-N和 {\mathrm{NO}}_{\mathrm{３}}^{-}-N含量,计算土壤净氮矿化量、净氮矿化速率、硝化率和硝化速率以及拟合各处理条件下土壤 {\mathrm{NH}}_{\mathrm{４}}^{＋}-N含量与培养时间t的回归公式以及模型特征值,分析不同处理的输入效果。【结果】与达到最大消耗速率所用时间的变化趋势相反,4个不同处理中初始消耗速率V₀和最大消耗速率V_max的趋势变化均为RCK123,初始消耗速率V₀的最大值(8.950 1 mg／(kg・d)),最大消耗速率V_max的最大值(13.019 8 mg／(kg・d))和达到最大消耗速率所用时间T_Vmax的最小值(1.502 1 d)均是RD₃处理;相同增氧浓度条件下,壤土土壤净氮矿化量和硝化率随时间的增加呈现上升趋势,而壤土土壤净氮矿化速率和净硝化速率随时间的增加呈现下降趋势;在同一培养时间时期下,壤土土壤净氮矿化量、净氮矿化速率、硝化率以及净硝化速率的变化趋势均呈RCK123处理的关系。【结论】增加输入水氧浓度会加速壤土氮素转化,增强土壤的矿化作用和硝化作用,改善土壤微生物的活动及矿物质的转化,提高土壤的供氮能力。     

Water rights, gender, and poverty alleviation. Inclusion and exclusion of women and men smallholders in public irrigation infrastructure development

Governmental and non-governmentalagencies worldwide have devoted considerablefinancial, technical, and organizational efforts toconstruct or rehabilitate irrigation infrastructure inthe last three decades. Although rural povertyalleviation was often one of their aims, evidenceshows that rights to irrigated land and water wererarely vested in poor men, and even less in poorwomen. In spite of the strong role of irrigationagencies in vesting rights to irrigated land and waterin some people and not in others, the importance ofagencies targeting practices is still ignored.This article disentangles how public irrigationagencies either included or excluded women and mensmallholders as right holders to irrigated land andwater. This is done on the basis of significant casestudies from Africa, Asia, and Latin America thatpoint in both positive and negative directions. Thegeneral conclusions are the following. Rights toirrigated land are related to the site-selection andphysical design of land-bound irrigationinfrastructure. These rights are vested in the pooreither by implementing a localized land reform or bydirectly selecting poor peoples land forimprovement. Among all potential land users in aselected site, water rights have to be defined. Thepoor are included as title holders if water rights arevested in land users rather than land owners, and inboth women and men, rather than in male householdheads. A common condition to get water rights is thatone has to participate in construction investments.Agencies need, firstly, to open up this condition forthe poor, also for women, and, secondly, ensure thatpoor peoples investments are linked to rights.Parallel to vesting land and water rights, externalagencies influence the composition of the local forumsin which decisions on land and water rights arerefined, endorsed, and implemented, and they influencethe order in which project activities are planned andundertaken. Early inclusion of the poor in theseforums and crystallization of expropriation andallocation criteria and procedures before constructionstarts are pivotal for poverty alleviation.     

The Relationship between Drought Tolerance of <Emphasis Type="Italic">Laurus nobilis</Emphasis> L. and Environmental Factors in Conditions of the Southern Coast of Crimea

The present studies have shown Laurus nobilis L. to be a drought tolerant species. When the plant was first subjected to dehydration, the rate of net photosynthesis decreased from Pn = (8–10) to –1 μmol/(m² s) and to –3 μmol/(m² s) during the second dehydration before it was subsequently irrigated. The rewatering on August 5 and August 8 promoted a sharp burst of this parameter, but the Pn value was restored to its original level only after August 8. Soil drought caused a drop in a rate of transpiration from 65–70 to 10 mg/(m² s). Watering soil up to a 15% moisture level brought an increase in E = 25 mg/(m² s), but only the second watering managed to fully restore it to the initial value. Apical growth of the plants was closely correlated with soil moisture. As the soil moisture was reduced to W = 15–5%, the terminal growth reached a saturation point and started to plateau. Watering the soil up to W = 15% promoted apical growth by 4 mm. Reducing soil moisture to W = 3–4% caused a complete cessation of the growth. Subsequent watering to W = 27–28% led to a gradual and complete recovery of turgor and an increase in the growth rate up to 6–8 mm per day. The surface response functions Pn = f(I, W) and E = f(I, W) allowed us to determine conditions and levels of potential maximums and boundaries of the areas of optimum photosynthesis and transpiration: optimum Pn = 8–9 μmol/(m² s) with I = 900–1400 μmol/(m² s) and W = 17–24% and the optimum E = 25–35 mg/(m² s) with I = 1000–1400 μmol/(m² s) and W = 16–24%.     

Some reflections on Eastern European agriculture an introductory essay to the special issue on “agriculture in Eastern Europe”

This article reviews three general themes pertaining to the transformation of Eastern European agriculture from a command system to a market oriented system. The first theme deals with the diverse character of Eastern European agriculture. In a context in which the agricultures of this region are often considered homogenous, acknowledgement of the varied dimension of this sector is a key element in both analytical and political terms. The second theme pertains to the market. The historical and theoretical dispute over the role of the market has not only been central in the socio-economic reorganization of Eastern European countries and agricultures but is also a common element shared with the West. The third and final theme refers to the changing social stratification of rural regions. The emergence of new and powerful social groups and the demise of others represent fundamental aspects in the understanding of possible trajectories for development. The article concludes with a review of the contributions contained in this special issue of Agriculture and Human Values.Alessandro Bonanno is Associate Professor of Rural Sociology at the University of Missouri-Columbia. He is the author of numerous journal articles and books, among themSmall Farms (1987),Sociology of Agriculture (1989),Agrarian Policies and Agricultural Systems (1990), andThe Agricultural and Food Sector in the New Global Era (1993). He is also co-editor of the forthcoming book From Columbus to ConAgra: The Globalization of Agriculture and Food. Since the late 1980s, he has been researching issues pertaining to the Agricultural and Food Sector in selected Eastern European Countries.     

Breed characteristics associated with <Emphasis Type="Italic">LEP</Emphasis> gene polymorphisms in Holstein cattle

Genotyping of the leptin gene locus (LEP) (SNP: R25C, Y7F, and A80V) has been performed in the animals from two groups in the Holstein cattle herd. Groups 1 and 2 included the fourth to seventh lactation cows and the heifers, respectively. The objective of the surveys was to study the Holstein cattle polymorphisms of the leptin gene associated with the productive longevity according to the related literature data. It has been ascertained that the LEP gene (SNP: R25C, Y7F, and A80V) polymorphism in the Holstein animals determines the certain breed characteristics that can be used for introduction to marker assisted selection. (Particularly, a low (0.04–0.15) frequency of occurrence of the F allele is typical for the LEP-Y7F SNP; as for SNP LEP-A80V, a low frequency of occurrence (0–0.14) is typical for the homozygous animals with the VV genotype when compared to a rather high frequency of occurrence (0.36–0.45) in the heterozygous animals).     

军队医学图书馆信息资源的现状及发展趋势

 

阐述了全军医学图书馆文献信息资源在军队卫生事业发展中的作用,对全军医学图书馆文献信息资源建设的现状、存在问题及发展趋势进行了分析,并提出了发展对策。

     

The future of terrace farming in Yemen: A development dilemma

The country of Yemen, on the southwestern corner of the Arabian Peninsula, is one of the most extensively terraced areas in the world. There is a well-documented tradition of both dryland and irrigated farming over the past three millennia and much of the indigenous agricultural knowledge survives. Development efforts over the past two decades in the north of Yemen have focused on expansion of tubewell irrigation at the expense of the major land use on dryland terraces and traditional subsistence crops. Despite millions of dollars in aid, Yemen is far from agriculturally self-sufficient and its scarce water resource is rapidly being depleted. This articles explores the relevance of indigenous Yemeni knowledge of agriculture and the environment for the future of terrace farming in the country. It is argued that farmer knowledge can contribute to sustainable production and can be grafted on to modern methods and technology. Within Yemen the existing community support networks and pride in national heritage would assist in a reinvestment effort for the existing resource of the terraces.