Development and validation of species-specific primers that provide a molecular diagnostic for virus-vector longidorid nematodes and related species in German viticulture

The nematode species Longidorus attenuatus, L. elongatus, L. macrosoma and Paralongidorus maximusare economically important pests to the viticulture industry due to their ability to vector two nepoviruses (Raspberry Ringspot Virus and Tomato Black Ring Virus) to grapevines. In Germany, these species occur in vineyard soil with other non-vector but morphologically similar longidorid species, L. helveticus, L.profundorum and L. sturhani. Species-specific primers were designed from ribosomal DNA for all seven species to facilitate taxonomic identification for non-specialists. Primers were assessed for their reliability by screening, where possible, a number of populations of each species. Furthermore, their selectivity and sensitivity were determined when challenged with closely related longidorid species and general nematode communities typical of vineyard soil. A multiplex approach using a common forward primer combined with species-specific reverse primers enabled three target nematode species to be detected in the same PCR reaction. All primers were highly specific, detecting all nematode developmental forms from disparate populations and were sufficiently sensitive to detect a single target nematode within a whole nematode community typical of a vineyard soil comprising of a range of non-target species. Given their specificity, sensitivity and reliability, these diagnostic primers should be of great benefit to both phytosanitary/quarantine services related to the viticulture industry and also as a decision management tool for growers.     

荷斯坦奶牛隐性乳房炎与乳用特征的相关性分析

随机抽取荷斯坦奶牛 472头 (1～ 11胎 )进行奶牛隐性乳房炎的检测 ,乳用特征性状 (楞角性、尻宽、尻角度、后肢侧视、蹄角度 )的线性评定 ,以及隐性乳房炎与乳用特征的相关性分析。结果表明 :奶牛隐性乳房炎的乳区阳性率与楞角性、尻宽、尻角度、后肢侧视、蹄角度的相关系数分别为 0 1171、0 10 3 0、0 0 681、0 0 180、-0 12 65 ,其中与楞角性、尻宽分别达到显著水平 (P <0 0 5 )的正相关 ,与蹄角度达极显著 (P <0 0 1)的负相关。奶牛阳性率与楞角性、尻宽、尻角度、后肢侧视、蹄角度的相关系数分别为 0 0 967、0 0 5 61、0 0 2 82、0 0 12 7和 -0 0 670 ,其中除与楞角性为显著水平 (P <0 0 5 )的正相关 (0 0 967)外 ,其余均不显著 (P >0 0 5 )。     

Is colourful self-sustaining forb vegetation mere fantasy?

Biodiversity in urban and suburban environments can be supported through establishment of low maintenance-requiring herbaceous vegetation types. Here, we attempt to provide a perspective on the possibilities and limitations of establishing forb-dominated vegetation to support local biodiversity and contribute to changing public aesthetics concerning green spaces. Plant ecological theories, methods and experiences are the foundation for the design and establishment of such vegetation types. We emphasise the importance of high plant density and recurrent disturbance for the maintenance of forb communities. Well-established ecological theory tells us that totally self-sustaining herbaceous vegetation is not a realistic possibility. Without intervention, herbaceous vegetation will change over time and eventually be colonized by woody species through the process of succession. However, by applying a creative and strategic approach to establishment and subsequent management involving small scale disturbances, rather than solely a uniform maintenance regime, it may be possible to maintain a colourful, aesthetically appealing and species-rich forb dominated community that will support biodiversity and increase public acceptance of alternatives to conventional lawns in urban and suburban environments.     

新疆吐鲁番地区‘无核白’葡萄水分和矿质元素周年吸收规律研究

为探究新疆吐鲁番地区‘无核白’葡萄水分和矿质元素的周年吸收规律,以4年生‘无核白’葡萄为试材,采用密闭式营养液循环供给系统栽培,避免了水分和矿质元素的流失,并设置低、中、高浓度(0.5、1.0和1.5倍标准配方浓度)的Hoagland营养液处理。在葡萄植株的生长发育过程中持续测定营养生长(新梢长度、新梢粗度、叶片面积)和生殖生长(果粒横径、果粒纵径、单果质量、可溶性固形物、可滴定酸)指标,检测和计算了不同发育阶段葡萄植株对水分和矿质元素的吸收量,并测定葡萄叶片和果实中矿质元素的含量变化。结果表明,中浓度营养液栽培的‘无核白’葡萄长势中庸,果实品质最佳,作为吐鲁番地区葡萄水分和矿质营养吸收量的参考依据,其生理需水量为每年4 149.5m~3·hm~(-2),矿质元素每公顷的吸收量分别为N 227.9 kg,P 22.9 kg,K 325.9 kg,Ca 341.8 kg,Mg 117.8 kg,Fe 1.9 kg,Mn 460.6 g,Cu 182.3 g,Zn 198.1 g,B 728.3 g。花后47~75 d,‘无核白’葡萄植株的水分和矿质元素吸收速率最大。叶片和果实中的矿质元素含量总体呈高浓度营养液处理中浓度营养液处理低浓度营养液处理的趋势。     

Responses of plant community to the linkages in plant-soil C:N:P stoichiometry during secondary succession of abandoned farmlands,China

Succession is one of the central themes of ecology;however,the relationship between aboveground plant communities and underground soils during secondary succession remains unclear.In this study,we investigated the composition of plant community,plant-soil C:N:P stoichiometry and their relationships during secondary succession after the abandonment of farmlands for 0,10,20,30,40 and 50 a in China,2016.Results showed that the composition of plant communities was most diverse in the farmlands after secondary succession for 20 and 50 a.Soil organic carbon and total nitrogen contents slightly decreased after secondary succession for 30 a,but both were significantly higher than those of control farmland(31.21%-139.10%and 24.24%-121.21%,respectively).Moreover,C:N ratios of soil and microbe greatly contributed to the changes in plant community composition during secondary succession of abandoned farmlands,explaining 35.70%of the total variation.Particularly,soil C:N ratio was significantly and positively related with the Shannon-Wiener index.This study provides the evidence of synchronous evolution between plant community and soil during secondary succession and C:N ratio is an important linkage between them.     

SCINTIGRAPHIC CHARACTERIZATION OF THE EQUINE FOREDIGIT AND METACARPOPHALANGEAL REGION FROM BIRTH TO SIX MONTHS OF AGE

Both foredigits and metacarpophalangeal joints of six Quarter Horse foals were scanned serially to six months of age using ⁹⁹Tc-methylene diphosphonate. Dorsal scans were made on day 1 and at two, four, six, ten, 14, 18, 22 and 26 weeks of age. Scans were assessed visually for distal third metacarpal, proximal phalangeal, and middle phalangeal physeal appearance and closure. Scans were also evaluated by computer region-of-interest (ROI) and line-profile analysis to characterize the physes quantitatively. Physeal region radioactivity relative to a disphyseal reference region was greatest at four weeks for all physes. Scintigraphic physeal closure of all physes occurred at approximately six months of age with a range of four and one half to greater than six months. The study was conducted to allow better assessment of diffuse and focal physeal disease by determining developmental times at which normal physeal region radioactivity has decreased enough to not obscure abnormal radioactivity and by quantifying scintigraphic physeal appearance which enables computer analysis to detect visually indeterminate physeal abnormalities.     

陕北水蚀风蚀交错区苜蓿地土壤水分过耗与恢复

采用野外定位观测法研究水蚀风蚀交错区苜蓿(Medicago sativa)草地土壤水分在天然降水作用下的恢复过程。结果显示:苜蓿地翻耕后,在降水作用下土壤水分有明显的恢复过程,第一年,150cm以上土壤水分得到一定恢复,第二年深度达到300cm,但上层土壤含水量并未增加;该地块植被大量消耗土壤储水导致土壤干燥化,高耗水植被消除后,土壤含水量逐渐增加。     

Soil degradation in the tropical lowlands of Santa Cruz,Eastern Bolivia

This paper examines the soil degradation processes that are threatening the productivity of the mechanized annual cropping areas in the Santa Cruz lowlands of tropical eastern Bolivia. The dominant process is that of machinery-induced and natural compaction, which has resulted in an estimated 50 per cent of the soils in the Central Zone being moderately to severely compacted, causing serious root restriction and the loss of both transmission and water-storage pores. Degradation has made the soils increasingly susceptible to moisture stress due to the combined effect of (i) restricted rooting as a result of compaction and the hardsetting characteristics of the soils, (ii) reduced rainfall infiltration due to the loss of transmission pores and surface crusting, and (iii) a decrease in available soil moisture caused by the loss of storage pores, the incorporation of wind-blown fine sand deposits, and soil organic matter losses due to accelerated decomposition rates. The loss of transmission pores has also made the soils more prone to waterlogging in periods of high rainfall. The degradation tendencies of these soils are exacerbated by the greater variability of seasonal rainfall during the last 20 years that has led to a greater frequency or extremely high or extremely low rainfall events than hitherto.     

高速公路沙害防治技术研究-以丹东-拉萨高速公路新地-麻黄沟段为例

本文以新地—麻黄沟高速公路防沙体系效益为依据,探讨分析了高速公路沙害的特点以及防沙体系建设的基本要求。研究表明,高速公路沙害防治需要采取适当抬高路基,建立稳固的防沙体系并要适当加大防护带宽度的综合措施。该地区公路防沙体系的结构配置对干旱、半干旱沙漠地区高速公路沙害防治具有一定的借鉴作用。     

洮河林区云冷杉林分类型多样性及稳定性研究

利用洮河林区云冷杉林择伐周期研究和森林资源二类清查样地资料,对该林区云冷杉林分类型多样性和林分的稳定性进行了研究。结果表明:该林区的林分类型多样性随郁闭度的降低而增加,林分的稳定性随多样性的增加而降低,林分处于逆向演替过程中,林分的稳定性处于最低限。云冷杉林与环境因子-海拔之间呈明显的负相关。在高海拔区云冷杉林十分脆弱,一旦原有种群的郁闭度低于0.3,森林的稳定性将被破坏,既使在完全封禁的条件下,25年生的疏林要恢复到有林地状态将需要40年的时间。