Molecular Variability of the Capsid Protein of the Prune Dwarf Virus

Sequences of the capsid protein gene and the preceding intergenic region of eleven isolates of prune dwarf virus from central Europe were determined. The isolates were obtained from plum, cherry and peach trees. Comparison of all sequenced isolates (including two sequences published previously) revealed high (88%) conservation of the capsid protein gene. The highest degree of identity was observed in the C-terminal half, where only 13 amino acid substitutions could be observed in contrast to the N-terminal half with 22 substitutions. No reasonable correlation between amino acid substitutions and host species and/or geographic origin of the isolates was observed. Alignment with capsid protein genes of other ilarviruses revealed apple mosaic virus, elm mottle virus, lilac ring mottle virus and prunus necrotic ringspot virus as the most related to prune dwarf virus. Unlike the isolates of related prunus necrotic ringspot virus all the isolates of prune dwarf virus shared extensive conservation of the intergenic region. Portions of RNA3 were selected for design of universal primers for PCR detection.     

鸭梨果实石细胞分化特性研究

以鸭梨为试材,利用透射电镜显微技术和组织化学技术对梨果实石细胞分化及次生壁形成过程进行研究。结果表明,石细胞分化始于开花第7天,原生质体收缩于细胞一侧,随后胞内出现颗粒状凝聚物,次生壁逐渐增厚,之后胞质继续收缩消失,早期形成的石细胞多以群体形式同时出现。石细胞次生壁形成是逐步进行的,即先形成纤维素或半纤维素网架结构,再进行木质化填充。透射电镜下石细胞分化过程中依次呈现出细胞核染色质凝聚、细胞核变形、核膜界限不清晰的现象;胞内出现同心层次的自噬泡,形成大量囊泡;细胞核消失,内质网断裂并大量增生,质膜向内突起形成泡状结构;次生壁增厚,胞内细胞器仅有线粒体和内质网,最终细胞质收缩消失。     

The influence of instream cover and predation risk on microhabitat selection of stone loach Barbatula barbatula (L.)

Abstract— The microhabitat selection of stone loach ( Barbatula barbatula ) in relation to instream cover and predation risk was investigated in artificial streams. In one experiment, stone loach were presented different combinations of shelter structures, two at a time, that provided visual isolation, flow refuge, both, or none. In all cases, visual isolation shelters were selected by the fish, with little use of clear shelters and no apparent selection of flow refuges. In a second experiment, diel activity patterns and habitat selection of stone loach were measured when visual isolation structures were placed in the riffle only, pool only, both riffle and pool or in no habitat. Stone loach were marked with passive integrated transponder tags and a sensor plate was placed between the riffle and pool habitats to measure diel activity patterns. Habitat use was measured by releasing drop gates between the two habitats at the end of each trial. More stone loach used the pool than the riffle in all treatments, but use of the riffle increased when cover was present only there. Furthermore, stone loach were most active between 2100 and 0300. To determine the effect of predation threat on habitat use by stone loach, one adult brown trout ( Salmo trutta ) was added to each pool. The presence of trout caused stone loach to move into the riffle, especially the smaller loach. Overall, the study showed that stone loach used cover in a visual isolation context, preferring deeper water when there was no predation risk, but made more use of shallower water in the presence of brown trout.     

填筑路堤的路堑开挖土石料性能分类研究

提出了以石块为主的用作路堤填料的路堑开挖土石料按岩性进行分类的依据和标准，讨论了用它们填筑路基的施工工艺，质量控制要点及质量指标检测方法。     

云南岩溶地区石漠化生态恢复的思路

云南岩溶面积达11.09万km2,占全省国土面积的28.14%,是西南地区岩溶集中分布区,岩溶石漠化面积已达2.15万km2.分析云南岩溶的分布,以及岩溶地区生态脆弱给当地人民带来生产、生活的生态危机,并结合云南石漠化治理的成功经验,提出岩溶地区生态恢复的思路.     

Spatiotemporal distribution of floral resources in a Brazilian city: Implications for the maintenance of pollinators,especially bees

Cities provide resources for the animals that live in them or their surroundings. There has been an increase in the number of ecological studies in urban areas, including interactions between plants and bees. Bees are pollinators that provide a vital ecosystem service to crops and wild plants. We assessed plant community structure in the campus of Universidade de São Paulo in Ribeirão Preto, Brazil, included in the neotropical Atlantic Forest biome, focusing on floristic composition, pollination syndromes, flowering phenology, and spatiotemporal distribution of floral resources for bees. Currently, the city is surrounded by sugar cane plantations. Once a month, from April 2011 to March 2012, we sampled plant species and individuals in bloom in an area with 500 m radius from the bee-rearing facilities of Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), totaling 78 hectares. We sampled 289 plant species of 73 families; Leguminosae was the richest family. Plants pollinated by bees predominated (67%), followed by plants pollinated by hummingbirds (18%). Melittophilous species flowered throughout the year and, hence, food availability for bees was continuous. The flowering of plant individuals that provided pollen, nectar, and floral oil was seasonal in all vegetation (except for nectar in shrubs), with peaks in resource availability in the transition from the dry to the rainy season, and also in the rainy season. Our results show that the campus is able to maintain bee populations amid a monoculture matrix, acting as a refuge. In addition, it provides a list of several attractive native plants to different pollinator groups, coupled with a phenogram, that can be used in the design and planning of urban areas.     

空心板板缝开裂的原因及预防措施

本文较为详细地论述了预制楼板裂缝产生的原因;预防预制楼板开裂的有效措施以及裂缝出现后的有效补救方法。     

海滨滩涂区抛石挤淤路基处理方案

本文从实例出发,仔细地分析了海滨填海路基的特点,针对具体情况提出相应的处理加固方法,对于其他地质条件下的软土路基处理有一定的参考性。     

Nature and origin of stone stripes on the Columbia Plateau

Beds of size-sorted stones forming stripes perpendicular to the contour are conspicuous on hillsides of the Columbia Plateau. Stripes occur on terrain ranging from 0° to about 30° in steepness, often beginning among Mima-type mounds on mesa tops and extending downward onto steep, unmounded slopes. Four mechanisms of their origin have been hypothesized: 1) water erosion, 2) solifluction and soil creep, 3) weathering of rock outcrops, and 4) tunneling by pocket gophers. We measured characteristics of five stripes on slopes of differing exposure and steepness. These stripes were 58–124 m long, and widths showed a maximum range of 0.55–3.70 m. Data on physical and biotic characteristics of the stripes suggest that pocket gopher tunneling is a basic mechanism of stripe formation on gentle slopes, and that this mechanism is augmented by outcrop weathering and colluvial dynamics on steeper slopes, with erosion playing a secondary role.     

Community‐Based Rehabilitation of Mountain Terraces in Cyprus

Participatory methods and community‐based approaches have an important role to play in combating land degradation. This paper follows a well‐defined participatory framework to identify key stakeholders and to select Sustainable Land Management approaches for reducing soil erosion and land degradation in the Troodos Mountains of Cyprus. Among the options suggested and evaluated by stakeholders, terrace rehabilitation had the best overall performance, followed by crop diversification and afforestation. Stakeholders agreed that the rehabilitation of dry‐stone terraces was the preferred option, as it is a practice with high environmental benefits and fits well in the local socio‐cultural context, despite the higher cost compared to other options. In the first year of implementing the approach, three mountain communities co‐organised hands‐on terrace maintenance events, engaging more than 160 people in rehabilitation activities. The community‐based approach has sparked the interest of people within and beyond the research site, and another series of events is scheduled for the coming season. This outcome indicates that social innovations can benefit from the integration of local and scientific knowledge, while participatory process can enhance the self‐confidence and organisational structures of local communities. Sustaining and enhancing the impact of the approach in the long‐run require developing local terrace maintenance institutions, actively engaging the youth in terrace management and improving the profitability of mountain farming through the differentiation of local products. Copyright © 2016 John Wiley & Sons, Ltd.