苹果套袋及除袋技术对果实微域温湿度及光照的影响

 探索套袋果实微域温湿度变化规律有助于进一步优化套袋栽培技术。本试验中采用温、湿度自动监测仪, 研究了套袋及除袋技术对果实微域温湿度的影响。结果表明, 套袋和除袋方法以及外界环境条件变化都能在一定程度上影响袋内微域温湿度及其果实表面温度。在一天中不同时刻除袋, 套袋果表面温度与气温和裸露果表面温度有所不同。除袋方法对果实温度有一定影响, 分次除袋更有利于果实对强光的适应。     

Woody habitats promote pollinators and complexity of plant–pollinator interactions in homegardens located in rice terraces of the Philippine Cordilleras

Bees are important pollinators of wild plants and crops, but little is known about bee habitat requirements and pollinator management in tropical mountainous agricultural regions. Here, smallholder farmers produce fruits and vegetables in homegardens that depend upon or benefit from bee pollination. We hypothesized that abundance and richness of wild and domesticated bees and the complexity of plant–pollinator interactions are higher in homegardens surrounded by woody habitats than in homegardens found farther from woodlands. Bees were sampled in 20 homegardens in the rice terraces of the Philippine Cordilleras. We used linear mixed effect models to analyse effects of woody habitats around homegardens on bee richness and abundance. Based on pooled observations for each garden category, we built pollinator–plant interactions networks to illustrate shifts in interaction frequencies. We recorded 354 bee individuals of 13 wild and one domesticated bee species (Apis cerana). Wild bee richness was significantly higher in homegardens surrounded by woody habitats. Bee abundance increased significantly with increasing flower cover. Wild bees visited cultivated plants significantly more often than domesticated bees. Six vegetable species and 76% of all flower visits on cultivated plants in total were performed by wild bees and three plant species and 24% by domesticated bees. Pollinator–plant networks were more complex in homegardens surrounded by woody habitats. We conclude that woody habitats increase abundance and richness of wild and domesticated bees. Increasing availability of floral resources also promotes bee abundance. In order to promote pollination services in the landscape mosaic of smallholder rice farms, woody habitats and forest fragments together with numerous floral resources should be protected and restored.     

How project approach influences adoption of SWC by farmers,examples from southern Mali

Choices in project approach affect the continuation of soil and water conservation (SWC) after project withdrawal, and thus the sustainability and cost effectiveness of the project. A SWC project was carried out in southern Mali between 1986 and 1998. Its features were the promotion of cheap and simple SWC measures, a participatory village extension approach with limited use of incentives, and the incorporation of the SWC programme in an existing Malian extension service. By 2000, farmers in half the 5000 villages in southern Mali had been trained in SWC. By 2002, erosion‐control measures had been installed in 94 per cent of the villages in southern Mali by 46 per cent of the farmers and in 15 per cent of the fields. Though external donor support has stopped, farmer adoption is steadily continuing and spreading to untargeted villages. Copyright © 2006 John Wiley & Sons, Ltd.     

Emerging invasive alien plants for the Mediterranean Basin

A major step in tackling invasive alien plants consists of identifying those species that represent a future threat to managed and unmanaged habitats. The European and Mediterranean Plant Protection Organization reviews and organizes data on alien plants in order to build an early warning system. A prioritization system is being developed to select species that represent emerging threats and require the most urgent pest risk analysis to implement preventive measures and to perform eradication and management measures. Attention has been drawn to the Mediterranean Basin which is particularly vulnerable because its climatic conditions potentially allow the establishment of sub‐tropical and tropical species. Surveys and rapid assessments of spread and impact have allowed identification of emerging invasive alien plants for Mediterranean countries: Alternanthera philoxeroides (Amaranthaceae), Ambrosia artemisiifolia (Asteraceae), Baccharis halimifolia (Asteraceae), Cortaderia selloana (Poaceae), Eichhornia crassipes (Pontederiaceae), Fallopia baldschuanica (Polygonaceae), Hakea sericea (Proteaceae), Humulus japonicus (Cannabaceae), Ludwigia grandiflora and L. peploides (Onagraceae), Hydrilla verticillata (Hydrocharitaceae), Microstegium vimineum (Poaceae), Myriophyllum heterophyllum (Haloragaceae), Pennisetum setaceum (Poaceae), Pistia stratiotes (Araceae), Salvinia molesta (Salviniaceae), Solanum elaeagnifolium (Solanaceae). These species represent priorities for action. Some other species are placed on the observation list, as available information does not allow them to be counted among the worst threats: Akebia quinata (Lardizabalaceae), Araujia sericifera (Apocynaceae), Delairea odorata (Asteraceae), Cabomba caroliniana (Cabombaceae), Nassella neesiana, N. tenuissima and N. trichotoma (Poaceae), Sesbania punicea (Fabaceae), and Verbesina encelioides (Asteraceae).     

Prima phacie1: a new European Food Safety Authority funded research project taking a comparative approach to pest risk assessment and methods to evaluate pest risk management options

In late 2009, a European Food Safety Authority (EFSA)‐funded project (Prima phacie) began work to review and test methodologies for conducting pest risk assessment by means of case studies on three phytoplasmas (Candidatus Phytoplasma mali, Ca. P. prunorum, Ca. P. pyri); two bacteria (Acidovorax avenae subsp. citrulli, Xanthomonas citri [=X. axonopodis] pv. citri); two fungi (Guignardia citricarpa, Mycosphaerella dearnessii); two nematodes (Meloidogyne chitwoodi, M. fallax); and an insect (Anoplophora glabripennis). Multiple risk assessment schemes and methods will be applied to each of the case study pests, allowing for a comparative assessment of methods. Methods to assess the effectiveness of possible risk management options for each pest will also be evaluated. The project will further develop the scientific basis for pest risk assessment within the European Community and identify methodologies most suitable for conducting risk assessments and for evaluating the effectiveness of possible risk management options by the EFSA Panel on Plant Health in order to support European decision making. The project lasts 29 months, and is being conducted by an international consortium of 11 partners consisting of phytosanitary organizations, research institutes and a university. Results will be disseminated via conventional publications and at a workshop in March 2012.     

Use of corn root protoplasts in herbicide absorption studies

Intact and viable protoplasts were enzymatically isolated from corn (Zea mays L.) seedling roots and collected for herbicide absorption studies by differential centrifugation and flotation through a Ficoll density gradient. A method was developed for terminating herbicide absorption by rapid centrifugation of protoplasts out of solutions without washing the protoplasts. Within 10 sec, atrazine [2-chloro-4-ethylamino-6-isopropylamino-s-triazine] accumulated in protoplasts to a concentration 36% greater than the external concentration; no further absorption occurred through 30 min. However, 2,4-D [2,4-dichlorophenoxyacetic acid] accumulated to twice and 16 times the external concentration at pH 6.5 and 4.5, respectively. Calculations of theoretical 2,4-D concentrations in protoplasts also predicted greater accumulation at pH 4.5 than at pH 6.5. Both atrazine and 2,4-D absorption were consistent with previous measurements of absorption by plant tissues. Thus, corn root protoplasts are feasible experimental material for studying absorption of herbicides at the cellular level.     

Haematological and febrile response to Escherichia coli lipopolysaccharide in 12‐week‐old cockerels of genetically diverse layer lines fed diets with increasing L‐arginine levels

Due to its decisive function in the avian metabolic, endocrine and immune system L‐arginine (Arg) is dietary indispensable for chickens. In 12‐week‐old cockerels of two high‐ and two low‐performing purebred layer lines, the effects of increasing dietary Arg on the haematological and febrile response were studied over 48 h after single lipopolysaccharide (LPS) injection. The offered diets contained Arg equivalent to 70%, 100% and 200% of recommended supply. Pathophysiological alterations in weight gain, feed intake, body temperature and differential blood count were examined in comparison with their physiological initial values. Within the first 24 h after LPS injection, cockerels reduced feed intake and lost body weight subsequently. Thereby, low‐performing genotypes lost body weight to a lesser extent than high‐performing ones. The loss of body weight was further intensified by deficient dietary Arg. Within the following 24 h, cockerels recovered by improving feed intake and weight gain. Furthermore, LPS induced genotype‐specific fever response: both brown genotypes showed initial hypothermia followed by longer lasting moderate hyperthermia, whereas the white genotypes exhibited biphasic hyperthermia. Fever response was accompanied by significant changes in differential blood counts. Characterized by lymphopenia and heterophilia, a severe leucopenia was observed from 4 to 8 h after LPS injection and replaced by a marked leucocytosis with longer lasting monocytosis up to 48 h after LPS injection. Under given pathophysiological conditions, deficiently Arg‐supplied cockerels showed higher total leucocyte counts than adequately and excessively Arg‐supplied cockerels. However, deficient and surplus dietary Arg tended to cause higher ratios between heterophils and lymphocytes. To conclude, present results confirmed that LPS induced numerous immunological changes in 12‐week‐old cockerels and emphasized that chicken's genotype is a source of variation to be considered for immunological studies. Deficient dietary Arg intensified acute changes in differential blood counts and weight gain during LPS‐induced inflammation.     

熔喷过程湍流模型中的气流场数值模拟

以熔喷过程中的气流场为核心,建立熔喷过程的数学物理模型,采用数值模拟的方法进行研究。以Navier-Stocks方程为基础,应用基于同位网格的SIMPLER算法并行化计算气流场的速度分布,将试验测试值与数值模拟进行比较,结果表明:采用的数值模拟方法是有效的,完全可以用于模拟双槽钝头型模具的熔喷过程。     

EU‐project DROPSA: first achievements regarding pathway analyses for fruit pests

The EU project ‘DROPSA’ started in 2014 and aims to improve plant health strategies in the fruit sector. The project is being conducted by an international consortium of 26 partners consisting of phytosanitary organizations, companies, research institutes and universities and will last 50 months. Results will be disseminated via conventional publications and will be brought together in the development of risk‐based strategies to prevent the introduction of new fruit pests. This article describes the task related to the preparation of alert lists of pests that may be introduced into Europe with the trade of fruit. Activities of this task include the investigation of pathways of introduction for fruit pests into Europe, the development of alert lists for selected fruit crops and a review of current legislation. A review of introductions, interceptions and outbreaks that occurred during the last 10–15 years was conducted and is summarized, showing the relevance of fruit trade for the international movement of pests. Work has started on the development of alert lists for selected pathways. In this context, important fruit crops (including Malus, Vaccinium, Vitis, Citrus) were selected.