大豆疫霉根腐病菌生理小种鉴定结果初报

本研究采用胚轴伤口接种方法用标准生理小种鉴别寄主对采自三江平原大豆田的１０凤霉病进行测定,其中有７个菌株在鉴别寄主上的反应型是一致的,都对Ｈａｒｏｓｏｙ表现感病,对其它寄主表现抗病,重复鉴定结果一致,与标准生理一种鉴定结果对照,认定是疫霉菌１号生理小种。     

Phenotypic Characteristics of Xanthomonas campestris pv. campestris from Nepal

Twenty strains of Xanthomonas campestris pv. campestris (Xcc) were isolated from two major crucifer-growing valleys, Chitwan and Kathmandu in Nepal and characterized by biochemical and pathogenicity tests. Strains were homogeneous in bacteriological characteristics. The ability of a strain to induce high or low disease severity index (DSI) on three host plants, broccoli, cabbage, and cauliflower, was interpreted as virulence. Strains that were associated with high or low virulence were significantly different (P>0.05). No relationship between virulence and biochemical characteristics was observed.     

Parasites of cultured and wild brown‐marbled grouper Epinephelus fuscoguttatus (Forsskål, 1775) in Lampung Bay,Indonesia

A total of 210 Epinephelus fuscoguttatus (brown‐marbled grouper) was examined for parasites. During three consecutive seasons (two rainy and one dry season from 2002 to 2004), 35 specimens each taken from floating net cages of the National Sea Farming Development Centre (Balai Budidaya Laut) and from wild catches in Lampung Bay, South Sumatra, Indonesia were studied. Twenty‐five (cultured grouper) and 30 (wild grouper) parasite species/taxa were identified, with an infracommunity ranging from one to nine (cultured) and three to 14 parasite species (wild), demonstrating a species‐rich parasite fauna even in the cultured fish. Protozoans (1 species), microsporeans (1), myxozoans (1), digeneans (8), monogeneans (5), cestodes (3), nematodes (8), acanthocephalans (2) and crustaceans (6) were found. The most abundant parasites were the monogeneans Pseudorhabdosynochus epinepheli and Pseudorhabdosynochus lantauensis for both, cultured and wild grouper during all seasons. For the cultured fish, the prevalence of monoxenous ectoparasites (e.g. P. epinepheli, P. lantauensis, Capsalidae gen. et sp. indet., Benedenia epinepheli) was in most cases higher than that of heteroxenous endoparasites. This contrasts the wild grouper, where heteroxenous parasites such as Allopodocotyle epinepheli and Raphidascaris sp. occurred at a similar prevalence compared with the fairly abundant Pseudorhabdosynochus spp. No seasonality of infestation was observed for both cultured and wild fish. The high levels of infestation of potentially pathogenic monogeneans throughout the year could result in significant parasite outbreaks at the locality studied.     

A review of ecological models for brown trout: towards a new demogenetic model

Abstract – Ecological models for stream fish range in scale from individual fish to entire populations. They have been used to assess habitat quality and to predict the demographic and genetic responses to management or disturbance. In this paper, we conduct the first comprehensive review and synthesis of the vast body of modelling literature on the brown trout, Salmo trutta L., with the aim of developing the framework for a demogenetic model, i.e., a model integrating both population dynamics and genetics. We use a bibliometric literature review to identify two main categories of models: population ecology (including population dynamics and population genetics) and population distribution (including habitat–hydraulic and spatial distribution). We assess how these models have previously been applied to stream fish, particularly brown trout, and how recent models have begun to integrate them to address two key management and conservation questions: (i) How can we predict fish population responses to management intervention? and (ii) How is the genetic structure of fish populations influenced by landscape characteristics? Because salmonid populations tend to show watershed scale variation in both demographic and genetic traits, we propose that models combining demographic, genetic and spatial data are promising tools for improving their management and conservation. We conclude with a framework for an individual‐based, spatially explicit demogenetic model that we will apply to stream‐dwelling brown trout populations in the near future.     

玉米穗腐病真菌毒素污染抗性遗传研究进展

玉米穗腐病的发生及其真菌毒素污染严重影响玉米产量与品质,威胁人畜健康。玉米对穗腐病及其真菌毒素抗性都是由多基因控制的复杂数量性状,受环境影响极大。简要介绍玉米穗腐病的发生与分布特点,重点总结玉米穗腐病主要真菌毒素类型及危害、玉米穗腐病主要真菌毒素抗性遗传、抗性基因以及全基因组选择在穗腐病抗性育种中的应用等方面的研究进展,分析该领域目前存在的主要问题及挑战,提出未来在该研究领域可能的方向和突破点,为玉米穗腐病的防治及真菌毒素污染的防控提供理论依据。     

Long-term variation in the abundance of the brown shrimp Crangon crangon (L.) population of the German Bight and possible causes for its interannual variability

Time series on Crangon crangon densities in the German Wadden Sea show a considerable degree of interannual variability, for the entire region in spring and in autumn as well as for three subareas, North Frisia, East Frisia and Elbe estuary. Across the entire survey area C. crangon density was inversely related to water depth. In autumn after the recruitment, settlement shrimp densities are correlated across a larger spatial scale (>100 km longshore), whereas in spring the overwintering adult spawning stock is uncorrelated across subareas. Interannually, extreme density variations can develop even over a short time span of 1 yr. On a large spatial scale shrimp abundance in autumn was correlated with year‐to‐year changes in physical environmental and biological parameters, winter water temperature, autumn river runoff and the winter NAO index. On a regional scale (North Frisia), density of gadoid predators was an additional component affecting shrimp stock abundance. No correlations to such parameters could be detected for the C. crangon stock in spring. Possible causes for the spring situation and additional sources for variability are discussed.     

不同储藏条件下糙米品质变化研究

将供试3种糙米(粳米、杂籼米和纯籼米)分别放在低温、常温、高温和真空条件下储藏,定期测定其浸出液电导率和丙二醛含量的变化.随着储藏时间的延长,糙米的浸出液电导率呈增加趋势,低温储藏的增加最小,真空储藏的次之,常温储藏的增加较大,高温储藏的增加最大;低温、常温和真空储藏条件下丙二醛含量随着储藏时间延长而增加,高温条件下先增加后减小.     

北京地区引种阿月浑子叶褐斑病的防治

1997-2006年研究了北京地区大棚和露地引进阿月浑子良种Kerman、Peters及对照新疆阿月浑子叶褐斑病的症状、病原菌、致病程度影响因子、防治措施和效果.结果表明:肉眼可见为叶正、背面的症状有褐色圆形或不规则的病斑,严重者成片叶色焦黄.病原菌除了已报道的尾孢属外还发现有交链孢属.感病主要条件是30 ℃以上的月均温和64%～70%的空气相对高湿度.病情与品种、树势及栽培条件有关:Kerman和Peters抗病性较强;树势健壮,叶片磷含量达1.750 3 g·kg-1且含有较多铜、硼的壮苗无病;栽植过密、叶面积指数7以上较易致病.采取预防为主严控灌水,保持土壤自然含水量在10%～20%.生长期空气相对湿度在60%以下较宜.通过栽植良种、合理密植、培育壮苗、药肥并施即0.5%(NH4)2 HPO4、0.5%K2HPO4与0.2%多菌灵、0.2%退菌特(轮流喷施),每周各1次,用量0.5 kg·m-2,可将病情指数控制在6%以下.     

软腐欧文氏菌致病性的研究进展

由Ecc,Ech,Eca三种主要病原菌引起的软腐病是世界农业生产上危害很严重的病害之一。目前,对软腐欧文氏菌与植物的互作在世界范围内的大量研究,已经为深入揭示其致病的分子机理提供了有效帮助,并将为软腐病的有效防治提供新的思路和手段。文章将就软腐欧文氏菌的重要致病因子、致病过程中病原菌与植物的基因表达等作综述。     

不同施肥结构对酸性黄棕壤修复效果研究

利用3年田间定位试验,研究了不同施肥结构对酸性黄棕壤酸性、交换性能以及微生物区系的影响。结果表明:连年施用有机肥以及配施石灰和白云石粉均能显著降低土壤中交换性酸和交换性Al~(3+)的含量,提高土壤pH,且不同施肥结构对修复黄棕壤酸性的效果为有机肥配施石灰有机肥配施白云石粉有机肥;连年施用有机肥以及配施石灰主要提高了土壤中交换性Ca~(2+)含量,而配施白云石粉则主要提高了土壤中交换性Mg~(2+)含量;有机肥配施石灰和白云石粉均降低了土壤中真菌的数量,但提高了土壤中细菌/真菌比、放线菌/真菌比以及细菌和放线菌数量,改善了土壤微生物群落结构,增加了烟叶的产量和产值。