种植密度及留叶数对津引品种‘KRK26’主要经济性状的影响

为探索津引品种‘KRK26’在云南省昭通市的栽培技术,研究种植密度和留叶数对其主要经济性状的影响。结果表明：以株行距为120 cm×55 cm、留叶数为21片的处理的产量、产值和产指最高;以株行距为120 cm×55 cm、留叶数为23片的处理的均价、级指和上等烟比例最高。在昭通市种植津引品种‘KRK26’以采用行距120 cm、株距55 cm、留叶数21~23片的栽培措施较适宜。     

基于自然灾害的农村贫困效应研究——以广西西南TL村的水灾调查为例

采取偶遇抽样的方法对TL村的贫困户与非贫困户进行了问卷调查,调查了2008年9月的水灾对该村贫困户与非贫困户的生计资产的影响。结果表明:贫困户的受教育水平和健康状况较差;耕地拥有量及作物面积少;房屋质量差;存款少、金融借贷能力低下;通过个人社会关系获取帮助的能力低下。     

茶叶渣对水溶液中Cu2+的吸附研究

为研究茶叶渣对水溶液中Cu2+的吸附及其机理,利用台湾高山茶叶渣对水溶液中Cu2+进行了吸附实验,考察pH、吸附时间、反应温度、Cu2+初始浓度等因素对吸附效能之影响。实验结果表明：台湾高山茶叶渣对Cu2+有很好吸附效果,吸附平衡时间约为60 min;随着反应温度增加,对Cu2+的吸附效能逐渐提高。在固定初始Cu2+浓度、吸附时间、震荡转速及反应温度下,pH会影响茶叶渣对Cu2+的吸附效能,pH 4时吸附效果最佳。对Cu2+的吸附效能均可使用Langmuir与Freundlich等温吸附方程式进行推估,但比较相关系数,前者较后者有更佳的推估能力;分别计算30、40和50℃下的吸附热力学参数,对应的吉布斯自由能(ΔG0)均为负,表明该反应自发进行;焓变(ΔH0)＞0,证实该反应为吸热反应;熵变(ΔS0)＞0,说明该吸附反应是熵增的过程;茶叶渣吸附前后的红外谱图分析,表明物理吸附为茶叶渣吸附Cu2+的主要机制。     

基于机器视觉的高原鼠兔智能监测系统

高原鼠兔是青藏高原以及邻近地区破坏草地生态的主要生物灾害之一.防治高原鼠兔的危害,就必须对该区的鼠兔数量、危害程度进行调查研究,才有可能采取经济有效的防治措施.传统的调查研究方法不仅耗费大量的人力、物力,并且难以实现对鼠兔长期、连续的监测.随着传感技术、生物识别等技术的发展,可以利用智能监测系统对鼠兔进行监测和研究.基于此,本文提出了一种基于机器视觉的高原鼠兔智能监测系统,对系统的构成进行了介绍,并对其中的关键技术做了说明.与传统的鼠害调查方法相比,该系统能够实现对鼠类活动无接触、动态、连续的监测,对鼠兔的防治以及改善高原的草地生态环境具有重要的意义.     

厚朴药材研究进展

就厚朴的分布、生物学特性、化学成分、药理作用及提取方法进行综述,以期为厚朴的开发应用提供依据。     

Glyphosate-resistant weeds of South American cropping systems: an overview

Herbicide resistance is an evolutionary event resulting from intense herbicide selection over genetically diverse weed populations. In South America, orchard, cereal and legume cropping systems show a strong dependence on glyphosate to control weeds. The goal of this report is to review the current knowledge on cases of evolved glyphosate-resistant weeds in South American agriculture. The first reports of glyphosate resistance include populations of highly diverse taxa (Lolium multiflorum Lam., Conyza bonariensis L., C. canadensis L.). In all instances, resistance evolution followed intense glyphosate use in fruit fields of Chile and Brazil. In fruit orchards from Colombia, Parthenium hysterophorus L. has shown the ability to withstand high glyphosate rates. The recent appearance of glyphosate-resistant Sorghum halepense L. and Euphorbia heterophylla L. in glyphosate-resistant soybean fields of Argentina and Brazil, respectively, is of major concern. The evolution of glyphosate resistance has clearly taken place in those agroecosystems where glyphosate exerts a strong and continuous selection pressure on weeds. The massive adoption of no-till practices together with the utilization of glyphosate-resistant soybean crops are factors encouraging increase in glyphosate use. This phenomenon has been more evident in Argentina and Brazil. The exclusive reliance on glyphosate as the main tool for weed management results in agroecosystems biologically more prone to glyphosate resistance evolution.     

Pathogenesis of Eutypa lata in grapevine: identification of virulence factors and biochemical characterization of cordon dieback

Eutypa lata is a vascular pathogen of woody plants. In the present study we (i) determined which component(s) of the cell wall polymers were degraded in naturally infected grapevines and in artificially inoculated grape wood blocks; (ii) compared the pattern of wood decay in the tolerant grape cv. Merlot versus the susceptible cv. Cabernet Sauvignon; and (iii) identified secondary metabolites and hydrolytic enzymes expressed by E. lata during wood degradation. Biochemical analyses and a cytochemical study indicated that glucose-rich polymers were primary targets of E. lata. Structural glucose and xylose of the hemicellulose fraction of the plant cell wall and starch were depleted in infected woods identically in both cultivars. Moreover, the more tolerant cv. Merlot always had more lignin in the wood than the susceptible cv. Cabernet Sauvignon, indicating that this polymer may play a role in disease resistance. In vitro assays demonstrated the production by E. lata of oxidases, glycosidases and starch degrading enzymes. Phytotoxic secondary metabolites were also produced but our data suggest that they may bind to the wood. Finally, we demonstrated that free glucose in liquid cultures repressed primary but not secondary metabolism.     

广东丰顺县青蒿产业化发展现状与对策

丰顺县已初步建成一定规模的青蒿种植基地,产业化模式初见端倪。通过建立"GAP"规范,推行标准化生产,打造特色品牌和新型的社会化服务体系等对策,为青蒿的产业化经营和可持续发展提供保障。     

Seasonal stability in parasite assemblages of the Brazilian flathead, Percophis brasiliensis (Perciformes: Percophidae): predictable tools for stock identification

A comparison of the composition and structure of parasite communities of the Brazilian flathead, Percophis brasiliensis Quoy et Gaimard (Perciformes: Percophidae) among seasons during one year was carried out in the Argentine Sea. A total of 195 fish specimens were examined and 25 parasite species were found. Parasite communities in seasonal samples showed a high degree of homogeneity in taxonomic composition and infection levels. Similarity analysis showed that the seasonal stability within and between samples was constant in both the composition and community structure throughout the year. Parasites can, therefore, be considered predictable markers for fish stock identification, independently of the season of capture, at least on an annual scale.     

香蕉原生质体培养研究进展

本文综述了20多年来香蕉原生质体培养的研究概况;对影响香蕉原生质体分离、培养及植株再生因素进行了综述,并提出了香蕉原生质体培养研究展望。