西北干旱半干旱区耕地面积变化与人口、经济发展的相关关系研究——以甘肃省为例

基于甘肃省1997-2006年耕地十年变化的数据,研究了甘肃省经济发展过程中耕地面积变化的过程,并运用统计分析方法,对近十年来耕地变化与人口以及固定资产投资、人均GDP等经济指标进行相关分析.结果表明:耕地面积与人口呈相反趋势,与固定资产投资、人均GDP、城市化水平呈正" U"型三次曲线相关,即固定资产投资总额、人均G...     

西安城市化进程与环境生态问题研究

通过对西安城市化过程的分析,得出50年来西安城市化的发展大体经历了三个阶段:快速发展阶段,停滞阶段和稳步上升阶段。城市化水平的提高与国民经济的增长基本同步,回归分析表明:西安城市化水平与人均GDP的对数呈正比关系,城市化水平的提高有效地推动了社会经济的发展。在城市化进程中,产业结构的调整与第二、第三产业比重的上升加速了城市化的推进。第三产业在国民经济中的比重与城市化水平呈正相关系。伴随城市化的发展,出现了耕地面积减少及大气污染、水污染、固体废物污染、噪声污染等环境生态问题,通过对城市化过程中的环境生态问题分析,指出实现西安城市化可持续发展的基本途径。     

京津冀地区城市化效率与生态效率时空耦合关系研究

运用非期望产出SBM模型、相对发展度模型与耦合度模型对京津冀地区城市化与生态环境两者的效率关系进行了耦合研究。结果表明:2005-2014年来京津冀地区城市化效率与生态效率波动交替上升,整体耦合度呈"W"型增长变化;耦合阶段由以中低度耦合为主转变为以中高度耦合为主。其中,京津两地耦合发展长期保持在较高水平而河北总体水平偏低,且各地区差异较大但整体发展趋势良好;在耦合类型方面,则经历了由城市化效率滞后型向生态效率滞后型转变,两者同步发展型地区数量增多的过程。     

祁连山高海拔雨养农业区油菜、小麦光合特性比较研究

在作物生长旺盛期,采用LI-6400便携式光合仪测定了祁连山高海拔雨养农业区环境因子和油菜、小麦叶片光合生理指标,比较了油菜、小麦及低海拔地区作物光合参数的差异性。结果表明:光合有效辐射和空气温度均呈单峰型日变化曲线,而空气湿度呈"S"型日变化曲线,大气CO2浓度为早晚较低,下午高。油菜和小麦的叶片净光合速率日变化均呈双峰型曲线,存在"午休"现象,且上午光合速率高于下午。油菜的蒸腾速率日变化呈双峰型曲线,小麦的蒸腾速率却呈单峰型曲线。气孔导度日变化大体呈"S"型曲线。光合有效辐射是影响叶片净光合速率和蒸腾速率的主要环境因子之一,空气湿度是气孔导度的主要影响因子。大气CO2浓度与小麦叶片的净光合速率、蒸腾速率和气孔导度呈显著正相关关系。     

1980年以来内蒙古城市化水平趋势及其特征

定量分析城市化水平及其动态变化过程具有重要意义.文中结合城市化的丰富内涵,构建指标体系,运用模糊综合评价法和层次分析法对1980年以来内蒙古城市化水平及其趋势进行了定量分析与评价.结果显示:1980-2007年间内蒙古城市化水平显著提升,城市化综合评价值从1980年的0.0990提升至2007年0.8848,具有波动发...     

干旱区绿洲型生态城市建设能力评价

绿洲生态系统是支撑绿洲城市国民经济和社会发展的重要生态要素.文中基于城市化与生态化两大子系统的作用机理,从人口空间城市化、经济城市化、社会生活城市化、生态环境水平、生态环境压力、生态环境抗逆水平六个层面构建干旱区绿洲型生态城市建设能力评价指标体系,并结合典型绿洲型城市奎屯市的实际情况,着重探讨了其城市化与生态化动态耦合...     

宝鸡市人口城市化发展研究

本文计算了宝鸡市55年来人口城市化水平,并与陕西省关中地区、陕西省其它城市以及全国几个重点城市进行对比分析,得出:宝鸡城市化发展趋势与关中地区基本一致;人口城市化水平全省排名第四位;与全国重点城市相比,城市化水平较低。进一步分析宝鸡城市化水平与GDP之间的关系及增长趋势,得出二者的相关关系。在分析宝鸡城市化发展缓慢的原因之上给出宝鸡市良性发展城市化的提升战略研究。     

新疆城市化进程及驱动力研究

城市化进程在不同发展阶段和经济分工地域,表现为不同的驱动机制。根据城市发展的一般规律和中国快速城市化的特殊表征,从人口、经济、社会、土地四个方面设计城市化进程综合评价指标体系,通过构建模型、权重分析及水平测度,得出:新疆城市化处于快速城市化的初级阶段,但综合水平及增长趋势明显滞后;经济增长和土地扩张是城市化主要驱动因子,人口和社会城市化动力不足;城市化进程在满足资源型经济增长的同时,未能充分发挥提高区域发展质量的带动效益;受产业结构、水资源及生态环境限制,城市用地扩张增量有限,劳动力转移和非农化转变缓慢,财政支持、重点建设与社会事业协调并进驱进缓慢。     

甘肃省经济发展与环境质量的交互耦合关系

改革开放以来,甘肃省经济持续发展,但与此同时,也不可避免地对环境产生了较大压力,付出了昂贵的生态环境成本。本文分别分析了人均GDP、工业总产值、城市化水平与工业废水、工业废气、二氧化硫及固体废弃物排放量的关系,得出以下结论:1)受特殊的经济发展态势、产业结构变动、污染治理资金投入、污染物排放及环境政策等因素的影响,甘肃省经济发展与环境质量的交互耦合关系并非呈典型的倒"U"型环境库茨涅茨曲线,而是呈三次曲线;2)甘肃省通过改变经济发展模式,走内涵式的新型工业化道路,可以避免倒"U"型峰值的出现。     

城市化与资源环境系统耦合研究——以西安市为例

分析论证了城市化与资源环境之间的耦合关系,并且根据其耦合特征,构建了耦合理论体系。通过对西安市城市化与资源环境复合系统耦合度的分析,表明:1988-2007年耦合度从0.25上升到0.58,系统经历了两个"S"型演化周期,跨越了低级耦合、颉颃阶段,2005年达到磨合阶段;耦合系统在1993-1995年、1999-2000年两个时间段分别受到环境与资源瓶颈的约束。城市化与资源环境耦合周期性与波动性的特点是国家政策、经济发展、基础设施建设和生态环境反馈综合作用的反映。     

Dermestid beetles in ‘evolution Canyon’, lower Nahal Oren, Mt. Carmel, including new records for Israel

Fifteen species of dermestid beetles were recorded at ‘Evolution Canyon’ (EC), Lower Nahal Oren, Mt. Carmel, Israel. They represent ~35% of known Israeli dermestid species. The following three species were recorded for the first time in Israel:Trogoderma svriaca Dalla Torre, 1911;Ctesias svriaca Ganglbauer, 1904; andAnthrenus (s.str.) jordaniens Pic, 1934. Adults of 13 species were collected on the more solar radiated, warmer and climatically more fluctuating south-facing slope (SFS); ten species were collected on the opposite, north-facing slope (NFS), which was cooler and climatically more stable. The abundance of adult dermestid beetles was 1.9 times higher on the SFS than on the NFS (86 and 47, respectively). Species richness and abundance distribution at EC (three collecting stations on each slope and one at the valley bottom) were significantly negatively correlated with the plant cover that consisted of trees and bushes (Spearmanr _s ,P=0.007 and 0.039, respectively) and perennials (Spearmanr _s ,P=0.039 and 0.077, respectively), indicating that non-woody plants were preferred by adult dermestid beetles.     

Epidemiology of Toxigenic Fungi and their Associated Mycotoxins for Some Mediterranean Crops

Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.     

A survey of the genera of<Emphasis Type="Italic">Microgaster</Emphasis> latreille and<Emphasis Type="Italic">Hygroplitis</Emphasis> thomson (Hymenoptera: Braconidae: Microgastrinae) from China

The genera ofMicrogaster Latreille 1804 andHygroplitis Thomson 1895 from China are presented systematically in this paper. Thirty-two species ofMicrogaster and three species ofHygroplitis are known in China. Diagnosis, character variation, distribution and host of each species among the two genera are presented, including its host and distribution. Keys to the species ofMicrogaster andHygroplitis are given. http://www.phytoparasitica.org posting Dec. 19, 2006.     

Plant Viruses Transmitted by Whiteflies

One-hundred and fourteen virus species are transmitted by whiteflies (family Aleyrodidae). Bemisia tabaci transmits 111 of these species while Trialeurodes vaporariorum and T. abutilonia transmit three species each. B. tabaci and T. vaporariorum are present in the European–Mediterranean region, though the former is restricted in its distribution. Of the whitefly-transmitted virus species, 90% belong to the Begomovirus genus, 6% to the Crinivirus genus and the remaining 4% are in the Closterovirus, Ipomovirus or Carlavirus genera. Other named, whitefly-transmitted viruses that have not yet been ranked as species are also documented. The names, abbreviations and synonyms of the whitefly-transmitted viruses are presented in tabulated form together with details of their whitefly vectors, natural hosts and distribution. Entries are also annotated with references. Whitefly-transmitted viruses affecting plants in the European–Mediterranean region have been highlighted in the text.     

Broad bean mottle virus in Morocco; curculionid vectors,and natural occurrence in food legumes other than faba bean (Vicia faba)

Broad bean mottle virus (BBMV) was transmitted from infected to healthy faba-bean plants by the curculionid weevilsApion radiolus Kirby,Hypera variabilis Herbst,Pachytychius strumarius Gyll,Smicronyx cyaneus Gyll, andSitona lineatus L. The latter appeared to be an efficient vector: acquisition and inoculation occurred at the first bite, the rate of transmission was c. 41%, and virus retention lasted for at least seven days.S. lineatus transmitted the virus from faba bean to lentil and pea, but not to the three genotypes of chickpea tested. This is the first report on the generaHypera, Pachytychius, andSmicronyx as virus vectors, and onA. radiolus, H. variabilis, P. strumarius, andS. cyaneus as vectors of BBMV.Out of 351 samples of food legumes with symptoms suggestive of virus infection, 16, 11, 19, and 17% of the samples of chickpea, lentil, pea, and common bean, respectively, were found infected when tested for BBMV in DAS-ELISA. This is the first report on the natural occurrence of BBMV in chickpea, lentil, pea, and common bean. The virus should be regarded as a food-legume virus rather than a faba-bean virus solely, and is considered an actual threat to food legume improvement programmes.     

Characterization of potato potyvirus Y (PVY) isolates from seed potato batches. Situation of the NTN, Wilga and Z isolates

A collection of 38 PVY isolates from seed potato batches, originating from several Western European countries, was characterized by using current biological, serological and molecular tools differentiating PVY strains and groups. The correlation between the three kinds of tests was good but not absolute. No single serological or PCR method was able to discriminate among the five isolate groups found. Twenty-nine isolates belonged to the PVY^N strain and six to the PVY^O strain. No PVY^C was found. Two other isolates reacted serologically like PVY^O, but were unable to elicit a hypersensitive response from the Ny_tbr gene and probably represent the PVY^Z group. At the molecular level, these two isolates showed a combination of both PVY^O and PVY^N and could be recombinants of these strains. Another isolate reacted serologically like PVY^O, but induced vein necrosis in tobacco, like PVY^N-Wilga. Some PVY^N isolates caused tuber ring necrosis in glasshouse conditions. These might belong to the PVY^NTN group. The PVY^NTN, PVY^N-Wilga and PVY^Z groups probably represent pathotypes within strains PVY^N and PVY^O, respectively. The present study also confirms previous reports showing a high genetic variation at the 5 end within the PVYN strain.     

The autumn leafroller: Phenology,damage and parasitoids in a Dutch apple orchard

The phenology of the autumn leafroller,Syndemis musculana, a local pest of apple, was studied in order to forecast larval emergence. From 1983–1986, peak flight as determined with sexpheromone traps was always between 13–18 May. The duration of embryonic development was determined at various constant temperatures and used to estimate the periods of egg hatch in these four years. Each year, most eggs should have hatched in the second decade of June.Differences in attack rates between apple cultivars seem to be explained largely by the variation in picking time. Larvae are only half grown at the beginning of harvest (cv. James Grieve), and have gone into hibernation when the latest variety (cv. Golden Delicious) is picked. Moreover, the varieties Cox's Orange Pippin and Belle de Boskoop, picked about half time, are liable to receive additional damage by caterpillars brought with the picked fruits into storage.Various hymenopterous parasites were reared from caterpillars. As the only leafroller in the orchard which hibernates as mature larva,S. musculana may promote winter survival of some parasitoids, like the eulophidColpyclypeus florus.Samenvatting De fenologie van de herfstbladroller (Syndemis musculana Hübner), een incidentele plaag op appel, werd nader bepaald met het doel het uitkomen van de eieren te kunnen voorspellen. In 1983–1986 viel de piekvlucht, bepaald met behulp van feromoonvallen, steeds tussen 13 en 18 mei.De ontwikkelingsduur van de eieren bij verschillende constante temperaturen werd gebruikt om de periode van uitkomen te schatten. De meeste eieren zullen ieder jaar in de eerste helft van juni uitkomen.Geconstateerde verschillen in schade tussen appelrassen blijken goeddeels terug te voeren op verschillen in pluktijdstip. De rupsen van de herfstbladroller zijn pas half-was als de eerste appels eind augustus geplukt worden, terwijl tegen het einde van de oogst begin oktober de meeste al in winterslaap zijn. Met name tussentijdse rassen, als Cox's Orange Pippin and Schone van Boskoop, lopen extra schade op doordat grotere rupsen met de geplukte vruchten in de kist terecht komen.Uit de rupsen werden negen, al van andere boomgaardbladrollers bekende, sluipwespen gekweekt, Omdat deze bladrollersoort, als enige in de boomgaard, als volgroeide rups overwintert, lijkt zij bij uitstek geschikt als winterwaard.This study was carried out at the Experimental Orchard De Schuilenburg, Schuilenburg 3, 4041 BK Kesteren, the Netherlands, to which address correspondence should be addressed.     

Diagnostics,genetic diversity and pathogenic variation of ascochyta blight of cool season food and feed legumes

Molecular diagnostic techniques have been developed to differentiate the Ascochyta pathogens that infect cool season food and feed legumes, as well as to improve the sensitivity of detecting latent infection in plant tissues. A seed sampling technique was developed to detect a 1% level of infection by Ascochyta rabiei in commercial chickpea seed. The Ascochyta pathogens were shown to be genetically diverse in countries where the pathogen and host have coexisted for a long time. However, where the pathogen was recently introduced, such as A. rabiei to Australia, the level of diversity remained relatively low, even as the pathogen spread to all chickpea-growing areas. Pathogenic variability of A. rabiei and Ascochyta pinodes pathogens in chickpea and field pea respectively, appears to be quantitative, where measures of disease severity were based on aggressiveness (quantitative level of infection) rather than on true qualitative virulence. In contrast, qualitative differences in pathogenicity in lentil and faba bean genotypes indicated the existence of pathotypes of Ascochyta lentis and Ascochyta fabae. Therefore, reports of pathotype discrimination based on quantitative differences in pathogenicity in a set of specific genotypes is questionable for several of the ascochyta-legume pathosystems such as A. rabiei and A. pinodes. This is not surprising since host resistance to these pathogens has been reported to be mainly quantitative, making it difficult for the pathogen to overcome specific resistance genes and form pathotypes. For robust pathogenicity assessment, there needs to be consistency in selection of differential host genotypes, screening conditions and disease evaluation techniques for each of the Ascochyta sp. in legume-growing countries throughout the world. Nevertheless, knowledge of pathotype diversity and aggressiveness within populations is important in the selection of resistant genotypes.     

Characterization of Sclerotinia minor populations in Texas peanut fields

In the summer of 2004 an epidemic of sclerotinia blight of peanut, a disease caused by Sclerotinia minor, occurred in Texas in fields where the disease was never previously detected. The disease was observed on many plants within one of the fields (>3000 disease foci), although most foci were <1 m. It is hypothesized that these observations were inconsistent with the recent introduction of a monocyclic pathogen, even if disease developed under conducive environmental conditions. The pattern of disease is most suggestive of the presence of foliar (ascospore) infections, although air temperature was above the known limits for apothecia development if the pathogen had arrived in the field in 2004 peanut seed. To further examine this epidemic, 232 isolates were collected, across a variety of spatial scales spanning this field and other Texas peanut fields, and evaluated for aggressiveness, fungicide sensitivity and genotypic diversity. There was wide variation among isolates for the phenotypic characteristics measured, but there was no evidence that a genotypically unique, highly aggressive, and fungicide resistant isolate had been introduced or evolved. The predominant genotype, TX1, which contained 154 isolates, was found in every county and field population.     

Eyespot of Cereals Revisited: ITS phylogeny Reveals New Species Relationships

Four species so far classified in Pseudocercosporella or Ramulispora (hyphomycetes) are associated with eyespot disease symptoms of cereals. Two of these have been linked to teleomorphs that were described in Tapesia. Sequence data derived from the Internal Transcribed Spacer region (ITS1, 5.8S and ITS2) of the rDNA operon showed, however, that the eyespot fungi associated with Tapesia are not congeneric with Ramulispora sorghi, the type of Ramulispora. The genus name Tapesia is now rejected in favour of the conserved name Mollisia, which appears to comprise heterogeneous fungi. Tapesia yallundae is not closely related to the type of Mollisia, M. cinerea, but clusters separately, being more closely allied to species with Cadophora anamorphs. A new holomorph genus, Oculimacula, is therefore proposed for teleomorphs of the eyespot fungi, while the anamorphs are accommodated in Helgardia gen. nov.