秦岭田峪河流域植被研究

田峪河流域位于秦岭北坡 ,北纬 33°47′～ 34°0 5′,东经 1 0 8°1 5′～ 1 0 8°2 7′。根据田峪河流域植物群落的外貌特征、种类组成及其构成特点 ,将该流域的植被分成 5个类型 : .次生灌丛 ; .落叶阔叶林 ; .针阔叶混交林 ; .针叶林 ; .亚高山灌丛。它与秦岭北坡的植被类型基本一致     

乌伦古河流域克孜赛水库浮游植物群落组成

克孜赛水库是乌伦古河源头的一个小型水库,2008年7月(夏季平水期)、2008年10月(秋季枯水期)和2009年5月(春季丰水期)对水库内浮游植物群落进行了调查分析,共鉴定出浮游植物102种(属),隶属于8个门,以硅藻门和绿藻门为主。3个时期浮游植物密度变化趋势为:枯水期(25.221±3.605×106ind/L)>平水期(12.539±1.064×106ind/L)>丰水期(1.052±0.077×106ind/L)。各季节优势种的组成因气候温度差异而变化,其中以夏季平水期最多,达9种。克孜赛水库温度和水量的变化共同导致了水库浮游植物种类组成、密度、优势种和生物多样性指数的季节变化。Shannon-Weaver多样性指数(H)和Pielou均匀度指数(J)变化趋势较一致:平水期>枯水期>丰水期,而Margalef丰富度指数(D)则于丰水期达最大值。     

Changes in agricultural intensity and river health along a river continuum

1. The impact of agricultural activities on waterways is a global issue, but the magnitude of the problem is often not clearly recognized by landowners, and land and water management agencies. 2. The Pomahaka River in southern New Zealand represents a typical lowland catchment with a long history of agricultural development. Fifteen sites were sampled along a 119-km stretch of the river. Headwater sites were surrounded by low-intensity sheep farming, with high-intensity pasture and dairying occurring in the mid-reach and lower reaches. 3. Water clarity decreased significantly from about 6 m in the headwaters to less than 2 m in the lower reaches. Benthic sediment levels increased significantly downriver, peaking at 35 mg m^??2 below several tributaries with high-intensity agriculture in their catchments. Periphyton levels were also significantly greater in the lower reaches than the headwaters, and coincided with increased nitrogen (DIN) and phosphorus (SRP) concentrations. 4. Macro-invertebrate species richness did not change significantly throughout the river, but species composition did with Ephemeroptera, and to a lesser extent, Plecoptera and Trichoptera dominating the headwater sites (where there was high water clarity, and low nutrient and periphyton levels). Downriver these assemblages were replaced by molluscs, oligochaetes and chironomids. 5. Canonical correspondence analysis indicated that agricultural intensity and physical conditions associated with agriculture activity (e.g. impacted waters, high turbidity and temperature) were strongly associated with the composition of benthic assemblages at differing reaches down the Pomahaka River. 6. The present results indicate that quantifying agricultural intensity within a catchment, particularly relative livestock densities, may provide a useful tool for identifying threshold levels above which river health declines.     

金沙江干热河谷(元谋段)丛枝菌根真菌多样性研究

从金沙江干热河谷(元谋段)75种植物的根际土壤中分离鉴定了44种丛枝菌根真菌, 分属无梗囊霉属Acaulospora、古孢霉属Archaeospora、内养囊霉属Entrophospora、巨孢囊霉属Gigaspora、球囊霉属Glomus和盾巨孢囊霉属Scutellospora, 其中,球囊霉属和无梗囊霉属为金沙江干热河谷中丛枝菌根真菌的优势属。齿状无梗囊霉A. denticulata、刺状无梗囊霉A. spinosa、瘤状无梗囊A. tuberculata,近明球囊霉Glomus claroideum、明球囊霉G. clarum、根内球囊霉G. intraradices、单孢球囊霉G. monosporum、弯丝球囊霉G. sinuosa是金沙江干热河谷(元谋段)的优势种。金沙江干热河谷土壤中丛枝菌根真菌的孢子密度为5~6400个/100g土壤,平均1504;每个根际土壤中丛枝菌根真菌的物种丰富度1~18种,平均9种。     

农业环境中土壤取样误差研究

对自然条件下8种土壤类型、39个取样地块的25个土壤理化参数的取样误差进行了综合研究。结果表明,不同地块间,按累计取样误差大小排序为:池塘>地块边缘>自留地>林地>商品菜地>旱地>水田>滩地。在所有地块测定项目中,取样误差最大的是Cl^-,平均高达70%以上,其次是土壤有效磷,除滩地外取样误差基本上都超过30%;有效钾和全硫的取样误差也多在20%以上;取样误差最小的理化参数与成土母质有关,其中包括各种重金属和全量P、K、Mg以及pH和砂粒等,除极个别外,误差都在10%以下;2种粒度的土壤水分、碳酸钙、粉砂、粘粒、有机碳、全量N、Na、Ca、B和As等11项理化参数的取样误差居中,误差变动于10%～20%之间。聚类分析可以将不同测定项目大致分为3类,客观反映了人类活动对土壤理化参数分布均匀性的影响。     

Detailed study of a river corridor plant distribution pattern provides implications for river valley conservation

River valleys have been subjected to human-induced changes for centuries, but they are still considered regional hotspots of biodiversity. In central Europe, some vascular plant species demonstrate confinement to the corridors of large rivers. They are termed river corridor plants (RCPs). RCPs are an important component of regional biodiversity and include a high proportion of threatened species, thus they deserve attention. Here we examine: (1) the detailed distribution pattern of RCPs within a river valley, (2) the habitat preferences of RCP species, and (3) the correlation between the richness of RCP species and selected variables. The studied variables include: river bed proximity, distance from the river mouth, floodplain coverage, richness of native, red listed and invasive species, and number of habitats considered to be of Europaean Community importance. Surveys were conducted in 10 transects running perpendicularly to the San River bed (Poland, central Europe). Each transect was divided into 14 plots (1 km × 1 km). In each plot, the site locations of RCPs as well as their habitats were recorded. The occurrence of all vascular plant species in a particular plot was also noted. The richness and abundance of RCP species depended on the distance from the river and the floodplain coverage in a plot. The plots located in the vicinity of the river were the richest in RCP species and usually harbored the largest number of native, red-listed and invasive species. They were also characterized by the largest number of habitats considered to be of importance to the European Community. RCP species differed in the degree of confinement to habitats regarded as typical for them. Some of the RCP species were recorded only within typical habitats while others were found in several different types of habitats, including anthropogenic ones. Knowledge concerning the RCP distribution pattern and its correlates can make restoration initiatives in river valleys more effective. While implementing conservation measures in river valleys, one should keep in mind that: (1) hotspots of RCP and invasive species spatially overlap and (2) anthropogenic linear elements occurring within river valleys constitute important habitats for some RCP species.     

青海湟水流域植物区系研究

湟水流域位于青海省的东部,约处于北纬35°56′～37°38′,东经100°35′～103°05′。属于青藏高原和黄土高原的过渡地带,海拔1650～4395m,全区面积约16600km~2,属于大陆性气候和高原大陆性气候类型。本区共有野生种子植物83科、400属、1234种。分别占本区所属的青藏高原植物亚区唐古特地区总科数的92.22％、总属数的78.74％、总种数的54.00％。研究表明,湟水流域植物区系特征为:①在唐古特地区中种类相对较丰富;②温带成分占92.80％,以绝对优势确定了本区系为明显的温带性质(属于以北温带成分,特别是欧亚大陆温、寒地带典型成分为优势的,兼具温性、寒温和高寒类型的温带区系性质,或可称为在温带区系中的过渡区系所具有的“复合型”区系特征);③木本类型少,大多数种类为多年生草本植物,缺乏古老和原始类群,一些中国特有种衍生于其广布的亲缘种中,表明本区系具有年轻和衍生的性质;④我国西南高山区系和华北区系对该区系具有双重影响;⑤为青藏高原植物亚区唐古特植物地区同华北植物地区相互过渡的代表区系之一;⑥特有属和特有种少。在中国种子植物区系分区中,本区属于青藏高原植物亚区中的唐古特地区。     

我国农业环境问题及其防治对策

从农业自然资源、生态环境破坏现状及环境污染3方面对我国农业环境问题现状进行了系统的总结,并对其产生原因进行了初步分析,在此基础上提出防治对策。总体上看,我国农业自然资源短缺且受污染严重;农业生态破坏较为严重;由化肥、农药和农膜等农业投入品造成的面源污染日趋严重;秸秆处置不当、畜禽养殖污染、农村生活污染控制不力造成的环境污染日益严重,乡镇企业及城镇污染向农村的转移又进一步使农业环境恶化。我国农业环境问题的产生很大程度上与部分农业政策的实施有关;此外,农业环境保护立法不完善、执法不力以及农村环境保护意识淡薄、环境管理体系不完善等也是其产生的主要原因。基于以上原因,提出解决农业环境问题的如下对策措施：开展农业政策战略环境评价;重视生态建设,推动资源高效利用,发展生态农业;合理控制农用化学品投入,实施种植业清洁生产;加强畜禽养殖污染控制监管;制定激励机制,减轻农业面源污染;建立健全农村环境污染监管机制;加强宣传教育,增强农民环境保护意识。     

Interactions of hexachlorocyclohexanes with lipid bilayers

Quenching of the fluorescence of a hydrophobic analogue of tryptophan incorporated into lipid bilayers has been used to measure partition coefficients for lindane and the α- and δ-isomers of hexachlorocyclohexane. Partition coefficients between water and lipid are comparable to those between water and octanol and exhibit a negative temperature coefficient. Binding to the lipid phase is limited by saturation of the aqueous phase rather than of the lipid phase. The binding of lindane has no detectable effect on membrane fluidity as measured by fluorescence polarisation of diphenylhexatriene, or on the permeability properties of the membrane, as measured by the leak of carboxyfluorescein.     

The influence of agricultural run-off on bacterial populations in a river

The microbiological quality of the River Riato (Spain) was evaluated. The influence of cattle that roam free in the warm season was marked. The degree of faecal pollution in the river was higher than predicted from the river basin geographical characteristics. The counts of faecal indicators greatly increased when the cattle were allowed to roam free. Counts of enterobacteria and faecal coliforms ranged from 10(3) to 10(6)/100 ml. Faecal streptococci counts were smaller (less than 10/100 ml). Escherichia coli and Pseudomonas aeruginosa were isolated from all samples. Streptococcus bovis was also isolated but not Strep. faecalis.     

The influence of agricultural run-off on bacterial populations in a river

The microbiological quality of the River Riato (Spain) was evaluated. The influence of cattle that roam free in the warm season was marked. The degree of faecal pollution in the river was higher than predicted from the river basin geographical characteristics. The counts of faecal indicators greatly increased when the cattle were allowed to roam free. Counts of enterobacteria and faecal coliforms ranged from 10³ to 10⁶/100 ml. Faecal streptococci counts were smaller (< 10/100 ml). Escherichia coli and Pseudomonas aeruginosa were isolated from all samples. Streptococcus bovis was also isolated but not Strep. faecalis .     

元江干热河谷乳油木果实特性及营养成分分析

乳油木(Vitellaria paradoxa)为非洲热带地区重要的生态恢复树种和油料作物,其果实含有丰富的果油和代可可脂,被称为“植物油中的翡翠”。然而,当乳油木被引种到中国干热河谷后,其果实特征及其营养物质研究未见报道。为大面积种植和综合开发乳油木,该研究以云南省元江县引种的乳油木为研究对象,采用田间调查和室内植物化学提取方法,对其果实生物学性状及营养成分进行分析和评价。结果表明:(1)引种到元江干热河谷的乳油木树形优美高大,果实大(22.15 g/个),可食率高(61.12%)。(2)果肉中膳食纤维含量达41.52 g/100 g,种仁中粗脂肪含量为33.72 g/100 g。(3)果实矿质元素K、Ca、Mg、Na、Fe和Zn含量分别为6 476.70、376.47、181.93、139.20、3.54和1.92 mg/100 g。(4)果肉中氨基酸种类极为丰富(17种),必需氨基酸含量占29.87%,其中天冬氨酸含量最高,为1.51 g/100 g。(5)该区域乳油木的果实形态、膳食纤维、种油、K、Ca和天冬氨酸含量均显著大于原产区。该研究不仅为元江干热河谷乳油木人工种植奠定了理论基础,也为乳油果产业化发展和深加工提供了一定的技术支撑。     

Dynamic patch mosaics and channel movement in an unconfined river valley of the Olympic Mountains

1. River valleys resemble dynamic mosaics, composed of patches which are natural, transient features of the land surface produced by the joint action of a river and successional processes over years to centuries. They simultaneously regulate and reflect the distribution of stream energy and exchanges of sediment, wood and particulate organic matter between riparian and aquatic environments. 2. We determined the structure, composition, dynamics and origin of seven patch types at the reach scale in the Queets River valley in the temperate coastal forests of the Olympic Mountains, Washington (U.S.A.). Patch types included: (1) primary and (2) secondary channels; (3) pioneer bars; (4) developing and (5) established floodplains; and (6) transitional and (7) mature fluvial terraces. 3. Lateral channel movements strongly shape patch distribution, structure and dynamics. The primary channel moved laterally 13 m year^?1, on average from 1939 to 2002, but was highly variable among locations and over time. Mean lateral movement rates ranged from 1 to 59 m year^?1 and moving averages (2 km) ranged from 3 to 28 m year^?1 throughout the valley. 4. Each patch type exhibited characteristic vegetation, soil and accumulations of large wood. Pioneer bars contained peak stem density (69 778 stems ha^?1) and volume of large wood (289 m³ ha^?1). Mature fluvial terraces contained the highest mean stem (1739 m³ ha^?1) and canopy volume (158 587 m³ ha^?1). These patches also contained the most soil nitrogen (537 kg ha^?1) and carbon (5972 kg ha^?1). 5. Patch half‐life (the time required for half of the existing patches to be eroded) ranged from 21 to 401 years among forested patch types. Erosion rates were highest in pioneer bars (2.3% year^?1) and developing floodplains (3.3% year^?1), compared with only 0.17% year^?1 in mature fluvial terraces. New forests formed continually, as pioneering vegetation colonised 50% of the channel system within 18 years, often unsuccessfully. 6. In the Queets River, the structure, composition, and dynamics of the patchy riparian forest depends on the interplay between channel movements and biophysical feedbacks between large wood, living vegetation and geomorphic processes. The cycle of patch development perpetuates a shifting‐mosaic of habitats within the river valley capable of supporting diverse biotic assemblages.     

内陆河流域水资源可持续利用多目标分析数学模型

通过分析内陆河流域水资源可持续利用的生态效益、经济效益、社会效益目标．考虑到水资源可持续利用的承载力和公平性约束条件．运用多目标决策理论建立了干旱区内陆河流域水资源可持续利用的多目标分析数学模型,描述了水资源可持续利用的生态、经济、社会效益目标的实现、构成及其在整个持续利用过程中的基本特性,为促进流域内经济可持续发展提供定量分析依据。     

Airborne fungal load in agricultural environment during threshing operations

The effect of threshing operations on the fungal spora of farm air, has been studied with the culture plate method. Air samples were taken before, during and after the threshing of paddy and wheat grains, at the end of the respective crop seasons. An immediate local increase in the airborne fungal load was observed during threshing operations. In case of wheat the high rise was due toAlternaria tenuissima, followed byDrechslera sp. andCladosporium herbarum. In Boro variety of paddy, the high count was contributed byAlternaria humicola andA. tenuissima, while in Aman variety,Helminthosporium oryzae was the dominant type followed byC. herbarum and unidentified yeasts.Aspergillus spp. were observed in significant numbers before the operation started; their occurrence was negligible during threshing. A considerable number of yeast was observed, particularly during threshing and after threshing operations.