Assessing the risks of wind pollination from fields of genetically modified Brassica napus ssp. oleifera

Summary Intensive research over the past 10 years has produced many genetically-mofified lines of oilseed rape with market potential. Assessment of these lines in statutory trials prior to their release as cultivars is necessary, owing to concern over the likelihood of transgene escape from such crops. Here, we examine the movement of airborne pollen grains from oilseed rape fields and assess their capacity for long-range geneflow.Pollen dispersal from isolated rape fields was monitored over two seasons and related to the distribution of fields and feral (domesticated plants growing outside cultivations) populations of the crop in Tayside and North East Fife regions of Scotland. Airborne pollen density declined with distance and at 360 m was 10% of that at the field margin. Pollen counts of 0–22 pollen grains m³ were observed 1.5 km from source fields and apparently were sufficient in number to allow seed set on emasculated bait plants. Oilseed rape pollen has greater capacity for long-range dispersal than had been suggested by small-scale field trials. Mean separation of oilseed rape fields in the survey area was 410 m and the mean distance from feral populations to commercial fields was 700 m. Sixty percent of feral populations with more than 10 plants occurred downwind and within 2 km of an oilseed rape field. Provided that the flowering biology of genetically-modified oilseed rape does not differ from the conventional crop, these data suggest that transgene movement to non genetically-modified fields or feral populations is likely following commercial release.     

Differentiating between physical and chemical constraints on pesticide and water movement into and out of soil aggregates

A laboratory experiment comparing the movement of ³H₂O and [¹⁴C]isoproturon into and release from soil aggregates is described. Small aggregates (2.0–2.4 mm) were prepared from a clay topsoil and maintained at three different initial moisture conditions. A small volume of the radioisotope solution was introduced prior to bathing the aggregates in a 2 mM CaCl₂ solution to represent new rainwater. Whilst the ³H₂O was imbibed by the air-dry aggregates, the pesticide did not follow the water but remained on the surface of the aggregates. This may be related to its sorptive properties and an excess of sorption sites on the sorbent with respect to the sorbate. Increasing the length of exposure of the moist aggregates to [¹⁴C]isoproturon reduced the initial release of the compound into the bathing solution, probably due to diffusion (retarded by sorption) into the aggregates. The diffusion model described by Crank and a non-equilibrium desorption model were used to analyse the ³H₂O and [¹⁴C]isoproturon release curves. This showed that the release of ³H₂O from the dry aggregates was controlled by diffusion. The release of isoproturon was probably controlled by non-equilibrium sorption/desorption from air-dry aggregates and by a combination of non-equilibrium sorption/desorption and diffusion from wet aggregates. © 1999 Society of Chemical Industry     

海水养殖废水灌溉条件下山东滨海盐土溶质迁移及其平衡研究

在半干旱的山东莱州地区,利用小型蒸渗装置研究海水养殖废水灌溉下滨海盐土溶质迁移特征以及溶质平衡。结果表明:在耐盐作物-菊芋的水分临界期(6月初)和水分最大效率期(9月初)海水养殖废水灌溉两次,根区土壤中的盐分对于不同淋洗分数的处理分别增加了89 78,92 35,96 10和102 85g,部分盐分被淋出土体,淋洗效率分别达到17 3%,24 4%,31 1%和36 8%。海水养殖废水灌溉后,土壤中的养分如硝态氮、氨态氮和活性磷酸盐均有所增加,其迁移能力分别为硝态氮>活性磷酸盐>氨态氮,说明硝态氮极易淋失。在选择较小淋洗分数(0 1和0 2)的情况下,大部分的氨态氮和活性磷酸盐被保留在土壤中成为作物的有效养分。此外,大强度的降雨对盐分的淋洗也起到关键性的作用,但也会导致养分的淋失。因此,适时适宜矿化度的海水养殖废水结合适当的淋洗分数补充灌溉耐盐植物,有效地增加了土壤养分,而盐分不会过量累积。     

鄱阳湖东北地区新构造运动与旅游用地资源的形成

从新构造运动的观点出发,讨论了在鄱阳湖东北地区新构造运动强烈抬升区内、沉降区内、轻微抬升区内及过渡区内的旅游自然景观的形成,特点,并提出了合理规划和开发不同区域内旅游用地的建议。     

松口蘑的镇咳、祛痰、平喘作用研究

用动物实验方法，研究松口蘑子实体水溶性提取液治疗支气管炎，咳、痰、喘三种症状的效果及其药理作用。给豚鼠腹腔注射松口蘑子实体水溶性提取液，能非常显著地增大方波刺激迷走神经的引咳阈值；给小白鼠灌胃。能非常显著增加其呼吸道的酚红排泌量；给豚鼠离体气管滴入提取液，对气管有非常显著的扩张效应；该提取液能非常显著地延长豚鼠的引喘潜伏期，对蛙口腔粘膜上皮的纤毛运动有一定的加快作用。松口蘑子实体水溶性提取液有明显的镇咳、祛痰和平喘作用。     

人工胡杨林地夏季水盐动态研究

针对新疆石河子150团人工胡杨林进行了夏季土壤水盐时空变化规律研究。结果表明:在时间变化上,土壤含水率主要受气温影响,随气温升高而降低;在土壤分层区间上,除表层土壤外,土壤盐分与水分具有同步变化趋势,体现了盐随水动的特点,盐水变化的相关性系数为0.98;同时,pH也随着月份的推移而表现出逐渐升高的趋势,pH与CO32-、HCO3-、Cl-、Ca2+呈现显著相关性。     

Spatiotemporal variations of soil surface roughness from in-situ laser scanning

Microtopography and roughness are highly dynamic properties of the soil surface and important factors governing surface runoff and erosion processes. While various remote sensing technologies were successfully applied for topography measurements at different spatial scales, there is a lack of field studies that collected systematically microtopography data over long observation periods. In this paper an approach to measure and quantify surface roughness in the field based on laser scanning technologies is presented. Between June 2004 and November 2005 97 in-situ measurements were conducted in a test site with two different sandy substrates in vegetation-free conditions. Two-dimensional high-resolution (1 mm) datasets where generated for eight micro erosion plots of 0.25 to 2.9 m² in size. Dynamics and pattern formation were quantified for surface roughness and surface height changes. Roughness patterns at different scales were analyzed by local roughness indices using sliding windows of 3 to 55 mm in size. Results show strong spatial and temporal dynamics in surface roughness as well as substrate-specific variations. Temporal roughness variations could be detected and were linked to precipitation patterns. The methods presented in this paper are considered suitable to generate high-resolution datasets on spatiotemporal and multi-scale microtopography patterns and to advance the understanding of surface processes at small scales in natural environments.     

滨海盐渍土水盐运动室内实验研究及治理对策

对滨海盐渍土水盐运动规律及其影响因素进行了实验研究,初步获得淋洗脱盐过程中3个盐峰阶段;同时利用相关分析和通径分析,取得了土壤盐分含量及主要盐分离子和土体构型、粘粒含量等对水盐运移的影响程度。提出了因地制宜、综合治理的对策。     

Seasonal movement patterns of Credit River brown trout (Salmo trutta)

Zimmer M, Schreer JF, Power M. Seasonal movement patterns of Credit River brown trout (Salmo trutta).
Ecology of Freshwater Fish 2010: 19: 290–299. © 2010 John Wiley & Sons A/S Abstract – Movement habits in riverine populations of brown trout vary among watersheds. Thus it is important to identify factors influencing differences in individual behaviour so as to improve the information resource base available for the design of river‐specific management strategies. Such information is particularly needed in the rapidly urbanising watersheds of eastern North America where relatively little is known about anthropogenic influences on brown trout populations. In this study, we examined the influence of water temperature on brown trout behaviour in the Credit River in south‐central Ontario, Canada with respect to seasonal movement patterns. Observed patterns of movement were also correlated with variations in river discharge and habitat quality. Forty‐three radio‐tagged, adult brown trout were tracked in a confined 39.8 km portion of the Credit River from 15 May 2002 to 28 July 2003. Fish were captured in three sections of the river that differed in distance downstream and habitat quality. Fish size had little impact on movement patterns. However, there was considerable variation in seasonal movement with upstream movements to summer positions, maintenance of summer positions, downstream and often extensive movements in fall. Also observed was maintenance of winter positions and repeated upstream movements in late spring‐early summer to previously used summer positions. The elaborate movement behaviour in the Credit River population was attributed to seasonal changes in thermal habitat quality. Fish tagged in less suitable thermal habitats moved significantly more than fish from more suitable thermal habitats.