街谷绿化消减机动车排放污染物的研究方法与进展

随着街道两侧建筑群向高密度、高层化发展,传统“树越多越好”的绿化模式在应对城市街谷空气污染时是否适用受到广泛关注。明晰街谷绿化植物特征及其种植设计模式对机动车排放污染物消减的调控机理是发挥其提升街谷空气品质的重要前提。本文通过对近年国内外相关文献的梳理,比较分析了现场观测、风洞试验和数值模拟3种研究方法的适用性及局限性,详细剖析了行道树、绿篱两类绿化模式对街谷空气污染物扩散与沉降的影响机制,提出了一套面向空气质量提升的街谷绿化适应性设计工作框架。最后,分别从典型街谷绿化设计图示语言研制、街谷空气污染暴露评估技术指南编制、计算机流体力学模型中街谷绿化效应物理过程参数化方案优化等方面进行探讨,以期为后续研究提供思路和借鉴。     

商代前期中原地区多品种农作物种植制度的初探：以河南新郑望京楼遗址为例

农业经济的发展是华夏文明形成的最重要的前提条件之一,郑洛地区作为夏商王朝建都和统治的核心区域,其农业经济发展状况一直是学术界研究的重点问题。相关研究表明,多品种农作物种植制度在龙山时期中原地区的出现,在华夏文明的形成过程中可能起到了至关重要的作用。为了探索这一种植制度在商代前期中原地区的具体实践情况,本文选取河南新郑望京楼遗址夏商时期（二里头文化和二里岗文化时期）29例先民肢骨和23例先民肋骨进行C、N稳定同位素分析。结果表明,先民骨胶原的δ¹³C值变化范围为-18.1‰~7.0‰,平均值为-9.5‰±2.1‰（n=52）,δ¹⁵N值变化范围为7.3‰~10.5‰,平均值为8.9‰±0.7‰（n=52）,先民仍以C₄类食物（粟黍）为主,但是也包含少量C₃类（水稻、小麦或大豆）食物,证明中原地区自龙山时代出现的多品种农作物种植制度,在商代得以延续,但是粟作农业的主导地位,始终未发生明显变化,这可能与中原地区长期以来的旱作农业经济模式习惯有关。     

乌天麻与红天麻杂交制种中定植升温时间研究

分析不同升温时间对乌天麻（Gastrodia elata f.glauca）、红天麻（Gastrodia elata f.elata）箭麻生长习性、花期同步及杂交种子发育影响,为早期获得高质量天麻杂交种子材料,促进天麻杂交种高效育苗提供科学依据。对乌天麻和红天麻箭麻不同时间定植升温（22℃）下花茎出苗时间、始花时间、花茎高度、杂交种子质量等进行分析。结果显示,不同升温时间是影响箭麻出苗时间、始花时间的主要因素,乌天麻集中于2月中下旬出苗,红天麻升温10～15 d后陆续出苗;生态变型是影响箭麻生育期长短、花期花朵数的主要因素,乌天麻比红天麻生育期长21.47 d,对花期及蒴果采收期无较大影响,红天麻比乌天麻更易完成抽薹;不同升温时间条件下,乌天麻挂果率为87.76%,红天麻挂果率为94.53%;母本决定杂交种子质量,以红天麻为母本、乌天麻为父本所得杂交种子活性为94.32%,优于以乌天麻为母本、红天麻为父本所得杂交种子活性。因此,生产中应于1月中旬对乌天麻开始升温,待乌天麻出苗后（15 d左右）开始对红天麻升温催芽,使得乌天麻与红天麻于3月中上旬花期同步,4月初可获得优良杂交天麻种子。     

An Introduction to a Special Issue on Large‐Scale Submerged Aquatic Vegetation Restoration Research in the Chesapeake Bay: 2003–2008

The Chesapeake Bay is one of the world's largest estuaries. Dramatic declines in the abundance and distribution of submerged aquatic vegetation (SAV) in the Chesapeake Bay over the last few decades led to a series of management decisions aimed at protecting and restoring SAV populations throughout the bay. In 2003, the Chesapeake Bay Program established a goal of planting 405 ha of SAV by 2008. Realizing that such an ambitious goal would require the development of large‐scale approaches to SAV restoration, a comprehensive research effort was organized, involving federal and state agencies, academia, and the private sector. This effort differs from most other SAV restoration programs due to a strong emphasis on the use of seeds rather than plants as planting stock, a decision based on the relatively low labor requirements of seeding. Much of the research has focused on the development of tools and techniques for using seeds in large‐scale SAV restoration. Since this research initiative began, an average of 13.4 ha/year of SAV has been planted in the Chesapeake Bay, compared to an average rate of 3.6 ha/year during the previous 21 years (1983–2003). The costs of conducting these plantings are on a downward trend as the understanding of the limiting factors increases and as new advances are made in applied research and technology development. Although this effort was focused in the Chesapeake Bay region, the tools and techniques developed as part of this research should be widely applicable to SAV restoration efforts in other areas.     

Preliminary estimates of the potential for carbon mitigation in European soils through no-till farming

In this paper we estimate the European potential for carbon mitigation of no-till farming using results from European tillage experiments. Our calculations suggest some potential in terms of (a) reduced agricultural fossil fuel emissions, and (b) increased soil carbon sequestration. We estimate that 100% conversion to no-till farming would be likely to sequester about 23 Tg C y^–1 in the European Union or about 43 Tg C y^–1 in the wider Europe (excluding the former Soviet Union). In addition, up to 3.2 Tg C y^–1 could be saved in agricultural fossil fuel emissions. Compared to estimates of the potential for carbon sequestration of other carbon mitigation options, no-till agriculture shows nearly twice the potential of scenarios whereby soils are amended with organic materials. Our calculations suggest that 100% conversion to no-till agriculture in Europe could mitigate all fossil fuel-carbon emissions from agriculture in Europe. However, this is equivalent to only about 4.1% of total anthropogenic CO₂-carbon produced annually in Europe (excluding the former Soviet Union) which in turn is equivalent to about 0.8% of global annual anthropogenic CO₂-carbon emissions.     

2010年宜昌市铜绿假单胞菌的耐药性分析

了解宜昌市铜绿假单胞菌（Pseudomonas aeruginosa）临床分离株的耐药现状。宜昌市城区5所医院临床分离的铜绿假单胞菌菌株,用K-B法作药敏试验,并根据统计其耐药情况及耐药表型（模式）分析可能存在的耐药机制。临床分离的铜绿假单胞菌共1 575株,耐药率依次为阿米卡星7.1%、美罗培南17.2%、头孢吡肟20.4%、头孢哌酮/舒巴坦21.0%、哌拉西林/他唑巴坦22.5%、环丙沙星23.1%、庆大霉素23.4%、头孢他啶25.0%、亚胺培南25.2%、哌拉西林30.4%、氨曲南34.5%、复方新诺明59.0%、米诺环素75.6%。多重耐药（MDR）和泛耐药（PDR）株分别占41.5%和0.17%。对各种抗假单胞菌药物分别耐药的菌株仍有13%～25.7%对阿米卡星敏感,提示在严重铜绿假单胞菌感染患者的治疗中,β内酰胺类抗假单胞菌药加氨基糖苷类仍是一个很好的联合用药组合。细菌耐药性仍呈增长趋势,临床上感染多重耐药和泛耐药的铜绿假单胞菌的治疗仍很棘手,应合理使用抗生素,尽量延缓耐药菌株的出现。     

Effects of planting method on the recovery of arboreal ant activity on revegetated farmland

Ecological restoration aims to re‐establish both biodiversity and ecological function in damaged ecosystems. Ants are important drivers of ecological functions and are early colonizers of restored ecosystems. Rates at which ants perform functions are thought to be fuelled by access to plant sugars. In revegetated farmland in south‐eastern Australia, I tested if ant activity on trees, which reflects use of arboreal sugars, follows a predictable trajectory of recovery towards a remnant‐like state. Additionally, I examined whether planting method alters this trajectory by comparing tube stock (TS), which results in low Eucalyptus densities, with direct seeding (DS), which results in high Eucalyptus densities. Replicate sites (n = 5) of young (planted between 1998 and 2001) and old (planted between 1989 and 1994) TS and DS revegetation, pastures and remnants were compared. Activity on trunks was significantly positively correlated with ant tending of Hemiptera in young and old revegetation. In DS plantings, activity and estimated liquid loads on Eucalyptus trees were low and rapidly approached that in remnants, while TS sites remained similar to high values observed in pastures with trees. Patterns for Acacia were less clear, reflecting consistent densities for this species between TS and DS. At the whole‐of‐field scale, planting methods did not differ. Importantly, although trajectories differed, neither TS nor DS sites approached the low activity or estimated liquid loads observed in remnants. Rates of ant use of arboreal sugars and associated sugar‐fuelled processes may thus take considerably longer to recover than the period covered by this study. This finding suggests planting method may affect the trajectory and outcome of revegetation for plant health, as well as sugar‐fuelled ecosystem functions performed by ants.     

茉莉酸甲酯和虫害诱导棉花对棉蚜及其天敌选择行为的影响

以棉蚜及其天敌十一星瓢虫、叶色草蛉为对象,通过Y型嗅觉仪测定了3种昆虫对不同味源物的行为反应。结果表明,健康棉株叶片对棉蚜的吸引作用与虫害棉叶和茉莉酸甲酯(MeJA)处理棉叶未存在显著性差异;十一星瓢虫和叶色草蛉对虫害棉叶的选择性是健康棉叶的2.7和2.2倍(P<0.001),对MeJA处理棉叶的选择性明显高于健康叶片(P<0.001),其中0.02μmol.mL-1处理的棉叶对天敌的吸引力最强,单一的MeJA对十一星瓢虫和叶色草蛉也具有吸引作用。     

Impact of cotton planting date and nitrogen fertilization on Bemisia argentifolii populations

The silverleaf whitefly (Bemisia argentifolii Bellows and Perring) is a widely distributed pest of cotton (Gossypium hirsutum L.) and the population levels may be affected by rates of nitrogen fertilization and planting date. Field experiments were conducted to investigate the impact of cotton planting date and nitrogen fertilization on silverleaf whitefly population dynamics. Cotton was planted on 26 April and 8 June, for the early and late plantings, respectively. Nitrogen treatments consisted of soil applications of 0, 112, 168 and 224 kg of nitrogen per hectare. The population levels of adult whiteflies were much higher on early-planted cotton than on late planting. Also, increased numbers of adult whiteflies on both early and late plantings occurred with increasing amounts of applied nitrogen.Applied nitrogen increased seed cotton yields of early plantings but had no effect on the yields of late plantings.     

A Comparative Test of Mechanized and Manual Transplanting of Eelgrass, Zostera marina, in Chesapeake Bay

Abstract The laborious process of manual seagrass transplanting has often limited the size of seagrass restoration efforts. This study tested the efficiency of a mechanized planting boat, previously used for transplanting Halodule wrightii, relative to manual transplanting methods for establishing Zostera marina in Chesapeake Bay. Eelgrass planting was conducted at two sites, one each in the Rappahannock and James rivers, in October 2001. The methods were evaluated by three criteria: (1) initial planting success = proportion of attempted planting units (PUs) initially established (number confirmed in sediment by divers/number attempted); (2) survival = proportion of the initially established PUs persisting over 1, 4, and 24 weeks; and (3) efficiency = labor (in person·seconds) invested in each surviving PU. Initial planting success was significantly lower for the planting boat (24 and 56% at the Rappahannock and James sites, respectively) than for manual transplanting (100% at both sites). At the Rappahannock site, survival of initially established PUs declined over time for both methods, but while mean survival was always higher for manually planted rows, differences in survival between methods were not statistically significant. At the James site, survival to 1 and 4 weeks was significantly lower for the machine than for the manual method, but survival to 24 weeks was not significantly different. While the machine was able to attempt PUs faster than the manual method (2.2 s/PU vs. 5.8 s/PU, respectively), this speed was offset by poorer planting success rates, resulting in a much greater total labor investment for each machine‐planted PU that persisted to 24 weeks than for each similarly persisting manually planted PU (40.6 person·seconds/PU and 22.4 person·seconds/PU, respectively, averaged across sites). In summary, those PUs successfully planted by the machine survived similarly to PUs planted by hand, but as a result of poorer initial planting success, the machine required a greater investment of labor and plant donor stock for each PU surviving to 24 weeks. Therefore, in its tested configuration this planting boat is not a significant improvement over the manual method for transplanting eelgrass.