中国植物地理学研究进展与展望

中国植物地理学从20世纪20年代初创到当前繁荣经历了100年的发展,近30年来测序技术和生物信息技术的进步,促进了分类、进化和生态等学科交叉融合,中国植物地理学在诸多方面取得了突破性进展,主要包括：① 植物类群和区系在中国整体上按纬度、经度和海拔呈现出规律性;物种丰富度、系统发生多样性和特有性热点集中分布在南部山地,少数分布在北方山地和干旱地区。② 关于大尺度植物多样性格局及形成机制,多数热带起源科的物种多样性格局受冬季低温的限制,而多数温带起源科的物种多样性格局由末次冰期以来的气候变化主导;中国山地植物和群落具有显著的垂直地带性和空间分布异质性,热量因子是中国高山植物区系地理分异的首要气候因子。③ 中国大多数现生被子植物属（约66%）是在中新世及其以后分化;500 mm年等降水线是中国植物区系年龄和植被分区最重要的分界线;中国植物区系、区系中的特征或关键类群的起源和多样化与青藏高原抬升和亚洲季风加强密切相关。未来,时间和空间的结合仍是植物地理学研究的主旋律,类群、群落和区系分化时间的估算及物种分布数据的分辨率是研究者关注的焦点,植物大数据的持续积累和完善将为学科发展提供强大动力和广阔前景。     

轻度沙埋对典型荒漠植物的影响北大核心CSCD

中国西北干旱区以荒漠生态系统为主体,是中国典型脆弱生态系统。沙埋对该区域植物生存和生长、植被分布和组成以及荒漠生态系统功能和结构有重要影响。以典型荒漠植物梭梭(Haloxylon ammodendron)、柽柳(Tamarix chinensis)、白刺(Nitraria tangutorum)、沙拐枣(Calligonum mongolicum)为研究对象,对比研究了轻度沙埋和非沙埋植物在生理和生长方面的差异,并从土壤盐分、土壤水分、土壤温度等方面探究了造成这种差异的原因。结果表明:轻度沙埋环境下,梭梭、柽柳、白刺、沙拐枣的光合速率普遍高于非沙埋植株,蒸腾速率显著低于非沙埋植株,水分利用效率也均高于非沙埋植株。轻度沙埋梭梭、柽柳、沙拐枣、白刺株高明显低于非沙埋植株,但地径、冠幅、叶面积指数普遍高于非沙埋植株。主要原因是轻度沙埋植物下方土壤黏粒含量、土壤湿度高于非沙埋植物下方,轻度沙埋植物下方土壤温度、含盐量低于非沙埋环境。     

Soil saturation index of salt marshes subjected to spring‐neap tides: a new variable for describing marsh soil aeration condition

Organized spatial distribution of plants (plant zonation) in salt marshes has been linked to the soil aeration condition in the rhizosphere through simplistic tidal inundation parameters. Here, a soil saturation index (ratio of saturation period to tidal period at a soil depth) is introduced to describe the soil aeration condition. This new index captures the effects of not only the tidal inundation period and frequency but also the flow dynamics of groundwater in the marsh soil. One‐dimensional numerical models based on saturated flow with the Boussinesq approximations and a two‐dimensional variably saturated flow model were developed to explore the behaviour of this new soil aeration variable under the influence of spring‐neap tides. Simulations revealed two characteristic zones of soil aeration across the salt marsh: a relatively well aerated near‐creek zone and a poorly aerated interior zone. In the near‐creek zone, soils undergo periodic wetting and drying as the groundwater table fluctuates throughout the spring‐neap cycle. In the interior, the soil remains largely water saturated except for neap tide periods when limited drainage occurs. Although such a change of soil aeration condition has been observed in previous numerical simulations, the soil saturation index provides a clear delineation of the zones that are separated by an ‘inflexion point’ on the averaged index curve. The results show how the saturation index represents the effects of soil properties, tidal parameters and marsh platform elevation on marsh soil aeration. Simulations of these combined effects have not been possible with traditional tidal inundation parameters. The saturation index can be easily derived using relatively simple models based on five non‐dimensional variables. Copyright © 2010 John Wiley & Sons, Ltd.     

The climate of Scotland over the last 5000 years inferred from multiproxy peatland records: inter‐site correlations and regional variability

The mid to late‐Holocene climates of most of Scotland have been reconstructed from seven peat bogs located across north–south and east–west geographical and climatological gradients. The main techniques used for palaeoclimatic reconstruction were plant macrofossil, colorimetric humification, and testate amoebae analyses, which were supported by a radiocarbon‐based chronology, aided by markers such as tephra isochrons and recent rises in pine pollen and in spheroidal carbonaceous particles (SCPs). Field stratigraphy was undertaken at each site in order to show that the changes detected within the peat profiles were replicable. Proxy climate records were reconstructed using detrended correspondence analysis (DCA) of the plant macrofossil data and a mean water table depth transfer function on the testate amoebae data. These reconstructions, coupled with the humification data, were standardised for each site and used to produce a composite record of bog surface wetness (BSW) from each site. The results show coherent wet and dry phases over the last 5000 years and suggest regional differences in climate across Scotland, specifically between northern and southern Scotland. Distinct climatic cycles are identified, all of which record a millennial‐scale periodicity which can be correlated with previously identified marine and ice core Holocene cycles. The key role of the macrofossil remains of Sphagnum imbricatum, a taxon now extinct on many sites, is discussed in relation to the identified climatic shifts. Copyright © 2005 John Wiley & Sons, Ltd.     

环境植物样品中铜铅锌铁锰的测定

将环境植物样品在４００─５００℃灰化，用硝酸、氢氟酸和高氯酸分解，用盐酸（１＋１）提取，控制２％─３％的盐酸介质，用火焰原子吸收分光光度法测定环境植物样品中的微量铜、铅、锌、铁、锰。该方法简单、快速、可靠。对环境植物标准样品的测定结果理想。     

浮床无土栽培植物控制池塘富营养化水质

采用浮床无土栽培技术,在池塘水面种植景观植物--陆生植物美人蕉(Cana generalis     

辽东山地老秃顶子冰缘地貌植物群落类型及基本特征

基于48个样地的群落调查数据,运用TWINSPAN分类方法,对辽东山地老秃顶子冰缘地貌植物群落类型进行了划分,并对群落结构、种类组成和生活型谱进行了系统研究.结果表明:老秃顶子冰缘地貌植被可划分为16个森林群系、6个灌丛群系,归并为落叶阔叶林、针阔混交林、暗针叶林、矮曲林、灌丛、灌草丛6个植被型.其中,石海地貌主要发育灌丛和灌草丛,也有针阔混交林和矮曲林分布;石河地貌主要发育针阔混交林和落叶阔叶林,也有暗针叶林分布;石流坡地貌主要发育针阔混交林、落叶阔叶林和灌丛,也有矮曲林分布.老秃顶子冰缘地貌植被由68科138属193种维管束植物组成;石海与石河间植物群落物种组成属中等不相似,而石河与石流坡间属中等相似.老秃顶子冰缘地貌植物群落中高位芽植物占38.0%,隐芽植物占36.3%,地面芽植物占21.8%,地上芽植物和一年生植物均很少,反映出辽东山地冰缘地貌区具有夏季温暖多雨、冬季寒冷漫长的气候特点.相对而言,石海、石流坡地貌中隐芽植物较多,石河地貌中高位芽植物较多,表明石海、石流坡地貌具有更为冷湿的小气候环境.     

Arsenic accumulation in the roots of Helianthus annuus and Zea mays by irrigation with arsenic-rich groundwater: Insights from synchrotron X-ray fluorescence imaging

The aim of this study was to investigate the accumulation of arsenic (As) in and on roots of Zea mays (maize) and Helianthus annuus (sunflower) by means of synchrotron-based micro-focused X-ray fluorescence imaging (μ-XRF). Plant and soil samples were collected from two field sites in the Hetao Plain (Inner Mongolia, China) which have been regularly irrigated with As-rich groundwater. Detailed μ-XRF element distribution maps were generated at the Fluo-beamline of the Anka synchrotron facility (Karlsruhe Institute of Technology) to assess the spatial distribution of As in thin sections of plant roots and soil particles. The results showed that average As concentrations in the roots (14.5–27.4 mg kg⁻¹) covered a similar range as in the surrounding soil, but local maximum root As concentrations reached up to 424 mg kg⁻¹ (H. annuus) and 1280 mg kg⁻¹ (Z. mays), respectively. Importantly, the results revealed that As had mainly accumulated at the outer rhizodermis along with iron (Fe). We therefore conclude that thin crusts of Fe-(hydr)oxides cover the roots and act as an effective barrier to As, similar to the formation of Fe plaque in rice roots. In contrast to permanently flooded rice paddy fields, regular flood irrigation results in variable redox conditions within the silty and loamy soils at our study site and fosters the formation of Fe-(hydr)oxide plaque on the root surfaces.     

云南风能资源及其开发利用研究进展

介绍了云南风能资源及其开发利用的研究现状和研究成果。分析了云南风能资源评价历程、分布特点和风电开发建设情况。总结了云南有关风电场选址、风能资源评估、风电功率预测预报以及山区风电场和风电机组设计的研究成果。剖析了云南风能资源及其开发利用中存在的问题并提出今后的发展方向。     

核电厂设计基准风速计算有关问题探讨

设计基准风速的确定对核电厂建构筑物的风荷载设计和结构设计至关重要。利用气象台站积累的历史极端风速资料,计算核电厂设计基准风速,并讨论了计算过程中应注意的有关问题。