人际元功能在企业简介英译人称系统选择中的实现

企业简介,如同企业名片一样,对于中国企业在国际市场上获取竞争优势以及树立良好形象起着至关重要的作用。然而大多数中文企业简介的英译质量都不尽如人意。人际功能是企业简介的重要功能之一。文章以韩礼德系统功能语法为理论框架,研究在企业简介英译过程中人际元功能的实现。     

The worldwide leaf economics spectrum

Bringing together leaf trait data spanning 2,548 species and 175 sites we describe, for the first time at global scale, a universal spectrum of leaf economics consisting of key chemical, structural and physiological properties. The spectrum runs from quick to slow return on investments of nutrients and dry mass in leaves, and operates largely independently of growth form, plant functional type or biome. Categories along the spectrum would, in general, describe leaf economic variation at the global scale better than plant functional types, because functional types overlap substantially in their leaf traits. Overall, modulation of leaf traits and trait relationships by climate is surprisingly modest, although some striking and significant patterns can be seen. Reliable quantification of the leaf economics spectrum and its interaction with climate will prove valuable for modelling nutrient fluxes and vegetation boundaries under changing land-use and climate.     

Methane emissions from terrestrial plants under aerobic conditions

Methane is an important greenhouse gas and its atmospheric concentration has almost tripled since pre-industrial times. It plays a central role in atmospheric oxidation chemistry and affects stratospheric ozone and water vapour levels. Most of the methane from natural sources in Earth's atmosphere is thought to originate from biological processes in anoxic environments. Here we demonstrate using stable carbon isotopes that methane is readily formed in situ in terrestrial plants under oxic conditions by a hitherto unrecognized process. Significant methane emissions from both intact plants and detached leaves were observed during incubation experiments in the laboratory and in the field. If our measurements are typical for short-lived biomass and scaled on a global basis, we estimate a methane source strength of 62-236 Tg yr(-1) for living plants and 1-7 Tg yr(-1) for plant litter (1 Tg = 10(12) g). We suggest that this newly identified source may have important implications for the global methane budget and may call for a reconsideration of the role of natural methane sources in past climate change.     

Increased CO2 uncouples growth from isoprene emission in an agriforest ecosystem

The emission of isoprene from the leaves of forest trees is a fundamental component of biosphere-atmosphere interactions, controlling many aspects of photochemistry in the lower atmosphere. As almost all commercial agriforest species emit high levels of isoprene, proliferation of agriforest plantations has significant potential to increase regional ozone pollution and enhance the lifetime of methane, an important determinant of global climate. Here we show that growth of an intact Populus deltoides plantation under increased CO2 (800 micromol x mol(-1) and 1,200 micromol x mol(-1)) reduced ecosystem isoprene production by 21% and 41%, while above-ground biomass accumulation was enhanced by 60% and 82%, respectively. Exposure to increased CO2 significantly reduced the cellular content of dimethylallyl diphosphate, the substrate for isoprene synthesis, in both leaves and leaf protoplasts. We identify intracellular metabolic competition for phosphoenolpyruvate as a possible control point in explaining the suppression of isoprene emission under increased CO2. Our results highlight the potential for uncoupling isoprene emission from biomass accumulation in an agriforest species, and show that negative air-quality effects of proliferating agriforests may be offset by increases in CO2.     

Interannual variability in the oxygen isotopes of atmospheric CO2 driven by El Niño

The stable isotope ratios of atmospheric CO(2) ((18)O/(16)O and (13)C/(12)C) have been monitored since 1977 to improve our understanding of the global carbon cycle, because biosphere-atmosphere exchange fluxes affect the different atomic masses in a measurable way. Interpreting the (18)O/(16)O variability has proved difficult, however, because oxygen isotopes in CO(2) are influenced by both the carbon cycle and the water cycle. Previous attention focused on the decreasing (18)O/(16)O ratio in the 1990s, observed by the global Cooperative Air Sampling Network of the US National Oceanic and Atmospheric Administration Earth System Research Laboratory. This decrease was attributed variously to a number of processes including an increase in Northern Hemisphere soil respiration; a global increase in C(4) crops at the expense of C(3) forests; and environmental conditions, such as atmospheric turbulence and solar radiation, that affect CO(2) exchange between leaves and the atmosphere. Here we present 30 years' worth of data on (18)O/(16)O in CO(2) from the Scripps Institution of Oceanography global flask network and show that the interannual variability is strongly related to the El Ni?o/Southern Oscillation. We suggest that the redistribution of moisture and rainfall in the tropics during an El Ni?o increases the (18)O/(16)O ratio of precipitation and plant water, and that this signal is then passed on to atmospheric CO(2) by biosphere-atmosphere gas exchange. We show how the decay time of the El Ni?o anomaly in this data set can be useful in constraining global gross primary production. Our analysis shows a rapid recovery from El Ni?o events, implying a shorter cycling time of CO(2) with respect to the terrestrial biosphere and oceans than previously estimated. Our analysis suggests that current estimates of global gross primary production, of 120 petagrams of carbon per year, may be too low, and that a best guess of 150-175 petagrams of carbon per year better reflects the observed rapid cycling of CO(2). Although still tentative, such a revision would present a new benchmark by which to evaluate global biospheric carbon cycling models.     

水稻冠层不同高度光合有效辐射动态与叶片光合作用特性研究

在当前CO₂环境以及600 μmol/mol air的开顶箱中, 测量水稻冠层离水田泥土45 cm和90 cm处光合有效辐射的变动以及叶片的动态光合速率, 探讨高CO₂环境下光强变动与光合作用关系的潜在变化。结果表明: 1) 水稻冠层90 cm处的平均光强是45 cm处的3~4倍, 但晴天光强的时间变异系数比45 cm处低55%~60%; 2) 上部叶片有更高的饱和光合速率以及照后CO₂固定, 下部叶片有较高的低光光合速率; 3) 高CO₂开顶箱冠层内部的光衰减百分比倾向于增大, 上, 下叶片的光合能力差异增大。因此, 冠层不同高度的光环境可能同时影响叶片的稳定态和动态光合特性, 高CO₂可能加大由不同冠层光环境差异造成的光合特性差异。     

CO2 and the end-Triassic mass extinction.

The end of the Triassic period was marked by one of the largest and most enigmatic mass-extinction events in Earth's history and, with few reliable marine geochemical records, terrestrial sediments offer an important means of deciphering environmental changes at this time. Tanner et al. describe an isotopic study of Mesozoic fossil soils which suggests that the atmospheric concentration of carbon dioxide (pCO2) across the Triassic-Jurassic boundary was relatively constant (within 250 p.p.m.v.), but this is inconsistent with high-resolution evidence from the stomatal characters of fossil leaves. Here I show that the temporal resolution of the fossil-soil samples may have been inadequate for detecting a transient rise in pCO2. I also show that the fossil-soil data are consistent with a large increase in pCO2 across the Triassic-Jurassic boundary when variations in the stable carbon isotope (denoted as delta13C) in terrestrial plant leaves are taken into account. These factors suggest that the linkage between pCO2, global warming and the end-Triassic mass extinction remains intact.     

银杏叶枯病初侵染源的研究

１９８９－１９９２年间，以银杏的冬芽、幼叶、嫩叶以及越冬后的落叶等为试验材料进行研究。结果表明，银杏叶枯病的三种病菌均能在冬芽和落叶上越冬。当春季节萌发后，银杏叶枯病的主要病原链格孢菌能转移到部分嫩叶上，继续进行潜伏侵染，但其数量显著下降。３－６月间，越冬后落叶上的链格孢菌可以大量形成呈丛状的分生孢子梗，并不断产生新的分生孢子。上一年在落叶上产后的分生孢子，越冬后仍具有一定的发芽率。就病害的侵染源     

福建主要茶区茶叶含氟量与茶区环境及土壤含氟量

研究了福建３个主要茶区典型茶树黄炎、水仙鲜叶含氟量与环境及土壤含氟量的关系。３个茶区的环境具有３种类型：（１）中南亚热带温气候花岗岩风化壳残积坡积区；（２）中亚热带湿润气候紫色砂岩风化壳母质堆积物化；（３）中亚热带潮湿气候现代河流冲积物区。     

Projected increase in continental runoff due to plant responses to increasing carbon dioxide

In addition to influencing climatic conditions directly through radiative forcing, increasing carbon dioxide concentration influences the climate system through its effects on plant physiology. Plant stomata generally open less widely under increased carbon dioxide concentration, which reduces transpiration and thus leaves more water at the land surface. This driver of change in the climate system, which we term 'physiological forcing', has been detected in observational records of increasing average continental runoff over the twentieth century. Here we use an ensemble of experiments with a global climate model that includes a vegetation component to assess the contribution of physiological forcing to future changes in continental runoff, in the context of uncertainties in future precipitation. We find that the physiological effect of doubled carbon dioxide concentrations on plant transpiration increases simulated global mean runoff by 6 per cent relative to pre-industrial levels; an increase that is comparable to that simulated in response to radiatively forced climate change (11 +/- 6 per cent). Assessments of the effect of increasing carbon dioxide concentrations on the hydrological cycle that only consider radiative forcing will therefore tend to underestimate future increases in runoff and overestimate decreases. This suggests that freshwater resources may be less limited than previously assumed under scenarios of future global warming, although there is still an increased risk of drought. Moreover, our results highlight that the practice of assessing the climate-forcing potential of all greenhouse gases in terms of their radiative forcing potential relative to carbon dioxide does not accurately reflect the relative effects of different greenhouse gases on freshwater resources.     

灌浆期不同温光对水稻叶、籽粒可溶性蛋白质及可溶性糖动态变化的影响

本文探讨温度和光强互作对水稻灌浆生理的影响 .1　材料与方法1 .1　实验设计供试品种为特三占 (劣质 )、毅丰 4 8(毅夫×丰澳占 ,优质 ) .植株在大田的自然条件下生长至孕穗 ,然后材料分两组 ,一组放在人工气候箱的高温条件下 ( 33℃昼温 /夜平均温 ) ,一半用50 %的遮光网遮光 ;另一组为大田的适温条件 ( 2 1℃昼温 /夜平均温 ) ,一半用 50 %的遮光网遮光 .抽穗受粉的当天选择生长一致的单稻穗挂牌标记 ,以后每隔 5ｄ随机抽取标记的稻穗每次 6穗 ,重复 3次 .1 .2　测定方法可溶性蛋白质含量用考马斯兰Ｇ - 2 50染色后在 595ｎｍ处比色测定 …     

中间锦鸡儿(Caragana intermedia)株丛的水分关系

中间锦鸡儿(Caragana intermedia)对风沙侵蚀有较强的适应性,在毛乌素沙地中,呈星散分布。有的中间锦鸡儿株丛与沙篙(Artemisia ordosica)、羊柴(Agriophlla squarroaum)等组成独特的沙地群落。本文着重研究了中间锦鸡儿株丛的水分关系:(1)中间锦鸡儿叶片的蒸腾速率。通常在上午10时和下午2时左右有峰值,中午时蒸腾速率稍有降低。早晨或阴天,光照较弱,气温较低,老茎叶片的蒸腾速率小于幼茎叶片;但在光照强,气温高的条件下,幼茎叶片的蒸腾速率小于老茎叶片。这意味着幼茎叶片比老茎叶片有较强的控制蒸腾失水的能力。(2)一个占地70-80m~2的中间锦鸡儿株丛的日蒸腾失水量达53kg(0.7mm),其中从老茎叶片腾掉的水分约占3/4。这是因为老茎叶量为幼茎叶量的3倍。(3)在毛乌素沙地,中间锦鸡儿通常生长在水势较高的(-0.42MPa)沙土中,却处在水势很低的(-109.20MPa)大气环境中。因此,中间锦鸡儿可从沙土中获得良好的水分供应。     

云南箭竹叶片对长期高温环境的适应性生理变化

通过对温室环境下培育6 a的云南箭竹与野外生长的云南箭竹的生理指标进行对比试验。结果表明:温室内高温环境条件下云南箭竹嫩叶、成熟叶、衰老叶的叶绿素a(Chl a)与叶绿素b(Chl b)含量均比野外条件下的高,但Chl a/b的比值却低于野外环境; 温室内云南箭竹竹叶中嫩叶、成熟叶的类胡萝卜素含量均高于野外云南箭竹竹叶中嫩叶、成熟叶的,但衰老叶中的类胡萝卜素含量情况却相反; 温室内成熟叶片及衰老叶片的可溶性糖含量比野外条件的高,除幼嫩叶片外,温室内成熟及衰老叶片超氧化物歧化酶的活性均比野外条件的低,而温室条件下成熟叶片过氧化氢酶活性比野外叶片的高; 除衰老叶片之外,温室内嫩叶与成熟叶中的丙二醛含量均比野外叶片的高。可见云南箭竹作为高山竹种尽管在温室中生长较长的时间,但依旧不能完全适应高温环境。     

干旱区红富士苹果新叶和功能叶叶绿素SPAD值变化规律研究

以红旗坡农场和依杆旗乡果园内的红富土苹果树为研究对象,随机选择5株同龄树上不同部位的新叶和功能叶为试验材料,采用SPAD-502 Plus叶绿素测定仪,连续2年定期快速测定了新叶和功能叶叶绿素SPAD值。结果表明：在2个果园的5株树当中,株1和株2苹果树的新叶和功能叶的叶绿素SPAD值均较高;且功能叶的叶绿素SPAD值均明显高于新叶;新叶的叶绿素SPAD值在7月份较高,而功能叶在8月份较高;依杆旗果园苹果功能叶叶绿素SPAD值高于红旗坡果园,但对新叶的影响不明显。     

Constant elevation of southern Tibet over the past 15 million years

The uplift of the Tibetan plateau, an area that is 2,000 km wide, to an altitude of about 5,000 m has been shown to modify global climate and to influence monsoon intensity. Mechanical and thermal models for homogeneous thickening of the lithosphere make specific predictions about uplift rates of the Tibetan plateau, but the precise history of the uplift of the plateau has yet to be confirmed by observations. Here we present well-preserved fossil leaf assemblages from the Namling basin, southern Tibet, dated to approximately 15 Myr ago, which allow us to reconstruct the temperatures within the basin at that time. Using a numerical general circulation model to estimate moist static energy at the location of the fossil leaves, we reconstruct the elevation of the Namling basin 15 Myr ago to be 4,689 +/- 895 m or 4,638 +/- 847 m, depending on the reference data used. This is comparable to the present-day altitude of 4,600 m. We conclude that the elevation of the southern Tibetan plateau probably has remained unchanged for the past 15 Myr.     

水杉赤枯病病原初探

<正>水杉赤枯病在江苏各地普遍发生,危害水杉苗和大树。春季,     

椰子心叶和成熟叶片对椰心叶甲生育指标的影响

研究发现椰一but-甲[Brontispa longissima（Gestro）]各项生育指标与椰子[Cocos nucifera（Linnaeus）]叶片的生长阶段关系密切．统计表明：从幼虫到成虫整个阶段的存活率心叶较成熟叶片高,分别为81％和77％,椰心叶甲完成一个世代在心叶上需要58．54d,在成熟叶片上需要52．92d．叶片生长阶段对虫质量和蛹质量的影响表现为取食心叶较重,且大部分龄期的幼虫质量和蛹质量的差异均显著．椰子心叶和成熟叶片上的成虫的性比分别为n（雌）：n（雄）=1．27：1和n（雌）：n（雄）=1．17：1,平均产卵量为143．3粒和161．93粒,成虫寿命分别为189．14d和172．36d,椰子心叶和成熟叶上的实验种群趋势指数分别为56．55和56．45．     

Analysis on water potential of Populus euphratica oliv and its meaning in the lower reaches of Tarim River, Xinjiang

Combined with materials measured on leaves water potential of Populus euphratica ofiv in the process of ecological water delivery in the lower reaches of Tarim River, the influence of ground-water depths and soil salinity on leaves water potential of P. euphratica was analyzed. We found that there was evident negative correlation between the leaves water potential of P. euphratica and ground-water depths. The deeper the ground-water depths were, the lower the leaves water potential of P. euphratica was, the more serious drought stress P. euphratica suffered from. Besides, there was evident negative correlation between the soil salinity and the leaves water potential of P. euphratica. The bigger the soil salinity was, the lower the leaves water potential of P. euphratica was, the more serious drought stress was indicated from which P. euphratica suffered. For sections rather distant for Daxihaizi Reservoir as well as for those places of wells rather distant from the river course, ground-water depths and the soil salinity were high; the leaves water potential of P. euphratica was low. The leaves water potential of P. euphratica can reflect the degree at which P. euphratica suffers from drought and salt stress, and has an important reference meaning in analyzing proper ground-water depths for the survival and growth of P. euphratic in the lower reaches of Tarim River.     

植物品种净光合速率测定的取样技术——以苎麻(Boehmeria nivea(L.)Gaud.)为例

植物净光合速率(Pn)测定的取样技术决定结果的可靠性,但很少有文献专门论述.为此,分析苎麻Pn的日变化、个体间、叶位间和叶片不同位点的差异,结果表明:1天中苎麻Pn在11:00左右达到最高值,此后迅速降低,虽在下午可能回升,但不同品种有差异;品种内个体间Pn差异显著;不同叶位以顶部展开叶往下数第5～7叶Pn最高;叶片不同位点的Pn差异不显著.据此建议苎麻品种的Pn测定在上午9:00～11:00进行;每个品种/处理至少选择5个生长一致的正常植株,测定从植株顶部展开叶往下数第5～7叶近叶尖位置的Pn.还要特别注意植株的代表性和不同品种/处理/植株的叶位统一,叶片颜色、形状正常,无病虫危害.