运用油松年轮揭示承德市硫及重金属污染的历史

本文利用油松年轮研究了承德市逢１８００年以来大气污染的历史过程,结果表明：避署出庄油松年轮内Ｓ含量自本世纪初开始升高,比１９世纪初增加１－２倍,至７０－８０年代达３－５倍,而在最近８－１０年则达到１０倍以上,其中碧峰门古松木质部年轮内Ｓ含量由４０－５０μｇ．ｇ＾－１达到目前的５７２．９μｇ．ｇ＾－１,从而指示出承德市大气ＳＯ２浓度由城市化初期的＜０．１ｍｇ．ｍ＾－３增加到目前的３０ｍｇ．ｍ＾－３,     

黄山松年轮硫及重金属元素含量动态特征

对黄山松80年的年轮序列中S及重金属元素Mn、Fe、Zn、Cu和Pb含量分析结果表明,年轮中S浓度可划分为3个等级:58.5%年轮段,S浓度<2mg·kg^-1;24.4%年轮段,S浓度3.65～6.0mg·kg^-1;17.1%年轮段,S浓度>11mg·kg^-1.年轮序列中S的积累有较大幅度的波动,可分为波动型(1917～1960年)、相对稳定型(1961～1980年)和持续增长型(1981年以后)3种类型;在1935～1938年、1959～1960年以及最近10年的年轮中,S含量均>11mg·kg^-1,表明该时段大气中S的浓度较高.统计分析表明,近18年来,旅游人数的增加与年轮中S含量呈显著相关性,一些景点较集中的燃料消耗可能造成局部大气污染,从而影响到树木.年轮序列中Pb的积累浓度低于土壤背景值;Mn、Fe、Zn和Cu在年轮中的积累均有明显的波动性;统计上无显著的相关性,表明这4种元素在年轮中的积累是独立的;Zn和Cu在年轮序列中积累的波动与树龄无关;Mn在年轮序列中的浓度随树龄增加而降低,在最新的几个年轮段又略有增加,Fe则相反.     

伊春西林铅锌矿区兴安落叶松年轮中重金属元素含量的年际变化

利用树木年轮环境学分析方法,测定了伊春西林铅锌矿附近兴安落叶松年轮中Pb、Cd、Zn、Cu、Mn 5种重金属元素含量的变化.结果表明:在矿区附近的兴安落叶松年轮中,Mn含量最高,Cd含量最低.近地面处年轮中的Cd、Zn、Cu含量显著高于胸高处,而近地面和胸高处的Pb和Mn含量差异不显著.1987-2010年,除Pb含量有轻微上升外,其他4种元素含量均呈下降趋势,其中Cd含量下降趋势最明显,Zn、Cu、Mn含量均先下降后上升.随着兴安落叶松年轮宽度的增加,Pb含量下降,其他4种元素含量均增加.近地面处Pb含量与其他4种元素含量呈显著正相关,而在胸高处的相关性不显著,Cd含量甚至随Pb含量增加而显著下降.兴安落叶松年轮中重金属元素含量变化受铅锌矿产量和采矿活动的影响,可利用年轮中Pb含量重建采矿历史.目前,Pb含量已经对周围环境造成污染,如果继续开采,应加强对尾矿中重金属元素的治理.     

行道树毛白杨树干中重金属元素分布

采用电感耦合等离子体发射光谱法(ICP),测定分析首都机场高速公路旁毛白杨(Populus tomentosa Carr.)树干中Pb、Cd、Cr、Cu、Zn、Ni和Mn 7种重金属元素的含量及积累量,比较分析树干不同组织、不同方位、不同龄级年轮重金属含量差异及与交通量、关键气候因子的相关性。结果表明:树干木质部中各重金属平均含量由大到小依次为Zn、Cu、Cr、Mn、Ni、Pb、Cd,树皮中依次为Zn、Mn、Cr、Pb、Cu、Cd、Ni,树皮中各重金属元素的含量明显高于木质部;同一树干木质部中,各重金属元素在不同方位的分布有所差异,其中,靠近车道一侧的各重金属元素含量均高于背离车道一侧,南北向比较中,Ni、Zn为南侧含量高于北侧,其他5种重金属元素均为北侧高于南侧;以5a为一个龄级将年轮划分为5个龄组,各龄级年轮中重金属含量随时间的变化趋势各异,其中Pb、Cd、Cu、Zn总体呈递减趋势,且与年降水量、最低气温、日照时数、雨天日数和大风日数呈正相关趋势,与年平均气温和最高气温呈负相关趋势;各元素在毛白杨树干木质部中的积累量表现为ZnCrCuMnPbNiCd。     

微波消解-ICP-MS法测定油菜蜂花粉咀嚼片中12种元素

采用微波消解法处理样品,研究了微波消解和ICP-MS的测定条件,测定了咀嚼片中Cr、Mn、CA、As、Sn、Ni、Zn、Co、Ag、Pb、Se、Te12种元素含量,在最佳实验条件下,方法测定下限介于0．01μg/g-0．10μg／g之间,RSD均小于5％,加标回收在97—103％之间,方法可用于实际样品分析。     

镉在互花米草中积累、转运及亚细胞的分布

研究了在不同Cd浓度(0、5、100、200μg·g-1)处理下,互花米草花序、叶、茎、根茎、须根中Cd含量、积累量、转运特征,及Cd在互花米草体内的亚细胞分布。结果表明,Cd在互花米草不同器官中的积累能力存在较大差异。茎、根茎、须根中Cd含量及积累量随处理浓度的增加而升高,其中须根中Cd含量及积累量均高于其他器官。Cd处理浓度为100gμ·g-1时,花序和叶中Cd含量达到最大值,分别为8.65和7.82μg·g-1。在Cd处理浓度为200μg·g-1时,须根中Cd含量可高达390.00μg·g-1,积累量达3200μg·株-1。Cd在互花米草体内转运能力极低,绝大部分Cd积累在地下部位。Cd在互花米草亚细胞中的分布规律为细胞壁>胞液>细胞器。随着Cd处理浓度的增加,Cd在细胞壁中的分配比例增大,胞液中Cd分布比例则相应减小,细胞壁和胞液相互协调,增强互花米草对重金属Cd的耐性。     

矿质元素在油松树干中分布的研究

通过树干年轮的元素分析,揭示矿质元素在树干中的转移与分布,以期有益于对森林生态系统矿质循环年进程的认识。通过对28龄油松(Pinus tabulaeJormis Carr.)树干圆盘年轮和树皮的元素分沂,揭示矿质元素钙、钾、镁、钠和锰的含量与年轮的年龄呈极显著负相关关系;磷、铜与轮龄呈显著正相关关系。树皮中钙、钾、镁、钠、铁、磷、锰、铜、铝和氮的含量,与树皮的年龄呈正相关关系。内树皮的矿质灰分相当高,分别为树皮和木质部的3.3倍和13倍。     

在蚯蚓影响下土壤Pb、Cd有效态的变化及小白菜对Pb、Cd的富集转移作用

研究了在蚯蚓影响下Pb、Cd添加量不同(Pb:500～1 700 μg·g-1;Cd:1～30 μg·g-1)的土壤中Pb和Cd有效态及其含量的变化以及小白菜(Brassica chinensis L. )对土壤中Pb和Cd的富集和转移作用.结果显示,在蚯蚓的影响下,Pb添加量为500～1 400 μg·g-1的土壤中酸提取态和可还原态Pb含量显著提高,有效态Pb总含量也随土壤中Pb添加量的提高逐渐增加;Cd添加量为5～20 μg·g-1的土壤中酸提取态Cd含量显著提高,有效态Cd总含量也随土壤中Cd添加量的提高而逐渐增加;当土壤中Pb和Cd添加量分别达到1 700和30 μg·g-1时,蚯蚓对Pb和Cd基本无活化作用.在蚯蚓的影响下,小白菜地上部分Pb含量显著提高,对Pb的转移系数也均高于各自的对照,地上部分和地下部分对Pb的富集系数分别为0.037～0.061和0.401～0.628.在蚯蚓影响下,在Cd添加量较低(1～5 μg·g-1)的土壤中小白菜地上部分和地下部分的Cd含量以及对Cd的富集系数均高于各自的对照;而在Cd添加量较高(10～30 μg·g-1)的土壤中小白菜地上部分和地下部分的Cd含量以及对Cd的富集系数均低于各自的对照,并随土壤中Cd添加量的提高逐渐降低;小白菜地上部分和地下部分对Cd的富集系数分别为1.196～11.516和1.744～20.425;各处理组小白菜对Cd的转移系数与各自的对照差异不显著.研究结果显示,蚯蚓主要对土壤中酸提取态和可还原态Pb以及酸提取态Cd有活化作用,并且可促进Pb由小白菜地下部分向地上部分的转移,但对Cd的转移无明显促进作用;此外,小白菜对Pb的富集作用不明显,但对Cd有一定的富集能力,这种能力的大小与土壤Cd含量有关.     

珠江三角洲马尾松年轮重金属含量年代变化

采用树木年轮化学分析手段,探讨了肇庆鼎湖山(相对清洁区)和南海西樵山(污染区)马尾松(Pinus massonianaL.)不同时期木质部6种重金属(Cu、Zn、Ni、Cd、Cr和Pb)含量的年代变化。结果表明:西樵山马尾松林地表层土壤Cu、Zn、Cd和Pb含量均超过其在广东省表层土壤环境背景值,鼎湖山马尾松林地表层土壤除Cd外其余重金属含量在背景值范围内;鼎湖山和西樵山马尾松木质部中Cu、Zn、Cr和Pb含量均呈现从心材到边材上升的分布格局,反映了珠江三角洲环境中可供植物利用的重金属在过去有了增加。Cu、Zn、Ni,特别是Cr和Pb的最大含量出现在1990年后形成的木质部中,两地环境(土壤和大气)中重金属含量增加是导致马尾松木质部重金属含量上升的主要原因;在相同时期形成的木质部中,西樵山马尾松木质部Cu、Cr和Pb的含量大于鼎湖山,Zn、Ni和Cd含量则小于鼎湖山,这与环境重金属含量差异有关,也与马尾松对不同重金属的富集能力有关。马尾松年轮化学分析的结果能够提供珠三角地区重金属的历史变化信息。     

草莓连作土壤酚酸类物质积累对土壤线虫的影响

通过大田试验和盆栽试验相结合的方式,对不同连作年限草莓土壤酚酸类物质含量、土壤线虫数量和食细菌线虫数量以及外源酚酸类物质对土壤线虫数量和食细菌线虫数量的影响进行了研究。结果表明:随连作年限的增加,草莓连作土壤中酚酸类物质含量明显增加,土壤线虫总数和食细菌线虫总数整体呈现下降趋势,且连作5年的土壤线虫总数和食细菌线虫数量最低,酚酸类物质含量与土壤线虫总数和食细菌线虫数量呈负相关;对羟基苯甲酸和对香豆酸在浓度低于200μg·g-1时使土壤线虫总数和食细菌线虫数量增加,而高于200μg·g-1时起抑制作用;肉桂酸在浓度低于100μg·g-1时增加了土壤线虫总数和食细菌线虫数量,而高于100μg·g-1时起抑制作用;随阿魏酸浓度的增加,线虫数量变化规律不明显,当其浓度高于100μg·g-1时起抑制作用;混合酚酸随浓度增加对土壤线虫总数和食细菌线虫数量的抑制作用增强。     

树木年轮 δ13C 值及其对我国北方大气CO2浓度变化的指示意义

 本文采样分析了承德市油松年轮中δ13C值自工业革命以来的变化,用以揭示我国北方大气CO2浓度的变化规律。结果表明：承德市油松年轮中的δ13C值自1810年以来平均下降了0.839‰,下降范围0.682‰～1.120‰,指示了大气CO2浓度逐渐升高的特点。δ13C值与历史时期全球大气CO2浓度之间存在显著相关关系(r＝ –0.5609,P<0.01)。应用树木年轮δ13C值与大气CO2浓度之间的关系式,推测出我国北方大气CO2浓度从工业革命以前的约278.4μmol·mol-1上升到目前的340μmol·mol-1。从而为我国的全球变化研究提供了CO2浓度历史变迁方面的证据。     

High-elevation mountain hemlock growth as a surrogate for cool-season precipitation in Crater Lake National Park,USA

Snow dominates the hydrology and climate of the United States’ central Pacific Coast, but because local measurements of snowpack and winter precipitation often extend back only a few decades, observations by themselves are not adequate to describe potential amplitude of wintertime conditions. Here we present a set of updated and extended mountain hemlock (Tsuga mertensiana [Bong.] Carr.) tree-ring width records from Crater Lake National Park, Oregon, and use these data to make inferences about snowpack prior to the start of instrumental monitoring. In July and August 2013, we collected cores from 228 trees at seven high-elevation hemlock stands that surround the crater’s rim. The oldest tree had an inner ring date of CE 1474, and the longest ring-width chronology maintained a satisfactory common signal back to the middle of the 16th century. The growth of high-elevation mountain hemlock is strongly and inversely related to cool-season precipitation, making these records some of the most southerly examples of a robust inverse cool-season moisture signal in North American tree rings. The growth of these snow-limited forests does not appear to have been affected by the substantial decline in spring snowpack observed in the past two decades across the broader Cascade Range, and we did not find any indication of changing relationships between tree growth and either monthly or seasonal winter precipitation since the early 1990s. The exceptional three-year sequence in Crater Lake tree rings between CE 1809 and 1811, which includes the narrowest ring since CE 1540 and anatomical abnormalities produced by cold weather, leads us to conclude that 1809–1810 was the most snowy and severe winter to affect south-central Oregon during the past four and a half centuries.     

Growth response of Sabina tibetica to climate factors along an elevation gradient in south Tibet

We examine the climate significance in tree-ring chronologies retrieved from Sabina tibetica Kom. (Tibetan juniper) at two sites ranging in elevation from 4124 to 4693 m above sea level (a.s.l.) in the Namling region, south Tibet. The study region is under the control of semi-arid plateau temperate climate. The samples were grouped into high- and low-elevation classes and standard ring-width chronologies for both classes were developed. Statistical analysis revealed a decreasing growth rate yet increasing chronology reliability with increasing elevation. Overall, correlation analyses showed that radial growth in S. tibetica at the study sites was controlled by similar climatic factors, regardless of elevation; these factors comprised early winter (November) and early summer (May–June) temperatures as well as annual precipitation (July–June). Slight differences in the correlation between tree growth along the elevation gradient and climate variables were examined. The correlations with early winter temperature varied from significantly positive at the low-elevation site to weakly positive at the high-elevation site, whereas the correlations between radial growth and early summer temperature increased from weakly negative at the low-elevation sites to strongly negative at the high-elevation sites. The abundant precipitation through the year may have masked variations in tree growth on different elevation aspects. Our results will aid future dendroclimatological studies of Namling tree rings in south Tibet and demonstrate the potential of S. tibetica Kom. for improving our understanding of environmental impacts on tree growth.     

Growth decline of Pinus Massoniana in response to warming induced drought and increasing intrinsic water use efficiency in humid subtropical China

Pinus Massoniana is the most widely distributed coniferous species in southern China and one of the most distributed species for plantation in China. It is not uncertain about the responses of tree growth to the combined effects of regional drying and the increase in the intrinsic water-use efficiency (iWUE) due to increased atmospheric CO₂. This study addressed this issue by comparing the tree growth patterns as represented by three tree-ring width chronologies with climate variables and three iWUE series derived from three tree-ring stable carbon isotope discrimination chronologies (Δ¹³C) from Pinus Massoniana in Daiyun Mountain, central Fujian province of China. Among these chronologies, we reported the first tree-ring carbon isotope discrimination chronologies (Δ¹³C) from Fuzhou area spanning last 210 years. It was found that tree radial growth is mainly limited by dry condition from May to October. Growth limitation by cold condition was only found in one high altitude site (780m) in early spring and late autumn. The tree-ring carbon discrimination was enhanced under conditions with low relative humidity and sufficient sunshine in late summer and autumn. In general, the iWUE showed a significantly increasing trend since the 1850s for all the sites in response to the increase in atmospheric CO₂. However, the growth promotion of the increased iWUE on tree growth could not compensate the growth limitation caused by drought. Especially since the 1960s, a growth decline was found at two drought stressed sites at low altitudes. On the other hand, the increase in temperature of spring and autumn and iWUE has most likely enhanced tree growth at the high altitude site.     

树种蒸腾作用、光合作用和蒸腾效率的比较研究

 各树种在年生长季不同测期的蒸腾速率日进程曲线一般呈单峰型。蒸腾速率与环境因子的相关性大小依次为：光照强度、气温、相对湿度和大气水势。蒸腾速率日变化一般可用具有光照因子的优化模型(即光照型、光温型、光湿型和光温湿型)来模拟。年生长季树种蒸腾速率(g·g-1LD·h-1)排序由大到小为：柠条(0.9269±0.2089)(平均值±标准差,以下同)、小叶杨(0.7177±0.2410)、河北杨(0.6256±0.1609)和北京杨(0.6007±0.2749);净光合速率(mgCO2·g-1LD·h-1)排序自高至低为：柠条(14.5949±4.6627)、小叶杨(13.4055±2.9994)、河北杨(13.2569±4.3531)和北京杨(11.6989±2.5884);蒸腾效率(gDM·g-1H2O)排序由高至低为：北京杨(1.41％±0.42％)、河北杨(1.35％±0.36％)、小叶杨(1.26％±0.23％)和柠条(1.00％±0.27％)。     

Heavy metal concentrations in oak wood growth rings from the Taunus (Federal Republic of Germany) and the Valdivia (Chile) regions

Summary Using a voltammetric procedure described previously, the radial distribution of Cd, Cu, Pb and Zn in annual growth rings of oak from two regions has been investigated: an unpolluted region in Valdivia (Chile) and a polluted region in Königstein (Taunus, FRG). The very low metal levels found in oak wood from the Valdivia region have necessitated that the method be improved and its accuracy tested with standard reference materials and by comparison with electrothermal atomic absorption spectrometry as an independent method. The radial distribution of the four metals investigated is similar in oaks from both regions. No significant differences have been observed in the average concentrations of the essential metals Zn and Cu in the oak tree rings from the two investigated regions. For the toxic metals Cd and Pb, however, a significant increase by a factor of 2 for Cd and by a factor of 12 for Pb has been found when comparing the Königstein and the Valdivia regions. This is evidence of expected pollution of the Königstein region by Pb and, to a lesser extent, by Cd since 1940 or earlier. The trees in both regions can be classified as sound (damage degree 0–1 in Königstein).Attached to the Institute of Chemistry, Universidad del norte, Antofagasta, Chile; material taken in part from Ph. D. Thesis, University of Bonn     

Fire history of Pinus nigra in Western Anatolia: A first dendrochronological study

Forests in the Mediterranean basin frequently experience fires due to both anthropogenic and natural causes. There are concerns that the fire season will prolong in the Mediterranean basin, the fire frequency will increase with ongoing climate change, moreover, the fire regimes will shift from surface fires to local crown fires. Here, we aim to improve our understanding of the fire regime components of black pine forests in Turkey by 1) reconstructing a high-resolution fire chronology based on tree rings, 2) revealing the seasonality of fires, 3) investigating the relationship between fire and climate, and 4) comparing our reconstruction results with documentary data from forest management units. We collected 62 fire-scarred trees from three sites in Kütahya and developed a 368 year-long (1652–2019) composite fire chronology using dendrochronological methods. We found that at two sites major fire years coincided with dry years. Two major fire years (1853 and 1879) were common to all sites and two additional fire years (1822 and 1894) were found at two sites. Our results show a sharp decline in fire frequency after the beginning of the 20th century at all sites that can be attributed to increased fire suppression efforts and forest management activities in the 20th century. Our results suggest that the spread of fires has been actively suppressed since the first forest protection law in Turkey. Yet, tree-ring based and documentary data corroboration shows that seasonality did not change over the past +350 years.