Blei-und Cadmiumgehalt von Buchenwurzeln (Fagus silvatica L.) in Stammfuß- und Zwischenstammbereichen

Lead and cadmium content of beech (Fagus silvatica L.) roots in the stem and interstem areas In an approximately 150 year old beech stand, soil acidification was detected in the stemflow area. Here, the lead content of beech roots is higher than in the interstem areas, although cadmium does not significantly differ. Soil samples of both areas have similar Pb and Cd concentrations.     

Wachstum und Mineralstoffernährung von Buche (Fagus sylvatica) und Spitzahorn (Acer platanoides) auf versauertem und schwermetallbelastetem Bodenmaterial aus dem Einsickerungsbereich von Stammabflußwasser in Buchenwäldern

Growth and mineral nutrition of beech (Fagus sylvatica) and maple (Acer platanoides) on soil, polluted by infiltration of acidic stemflow Stemflow in beech stands in areas with atmospheric pollution may become highly acidic and enriched with heavy metals due to interception of pollutants in the canopy. Over long periods soil properties in the infiltration zone of such stemflow change significantly. Soil samples from the infiltration zone of stemflow and samples from zones more distant from the trunks were collected in the Vienna Woods and used in a pot experiment to assess the influence of soil pollution on tree growth. This method was considered superior to experiments with artificial acidification, as soil changes in the infiltration zone of stemflow in old growth beech stands are the result of steady input of highly diluted pollutants over a long span of time in proportions typical to these sites. Soil analyses (table 1) showed leaching of Ca, Mg and Mn, a decrease in pH, increased Al-availability and modest Pb-enrichment. Plant growth (fig. 1) was reduced on the acidic substrate and root damage, especially dieback of root tips and brooming of new roots in beech could be observed. Mineral nutrition (fig. 2,3 and table 2) of plants on the acidic substrate was characterized by a dramatic increase in foliar levels of manganese and a decrease in Ca/Al ratios. Nitrogen and phosphorus levels increased, probably as result of concentration effects due to stunted growth. Discernment between Al- or Mn-toxicity was not possible. However for the soil tested, foliar Mn-levels appear to be useful for diagnosis of mineral stress induced by acidification because of the pronounced response.     

Schwermetallanreicherung und Schwermetallverfügbarkeit im Einsickerungsbereich von Stammablaufwasser in Buchenwäldern (Fagus sylvatica) des Wienerwaldes

Heavy metal enrichment and mobility in the infiltration zone of stemflow from beech (Fagus sylvatica) in the Vienna woods Filtering action of beech crowns in a polluted atmosphere produces acidic stemflow enriched with heavy metals. Series of soil profiles through the infiltration zone of stemflow waters were analyzed in three old growth beech stands on pseudogley (aqualf) soils of the northeastern Vienna Woods to study soil acidification and heavy metal accumulation and mobility: + In the infiltration zone of stemflow soil pH can be less than pH 3 and thus more than 2 pH units lower than in profiles more distant from the stem base. + Heavy metal contents of the soil peaked near the stembase. Maximum values for lead were 500 to 1.200 mg·kg^?1 soil, for copper 70 to 150 mg·kg^?1 soil and for zinc 250 to 500 mg·kg^?1 soil. + Manganese was not enriched but leached out from the soil profile. + The proportion of AED-complexable lead and copper to total lead and copper decreased under stemflow influence in the topsoil but increased in the subsoil. These results indicate that significant amounts of heavy metals are deposited with stemflow in beech stands of the Vienna Woods. Strong soil acidification enhances heavy metal solubility and thus promotes leaching into deeper soil strata.     

Changes in chemistry and mineralogy of forest soils by acid rain

The goal of the present study was a qualitative and quantitative determination of chemical and mineralogical changes in forest soils due to acid atmospheric depositions. In the NE/SE Vienna Woods soil samples were taken at 4 depths (0 to 5 cm, 5 to 10 cm, 10 to 20 cm, 20 to 30 cm) in the contaminated infiltration zone of stemflow (S) of 8 beech trees (Fagus sylvatica), strongly influenced by acid atmospheric depositions (soil-pH 2.8 to 3.0) and in their non contaminated reference areas (R) between trees, where acid imput is much smaller (soil-pH 5.0 to 6.0). The results show that intensive weathering processes took place in the contaminated soil areas, which show higher clay and silt contents and smaller aggregates, as well as clay illuviation. Moreover, in the top of the contaminated soil areas higher contents of C_t and S_t and of the heavy metals Pb, Zn and Cu could be observed, accompanied by extreme low base saturation (expecially of Ca and Mg) and high Al-saturation (50 to 80% of the CEC). These data were confirmed by analysis of the water saturation extract. Moreover, in the contaminated top soils high amounts of Fe-oxides were found, whereas no “secondary” Al-chlorite (due to its instability at pH-values <4.0) could be traced. The desilification process which took place at the same time could be shown through total element analysis. In the clay-fraction strong weathering led to a loss of layer charge and to the genesis of highly expandable three-layer-silicates which could be determined by X-ray diffraction using n-alkylammonium-chloride technics and other chemical treatments.     

昆山市农业土壤基本性质与重金属含量及二者的关系

研究了昆山市农业土壤基本性质和土壤中的重金属含量,并对二者的相关关系进行了分析。结果表明:昆山市农业土壤基本全为壤土,土壤pH值平均为6.50,土壤有机质平均含量为30.53g/kg,土壤CEC平均值为17.51cmol/kg,且各区之间变幅不大;昆山市主要污染重金属Cd、Pb和Hg全量大小排序基本为黄泥土>青泥土>青紫土>乌栅土;土壤重金属含量和土壤理化性质间的关系复杂,如全量As与pH值、有机质含量和全N含量呈极显著负相关,而全量Hg与土壤中有机质含量、全N含量、碱解N含量、CEC呈极显著正相关。     

Zum Einfluß von pH und organischem Kohlenstoffgehalt auf die Löslichkeit von Eisen,Blei, Mangan und Zink in Waldböden

Influence of pH and organic carbon content on the solubility of iron, lead, manganese and zinc in forest soils Several soil factors determine the solubility of heavy metals in soils. The contents of exchangeable and in consequence potentially plant available heavy metals are mainly influenced by the pH and the content of organic carbon. Samples of the A_h-horizon from the stemflow area and from soil not influenced by stemflow water were investigated in beech forests. The solubility or iron, lead, manganese and zinc is described in relation to the pH and the content of organic carbon. Exchangeable iron and lead appear in significant amounts at pH below 3.5 and 4.5, respectively, regardless to the content of organic carbon. Manganese and zinc are exchangeable at pH below 5.0 and are leached for about 90% from the A_h-horizon at pH values below 3.0. The effects of higher soluble iron and lead contents on the distribution of herbaceous plants are discussed.     

Zur Frage der Melioration versauerter Böden aus schadstoffbelasteten Buchenwäldern durch Zufuhr von Kalk oder halbgebranntem Dolomit. Ein Gefäßversuch mit Rotbuche (Fagus sylvatica)

The melioration of soils in beech forests acidified by deposition of atmospheric pollutants. Liming or addition of half-burnt dolomite in a pot experiment with beech (Fagus sylvatica) Soils in the infiltration zone of polluted stemflow in beech stands are frequently highly acidic and enriched with heavy metals. It has been shown that beech (Fagus sylvatica) and maple (Acer platanoides) grow poorly on such soils and show characteristic root damage as well as nutritional disorders, such as excessive manganese uptake. In a follow-up experiment amendments with lime (CaCO₃) or half-burnt dolomite (CaCO₃/MgO) were tested. A pot experiment with beech (Fagus sylvatica) showed that the availability of potentially toxic metals decreased with increasing pH-values of the soil. The beech plants showed significantly improved growth and a healthy root system. Especially with regard to root ramification and root biomass, half-burnt dolomite proofed to be better than pure calzium carbonate. With both amendments insufficient nutrition with other nutrients has to be considered as a consequence of antagonisms and dilution due to increased biomass production.     

重庆地区紫色土锗的背景含量及分布特征

对重庆地区分布的5种主要紫色土的116个背景土壤剖面,261个土样中的锗含量及分布进行了研究,结果表明:紫色土中锗的含量服从对数正态分布,几何均值为0.67×/÷1.4 mg/kg,算术均值为(0.71±0.26)mg/kg,略低于世界土壤平均值(1.0 mg/kg).背景土壤剖面C层锗含量高于A层、B层,但在燃煤所致降尘和酸雨重污染地区及某冶炼厂附近土壤(灰棕紫泥属)中,其表层锗含量明显高于底层,亦高于其它非污染地区同属土壤表层,因此,局部地区土壤可能存在锗污染问题,值得重视.紫色土壤锗含量与土壤阳离子交换量(CEC),Cu含量呈显著负相关,与土壤Pb,As含量呈显著正相关,而与土壤pH、有机质(OM)、碳酸盐含量及土壤其它化学成分(Hg,CA,Zn,Al_2O_3,Fe_2O_3,K_2O.Na_2O,CaO.MgO,Mn,Cr,Ni,TiO_2)间相关性很差.     

Long-Term Soil Reaction Changes in a Temperate Beech Forest Subject to Past Alkaline Pollution

Changes in deposition exert effects on forests. Some evidence for a slow recovery of strongly alkalised forest soils after a reduction in alkaline pollution exists, but the recovery rate is little known. The objective of this study was to estimate temporal soil reaction changes. For this purpose, measurements of soil reaction under a beech forest near magnesite works in Central Slovakia were taken in 1991 and 2006, following the alkaline pollution reduction in 1992. As a result, the mean active soil reaction decreased from pH 7.8 to 6.6. Beyond the range of beech stemflow, which amplifies water and acid pollution inputs into soils locally, soil reaction dropped from pH 7.8 to 6.8. The effect of stemflow on local exchangeable reaction minima was detected even before the pollution reduction. The logarithmic function fitted on the pH data indicates considerable differences between neutralisation rates within and outside the stemflow zone.     

生物炭与沸石复配对碱性土壤铅镉有效性的影响

【目的】以生物炭单施及其与沸石复配为钝化剂,研究其对铅镉复合污染碱性土壤理化性质及铅镉有效性的影响,以期用钝化技术为碱性土壤重金属污染原位修复提供理论和实践支持。【方法】以河南某金属冶炼厂附近铅(Pb)镉(Cd)污染的碱性菜地土壤(Pb 227.75 mg kg^-1、Cd 3.38 mg kg^-1)为研究对象,采用盆栽试验,研究生物炭单施及其与沸石复配(生物炭∶沸石=1∶1)不同施入量(0、1%、2.5%、5%)对土壤理化性质、土壤Pb、Cd有效态含量、青菜根和叶中Pb、Cd含量以及青菜富集转运Pb、Cd的影响。【结果】与对照相比,生物炭单施及其与沸石复配处理,使土壤pH提高了0.03～0.17个单位,与对照无显著差异,但显著提高了土壤有机质、碱解氮、有效磷和速效钾含量(P <0.05)。土壤有效态Pb、Cd含量随钝化剂施用量增加呈下降趋势,分别下降了10.69%～32.75%和7.63%～26.72%,相同施用量下复配处理效果优于单施处理。生物炭及其复配沸石促进了青菜生长,降低了青菜Pb的含量,根部和茎叶中Pb的含量比对照分别下降了2...     

Effects of acidic deposition on soil ecosystems under forest in the Chongqing region of China

The effects of acidic deposition on soil ecosystems under temperate coniferous forest in the Chongqing region of China were investigated from 1993 to 1994. Precipitation, throughfall, stemflow, soil solutions, and soil samples were collected to estimate the acidification of soil ecosystems through the changes of their chemical components. The concentrations of ion species in the throughfall and stemflow under masson pine forest in Mt. Zhenwu were higher than those under mixed coniferous forest in Mt. Jinyun and under camphor tree forest in Laojundong, suggesting that Mt. Zhenwu is located in the vicinity of the Chongqing center and that it allowed the canopy of masson pine to intercept air pollutants. However, the level of aluminum dissolution into soil solutions was relatively low under masson pine forest in Mt. Zhenwu in spite of the low pH in the stemflow.     

Die „Baumfuß-Methode”︁, dargestellt anhand einer Untersuchung der Immissionsbelastung von Nordwest-Jugoslawischen Buchenwäldern

The “Trunk Base Method”, Demonstrated by an Investigation on Immission Load of Beech Stands in Northwestern Yugoslavia Due to stemflow, the soil area close to the stem of old beech trees (Fagus sylvatica) differs from the soil farther from the stem as a consequence of higher input rates of all elements. It is postulated that the level of deposition determines the degree of deviation in soil chemical properties of the trunk base area (“Baumfußbereich” = “micro-habitat”) compared with soil which is not influenced by stemflow water (“Vergleichsstandort” = “macro-habitat”). The paper attempts to estimate the relative load of air pollution in 10 beech stands (mainly Rendzinas and Cambisols from limestone and dolomite) of northwestern Yugoslavia. In each plot 10 micro- and macro-habitats were chosen, for analysis of soil samples of Ah horizons for pH and exchangeable cations after percolation with NH₄Cl. The differences in pH, base saturation and saturation of (H+Fe) between trunk base area and related soil are used to determine acid loading. The saturation of (H+Fe) turned out to be the most appropriate indicator to describing the acidification. The results indicate high acid deposition rates at sites 1–5,9 and 10, but low rates at stands 6–8. It is assumed, that the main sources of pollutants reaching the plots 1–5, which are located at the western declivity of Risnjak, are industrial plants in northern Italy and towns at the Adriatic coast. The sources of pollutants reaching the sites 9 and 10, which are located at the eastern declivity of Gorski Kotar, respectively Lika region, are the industrial plants in northern Yugoslavia and Hungary.     

Heavy metals mobility,sources, and risk assessment in soils and uptake by apple (Malus domestica Borkh.) leaves in urban apple orchards

The aim of the study was determine potential mobility, sources, and environmental impacts of heavy metals in soil of urban apple orchards using a sequential extraction procedure and multivariate analysis. The soil and apple (Malus domestica Borkh.) leaf samples were collected from apple orchards of urban areas in Çanakkale, Turkey. A sequential extraction procedure was employed to determine the binding forms of Cd, Cr, Cu, Ni, Pb, and Zn in soil samples. Sequential extraction procedure revealed that mobile fractions (acid soluble, reducible, and oxidizable) of Cd (60.2%) and Pb (56.8%) were higher than their immobile fractions. Such higher mobile fractions indicate the anthropogenic sources, and multivariate analysis results also supported the existence of such sources. The relationship between pH and mobile fractions of the metals (sum of acid soluble, reducible, and oxidizable) indicates that Cd and Pb become more mobile under decreasing pH conditions. Considering all metals, except for Cd, a strong relationship was observed between metal concentrations of apple leaves and mobile fractions, and plants were primarily able to uptake the metals in these fractions. Contamination factor and risk assessment code results together also revealed that Cd was highly mobile; retained less and had high risk for the environment.     

Root colonisation by arbuscular mycorrhizal, fine endophytic and dark septate fungi across a pH gradient in acid beech forests

Colonisation by root endophytes can be beneficial to plants growing on acid, nutrient-poor soils. Arbuscular mycorrhizal (AM) fungi can supply herbs with nutrients and may give protection against aluminium toxicity. Two other root colonising fungi, fine endophytes (FE) and dark septate fungi (DSE), are less well known but are potentially of benefit to their host plant. AM fungi are the most prevalent symbionts in herbs at neutral to acidic soil pH. At extremely low pH, fungal growth can be limited and AM colonisation is usually rare. Fine and dark septate endophytes, on the other hand, have been observed more often under these conditions. In order to relate endophyte colonisation to a gradient in soil pH, we investigated root colonisation by AM, FE and DSE in Maianthemum bifolium, Galium odoratum, Mercurialis perennis and Stellaria nemorum, from a range of acidic beech forests. With decreasing pH, colonisation by AM decreased, whereas the other two endophytes increased. AM and FE colonisation were inversely correlated in Maianthemum bifolium. We compared changes in root colonisation with those in chemical composition of soil and leaf samples and found a positive correlation between leaf magnesium concentrations and the presence of DSE in Galium odoratum. Aluminium concentration in Maianthemum bifolium tended to be lower when FE colonisation was high, suggesting a possible role for the fungi in plant protection against Al. We suggest that FE and DSE may replace AM fungi in herbaceous vegetation at extremely low pH, counteracting some of the negative effects of high soil acidity on plants.     

Modelling the Fate of Chromated Copper Arsenate in a sandy Soil

Afforestation of former agricultural land changes soil characteristics such as pH and organic matter content, which may affect heavy metal solubility in the soil. In this study the effects of different tree species on heavy metal solubility were investigated at four 34 years old adjacent stands of beech (Fagus sylvatica L.), grand fir (Abies grandis Lindl.), Norway spruce (Picea abies (L.) Karst.) and oak (Quercus robur L.) planted on former agricultural land at four different sites in Denmark. The sites differ in soil characteristics and represent two texture classes (loamy sand and sandy loam). Soil pH and soil organic matter content was measured in the 16 stands and soil solution was isolated by centrifugation from three depths at four different occasions. Dissolved organic carbon (DOC), pH in the soil solution and the soil solution concentrations (availability) of Cd, Cu, Ni, Pb and Zn were determined. Analysis of variance showed that the tree species affects soil pH and organic matter content in the topsoil, but not in the lower horizons. Norway spruce and grand fir acidify more than beech and oak, and the highest amount of accumulated soil organic matter is in the topsoil under Norway spruce. The effects of tree species on soil solution pH and DOC resemble the effect on soil pH and organic matter content. Grand fir enhances the solubility of Cd and Zn in the topsoil with the lower solubility found under beech and oak and Norway spruce enhances the solubility of Cu, Ni and Pb in the top horizons. The lowest solubility of Ni and Pb is found under beech and oak, whereas the lowest Cu concentrations in the soil solution are found under grand fir. After 34 years of afforestation no effects of tree species on the concentrations of heavy metals in the soil solution from the C-horizons were found. The tree species effect on the concentration of Cd, Cu and Ni in the soil solution depends on the soil characteristics with the higher concentrations found in sandy loam soils, whereas no effect of site on the solution concentration was found for Pb and Zn. It was not possible to find a clear correlation between the soil solution concentrations of heavy metals, pH and DOC concentration.     

Acidity,nutrient stocks,and organic‐matter content in soils of a temperate deciduous forest with different abundance of European beech (Fagus sylvatica L.)

The production and composition of leaf litter, soil acidity, exchangeable nutrients, and the amount and distribution of soil organic matter were analyzed in a broad‐leaved mixed forest on loess over limestone in Central Germany. The study aimed at determining the current variability of surface‐soil acidification and nutrient status, and at identifying and evaluating the main factors that contributed to the variability of these soil properties along a gradient of decreasing predominance of European beech (Fagus sylvatica L.) and increasing tree‐species diversity. Analyses were carried out in (1) mature monospecific stands with a predominance of beech (DL 1), (2) mature stands dominated by three deciduous‐tree species (DL 2: beech, ash [Fraxinus excelsior L.], lime [Tilia cordata Mill. and/or T. platyphyllos Scop.]), and (3) mature stands dominated by five deciduous‐tree species (DL 3: beech, ash, lime, hornbeam [Carpinus betulus L.], maple [Acer pseudoplatanus L. and/or A. platanoides L.]). The production of leaf litter was similar in all stands (3.2 to 3.9 Mg dry matter ha^–1 y^–1) but the total quantity of Ca and Mg deposited on the soil surface by leaf litter increased with increasing tree‐species diversity and decreasing abundance of beech (47 to 88 kg Ca ha^–1 y^–1; 3.8 to 7.9 kg Mg ha^–1 y^–1). The soil pH_(H2O) and base saturation (BS) measured at three soil depths down to 30 cm (0–10 cm, 10–20 cm, 20–30 cm) were lower in stands dominated by beech (pH = 4.2 to 4.4, BS = 15% to 20%) than in mixed stands (pH = 5.1 to 6.5, BS = 80% to 100%). The quantities of exchangeable Al and Mn increased with decreasing pH and were highest beneath beech. Total stocks of exchangeable Ca (0–30 cm) were 12 to 15 times larger in mixed stands (6660 to 9650 kg ha^–1) than in beech stands (620 kg ha^–1). Similar results were found for stocks of exchangeable Mg that were 4 to 13 times larger in mixed stands (270 to 864 kg ha^–1) than in beech stands (66 kg ha^–1). Subsoil clay content and differences in litter composition were identified as important factors that contributed to the observed variability of soil acidification and stocks of exchangeable Ca and Mg. Organic‐C accumulation in the humus layer was highest in beech stands (0.81 kg m^–2) and lowest in stands with the highest level of tree‐species diversity and the lowest abundance of beech (0.27 kg m^–2). The results suggest that redistribution of nutrients via leaf litter has a high potential to increase BS in these loess‐derived surface soils that are underlain by limestone. Species‐related differences of the intensity of soil–tree cation cycling can thus influence the rate of soil acidification and the stocks and distribution of nutrients.     

续断菊与玉米间作的铅累积及根系低分子量有机酸分泌特征研究

为探明间作作物根系分泌低分子量有机酸对土壤重金属生物有效性的影响,采用矿区周边农田土壤进行室内盆栽试验,研究了云南本土超累积植物续断菊(Sonchus asper L. Hill)和玉米(Zea mays L.)间作下,植物生长、根系低分子量有机酸分泌量、根际土壤Pb提取形态以及植物Pb积累特点。结果表明:与单作相比,间作续断菊地上部和根部生物量、根长、根内径和根系体积均显著增加(P0.05);间作玉米根部生物量、根长、根内径和根系体积显著增加(P0.05)。柠檬酸、草酸是续断菊和玉米根系分泌的主要低分子量有机酸,间作导致续断菊根系低分子量有机酸的分泌量增加,玉米根系低分子量有机酸的分泌量降低。续断菊根际土壤生物有效态Pb含量增加85.2%(P0.05),而玉米根际土壤生物有效态Pb含量降低26.1%(P0.05)。续断菊体内Pb含量显著增加18.0%～43.2%(P0.05),富集系数提高26.0%,而转运系数降低42.0%;玉米地上部Pb含量显著降低24.3%(P0.05),转运系数降低43.1%。续断菊根系分泌的柠檬酸和草酸数量,均与土壤生物有效态Pb含量呈显著正相关,且土壤有效态Pb含量分别与续断菊地上部和根部的Pb含量呈显著正相关。表明间作增加了续断菊对Pb的吸收积累量,与间作体系植物根系分泌的低分子有机酸介导下的土壤有效态Pb含量增加密切相关。     

黔产山银花及其产地土壤重金属含量分析与评价

[目的]探明黔产山银花及其产地土壤重金属污染特征,为山银花品质保障、产地土壤重金属防控及规范化种植提供指导。[方法]以贵州山银花及其产地土壤为供试样品,采用ICP-MS测定重金属铜(Cu)、砷(As)、铅(Pb)、镉(Cd)、汞(Hg)、铬(Cr)的含量,采用单因子指数法和内梅罗综合指数法进行分析评价,对黔产山银花及土壤重金属污染水平进行探讨。[结果]结果表明:土壤中6种重金属As,Pb,Cd,Cr,Hg和Cu平均含量分别为9.79,14.30,0.10,19.89,0.12和3.81mg/kg,均未超标;根区与非根区土壤的重金属综合污染指数分别为0.46和0.83,污染等级分别处于安全和警戒线。山银花中Cr,As,Cd,Pb,Cu平均含量分别为5.19,0.16,1.87,0.39和6.86mg/kg,Hg未检出;Hg,As,Pb,Cu未超标,而Cd远超出限量值,超标率为100%,山银花对Cd中具有很强的富集效应。[结论]研究区土壤环境质量总体适宜山银花种植。     

沿海滩涂区土壤重金属含量分布及其有效态影响因素

为揭示沿海地区土壤重金属含量的空间分布特征及其与自然、人为因素的关联,以近年来围垦开发强度较大的江苏沿海某滩涂区为研究对象,采用经典统计与地统计相结合的方法研究了表层土壤主要重金属Pb、Cr、Cd、As全量与有效态含量状况及其空间分布,分析了沿海滩涂区土地利用方式对重金属含量的影响,探讨了重金属有效态含量与土壤理化性质的相关性。结果表明:目前研究区土壤环境质量状况良好,土壤Pb、Cr、Cd、As均呈累积趋势但基本都低于土壤环境质量一级标准值;土地利用方式不同程度地影响了Pb、Cr、Cd全量与有效态含量,As全量与有效态含量受土地利用方式影响较小;研究区土壤Pb、Cr、Cd全量与Pb、Cr有效态含量具有明显的趋势效应,且研究区土壤重金属全量与有效态含量的空间分布受大尺度的潮汐作用与小尺度的人为因素的共同控制;土壤Pb、Cr、Cd有效态含量与黏粒含量、阳离子交换量和p H显著负相关,与有机质呈显著正相关,土壤As有效态含量仅与土壤p H显著正相关。本研究为沿海滩涂区土壤重金属源头减量、活性钝化、污染消减与风险防范提供科学依据。     

Mycorrhizal colonization and lead distribution in root tissues of Norway spruce seedlings

Non-inoculated spruce seedlings (Picea abies Karst.) and spruce seedlings colonized with Lactarius rufus Fr., Pisolithus tinctorius Coker & Couch or Paxillus involutus Fr. were grown for 35 or 37 weeks in a microcosm system on two types of natural forest humus differing in Pb content. Using X-ray microanalysis, the distribution and content of Pb in the tissues of mycorrhizal and non-mycorrhizal root tips were compared. No significant difference in the Pb contents of root cortex cell walls of non-mycorrhizal and seedlings colonized by Lactarius rufus, Pisolithus tinctorius, or indigenous mycorrhizal fungi (mainly Tylospora sp.) was found. However, in root tips of seedlings colonized by Paxillus involutus, due to a higher binding capacity for cations, the Pb content in cell walls of the root cortex were higher than in non-mycorrhizal roots. Pb contents in cell walls of the cortex of mycorrhizal and non-mycorrhizal roots were 3 times higher in plants growing in humus with a high Pb content than in plants growing in humus with a low Pb content. It is concluded that increasing contents of Pb in the organic matter may lead to an increased loading of the apoplast with Pb. The mycobionts tested in this investigation did not exclude Pb from root tissues.