Effects of acid rain treatments on the birch rust,Melampsoridium betulinum and birch,Betula pendula

Effects of acidic rain on birch rust and on the growth of Betula pendula seedlings were studied by irrigating with acidic water at pH 3, 4 and 5.6. The seedlings were inoculated with uredospores of Melampsoridium betulinum and the development of rust and the severity of rust infection was examined. The increasing acidity of the irrigation water did not affect on the development of the rust, but the nitrogen in the acidified water resulted in an extension of seedling growth, and hence the leaves became senescent at a later date in autumn and the rust grew for a longer time.     

Pre-penetration behaviour of the urediniospores of birch rust,Melampsoridium betulinum,on greenhouse-grown and microcultured leaves of Betula spp.

In two different experiments the urediniospores of Melampsoridium betulinum from Betula pendula and Betula pubescens germinated both on mature leaves of greenhouse-grown plants and on sterile in vitro leaves of micropropagated plantlets, which were cloned from the same B. pendula and B. pubescens genotypes. The urediniospores and germ tubes were more easily detached from the leaf surfaces of in vitro leaves. If germination took place on a leaf vein, the growth continued across the veinal ridges; otherwise, no determined growth towards the stomata could be observed with either of the leaf types studied. In both experiments on the in vitro leaves of B. pubescens clone V5944, the germ tubes of the rust isolate from B. pendula mislocated appressoria significantly more often than the germ tubes of the rust isolate from B. pubescens. On the mature leaves of B. pendula clone E4214 and B. pubescens clone V5940 there were also significant differences in appressorial locations between the two rust isolates but the clonal responses were inconsistent. The results of the inoculations suggest that the incompatibility of the rust isolates from B. pendula on the leaves of B. pubescens is not related to the significantly higher ratio of failures in locating appressoria in this host-rust combination.     

Productivity and economics of mixed two-storied spruce and birch stands in Southern Finland simulated with empirical models

The profitability of growing a naturally emerged birch (Betula pendula Roth or Betula pubescens Ehrh.) overstory in a young Norway spruce (Picea abies (L.) Karst.) plantation was examined with empirical stand structure, growth and yield, logging cost, and logging damage models. In the projected alternatives, an overstory of either birch species was thinned to 200–1000 stems per ha at the age of 15 years and retained for another 15 years. Development of the remaining spruce stand was simulated up to rotation age (70–85 years). Alternative treatments included removing the overstory completely at 15 years, and managing a pure spruce stand that was kept free of birch throughout.

Growing a birch overstory of 200–1000 stems per ha up to age 30 years resulted in a 61–93 m³ ha⁻¹ or 9.1–16.8% yield loss for the spruce stand due to growth retardation, and a mortality of 382–498 out of 1900 stems per ha through logging damage. This was compensated for or exceeded by the additional yield of the birch (54–173 m³ ha⁻¹) except for the lowest stocking (200–400 stems per ha) alternatives with B. pubescens. Treatment regimes with a birch overstory were clearly the most profitable alternatives, yielding up to 151% (B. pendula) and 113% (B. pubescens) of the net present value of the pure spruce alternative, at 4% interest rate. Removing the birch overstory already at 15 years was the least profitable alternative with 79 and 83% net present values, respectively. The most profitable treatment with current technology, price, and cost structure appears to be to grow 500–800 birch per ha up to about age 40 years for B. pendula and 45–50 years for B. pubescens.     

7个造林树种对重金属污染的吸滞能力评价试验

通过杞柳、水杨梅等7个造林树种的造林试验,测定了各树种1年生根部组织内Hg、Cd、Ni、Cr、Cu、Mn、Zn、Pb和As等9种重金属指标的含量。测定结果显示：7个树种对重金属均有一定的吸滞能力,其中杞柳对所有测定的重金属均有较强的吸滞能力,其他树种对不同重金属指标吸滞能力表现不一。通过综合吸滞能力评价,按CI值将7个树种的综合吸滞能力种排序：杞柳〉池杉〉垂柳〉落羽杉〉湿地松〉水杨梅〉杨树。     

Response of Platanus orientalis leaves to urban pollution by heavy metals

Atmospheric pollution is an important concern in urban environments.The impact of urban pollution on the physiological,biochemical and anatomical properties of leaves of oriental plane(Platanus orientalis L.)was studied.The leaves were collected from an urban site(Tehran,Iran)and a non-urban forest park(Chitgar Forest Park).Anatomical(stomata,parenchyma,and cuticle)and physiological(chlorophyll content,enzyme activities)properties were analyzed.The concentrations of Cd(cadmium),Pb(lead),Ni(nickel),and Cr(chromium)in leaves were significantly higher and Zn(zinc)lower at the urban site relative to the forest park.Chlorophyll a,total chlorophyll,and carotenoid content in leaves of the urban site were significantly less than those of the forest park,but there was no significant difference in chlorophyll b.In addition,the activities of superoxide dismutase,catalase,ascorbate peroxidase,and guaiacol peroxidase in urban leaves were significantly higher than in the leaves of the forest park.In the urban area,leaves experienced a significant decrease in leaf surface area,stomata density,stomata pore area,epidermis,and spongy mesophyll thickness,but a significant increase in cuticle and palisade thicknesses relative to forest park leaves.The increase in enzyme activities may indicate that the trees are attempting to cope with increased reactive oxygen species(ROS)because of pollution-induced stress.Our study suggests that oriental plane trees alter their physiological and anatomical properties when living in a polluted urban environment.     

外生菌根真菌与重金属相互作用研究现状

根据国内外的菌根文献资料,综述了外生菌根真菌与重金属相互作用,外生菌根真菌与重金属的作用是相互的,同时阐述了外生菌根真菌对重金属的抵抗机理,及其在森林土壤污染治理中的应用前景。     

绿化林带对公路环境中重金属和S、N元素的吸收效应研究

测定了公路边落羽杉与杨树林带内土壤和树木叶片中9种重金属和S、N元素的含量,并对重金属在杨树8种不同部位中的含量分布以及树干皮、树枝皮和叶片对重金属的吸附量及吸附率等指标进行了研究。结果表明:路侧林带表层土壤中A l、Fe、Mn、Cu、Zn、As、Cd、Cr和Pb等重金属的含量均不同程度地高于相对清洁点植物园,以Fe、Mn和Cd的增加最显著;N和S含量水平接近或低于相对清洁点,以N的下降较显著。落羽杉树叶对公路环境中A l、Fe、Mn、Cu、Zn、As、Cr、Pb和N等元素都具有明显的吸收累积效应,其叶片中重金属含量距路侧均越远而越低;N随距离的增加有较显著地升高,S则不明显。杨树叶中除As和S,其他元素的含量均不同程度地高于相对清洁点,以A l、Fe、Cu、Pb和N的增加较显著;仅B段林带树叶中A l、As和N随距路侧越远而表现显著地下降。此外,路侧杨树林带树木各部位对重金属的吸收和吸附能力存在明显的差异性,如细根和叶片对A l、Fe和Mn的吸收蓄积能力高于较其他部位,而对Cr、Pb和N i的吸收累积以细根及侧根皮较强;叶片对A l、Fe和Pb的吸附能力较树干皮和树枝皮强。     

喷灌对毛竹春笋生长的影响

水分是影响毛竹生长的主要因子之一。通过采取不同喷灌方式对毛竹春笋生长的影响分析,结果表明:喷灌对春笋产量和数量的影响极显著,土壤湿度提高,春笋产量和数量也随着增加。在大年期秋冬季节天气干旱的条件下对毛竹林进行喷灌,可以大幅度提高竹林单位面积产量和产值。     

Initial seedling emergence of hairy birch and silver birch on abandoned fields following different site preparation regimes

Experiments were carried out at four sites in Sweden to investigate the possibility of establishing hairy birch (Betula pubescens Ehrh.) and silver birch (Betula pendula Roth) on abandoned fields using natural regeneration and (or) direct seeding. The effects of six soil preparation methods (no preparation, ordinary ploughing, rotary cultivation, deep ploughing, inverted ground, removal of top-soil) and five additional treatments (no treatment, herbicide, peat litter, wood-ashes, slaked lime) on seedling emergence percentages (SEP) and vegetation cover percentages (VCP) were studied. SEP-values were estimated in June (SEP(J)) and October (SEP(O)). The experimental designs used were: 1) split-plot design with whole plots in a randomized complete block design (RCBD); 2) RCBD. The SEP-values observed with no preparation were close to 0% while the SEP-values obtained with mechanical soil preparation methods mostly were much higher (p0.014). Seedbeds with top-soil in the surface, created by ordinary ploughing or rotary cultivation, and seedbeds with mainly bare mineral soil in the surface, created by deep ploughing, inverted ground or removal of top-soil, obtained SEP-values of equal merit on silty soils, reaching SEP(O)-values up to 15%. The latter seedbeds obtained the best results on sandy soil, with as high SEP(O)-values as 47% after removal of top-soil. Seedbeds with top-soil in the surface were quickly colonized by ground vegetation, reaching VCP-values between 70% and 100%. Herbicide spraying with glyphosate and application of peat litter to the seedbed surface promoted seedling emergence. However, herbicide spraying before soil preparation was of little effect when followed by mechanical soil preparation.     

Decontamination of synthetic solutions containing heavy metals using chemically modified sawdusts bearing polyacrylic acid chains

New materials containing carboxylate groups have been synthesized by grafting polyacrylic acid onto sawdust. These new adsorbents were subjected to continuous extraction of different metal ions using packed columns to determine their maximum binding capacities. They exhibit binding capacities 15–40 times higher than unmodified sawdusts for removal of Cu²⁺, Ni²⁺, and Cd²⁺ chosen as representative heavy metal ions. Cation desorption and adsorbent regeneration could be effected by elution with a diluted HCl solution; water as an eluent has no effect on metal desorption.     

公路土壤重金属污染对农作物的影响

探讨了公路旁土壤重金属污染对农作物的质量和产量的影响,土壤中重金属含量与农作物中的重金属含量之间的关系以及重金属在农作物不同器官的积累分布等,旨在对公路重金属污染的防治及公路旁农作物的种植提供科学依据。     

Effects of various stress treatments on growth and ethylene evolution in seedlings and sprouts of betula pendula Roth and B. pubescens Ehrh.

Experiments were conducted to determine growth and ethylene evolution in seedlings and coppiced plants of Betula pendula Roth and B. pubescens Ehrh. when subjected to stresses relevant to the maintenance of natural forests, and especially in fuelwood plantations, i.e. cutting of the stem, thinning, bending, flooding and various combinations of these. Most of the experiments were carried out in the laboratory using 1‐year‐old seedlings or 1‐month‐old sprouts. Height and diameter growth, biomass production, morphology and ethylene evolution were studied for 1–2 months. Material for comparison was obtained from young sprouts on the stumps of fully developed trees growing under natural conditions and natural seedlings of a comparable age. Exposure of seedlings and coppiced plants to stress factors usually altered growth and increased ethylene evolution. Cutting of the stem and thinning had similar effects in that they stimulated transient ethylene evolution by both roots and stems. Bending retarded the height growth to some extent, while increasing the ethylene content especially on the lower side of the horizontal stem. Flooding arrested height growth and increased ethylene evolution in the roots. The two species reacted basically in similar ways, but B. pendula produced more ethylene. though at a slower rate, and also showed a more pronounced retardation of growth. The sprouts had a higher ethylene content than the seedlings and also increased their ethylene evolution more rapidly. The changes in ethylene evolution and growth are discussed from the point of view of the resilience of the plants and as an indication of stress factors in experimental plots.     

Effect of fertilization on the litter fall of pinus sylvestris and betula pubescens on drained peatlands

NPK fertilization on a dwarf shrub pine bog initially increased the amount and nutrient content of the tree litter. Eight years after fertilization, however, the amount of micronutrients decreased compared to the amount of N and P in the litter. Fertilization on a fertile mire also increased the nutrient content of the litter fall, especially in the mature pine and birch stands. The amount of nutrients in the litter fall of the birch stands was considerably greater than that in the pine stand of the same volume.     

黄芩对土壤中重金属吸收规律的研究

研究黄芩对土壤中重金属的吸收规律以及造成黄芩药材超标的土壤重金属含量限值,旨在为黄芩的无公害生产提供理论参考和技术支撑。采用盆栽方法,通过重金属Cu、Hg、As、Cd、Pb不同水平栽培试验,分析检测黄芩药材重金属含量。结果表明,在本试验条件下,黄芩药材中重金属含量与其在土壤中含量呈较强的正相关性,对土壤中重金属元素吸附强度的顺序为:Cu>Cd>Hg>As>Pb。Cu、Hg、As、Cd、Pb致使黄芩药材污染超标的土壤限值分别为:116.80 mg/kg、1.93 mg/kg3、6.91 mg/kg、3.43 mg/kg、243.81 mg/kg。     

Effects of non-native spruce plantations on small mammal communities in subarctic birch forests

Voles and shrews are key species in northern forest ecosystems. Thus, it is important to quantify to what extent new forestry practices such as planting of non-native tree species impact these small mammals. In northern Norway stands of coastal subarctic birch forests have increasingly been converted to non-native spruce stands during the last century. This leads to changes in the forest floor vegetation and soil conditions that can be expected to negatively impact the community of ground-dwelling small mammals. In this 10-year trapping study we contrasted seasonal small mammal population abundances in spruce plantations with four birch forest varieties. Six different small mammal species were trapped (in descending order of abundance; common shrew Sorex araneus, red vole Myodes rutilus, field vole Microtus agrestis, grey-sided vole M. rufocanus, pygmy shrew S. minutus and water shrew Neomys fodiens). None of the voles appeared to exhibit temporal dynamics resembling population cycles. The three most numerous species were clearly less abundant in the spruce plantations compared to the other forest types. Autumn abundances were most impacted by spruce plantations, indicating that growth rates in the reproductive season were more influenced than winter declines. Species associated with productive forest habitats (i.e. field vole and common shrew) were most impacted by tree species conversion. Still young spruce plantations inter-mixed with birch trees and the ecotone habitat, sustained small mammal abundances comparable to the native birch forests. This implies that managing spruce plantations to maintain a mix of different tree species and high spatial heterogeneity (i.e. more ecotones), will reduce the negative impacts on the small mammal community. On the contrary, if young spruce plantations, as they age become spruce monocultures covering larger parts of the landscapes than they do presently, the negative effects on small mammal communities may be larger than observed in the present study.     

Effect of CCC on the morphology and growth potential of containerised silver birch seedlings

The objective of the experiment described here was to assess the effect of the synthetic growth regulator CCC on the quality of containerised silver birch seedlings. The time course of stem elongation during the growing season, the morphology and size of the seedlings at the end of the growing season, and the growth potential after winter storage were measured and the following results obtained: (1) Stem height, root-collar diameter and total dry weight of the seedlings were decreased by CCC. (2) Stem-height:root-collar-diameter ratio was slightly decreased and root weight ratio was increased by CCC. (3) Stem flexibility was not significantly affected by CCC, although it was significantly correlated with total plant dry weight and with the stem-height:root-collar-diameter ratio. (4) Root-growth potential was decreased at high doses of CCC while shoot growth potential was not affected.     

Growth,stem quality and nutritional status of Betula pendula and Betula pubescens in pure stands and mixtures

The growth, technical quality and nutritional status of pure and mixed silver birch (Betula pendula Roth) and downy birch (Betula pubescens Ehrh.) plantations were studied 21 and 22 years after planting on afforested organic soil arable land and on upland forest soil. In mixtures, 50% of both birch species was planted. Silver birch trees grew better, but had higher mortality than downy birch trees on both sites. Mortality of both species was highest, and the difference in their growth smallest, on organic soil. In pure stands on organic soil, downy birch dominant height, diameter and mean volume were 96%, 92% and 82% of those of silver birch and on mineral soil 87%, 84% and 60%, correspondingly. On mineral soil, silver birch had a higher mean annual increment (MAI) (5.8 m³ ha^?1a^?1) than downy birch (3.9 m³ ha^?1a^?1), but on organic soil the MAI of both species was similar (3.3–3.4 m³ ha^?1 a^?1). Planting birches in mixture did not affect the growth of the trees on organic soil. On mineral soil, the mean diameter and mean volume of silver birch trees were higher in mixed than in pure plantations. The technical stem quality of both tree species was low. On mineral soils, pure silver birch is more productive than mixture, but on peat soil the higher growth of silver birch could contribute to increased productivity and downy birch would ensure sufficient survival for future timber production.     

Differences in the rust resistance of greenhouse and outdoor-grown white birch species,Betula spp.

The 2-year-old seedlings of five different white birch species (Betula platyphylla, Betula papyrifera, Betula pubescens, Betula pendula (two types) and Betula resinifera x Betula pendula) grown both in a greenhouse and outdoors, were inoculated in a leaf disc assay with two different birch rust (Mel-ampsoridium betulinum) isolates from B. pendula and B. pubescens. The resistance of these birch species varied significantly. Resistance to the B. pubescens rust isolate was not related to the resistance of the B. pendula rust isolate. The behaviour of a birch genotype grown in the greenhouse did not correspond to the behaviour of the same genotype grown outdoors. The outdoor growth environment greatly increased the contents of soluble proteins, rubisco, chloro-phyll and nitrogen in the leaves of diploid birch species (B. platyphylla, B. pendula and B. resinifera x B. pendula). For tetraploid and pentaploid species (B. pubescens and B. papyrifera, respectively) there was no such clear difference in the leaf physiological status between the seedlings grown outdoors and in the greenhouse. The C:N ratio was higher for the greenhouse-grown seedlings in all the birch species, but the difference was significant only with the diploid species. The incidence of rust in the birch species did not correlate with any of the leaf physiological parameters studied. The adaptability of birch genotypes to the environment in relation to their resistance to birch leaf rust is discussed.     

不同施肥处理对雪灾后毛竹林恢复生长的影响

2008年春天我国南方发生的严重雨雪冰冻天气对毛竹林造成严重危害,作者调查了富阳区毛竹林的受灾特征及其影响因子,并在此基础上研究了不同施肥处理对受灾毛竹林恢复生长的影响。结果表明：1）毛竹林受灾程度与其所处的海拔、坡向、坡度、坡位、竹林地土壤厚度等环境因子以及毛竹林林分结构密切相关,其中海拔高度的影响最为显著;2）不同施肥处理对毛竹林恢复生长的影响差异显著,在试验的几个处理中,以在高海拔（500 m）区使用大剂量施肥（生物肥料160 kg/667 m²和复合肥40 kg/667 m²）和在低海拔（300 m）区使用小剂量施肥（生物肥料100 kg/667 m²和复合肥20 kg/667 m²）的新竹产量为高,每年产量分别达到2 243.3 kg/667 m²和2 258.3 kg/667 m²,分别比对照增加65.4%和63.3%;3）高海拔地区的毛竹林因受损严重,在适当施肥后其新竹萌发量比低海拔地区的要高,但立竹直径明显低于低海拔地区。     

Spatial distribution of heavy metals (Cu,Pb, Zn,and Cd) in sediments of a coastal wetlands in eastern Fujian,China

We investigated the spatial distribution (horizontal and vertical concentrations) of copper (Cu), lead (Pb), zinc (Zn), and cadmium (Cd) in five wetland types (mudflat, aquaculture wetland, water area,...