白桦天然种群木材化学成分的地理变异与相关性研究

以东北地区5个天然白桦种群为研究对象,进行了木材的化学成分分析。结果表明：除1% NaOH抽出物、综纤维素、聚戊糖外,种群间化学成分含量差异都显著,并且各种群变异较大,这为白桦纸浆材种群间选择和种群内选择提供了可能。白桦天然种群间灰分与苯醇抽出物含量呈显著正相关,综纤维素与聚戊糖含量呈显著正相关。灰分和抽出物含量的变异与经度呈一定程度负相关,综纤维素和聚戊糖与纬度呈一定程度正相关,木素与纬度呈一定程度负相关。这表明,选择较高经纬度地区的白桦,可以降低灰分、抽出物、木素含量,提高综纤维素和聚戊糖含量。     

Plant phenological data and tree-rings as palaeoclimate indicators in south-west Finland since AD 1750

Plant phenological data and tree-rings were tested for their palaeoclimatic value in south-west Finland since AD 1750. The information from fragmentary, partly overlapping, partly non-systematically biased plant phenological records of 14 different phenomena (a total of 3,144 observations) was combined into one continuous time series of phenological indices. All site- and phenomenon-specific series were standardized to present an average of zero and standard deviation of one. The mean phenomenon-specific series were then averaged as arithmetic means for annually resolved time series representing the variability in the particular plant phenomenon. Consequently, each phenomenon-specific mean series was based on spatially normalized site-specific index series. These series were compared to each other, living-tree and subfossil tree-rings, and to early and modern meteorological time series. Phenological indices showed strong positive correlation with February to June temperatures. On the other hand, the correlations between phenological indices and precipitation data were around zero. Analysis using time-dependent running correlations showed non-stationary relationship between the tree-rings and phenological indices and observed spring temperatures. The skill of phenological data for reconstructing the spring temperatures was statistically proved.     

转UGPase基因喜树木材化学成分与生长速率研究

分析了田间栽培条件下2年生转UGPase基因喜树与对照株的木材化学成分与生长速率。结果表明,转UGPase基因喜树综纤维素含量达到78.87%,比对照株相比提高了2.23%;纤维素含量为36.34%,与对照株相比没有明显提高;木质素含量为15.05%,较对照株降低了1.75%;两者的灰分含量均较低且无显著差异;冷、热水抽提物含量为7.62%与10.17%,分别提高了2.04%与2.13%;1% NaOH抽提物含量为27.13%,提高了1.27%。因此,就综纤维素、木质素、灰分含量而言,转UGPase基因喜树为优质纸浆材,水抽提物和1% NaOH抽提物的含量略高,在纸浆生产中需加以重视。本文还对转UGPase基因喜树与对照株的株高、基径、生物量进行了动态监测,结果表明,从5月25日到11月10日的生长季中,其株高平均增加121 cm,对照株平均仅67.8 cm,株高生长速率提高了78.47%;基径平均增加1 792 cm,对照株平均仅0.532 8 cm,提高了236.37%;地上部分生物量的积累与对照相比提高了322.61%,即转入UGPase基因使喜树生长速率显著提高。因此,虽然转UGPase基因喜树的综纤维素和纤维素含量没有明显提高,但其生长速率快,生物量增长显著,间接提高了纤维素与喜树碱的产量。因此,转基因喜树较普通喜树更符合纸浆材速生、纤维素含量高和产量高、木质素含量低的基本要求,可在生产中进一步推广。     

Tree rings as a surrogate for economic stress – an example from the Puna of Jujuy, Argentina in the 19th century

This paper illustrates the use of tree-ring indices as an indicator of economic stress. In the 19th century the rural economy in the Puna of Jujuy, Northwestern Argentina was based on livestock (llamas and sheep), and was heavily dependant on the availability of pasture and water in this arid landscape. In the absence of traditional indicators of socioeconomic stress, we used tree-ring indices from moisture sensitive trees (Juglans australis Griseb. and Polylepis tarapacana Phil.) as a proxy for droughts and their related economic stresses. Examining the relationship between population mortality and ring-width indices allows inferences to be drawn about the relative importance of environmental and sociopolitical factors in determining mortality patterns that contributed to the depopulation of this area in the late 19th century.     

Tree growth and climate sensitivity in open and closed forests of the southeastern Tibetan Plateau

The creation of forest openings is a frequently observed phenomenon in many types of forests. On the southeastern Tibetan Plateau, where the average elevation is greater than 4000 m above sea level, differences in tree growth between forest stands with openings and completely closed stands are poorly characterized. Here, we presented a dendrochronological study of Tibetan juniper (Juniperus tibetica Kom.) and Sikkim spruce (Picea spinulosa (Griff.) Beissn.) in an open and a closed stand, near Qamdo of eastern Tibet. We found that the growth of juniper responded to climate in a similar way in the open and closed stands, and was positively correlated with temperature from October to January and with the Palmer Drought Severity Index (PDSI) from September to June. In contrast, the growth of spruce responded to climate differently in the open and closed stands: growth was positively correlated with the PDSI from September to May in the open stand, whereas it was positively correlated to November and December temperatures (of the prior year) and current June temperature in the closed stand. Interannual variation in, and standard deviations among, juniper tree ring widths were similar in both stands for the past four centuries, whereas they differed in spruce over the past two centuries, particularly in the 1900s. These results suggest that juniper tree ring growth is less sensitive to stand structure than that of spruce, thus providing more reliable climate signals. The data obtained from our study will help forest managers understand the ecology of juniper and spruce in open and closed stands and are therefore useful for management planning.     

Development of facies and C/O-isotopes in transects through the Ludlow of Gotland: Evidence for global and local influences on a shallow-marine environment

Summary The Silurian of Gotland is characterized by repeated changes in depositional facies development. The deposition of uniform sequences of micritic limestones and marls was interrupted four times by the growth of reef complexes and the formation of expanded carbonate platforms. Coinciding with these, often abrupt, facies changes extinction events occurred which predominantly affected nektonic and planktonic organisms. Ratios of carbon- and oxygen-isotopes covary with the facies development. Periods in which the deposition of limestonemarl alternations prevailed are characterized by relatively low C- and O-isotope values. During periods of enhanced reef growth isotope values are high. For these changes,Bickert et al. (1997) assume climatic changes between humid “H-periods”, with estuarine circulation systems and cutrophic surface waters with decreased salinity in marginal seas, and arid “A-periods”, with an antiestuarine circulation and oligotrophic, stronger saline surface waters. In order to separate local and regional influences on the isotopic development from the global trend, the interactions between facies formation and isotope record have to be clarified. For this purpose, the patterns of isotope values in the upper part of the Silurian sequence on Gotland (upper Wenlock —upper Ludlow) has been determined and stratigraphically correlated along four transects through different facies areas. Facies formation during this time interval was investigated by differentiation and mapping of twelve facies complexes in the southern part of Gotland. These include shelf areas, reef complexes with patch reefs and biostromes, backreef facies, and marginal-marine deposits. The good correspondence between the carbon-isotope records of the four transects suggests that local environmental conditions in the different facies areas did not influence the δ¹³C values. Therefore, a supra-regional or even global mechanism for the C-isotope variations is likely. In contrast to carbon istopes, the oxygen-isotope values of the four transects generally show parallel trends, but higher variabilities and in parts distinctly deviating developments with a trend to more negative values. These are interpreted as an effect of local warming in small shallow-water areas which developed during arid periods in reef complexes and backreef areas. The boundaries between A-periods and H-periods, as defined by δ¹³C values, which are interpreted as isochrones, can be mapped. From the upper Homerian to the Pridolian six parastratigraphic isotope zones are defined which only partly match the stratigraphic division ofHede (1942, 1960). The isotope stratigraphy results in an improved correlation between the shallow and marginal-marine areas in the eastern part of Gotland and the uniform shelf areas at the west coast of the island. Furthermore, a detailed relationship between the development of carbon and oxygen isotope ratios, the carbonate facies formation, and the succession of palaeontological events could be observed. At the transition from H-periods to A-periods, major extinction events occurred prior to the first increase of δ¹³C and δ¹⁸O values. Extinction events affected conodonts, graptolites, acritarchs, chitinozoans, and vertebrates and resulted in impoverished nektonic and planktonic communities. The reef-building benthos was less affected. Parallel to a first slight increase of isotope values, facies began to change, and reefs developed in suitable locations. The subsequent rapid increase of C- and O-isotope values occurred contemporarily with strong facies changes and a short-term drop of sea-level. Oligotrophic conditions in the later stages of A-periods led to strong reef growth and to an expansion of carbonate platforms. The transitions from A-periods to H-periods were more gradual. The δ¹³C values decreased slowly, but reef growth continued. Later the reefs retreated and were covered by the prograding depositional facies of shelf areas. The diversity of planktonic and nektonic communities increased again. The close relationship between facies formation, palaeontological events and isotope records in the Silurian suggests common steering mechanisms but gives no indication of the causes for the repeated extincion events related to H-period/A-period transitions. Especially the observation, that strong extinctions occurred prior to changes of isotope values and facies, points to causes that left no signals in the geological record. Hypothetical causes like collapse of trophical nets, anoxias, or cooling events are not evident in the sediment record or do not fit into the regular succession of period transitions.     

与杨树木材密度、纤维性状相关的SSR分子标记

通过对美洲黑杨 (Populusdeltoides)×青杨 (P .cathayana)的 68个F2 、双亲及其 4个F1无性系田间随机区组设计 ,5次重复 ,分析了与木材材性有关的木材密度、纤维长、纤维宽以及微纤丝角等性状。结果表明 :纤维长有明显的杂种优势 ,控制该性状表现的基因之间具有正效应的互作 ;控制木材基本密度的基因之间具有负效应的互作。结合SSR分子标记结果 ,采用单因素方差分析法进行标记与性状的相关分析 ,共找到与木材密度、纤维长、纤维宽以及微纤丝角相关联的标记分别为 5、7、4、2个 ;青杨在这 4个材性性状方面也具有对性状起贡献的标记 ,如与木材密度相关的PMGC2 873 1(贡献率 4 88% )标记 ,与纤维长相关的PMGC456 3 (贡献率 2 2 96% )、PMGC2 70 2 2 (贡献率9 17% )标记 ,与纤维宽相关的PMGC2 40 8 1(贡献率 7 18% )标记 ,与微纤丝角相关PMGC2 52 5 1(贡献率 16 59% )标记 ,在育种中如果能正确加以利用 ,也可起到一定的材性改良作用     

Tree age estimates in Fagus sylvatica and Quercus robur: testing previous and improved methods

The accuracy of direct (based on increment cores) and indirect (based on age-size relationships) methods of tree age estimation in Fagus sylvatica and Quercus robur was tested. This was done through increment cores and stem discs taken in an old-growth forest of Northern Spain. It was found that cross-dating was more precise than ring counting by up to 7 years per tree. Furthermore, cross-dating permitted the estimation of the age of trees with floating ring-width series, which were 7% of cored F. sylvatica and 40% of Q. robur ones. In partial cores with the arcs of the inner rings, the length of the missing radius was estimated with both a geometric method, based on the curvature of the arcs, and a new graphical method, based on the convergence of xylem rays at the pith. The graphical method was more accurate when the radial growth was eccentric, as happens in Q. robur, while both methods showed a similar accuracy for F. sylvatica, whose growth is relatively concentric. Empirical models of initial radial growth (IRG), built to estimate the number of missing rings, reduced the errors associated with other methods that assume constant growth rates. Age estimates obtained from the graphical method combined with the IRG models were within 4% of the actual age. This combination ensured age estimates with a mean accuracy of 8 years for 98% of the F. sylvatica trees, and 4 years for 89% of the Q. robur. In partial cores without the arcs of the inner rings, the length of the missing radius was estimated as the distance to the geometric centre of the tree. In that case, age estimates obtained by extrapolating the mean growth rate of the 20 innermost rings in the cores were from 10 to 20% of actual age, which coincided with results obtained in other tree species with this method. Finally, the age-diameter equations of the different cohorts produced better age estimates (from 8 to 14% of actual age) than equations of the population as a whole (from 20 to 40% of actual age). These results proved that the errors derived from doubtful assumptions, such as concentric radial growth, constant growth and recruitment rates, or the absence of anomalous rings, could be reduced by applying more realistic methods of tree age estimation.     

Environmental stress and diagenetic modifications in inoceramids and belemnites from the Upper Cretaceous James Ross Basin, Antarctica

Summary New petrographic and isotopic data from inoceramid bivalve shells and belemnite rostra from the lower Campanian and belemnite rostra from the mid-upper Maastrichtian of the Marambio Group, James Ross Basin, Antarctica are presented. Most of the inoceramid data were processed from shell fragments of the large formAntarcticeramus rabotensis (Crame and Luther) at the stratigraphic level marking the extinction of the inoceramids in the James Ross Basin (uppermost early Campanian-basal late Campanian). Standard transmitted light microscopy and cathodoluminescence (CL) studies in thin sections ofA. rabotensis show clear evidence of environmental stress, which is reflected as marked growth breaks in the shell banding of this large inoceramid bivalve. At Redonda Point, CL and the mean oxygen isotopic value (δ¹⁸O=-3.11‰ 3 (PDB); n=11; t°=25.4°C) indicate a varied degree of diagenetic modification, but without any evidence of neomorphism along the prismatic microstructures. Early Campanian belemnite rostra are much less diagenetically modified (at the Brandy Bay section; and the Santa Marta section; δ¹⁸O=-0.50‰ (PDB); n=5; t°=14.0°C and 3 δ¹⁸O=-0.94‰ (PDB); n=21; t°=15.8°C) and are non luminescent 3 except for localized, organic-rich bands. The mean oxygen isotopic value for mid-late Maastrichtian belemnite rostra (at the Seymour Island section; δ¹⁸O=-0.11‰ 3 (PDB); n=5; t°=12.5°C) indicates a substantial drop in the sea-water paleotemperature, suggesting a causal relationship between the early extinction of the inoceramid bivalves in high latitudes of the Southern Hemisphere and the falling sea-water temperature.     

Wood density and vessel traits as distinct correlates of ecological strategy in 51 California coast range angiosperms

Wood density and vessel characteristics are functionally interrelated, yet they may have distinct ecological associations. In a comparative study of 51 angiosperm species ranging from chaparral shrubs to riparian trees, we examined relationships among wood density and vessel traits and their ecological correlates. Mean vessel lumen area and vessel density (number mm(-2)) varied widely (7- to 10-fold). In multivariate analyses, both vessel traits were negatively correlated with wood density, which varied more narrowly (< 2-fold). Vessel density and lumen area were inversely related across species, allowing a broad range of vessel traits within a narrow range of wood density. Phylogenetic independent contrasts indicated correlated inverse evolutionary change in vessel traits. Each trait had a distinct pattern of ecological correlation -- wood density was most strongly associated with soil water, and vessel traits showed contrasting relationships with plant height. Within a narrow range of wood density, there was significant variation in vessel traits. Given their particular ecological associations, the results suggest that wood density and vessel traits describe two distinct ecological axes.     

Wood preservation hygiene and environment in the lime-light of actually

Summary Under the ?Bois plus? scheme, the CTBA is currently developing a third party certification, based on the Scrivener law, with the aim of defending the consumers' interests. At this early stage, wood preservatives and treated wood are checked for the efficacy of treatments in order to ensure the stability and security of works in buildings and civil engineering. According to the different classes of risks in service, ?Bois plus? provides the most adeguate level of protection. In the close future, the industry is planning to incorporate, with the help of the CTBA and experts, health criteria within the frame of the ?Bois plus? certification scheme. The means could beSafety indexes, which are objectives of quality for professionals.Safety indexes are concentrations of substances in wood which can be taken as safe for humans and the general environment, while still toxic for the wood pests. This attractive experience aims to make with the brandname ?Bois plus? a synonym of efficacy and safety. This approach meets the essential requirements 1, 3, 4 of the 89/106 EEC directive: mechanical resistance and stability/hygiene, health and environment/safety in use.     

Saproxylic Beetles in Standing Dead Wood Density in Relation to Substrate Sun-exposure and Diameter

Species-specific densities of saproxylic beetles in cut 4-m high, medium to large diameter stumps of spruce, birch, aspen and oak were monitored for 7 years after cutting, by trapping emerging insects within seasonally applied net enclosures. A total of 47,038 individuals, representing 316 saproxylic beetle species including 40 red-listed species, were recorded. Densities of 86 species were modelled in relation to stump diameter and measured levels of sun-exposure. Two thirds of the species favoured semi- or fully exposed substrates, while one third performed better in shade. Few species seemed to be specifically adapted to semi-exposed conditions. Diameter was generally of less importance than exposure, and similar numbers of species favoured medium and large diameter substrates. Group mean diameter and exposure calculated from means per individual and species were similar for groups of modelled and non-modelled species, and for groups of red-listed and non-red-listed species, respectively. This indicates that the proportions found in the models are representative for the diverse regional fauna of saproxylic beetles that utilise high stumps of spruce, birch, aspen and oak in early stages of decay. The results suggest that sun-exposed dead wood substrates generated and retained in managed forest landscapes are potentially important for many species. However, stands of unmanaged self-thinning successions of deciduous trees, as well as substantial areas of old-growth spruce-forests are also necessary to address the wide spectrum of saproxylic beetles.     

Solute Sources in Stream Water during Consecutive Fall Storms in a Northern Hardwood Forest Watershed: A Combined Hydrological, Chemical and Isotopic Approach

Understanding the effects of climate change including precipitation patterns has important implications for evaluating the biogeochemical responses of watersheds. We focused on four storms in late summer and early fall that occurred after an exceptionally dry period in 2002. We analyzed not only the influence of these storms on episodic chemistry and the role of different water sources in affecting surface water chemistry, but also the relative contributions of these storms to annual biogeochemical mass balances. The study site was a well studied 135-ha watershed in the Adirondack Park of New York State (USA). Our analyses integrated measurements on hydrology, solute chemistry and the isotopic composition of NO₃⁻(δ¹⁵N and δ¹⁸O) and SO₄²⁻(δ³⁴S and δ¹⁸O) to evaluate how these storms affected surface water chemistry. Precipitation amounts varied among the storms (Storm 1: Sept. 14–18, 18.5 mm; Storm 2: Sept. 21–24, 33 mm; Storm 3: Sept. 27–29, 42.9 mm; Storm 4: Oct. 16–21, 67.6 mm). Among the four storms, there was an increase in water yields from 2 to 14%. These water yields were much less than in studies of storms in previous years at this same watershed when antecedent moisture conditions were higher. In the current study, early storms resulted in relatively small changes in water chemistry. With progressive storms the changes in water chemistry became more marked with particularly major changes in C_b (sum of base cations), Si, NO₃⁻, and SO₄²⁻, DOC and pH. Analyses of the relationships between Si, DOC, discharge and water table height clearly indicated that there was a decrease in ground water contributions (i.e., lower Si concentrations and higher DOC concentrations) as the watershed wetness increased with storm succession. The marked changes in chemistry were also reflected in changes in the isotopic composition of SO₄²⁻ and NO₃⁻. There was a strong inverse relationship between SO₄²⁻ concentrations and δ³⁴S values suggesting the importance of S biogeochemical redox processes in contributing to SO₄²⁻ export. The isotopic composition of NO₃⁻ in stream water indicated that this N had been microbially processed. Linkages between SO₄²⁻ and DOC concentrations suggest that wetlands were major sources of these solutes to drainage waters while the chemical and isotopic response of NO₃⁻ suggested that upland sources were more important. Although these late summer and fall storms did not play a major role in the overall annual mass balances of solutes for this watershed, these events had distinctive chemistry including depressed pH and therefore have important consequences to watershed processes such as episodic acidification, and the linkage of these processes to climate change.     

Wood anatomy and wood density in shrubs: Responses to varying aridity along transcontinental transects

Wood density plays a key role in ecological strategies and life history variation in woody plants, but little is known about its anatomical basis in shrubs. We quantified the relationships between wood density, anatomy, and climate in 61 shrub species from eight field sites along latitudinal belts between 31° and 35° in North and South America. Measurements included cell dimensions, transverse areas of each xylem cell type and percentage contact between different cell types and vessels. Wood density was more significantly correlated with precipitation and aridity than with temperature. High wood density was achieved through reductions in cell size and increases in the proportion of wall relative to lumen. Wood density was independent of vessel traits, suggesting that this trait does not impose conduction limitations in shrubs. The proportion of fibers in direct contact with vessels decreased with and was independent of wood density, indicating that the number of fiber-vessel contacts does not explain the previously observed correlation between wood density and implosion resistance. Axial and radial parenchyma each had a significant but opposite association with wood density. Fiber size and wall thickness link wood density, life history, and ecological strategies by controlling the proportion of carbon invested per unit stem volume.     

Fungal diversity and deterioration in mummified woods from the ad Astra Ice Cap region in the Canadian High Arctic

Non-permineralized or mummified ancient wood found within proglacial soil near the ad Astra Ice Cap (81°N, 76°W), Ellesmere Island, Canada was investigated to ascertain the identification of the trees, current morphological and chemical characteristics of the woods and the fungi within them. These woods, identified as Betula, Larix, Picea and Pinus, were found with varying states of physical and chemical degradation. Modern microbial decomposition caused by soft rot fungi was evident and rDNA sequencing of fungi obtained from the samples revealed several species including Cadophora sp., Exophiala sp., Phialocephala sp., as well as others. Analytical ¹³C-labeled tetramethylammonium hydroxide thermochemolysis showed the lignin from the ancient wood was in a high degree of preservation with minor side chain alteration and little to no demethylation or ring hydroxylation. The exposure of these ancient woods to the young soils, where woody debris is not usually prevalent, provides carbon and nutrients into the polar environment that are captured and utilized by unique decay fungi at this Arctic site.     

我国林蛙的研究概况和开展环渤海区域林蛙多样性研究的意义

林蛙是一个复杂多样的类群,我国现有13种,历来是两栖动物分类学和系统学研究的热点之一。本文简要概述了我国林蛙研究的历史及其近10年来的最新研究成果。同时,结合作者近年来的研究,提出环渤海区域是我围林蛙的一个分化中心和热点地区。开展该区域林蛙研究具有重要的科学意义。