Experimental Investigations on the Environmental Determination of {delta}13C at Different Altitudes

The influence of environmental variables which are known tochange with altitude on the ¹³C of leaves of Nardus stricta,have been investigated in controlled environment experiments.Low temperature and an increased incidence of freezing temperaturescaused ¹³C to increase. In contrast, lowered atmospheric pressurereduced ¹³C. Increased leaf surface wetness and soil water contentalso caused a decrease. Plants from different altitudes didnot differ consistently or significantly in their responses. Key words: Carbon isotope discrimination, altitude, temperature, atmospheric pressure, freezing     

Vapour Pressure Deficit Response of Cuticular Conductance in Intact Leaves of Fagus sylvatica L.

The cuticular conductance (g_c) of the astomatous adaxial surfaceof Fagus sylvatica L. leaves was determined under varying vapourpressure deficits at a constant temperature of 20 °C. Cuticularconductance was determined from the weight loss of detachedleaves after both the stomatous abaxial surface and the cutend of the petiole had been sealed using low melting-point paraffinwax. Cuticular conductance was found to decrease as the watervapour pressure was increased in steps. No response was observedwhen vapour pressure deficit was decreased from an initiallyhigh value. It is concluded that these results are consistentwith the hypothesis that cuticular conductance is influencedby the water content of the cuticle and that the apparent hysteresisis likely to be a result of the long time-constant for the processof cuticle rehydration in intact leaves. Key words: Cuticle, cuticular conductance, Fagus sylvatica L., Fagaceae, vapour pressure deficit, VPD     

{delta}15N and {delta}13C Measurements of Antarctic Peninsula Fauna: Trophic Relationships and Assimilation of Benthic Seaweeds

Measurements of ¹³C, ¹⁵N, and C/N for a variety of Antarcticpeninsula fauna and flora were used to quantify the importanceof benthic brown algae to resident organisms and determine foodweb relationships among this diverse littoral fauna. ¹³C valuesranged from–16.8 for benthic algal herbivores (limpets)to –29.8 for the krill, Euphausia superba; the averagepooled value for brown macroalgae, including their attachedfilamentous diatoms, was–20.6. There was no correlationbetween biomass ¹³C or ¹⁵N with C/N content, and consequentlyboth ¹³C and ¹⁵N values were useful in evaluating trophic relationships.¹⁵N values of the fauna ranged from 3.1 to 12.5, with lowestvalues recorded in suspension feeders (e.g., bryozoans) andhighest values in Adelie penguins (12.5) collected in 1989.The comparatively lower ¹⁵N value for a Chinstrap penguin (6.9)collected in 1997 is attributed to the different dietary foodsources consumed by these species as reflected in their respective¹³C values. Significant amounts of benthic macroalgal carbonis incorporated into the tissues of invertebrates and fishesthat occupy up to four trophic levels. For many benthic andepibenthic species, including various crustaceans and molluscs,assimilation of benthic algal carbon through detrital pathwaysranges from 30 to 100%. Consequently, the trophic importanceof benthic brown algae may well extend to many pelagic organismsthat are key prey species for birds, fishes, and marine mammals.These data support the hypothesis that benthic seaweeeds, togetherwith their associated epiphytic diatoms, provide an importantcarbon source that is readily incorporated into Antarctic peninsulafood webs.     

Mechanism of freeze-induced embolism in Fagus sylvatica L.

 The mechanism of freeze stress-induced embolism in Fagus sylvatica L. branches was analyzed under controlled conditions. Excised branches were exposed to successive freeze-thaw cycles in temperature controlled chambers. Thermocouples were placed on the bark to detect sap freezing exotherms. The degree of xylem embolism was estimated after each cycle by the loss of hydraulic conductivity. After one freeze-thaw cycle the degree of embolism was found to decrease with xylem specific hydraulic conductivity, small apical shoots being more susceptible to embolism. Exotherms revealed that distal shoots were freezing first and exuded sap as a result of water expansion. The lower water content in apical shoots upon freezing probably induced higher sap tensions which promoted air bubble expansion and vessel cavitation preferentially near the apices. When the decrease in water content was experimentally prevented, embolism developed to a lesser extent. The higher vulnerability of shoot apices may protect the rest of the branch from winter damage. Received: 29 May 1998 / Accepted: 15 August 1998     

Characterization of microsatellite markers in Fagus sylvatica L. and Fagus orientalis Lipsky

Using an enrichment procedure, we cloned microsatellite repeats from European beech (Fagus sylvatica L.) and developed primers for the amplification of microsatellite markers. Six polymorphic loci were characterized which produced 3–21 alleles in 70 individuals from one Italian population, with an observed heterozygosity between 0.58 and 0.85. All six loci amplified fragments which were polymorphic in the closely related species, Fagus orientalis, also. Owing to their very high degree of variation, these markers should be very useful in gene flow studies of these species.     

Blue radiation stimulates photosynthetic induction in Fagus sylvatica L.

This study was designed to test the hypothesis that the spectral composition of incident radiation, as defined by the relative proportions of blue (B; λ_max = 455 nm) and red (R; λ_max = 625 nm) photons, can affect photosynthetic induction, since B photons stimulate stomatal opening and are more effectively absorbed by leaves than R photons. Different stages of photosynthetic induction, primarily determined by the photo-modulation of Rubisco activity and stomata opening, were investigated in dark-adapted leaves of Fagus sylvatica transferred to saturating irradiance [800µmol(photon) m^?2 s^?1] at B/R ratios of 1/3, 1/1, or 3/1. In agreement with our hypothesis, photosynthesis was induced faster by irradiance with a high B/R ratio (3/1); as demontrated by a higher IS₆₀ (induction state 60 s after leaf illumination) and lower T ₉₀ (the time period required to reach 90 % of maximum steady-state photosynthesis). However, there were no differences in induction between leaves receiving equal (1/1) and low (1/3) B/R ratios. Electron transport was highly sensitive to radiation quality, exhibiting faster induction kinetics with increasing B/R ratio. Such stimulation of carbon-assimilatory processes corresponds with faster activation of Rubisco and lower non-photochemical quenching (NPQ) as the proportion of B photons is increased. In contrast, the kinetics of stomatal opening was independent of the spectral composition of incoming radiation. Since slightly higher absorption efficiency of high B/R radiation does not fully explain the changes in induction kinetics, the other possible mechanisms contributing to the stimulation of electron transport and Rubisco activity are discussed.     

On the ultrastructure of resting cambium of Fagus sylvatica L.

Summary Cells of the resting cambium contain strands of smooth endoplasmic reticulum which is often arranged as a series of parallel membranes. Single membrane bound bodies of different types including lipid droplets, protein bodies, many different intermediate forms, and structures that are empty and vacuolelike are present. The possibility that vacuoles are formed by the progressive dissolution of stored lipids and protein, during the onset of cambial activity, is suggested.     

Callus formation from mesophyll protoplasts of Fagus sylvatica L.

Viable protoplasts of European beech (Fagus sylvatica L.) were isolated from sterilized young leaves of juvenile (3–5 years) and mature (40 years) trees. Isolation in a saline solution containing 0.5% (w/v) Pectinol and 2% (w/v) Cellulase R-10 yielded 3×10⁷ protoplasts per gram fresh weight. Protoplast culture in modified Kao and Michayluk (1975) medium resulted in cell wall regeneration and sustained cell divisions with the formation of colonies and microcalli.Abbreviations KM Kao and Michayluk (1975) - LS Linsmaier and Skoog (1965) - MES 2(N-morpholino)-ethane-sulfonic acid - NAA 1-naphthalene acetic acid - PVP Polyvinylpyrrolidone - Tween 80 Polyoxy-ethylene-sorbitan-monooleate Dedicated to Landesforstmeister Prof. Dr. Hans-Joachim Fröhlich on the occasion of his 65th birthday.     

Hypersensitivity of Fagus sylvatica L. against leaf galling insects

Hypersensitivity is known as a localized resistance of plants against pathogens. It also can be detected in response to galling insects, i.e., in the area immediately adjacent to the site of oviposition and attempted penetration by the galling larva. This host response includes morphological and histological changes that cause the death of the attacked tissue. It is observed as a rounded dark brown halo around the gall induction site. We provide the first observation on the occurrence and possible relevance of this induced mechanism by which one of the most common tree species in Germany, Fagus sylvatica L., resists attack by two of its most common galling insects, Mikiola fagi and Hartigiola annulipes (Diptera: Cecidomyiidae). Galls induced by these cecidomyiids were extremely common in the studied area in beech forests around Darmstadt, Germany. The availability of resources (leaves on a stem) was a poor predictor of attack by the galling insects as well as for gall abundance (galls successfully formed). Hypersensitive reaction was the most important factor acting against the galling population studied. More than 77% of the attempts of the insects to induce galls on F. sylvatica resulted in failure and consequently the death of the galling larvae. Therefore, few live galls remained to be found and destroyed by natural enemies. This corroborates the view that in galling insect–host plant system interactions plant-driven factors may play a major role in determining herbivore failure and success, and perhaps the resulting community structure.     

Towards an understanding of the Holocene distribution of Fagus sylvatica L.

Aim Understanding the driving forces and mechanisms of changes in past plant distribution and abundance will help assess the biological consequences of future climate change scenarios. The aim of this paper is to investigate whether modelled patterns of climate parameters 6000 years ago can account for the European distribution of Fagus sylvatica at that time. Consideration is also given to the role of non‐climatic parameters as driving forces of the Holocene spread and population expansion of F. sylvatica. Location Europe. Methods European distributions were simulated using a physiologically‐based bioclimatic model (STASH) driven by three different atmospheric general circulation model (AGCM) outputs for 6000 years ago. Results The three simulations generally showed F. sylvatica to have potentially been as widespread 6000 years ago as it is today, which gives a profound mismatch with pollen‐based reconstructions of the F. sylvatica distribution at that time. The results indicate that drier conditions during the growing season 6000 years ago could have caused a restriction of the range in the south. Poorer growth conditions with consequently reduced competitive ability were modelled for large parts of France. Main conclusions Consideration of the entire European range of F. sylvatica showed that no single driving force could account for the observed distributional limits 6000 years ago, or the pattern of spread during the Holocene. Climatic factors, particularly drought during the growing season, are the likely major determinants of the potential range. Climatic factors are regionally moderated by competition, disturbance effects and the intrinsically slow rate of population increase of F. sylvatica. Dynamic vegetation modelling is needed to account for potentially important competitive interactions and their relationship with changing climate. We identify uncertainties in the climate and pollen data, as well as the bioclimatic model, which suggest that the current study does not identify whether or not climate determined the distribution of F. sylvatica 6000 years ago. Pollen data are better suited for comparison with relative abundance gradients rather than absolute distributional limits. These uncertainties from a study of the past, where we have information about plant distribution and abundance, argue for extreme caution in making forecasts for the future using equilibrium models.     

Analysis by {delta}13C Measurement on Mechanism of Cultivar Difference in Leaf Photosynthesis of Rice (Oryza sativa L.)

Our previous paper showed that cultivar difference of flag leafphotosynthesis (LPS) in rice (Oryza sativa L.) was attributedto the difference in mesophyll resistance (r_m). In this paper,we tried to divide r_m into CO₂ transfer resistance (r_m) andCO₂ fixation resistance (r_c) for further analysis of r_m by meansof     

Interspecific variability and environmental influence on particulate organic carbon {delta}13C in cultured marine phytoplankton

The stable carbon isotope composition of particulate organicmatter expressed as ¹³C was measured in cultures of 13 speciesof marine microalgae in different phylogenetic groups. The effectsof salinity variations and changes in photoperiod were alsoassayed for three of them (i.e. Skeletonema costatum, Amphidiniumopercularum and Isochrysis galbana); the effect of nature ofnitrogen supply (nitrate. ammonium) was studied for one (S.costatum).These environmental parameters were chosen because of theirvariability in the ocean and their possible effects on ¹³C valuesof phytoplankton organic carbon. Batch culture conditions andsampling time after inoculum were strongly controlled in orderto provide cells in good physiological state which were comparablefrom one culture to the other. In the same way, sampling waslimited to the first 2 days of exponential growth, in orderto avoid a possible dissolved inorganic carbon (DIC) limitation.Carboxylase activities [of the enzyme ribulose 1,5-bisphosphatecarboxylase oxygenase (Rubisco), and the three ß carboxylases:phosphoenolpyruvate carboxylase (PEPC), phosphoenolpyruvatecarboxykinase (PEPCK) and pyruvate carboxylase (PC)] and totalchlorophyll a concentrations were assayed simultaneously. The¹³C values observed were between –30.2 and –12.7i.e. comparable to those observed in the world's oceans. Theisotopic composition of phytoplankton organic carbon was shownto be under the influence of the parameters tested but ¹³C variationsare specific to the species considered. The nature of ßcarboxylase found in each species, or systematic position, couldnot be linked to the isotopic composition of organic carbon.No linear or single correlation between ¹³C variations and environmentalmodifications were observed and there is no evidence for a simpleand universal relation between ¹³C of phytoplankters and theirenvironment. In monospecific cultures as in the field, ¹³C fractionationby Rubisco (and eventually by PEPCK) may be counterbalancedby other mechanisms.     

Gene Flow in European Beech (Fagus sylvatica L.)

Three relatively isolated stands were used to study gene flow in European beech (Fagus sylvatica L.) in Northern Germany. Nine allozyme loci (Got-B, Idh-A, Lap-A, Mdh-B, Mdh-C, Mnr-A, 6-pgdh-A, Pgi-B and Pgm-A) were utilized for multilocus-genotyping adult trees and seeds. Expected heterozygosity (He) ranged from 0.325 to 0.351 for the three stands. F(ST) revealed that there was small differentiation among stands (mean F(ST) = 0.013). The indirect estimates of gene flow (Nm) based on the mean F(ST) were high and the average Nm was 19.14. External gene flow by pollen ranged from 0.7 to 1.2% inferred from new alleles in seed samples. Moreover, paternity analysis was used to assess effective pollen dispersal by inferring paternity of offspring. The weighted mean distances of pollen dispersal for these three stands were 36.8 and 37.1 m based on simple exclusion procedure and most-likely method, respectively. Two of the trees in one stand had rare allozyme alleles (Lap-A1 and Idh-A4, respectively), which were used to directly measure pollen movement away from those trees. The frequency of the rare Lap and Idh alleles in seeds declines as the distance from the source tree increases. The weighted mean distance of pollen dispersal with rare allele Lap-A1 or Idh-A4 was 26.3 m.     

Factors influencing the storability of Fagus sylvatica L. seeds after release from dormancy

Seeds of beech (Fagus sylvatica L.) that have been subjected to dormancy breaking consisting of 10 weeks of prechilling at 3 °C and 34 % water content (WC) and then desiccation to 10 % WC, are non-dormant (ND). ND seeds are characterised by greater sensitivity to storage conditions, than no prechilled, dormant (D) seeds. The aim of the present work was to investigate factors affecting the loss of seed viability during storage of D and ND beech seeds at different temperatures (4 and 20 °C) and humidity levels (45 and 75 % RH) for 3 weeks. In general, both D and ND seeds maintained a high germination capacity after storage at 4 °C. At 20 °C and 45 and 75 % RH the germination capacity of D seeds diminished to 80 and 28 %, respectively. Under the same conditions, ND seeds lost germination capacity to a greater degree, with only 62 and 7 % germinated seeds, respectively. At 20 °C, an increase in production of reactive oxygen species was observed, and the increase was significantly higher in ND seeds. The loss of germination capacity was coincident with an increase in electrolyte leakage and accumulation of free fatty acids, which suggests that membrane deterioration was the cause of the decline in germinability. ND seeds stored at 20 °C and 45 and 75 % RH showed a greater decrease than D seeds in contents of the primary phospholipids phosphatidylcholine (PC) and phosphatidylethanolamine (PE) as well as in polyunsaturated fatty acids (18:2 and 18:3). ND seeds possessed more unsaturated fatty acids, especially 18:3, than D seeds in the phospholipid fraction before storage. D seeds were characterised by a significantly higher level of α-tocopherol and UV-absorbing phenols. The level of ascorbate was similar in D and ND seeds. D seeds contained glutathione in both reduced (GSH) and oxidised (GSSG) forms, and GSSG dominated GSH. ND seeds contained more GSSG form than D seeds. We concluded that the membranes of ND seeds are exposed to greater oxidative stress during storage due to higher levels of unsaturation and lower levels of α-tocopherol, the main antioxidant that protects membranes against free radical attack.     

欧洲水青冈(Fagus sylvatical L.)构筑型与形态多样性研究

通过对植物构件和构筑型的分析,可以了解植物的整体结构与系统演化关系。高等植物构筑型的研究以树木最为深入,植物学家对全球的树木进行了构筑模式的分类,并确定了２３个基本的构筑类型。植物的构筑型和其形态的多样性是密不可分的。构筑奕型确定了植物所属的整体形态类型,而对每种植物具体的形态多样性分析可以深入了解每种构筑型的数量特征及其形成过程。在概述了树木树筑型研究的基础上,系统说明了欧洲水青冈构筑才形态多样性分析的步骤和步骤和分析的意义。水青冈属（Fagus)为Ｔroll型构筑模式,处于不同生态条件下的同一种的不同种群之间,在形态、解剖、生理和遗传多样性方面都存在着差异。树木的形态多样性虽然主要受遗传因素的控制,但生态条件对其形态和遗传多样性也有非常显著的影响。在对树木进行构筑型分析时,道德要根据构筑要素（主要是形态与生长特性）确定它所属的构筑类型,其次是分析它的形态特征与环境条件的关系,进行进一步分析其遗传多样性。     

Fagus sylvatica L. provenances maintain different leaf metabolic profiles and functional response

Most temperate forest tree species will suffer important environmental changes as result of the climate change. Adaptiveness to local conditions could change at different sites in the future. In this context, the study of intra-specific variability is important to clarify the singularity of different local populations. Phenotypic differentiation between three beech provenances covering a wide latitudinal range (Spain/ES, Germany/DE and Sweden/SE), was studied in a greenhouse experiment. Non-target leaf metabolite profiles and ecophysiological response was analyzed in well-watered and water stressed seedlings. There was a provenance-specific pattern in the relative concentrations of some leaf metabolites regardless watering treatment. The DE and SE from the center and north of the distribution area of the species showed a clear differentiation from the ES provenance in the relative concentration of some metabolites. Thus the ES provenance from the south maintained larger relative concentration of some organic and amino acids (e.g. fumaric and succinic acids or valine and isoleucine), and in some secondary metabolites (e.g. kaempferol, caffeic and ferulic acids). The ecophysiological response to mild water stress was similar among the three provenances as a consequence of the moderate water stress applied to seedlings, although leaf N isotope composition (δ¹⁵N) and leaf C:N ratio were higher and lower respectively in DE than in the other two provenances. This would suggest potential differences in the capacity to uptake and post-process nitrogen according to provenance. An important focus of the study was to address for the first time inter-provenance leaf metabolic diversity in beech from a non-targeted metabolic profiling approach that allowed differentiation of the three studied provenances.