Peroxidase Activity in Poplar Inoculated with Compatible and Incompetent Isolates of Paxillus involutus

Peroxidase activity of the hybrid poplar Populus x canescens (Ait.) Sm. (= P. tremula L. x P. alba L.) inoculated with compatible and incompetent isolates of Paxillus involutus (Batsch) Fr. was investigated. Screening of the ectomycorrhizal fungal isolates was initiated with exploration of mycelial growth characteristics and mycorrhizal ability in vitro with poplar. Both traits varied within the fungus although they did not seem to be genetically correlated. While isolates SCO1, NAU, and 031 grew faster than others, only isolates MAJ, SCO1, and 031 were able to form ectomycorrhiza with poplar. Isolates MAJ (compatible) and NAU (incompetent) were subsequently selected for further experiments. Activity of peroxidase, one of the defense-related enzymes, was examined in pure culture and short root components of compatible and incompetent interactions between poplar and P. involutus. Peroxidase activities increased significantly in poplar inoculated with incompetent isolate of the fungus compared to control, while induction of the same enzyme was not detected in compatible associations

FTIR-ATR-based prediction and modelling of lignin and energy contents reveals independent intra-specific variation of these traits in bioenergy poplars

Background: there is an increasing demand for renewable resources to replace fossil fuels. However, different applications such as the production of secondary biofuels or combustion for energy production require different wood properties. Therefore, high-throughput methods are needed for rapid screening of wood in large scale samples, e.g., to evaluate the outcome of tree breeding or genetic engineering. In this study, we investigated the intra-specific variability of lignin and energy contents in extractive-free wood of hybrid poplar progenies (Populus trichocarpa × deltoides) and tested if the range was sufficient for the development of quantitative prediction models based on Fourier transform infrared spectroscopy (FTIR). Since lignin is a major energy-bearing compound, we expected that the energy content of wood would be positively correlated with the lignin content.Results: lignin contents of extractive-free poplar wood samples determined by the acetyl bromide method ranged from 23.4% to 32.1%, and the calorific values measured with a combustion calorimeter varied from 17260 to 19767 J g-1. For the development of calibration models partial least square regression and cross validation was applied to correlate FTIR spectra determined with an attenuated total reflectance (ATR) unit to measured values of lignin or energy contents. The best models with high coefficients of determination (R2 (calibration) = 0.91 and 0.90; R2 (cross-validation) = 0.81 and 0.79) and low root mean square errors of cross validation (RMSECV = 0.77% and 62 J g-1) for lignin and energy determination, respectively, were obtained after data pre-processing and automatic wavenumber restriction. The calibration models were validated by analyses of independent sets of wood samples yielding R2 = 0.88 and 0.86 for lignin and energy contents, respectively.Conclusions: these results show that FTIR-ATR spectroscopy is suitable as a high-throughput method for lignin and energy estimations in large data sets. Our study revealed that the intra-specific variations in lignin and energy contents were unrelated to each other and that the lignin content, therefore, was no predictor of the energy content. Employing principle component analyses we showed that factor loadings for the energy content were mainly associated with carbohydrate ring vibrations, whereas those for lignin were mainly related to aromatic compounds. Therefore, our analysis suggests that it may be possible to optimize the energy content of trees without concomitant increase in ligni

FTIR-ATR Spectroscopic Analysis of Changes in Fiber Properties During Insulating Fiberboard Manufacture of Beech Wood

Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy was applied to trace changes in chemical fiber properties during the production process of insulating fiber mats. In combination with cluster analysis, FTIR spectra were used to interpret the homogeneity of the products. Beech wood (Fagus sylvatica L.) was used as a novel sustainable material for fiberboard production. The insulating fiberboards were either processed without binder or with potato pulp or potato starch as renewable binders and dried in a dryer or a microwave. FTIR spectral analyses revealed chemical modifications at the O-H association band of carbohydrates that distinguished the two different drying methods. Additions of plant-based renewable binders diminished the absorbance of the resulting products at characteristic wavenumbers in the IR. These decreases were closely correlated with the amount of added binder and thus have the potential to quantify binder additions to the fiberboards. Cluster analysis grouped FTIR spectra of samples from different production steps or processes correctly and therefore is an effective and simple technique for quality control of insulating fiberboards from renewable resources

Influence of Environmental Pollution on Leaf Properties of Urban Plane Trees, Platanus orientalis L.

To investigate whether leaves of plane trees (Platanus orientalis) are damaged by traffic pollution, trees from a megacity (Mashhad, Iran) and a rural area were investigated. Soil and air from the urban centre showed enrichment of several toxic elements, but only lead was enriched in leaves. Leaf size and stomata density were lower at the urban site. At the urban site leaf surfaces were heavily loaded by dust particles but the stomata were not occluded; the cuticle was thinner; other anatomical properties were unaffected suggesting that plane trees can cope with traffic exhaust in megacities

Peroxidase Activity in Poplar Inoculated with Compatible and Incompetent Isolates of Paxillus involutus

Peroxidase activity of the hybrid poplar Populus x canescens (Ait.) Sm. (= P. tremula L. x P. alba L.) inoculated with compatible and incompetent isolates of Paxillus involutus (Batsch) Fr. was investigated. Screening of the ectomycorrhizal fungal isolates was initiated with exploration of mycelial growth characteristics and mycorrhizal ability in vitro with poplar. Both traits varied within the fungus although they did not seem to be genetically correlated. While isolates SCO1, NAU, and 031 grew faster than others, only isolates MAJ, SCO1, and 031 were able to form ectomycorrhiza with poplar. Isolates MAJ (compatible) and NAU (incompetent) were subsequently selected for further experiments. Activity of peroxidase, one of the defense-related enzymes, was examined in pure culture and short root components of compatible and incompetent interactions between poplar and P. involutus. Peroxidase activities increased significantly in poplar inoculated with incompetent isolate of the fungus compared to control, while induction of the same enzyme was not detected in compatible associations. Key words: ectomycorrhiza, Paxillus involutus, peroxidase, plant defense, popla

Defence reactions in the apoplastic proteome of oilseed rape (Brassica napus var. napus) attenuate Verticillium longisporum growth but not disease symptoms

<p>Abstract</p> <p>Background</p> <p><it>Verticillium longisporum </it>is one of the most important pathogens of <it>Brassicaceae </it>that remains strictly in the xylem during most stages of its development. It has been suggested that disease symptoms are associated with clogging of xylem vessels. The aim of our study was to investigate extracellular defence reactions induced by <it>V. longisporum </it>in the xylem sap and leaf apoplast of <it>Brassica napus </it>var. <it>napus </it>in relation to the development of disease symptoms, photosynthesis and nutrient status.</p> <p>Results</p> <p><it>V. longisporum </it>(strain VL43) did not overcome the hypocotyl barrier until 3 weeks after infection although the plants showed massive stunting of the stem and mild leaf chlorosis. During this initial infection phase photosynthetic carbon assimilation, transpiration rate and nutrient elements in leaves were not affected in VL43-infected compared to non-infected plants. Proteome analysis of the leaf apoplast revealed 170 spots after 2-D-protein separation, of which 12 were significantly enhanced in response to VL43-infection. LS-MS/MS analysis and data base searches revealed matches of VL43-responsive proteins to an endochitinase, a peroxidase, a PR-4 protein and a β-1,3-glucanase. In xylem sap three up-regulated proteins were found of which two were identified as PR-4 and β-1,3-glucanase. Xylem sap of infected plants inhibited the growth of <it>V. longisporum</it>.</p> <p>Conclusion</p> <p><it>V. longisporum </it>infection did not result in drought stress or nutrient limitations. Stunting and mild chlorosis were, therefore, not consequences of insufficient water and nutrient supply due to VL43-caused xylem obstruction. A distinct array of extracellular PR-proteins was activated that might have limited <it>Verticillium </it>spreading above the hypocotyl. In silico analysis suggested that ethylene was involved in up-regulating VL43-responsive proteins.</p

The role of the poplar’s volatiles for the butterflies of the forest margin

Pappeln wie die Zitterpappel (Populus tremula) bilden am Waldrand wichtige Habitate für Nachtfalter. Der Pappelschwärmer (Laothoe populi) und das Abendpfauenauge (Smerinthus ocellata) legen ihre Eier auf den Blättern ab. Als Nachtfalter sind sie auf andere Signale als die optischen angewiesen, um den optimalen Ovipositionsplatz zu finden. Je nach Vitalität des Baumes und seiner Exposition sind die entwicklungsbedingungen der Raupe verschieden. Diese Studie soll aufzeigen, welche Duftstoffe durch Änderungen der Vitalität des Baumes beeinflusst und welche durch die Nachtfalter wahrgenommen werden können.Forest margins are environments very rich in species. The softwood communities found there are unique habitats for many butterflies. The studies conducted in the vicinity of Göttingen resulted in 83 Makrolepidoptera taxa found on willow (Salix caprea) and 65 on poplar (Populus tremula). Since different plants emit different volatiles, many insects are able to follow the odour plumes and find their hosts by perceiving various odours. The emission of volatiles can be influenced by different external factors, like surplus of salts, drought, mycorrhiza. A gas-chromatograph with mass-spectrometric and parallel electroantennographic detector (GC-MS/EAD) was employed to measure in what way the volatile pattern changed and which of the associated chemical substances could be detected by the insect antennae. The volatile pattern is very important for butterflies to find their habitat