排序方式: 共有13条查询结果,搜索用时 31 毫秒
1.
The year-round dynamics of laccase and acid phosphatase activities of ectomycorrhizas (EM) were monitored in an oak forest, with a microplate photometric method using individual EM root tips. Among the most frequent and abundant EM morphotypes, those of Lactarius quietus and Cortinarius anomalus showed a peak of laccase activity in spring, while those of Xerocomus chrysenteron displayed highest laccase activities in summer and autumn. In comparison, less seasonal differences were observed in EM acid phosphatase activity. This suggests that the different EM types within the EM community perform complementary functions depending on season. 相似文献
2.
The ectomycorrhizas (ECM) formed by Lactarius quietus, an ECM fungus specifically associated with Quercus spp., are abundant all the year long. Root and stem growth, beginning before bud break in oak, are strong carbon sinks partially fulfilled with carbohydrate reserves. We hypothesized that L. quietus contributes to providing trees with carbon at bud break through enzymatic activities before photosynthesis begins. Activities of eight secreted enzymes (xylosidase, glucuronidase, cellobiohydrolase, β-glucosidase, N-acetyl-glucosamine, leucine aminopeptidase, acid phosphatase and laccase) relevant to carbon cycling and the release of phophorus and nitrogen from soil organic matter were measured on L. quietus ECMs before, during and after the bud break. Phenological, climatic and pedoclimatic parameters were also measured. Laccase, glucuronidase, cellobiohydrolase and β-glucosidase activities proved to be significantly related to tree reactivation and climate. All these activities can help the formation of new tissues by supplying carbon. L. quietus can behave saprotrophically, using soil organic matter as substrate. This is consistent with the hypothesis that it provides the oak trees with carbon when demand is high and photoassimilates are not yet available. 相似文献
3.
4.
• Introduction
Many studies deal with taxonomic diversity (TD) or estimation of functional traits of ectomycorrhizal communities. However, to our knowledge, none of them has ever tried to calculate the functional diversity (FD) of those communities, which is of critical importance for the diversity and reliability of nutrient supply to the tree. 相似文献5.
Marion Thépaut Teddy Grandjean Didier Hober Pierre-Emmanuel Lobert Perrine Bortolotti Karine Faure Rodrigue Dessein Eric Kipnis Benoit Guery 《Veterinary research》2015,46(1)
The murine norovirus (MNV) is a recently discovered mouse pathogen, representing the most common contaminant in laboratory mouse colonies. Nevertheless, the effects of MNV infection on biomedical research are still unclear. We tested the hypothesis that MNV infection could alter immune response in mice with acute lung infection. Here we report that co-infection with MNV increases survival of mice with Pseudomonas aeruginosa acute lung injury and decreases in vivo production of pro-inflammatory cytokines. Our results suggest that MNV infection can deeply modify the parameters studied in conventional models of infection and lead to false conclusions in experimental models. 相似文献
6.
Deniz Yilmaz Patrice Cannavo Geoffroy Séré Laure Vidal-Beaudet Michel Legret Olivier Damas Pierre-Emmanuel Peyneau 《Journal of Soils and Sediments》2018,18(2):442-455
Purpose
The densification and expansion of urban areas will increase the streams of waste materials such as bricks, concrete and street sweeping waste. In parallel, green areas offer the potential to overcome many challenges that face growing/expanding cities but require the use of large amounts of natural resources such as natural topsoil and aggregates. In this work, various waste materials mixed with organic debris are tested for greening applications in urban environments as an alternative to the consumption of natural resources.Materials and methods
Five combinations of artefacts were studied either as “growing material” (i.e. dedicated to plant growth) or “structural material” (as support for traffic). These constructed Technosols were studied in situ in lysimeters under two sets of contrasting climatic conditions at two sites in France (Angers, oceanic climate, and Homécourt semi-continental climate). They were planted with trees (Acer platanoides) and with ryegrass (Lolium perenne L.).Results and discussion
Compared to natural soils, the constructed Technosols exhibited high porosities and highly saturated hydraulic conductivities (up to 0.76 m3 m?3, and to 34.74 cm h?1, respectively). The physical properties–i.e. macroporosity and microporosity–of these artificial soils revealed high water supply for plants, with available soil water ranging from 0.5 to 2.9 mm cm?1. Tree and ryegrass roots were able to grow in the entire soil volume available in the lysimeters. Organic matter nature and soil pH conditions appeared to be the main drivers of plant development.Conclusions
Constructed Technosols are suitable for vegetation growth and constitute a valuable alternative to the consumption of natural arable earth for urban greening applications, e.g. gardens, parks, and tree lines. Furthermore, they can provide high levels of relevant ecosystem functions in cities such as water retention and infiltration, plant settlement, carbon sequestration and even biodiversity habitats.7.
Franois Rineau Pierre-Emmanuel Courty Stphane Uroz Marc Bue Jean Garbaye 《Soil biology & biochemistry》2008,40(9):2460-2463
The ability of ectomycorrhizal (ECM) fungi to mobilize soil inorganic nutrients has been well documented for a diversity of species. However, most of these studies were performed with tree seedlings or fungal cultures, making them hardly comparable. We propose here three microplate assays to compare iron chelation, free iron uptake and oxalate production by ECMs freshly sampled in mature forest ecosystems. These assays proved to be sensitive enough to detect significant differences between two common ECM types. Lactarius subdulcis was less efficient than Xerocomus sp. for accessing to free or complexed iron, but produced 100 times more oxalate. These preliminary results open the way to study the contribution of ECM communities to nutrient cycling in forest ecosystems. 相似文献
8.
9.
The ectomycorrhizal community of an oak forest has been monitored monthly throughout fifteen months. Eight enzymatic activities secreted by the ectomycorrhizal root tips and involved in the mobilization of nutrients from soil organic matter have been measured using microplate assays, resulting in potential activity patterns of individual fungal species. Both the species structure of the community and the specific activity level of each individual species changed with the season and soil horizon. This versatility may be an adaptative response of the ectomycorrhizal fungal community to a highly variable environment. The results also suggest that some ectomycorrhizal fungi behave as occasional saprobes and contribute to the decomposition of soil organic matter and nutrient cycling together with true saprotrophic fungi. 相似文献
10.
Lobert JM Butler JH Montzka SA Geller LS Myers RC Elkins JW 《Science (New York, N.Y.)》1995,267(5200):1002-1005
Surface waters along a cruise track in the East Pacific Ocean were undersaturated in methyl bromide (CH(3)Br) in most areas except for coastal and upwelling regions, with saturation anomalies ranging from + 100 percent in coastal waters to -50 percent in open ocean areas, representing a regionally weighted mean of -16 (-13 to -20) percent. The partial lifetime of atmospheric CH(3)Br with respect to calculated oceanic degradation along this cruise track is 3.0 (2.9 to 3.6) years. The global, mean dry mole fraction of CH3Br in the atmosphere was 9.8 +/- 0.6 parts per trillion, with an interhemispheric ratio of 1.31 +/- 0.08. These data indicate that approximately 8 percent (0.2 parts per trillion) of the observed interhemispheric difference in atmospheric CH3Br could be attributed to an uneven global distribution of oceanic sources and sinks. 相似文献