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Seedlings of seven temperate tree species (Acer pseudoplatanus L., Betula pendula Roth, Fagus sylvatica L., Fraxinus excelsior L., Juglans regia L., Quercus petraea Matt. Liebl. and Quercus robur L.) were grown in a nursery under neutral filters transmitting 45% of incident global irradiance. During the second or third year of growth, leaf photosynthetic(More)
The objectives of the study were to identify the relevant hydraulic parameters associated with stomatal regulation during water stress and to test the hypothesis of a stomatal control of xylem embolism in walnut (Juglans regia x nigra) trees. The hydraulic characteristics of the sap pathway were experimentally altered with different methods to alter plant(More)
Savannas are globally important ecosystems of great significance to human economies. In these biomes, which are characterized by the co-dominance of trees and grasses, woody cover is a chief determinant of ecosystem properties. The availability of resources (water, nutrients) and disturbance regimes (fire, herbivory) are thought to be important in(More)
The acclimation responses of walnut leaf photosynthesis to the irradiance microclimate were investigated by characterizing the photosynthetic properties of the leaves sampled on young trees (Juglans nigraxregia) grown in simulated sun and shade environments, and within a mature walnut tree crown (Juglans regia) in the field. In the young trees, the CO(2)(More)
Photosynthetic light acclimation of leaves can result from (i) changes in mass-based leaf nitrogen concentration, Nm, (ii) changes in leaf mass:area ratio, Ma, and (iii) partitioning of total leaf nitrogen among different pools of the photosynthetic machinery. We studied variations in Nm and Ma within the crowns of two peach (Prunus persica L. Batsch) trees(More)
Compost amendment has been reported to impact soil microbial activities or community composition. However, little information is available on (i) to what extent compost amendment concurrently affects the activity, size and composition of soil microbial community, (ii) the relative effect of the addition of a material rich in organic matter versus addition(More)
Analysing the consequences of the decrease in biodiversity for ecosystem functioning and stability has been a major concern in ecology. However, the impact of decline in soil microbial diversity on ecosystem sustainability remains largely unknown. This has been assessed for decomposition, which is insured by a large proportion of the soil microbial(More)
In ecology, biodiversity-ecosystem functioning (BEF) research has seen a shift in perspective from taxonomy to function in the last two decades, with successful application of trait-based approaches. This shift offers opportunities for a deeper mechanistic understanding of the role of biodiversity in maintaining multiple ecosystem processes and services. In(More)
Predicting biodiversity effects on ecosystem functioning requires adequate evaluation of the mechanisms explaining why more diverse systems could perform better than less diverse ones. In this context, tackling functional diversity has become an important issue. Even though the aggregation of species into functional groups supposes niche differences among(More)
Early season leaf growth depends largely on nitrogen (N) provided by remobilization from storage, and many studies have tested the effect of N availability to roots on the amount of N provided for new leaf development by remobilization. Although it is well known that the light regime experienced by a leaf influences the amount of N per unit leaf area (LA),(More)