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Firenze, Italy

Calic I.,Piazzale delle Cascine | Calic I.,Research and Innovation Center | Calic I.,University of California at Davis | Bussotti F.,Piazzale delle Cascine | And 2 more authors.
Tree Genetics and Genomes

Landscape genomics is potentially a powerful research field for discovery of genes underlying complex patterns of adaptation in forest ecosystems. The general approach is to search for associations between genetic variation in tree populations and environmental variation in the habitats these trees occupy. For example, environmental data from GIS databases can be associated with single nucleotide polymorphisms in genes for large samples of trees sampled from within environmentally heterogeneous landscapes. In this opinion paper, we seek to assess the commonality of recent landscape genomics studies in forest trees. When we compare results across different species, we find very few examples of the same genes being detected that associate to similar environmental variables. We also find the absence of commonality when we compare three studies in Norway spruce with similar experimental design. We thus argue that landscape genomics research in forest trees is in its infancy and currently reported that results should be viewed with caution. Further, improvements in study design and analyses of replicated studies will be needed before this very promising approach can be brought to application for managing forests under changing climate. © 2015, Springer-Verlag Berlin Heidelberg. Source

Menichetti L.,Swedish University of Agricultural Sciences | Menichetti L.,Cranfield University | Reyes Ortigoza A.L.,National Autonomous University of Mexico | Garcia N.,National Autonomous University of Mexico | And 3 more authors.
Biology and Fertility of Soils

We studied the responses of soil microbial biomass, respiration and enzyme activities to temperature in three Mexican soils. Soils were incubated at temperature range of 15–550 °C at 50 (wet) and 10 % (dry) of their water holding capacity. Soils were assayed for their adenosine triphosphate (ATP) content, CO2-C evolution and acid and alkaline phosphomonoesterase, phosphodiesterase, β-glucosidase, urease, and protease activities. Thermal responses of soil enzyme activities were fitted to both the equilibrium model (EM) and the classical Q10 model to describe the effects of temperature on enzyme activity. Total organic C, Fe speciation, available P, and inorganic N contents were also determined in all soils and at all temperatures. The results showed that the ATP content, CO2-C evolution, and enzyme activities of soil increased within the temperature range 15–65 °C, and at higher temperatures, soil enzyme activities were more resistant than the ATP content and CO2-C evolution. The effects of temperature were more drastic in wet than in dry soil, although the two soil series displayed similar trends. The enzyme activities showed a good fit to the EM, making this model suitable for determining activation energy, enthalpy of inactivation, and equilibrium inactivation temperatures of soil enzymatic reactions. The results of the EM indicated that soil chemical parameters may not affect the activation energy of enzyme reactions, but may influence the enzyme resistance to inactivation at higher temperature. The results also indicated that the EM model can be used for predicting the impact of high temperatures on soil enzyme activities. © 2014, Springer-Verlag Berlin Heidelberg. Source

Pathan S.I.,Piazzale delle Cascine | Ceccherini M.T.,Piazzale delle Cascine | Pietramellara G.,Piazzale delle Cascine | Puschenreiter M.,University of Natural Resources and Life Sciences, Vienna | And 5 more authors.
Plant and Soil

Results: High NUE Lo5 maize induced faster inorganic N depletion in the rhizosphere and larger changes in microbial biomass and enzyme activities than the low NUE T250 maize line. The two maize lines induced differences in the studied microbial groups in the rhizosphere, with the larger modifications induced by the high NUE Lo5 maize line.Aims: Study of the changes in soil microbial biomass, enzyme activity and the microbial community structure in the rhizosphere of two contrasting maize lines differing in the nitrogen use efficiency (NUE).Methods: The Lo5 and T250 inbred maize characterized by high and low NUE, respectively, were grown in rhizoboxes allowing precise sampling of rhizosphere and bulk soil and solution. We also determined microbial biomass, enzyme activities involved in the C, N, P and S cycles, and the microbial community structure using a phylogenetic group specific PCR-DGGE approach in the rhizosphere and bulk soil of both Lo5 and T250 maize lines.Conclusions: The Lo5 maize line with higher NUE induced larger changes in soil chemical properties and in the enzyme activity, soil microbial biomass and community structure than the low NUE T250 maize line, probably due to differences in the root exudates of the two maize lines. © 2014, Springer International Publishing Switzerland. Source

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