Examining wheat yield sensitivity to temperature and precipitation changes for a large ensemble of crop models using impact response surfaces

Impact response surfaces (IRSs) depict the response of an impact variable to changes in two explanatory variables as a plotted surface. Here, IRSs of spring and winter wheat yields were constructed from a 25-member ensemble of process-based crop simulation models. Twenty-one models were calibrated by different groups using a common set of calibration data, with calibrations applied independently to the same models in three cases. The sensitivity of modelled yield to changes in temperature and precipitation was tested by systematically modifying values of 1981-2010 baseline weather data to span the range of 19 changes projected for the late 21st century at three locations in Europe

Model inter-comparison on crop rotation effects ? an intermediate report

Data of diverse crop rotations from five locations across Europe were distributed to modelers to investigate the capability of models to handle complex crop rotations and management interactions

Wheat yield sensitivity to climate change across a European transect for a large ensemble of crop models

The sensitivity of a 26 member ensemble of process based wheat simulation models to perturbations in baseline temperature and precipitation was examined to construct impact response surfaces (IRS) of simulated yields

Unrestricted quality of seeds in European broad-leaved tree species growing at the cold boundary of their distribution

BACKGROUND AND AIMS: The low-temperature range limit of tree species may be determined by their ability to produce and disperse viable seeds. Biological processes such as flowering, pollen transfer, pollen tube growth, fertilization, embryogenesis and seed maturation are expected to be affected by cold temperatures. The aim of this study was to assess the quality of seeds of nine broad-leaved tree species close to their elevational limit. METHODS: We studied nine, mostly widely distributed, European broad-leaved tree species in the genera Acer, Fagus, Fraxinus, Ilex, Laburnum, Quercus, Sorbus and Tilia. For each species, seeds were collected from stands close to optimal growth conditions (low elevation) and from marginal stands (highest elevation), replicated in two regions in the Swiss Alps. Measurements included seed weight, seed size, storage tissue quality, seed viability and germination success. KEY RESULTS: All species examined produced a lot of viable seeds at their current high-elevation range limit during a summer ranked ‘normal’ by long-term temperature records. Low- and high-elevation seed sources showed hardly any trait differences. The concentration of non-structural carbohydrates tended to be higher at high elevation. Additionally, in one species, Sorbus aucuparia, all measured traits showed significantly higher seed quality in high-elevation seed sources. CONCLUSIONS: For the broad-leaved tree taxa studied, the results are not in agreement with the hypothesis of reduced quality of seeds in trees at their high-elevation range limits. Under the current climatic conditions, seed quality does not constitute a serious constraint in the reproduction of these broad-leaved tree species at their high-elevation limit

The interplay between classical and alternative isoprenoid biosynthesis controls gammadelta T cell bioactivity of Listeria monocytogenes

Isoprenoids are synthesised either through the classical, mevalonate pathway, or the alternative, non-mevalonate, 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway. The latter is found in many microbial pathogens and proceeds via (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), a potent activator of human Vgamma9/Vdelta2 T cells. Listeria monocytogenes is the only pathogenic bacterium known to contain both pathways concurrently. Strategic gene knockouts demonstrate that either pathway is functional but dispensable for viability. Yet, disrupting the mevalonate pathway results in a complementary upregulation of the MEP pathway. Vgamma9/Vdelta2 T cell bioactivity is increased in DeltalytB mutants where HMB-PP accumulation is expected, and lost in DeltagcpE mutants which fail to produce HMB-PP

Data format for model in- and output

A common format for model input variables and model output variables has been defined to be distributed to modellers participating in the model inter-comparison and improvement. The aim of common formats is to support the communication between the modellers, those providing empirical data of the experiments and those analysing the simulation results. The input format facilitates the model application in a way that each cropping-system to be modelled will be defined in the same way. Data will be delivered in EXCEL sheets with sub-tables for each block of inputs. Tables are mostly organized in a way that allows export and sequential read-in by the models. The common output format enables effective processing of results estimating model performance indicators