ABSTRACT
The effectiveness of hedgerows as functional corridors in the face of climate warming has been little researched. Here we investigated the effects of warming temperatures on plant performance and population growth of Geum urbanum in forests versus hedgerows in two European temperate regions. Adult individuals were transplanted in three forest-hedgerow pairs in each of two different latitudes, and an experimental warming treatment using open-top chambers was used in a full factorial design. Plant performance was analysed using mixed models and population performance was analysed using Integral Projection Models and elasticity analyses. Temperature increases due to open-top chamber installation were higher in forests than in hedgerows. In forests, the warming treatment had a significant negative effect on the population growth rate of G. urbanum. In contrast, no significant effect of the warming treatment on population dynamics was detected in hedgerows. Overall, the highest population growth rates were found in the forest control sites, which was driven by a higher fecundity rather than a higher survival probability. Effects of warming treatments on G. urbanum population growth rates differed between forests and hedgerows. In forests, warming treatments negatively affected population growth, but not in hedgerows. This could be a consequence of the overall lower warming achieved in hedgerows. We conclude that maintenance of cooler forest microclimates coul, at least temporarily, moderate the species response to climate warming.
Subject(s)
Geum , Climate Change , Forests , Microclimate , Plants , TemperatureABSTRACT
In an attempt to make our own set of DP typing reagents, we used lymphocytes from 12 unrelated donors, who were all HLA-A1,2; B7,8; DR2,3; DQW1,2. They all had been previously typed for DP using a reference set of well established reagents obtained from Dr. S. Shaw (NIH, Bethesda). Thirty-six promising responder-stimulator combinations were primed in bulk MLC and tested for their specificity in secondary MLC. All reagents gave reaction patterns which were concordant with the sensitizing DP types, with the exception of those combinations where a donor was used in which DR2 appeared to be associated with a non-DW2 HLA-D type. Over 1,200 reactions obtained with the new reagents were compared with those obtained with the established ones, in six different experiments. High correlation coefficients (r values) were found between the two kinds of reagents. The typings of a panel of individuals with the reference set and with our new typing set revealed an excellent agreement for DP assignments with the two sets, with the exception of the specificity DP4. The DP gene frequencies for random Dutch Caucasoids were defined.
Subject(s)
Histocompatibility Antigens Class II/immunology , Histocompatibility Testing/methods , Indicators and Reagents/isolation & purification , Gene Frequency , HLA-DP Antigens , Histocompatibility Antigens Class II/genetics , Humans , Lymphocytes/immunology , Netherlands , White PeopleABSTRACT
To investigate the role of SB in MLC typing responses, reactions of lymphocytes from 23 DW3-positive, HLA-D-heterozygous individuals against 9 Dw3 homozygous typing cells (HTCs) were evaluated. Significantly more clear typing reactions were observed in those combinations that were matched for SB as compared with those that were mismatched. Nevertheless, MLC responses towards HTCs that were HLA-D/DR- and SB-compatible could be very strong. An additional analysis of the influence of HLA-B and the newly defined determinants LB-Q1 and LB-Q2 demonstrated that in combinations that were matched for these markers as well, stabilized relative responses could still be over 100%.
Subject(s)
HLA Antigens/immunology , HLA-A Antigens , HLA-DR Antigens , Histocompatibility Antigens Class II/immunology , Humans , Lymphocyte Culture Test, MixedABSTRACT
The primed lymphocyte test (PLT) was used to prepare reagents between HLA-D/DR identical individuals. Two sets of primed lymphocytes were obtained which recognized the new determinants referred to as LB-Q1 and LB-Q2, respectively. LB-Q2 is significantly associated with HLA-A1, -B8, and -D/DR3. Nevertheless, LB-Q1 and LB-Q2 seem to be distinct from any of the established HLA antigens. No association with any of the alleles of the SB system was observed. A recombination between HLA-D/DR and HLA-B suggested that the locus encoding LB-Q2 is situated on the telomeric side of HLA-D/DR.
