ABSTRACT
Evolutionary processes are expected to be crucial for the adaptation of natural populations to environmental changes. In particular, the capacity of rear edge populations to evolve in response to the species limiting conditions remains a major issue that requires to address their evolutionary potential. In situ quantitative genetic studies based on molecular markers offer the possibility to estimate evolutionary potentials manipulating neither the environment nor the individuals on which phenotypes are measured. The goal of this study was to estimate heritability and genetic correlations of a suite of leaf functional traits involved in climate adaptation for a natural population of the tree Fagus sylvatica, growing at the rear edge of the species range. Using two marker-based quantitative genetics approaches, we obtained consistent and significant estimates of heritability for leaf phenological (phenology of leaf flush), morphological (mass, area, ratio mass/area) and physiological (δ(13)C, nitrogen content) traits. Moreover, we found only one significant positive genetic correlation between leaf area and leaf mass, which likely reflected mechanical constraints. We conclude first that the studied population has considerable genetic diversity for important ecophysiological traits regarding drought adaptation and, second, that genetic correlations are not likely to impose strong genetic constraints to future population evolution. Our results bring important insights into the question of the capacity of rear edge populations to evolve.
Subject(s)
Biological Evolution , Fagus/genetics , Microsatellite Repeats , Models, Genetic , Plant Leaves/physiology , Adaptation, Physiological/genetics , Bayes Theorem , Carbon Isotopes , Droughts , Fagus/physiology , France , Genetic Markers , Genetic Variation , Genetics, Population , Plant Leaves/genetics , Quantitative Trait, HeritableABSTRACT
A new kind of ultrasonically-assisted heat exchanger has been designed, built and studied. It can be seen as a vibrating heat exchanger. A comprehensive description of the overall experimental set-up is provided, i.e. of the test rig and the acquisition system. Data acquisition and processing are explained step-by-step with a detailed example of graph obtained and how, from these experimental data, energy balance is calculated on the heat exchanger. It is demonstrated that ultrasound can be used efficiently as a heat transfer enhancement technique, even in such complex systems as heat exchangers.
