Biogeography of Arabidopsis thaliana (L.) Heynh. (Brassicaceae)

Aim The biogeography of the genetic model plant, Arabidopsis thaliana (L.) Heynh., is studied using a climatic model of its distribution range. The climatic tolerance or amplitude of A. thaliana, as can be inferred from the general distribution range of the species, is compared with results of experimental studies addressing the species' responses to environmental stress. This is used for corroboration of the model and to reveal particular climatic conditions, whose influences on the plant species are not sufficiently known. Furthermore, this investigation shows climatic range boundaries and, thus, limits for exploiting natural variability of this species for plant physiological studies, plant genetics, and genetic engineering of crop plants. The growth conditions of A. thaliana in the greenhouse are compared with the climatic conditions of its natural range. Location Arabidopsis thaliana is native to Western Eurasia. Its natural and synanthropous northern hemispheric range is considered in the model. Methods Frequency distributions of the species' occurrence along climatic gradients are calculated and used recurrently for modelling the range. The frequency diagrams, maps of the distribution of suitable monthly climatic conditions, and the climatic range model are used for the assessment of range limiting climatic factors. The greenhouse conditions are simulated using mean monthly temperatures above 22 C. Water resources cannot be easily assessed because abundant supplies of water in the greenhouse can hardly be translated into terms of monthly precipitation. Results The frequency diagrams show the climatic amplitude of the species in natural conditions. The archeophytic western Eurasian range is well represented in the climatic model. Differences between model and range are to be found in America where, apparently, different climatic conditions are to be found compared with Eurasia. The major range limiting climatic conditions extracted from the model and the experimental data, obtained from the literature are congruent. However, at high precipitation no range limiting conditions could be observed. Laboratory conditions (rather high temperatures and ever sufficient moisture) have been shown to be highly artificial, and were only found in the species' synanthropous North American range. Main conclusions The study of the climatic amplitude of A. thaliana revealed the potentials and limits of this species as a model plant for studying ecological and ecophysiological traits. Congruencies between model and experimental data may allow us to draw conclusions from the general distribution range of species as to their ecogeographical amplitude.