Morpho-physiological traits characterizing environmental adaptation of Avena barbata

Seventeen morphological and physiological characteristics of three Arena barbata L. populations from Israel were measured in order to define possible combinations explaining adaptation of these populations to different precipitation, temperature and altitude regimes. Five genotypes from each A. barbata populations were collected from Ashqelon (31°63'N, low annual precipitation), En Hamifraz (32°46'N, high temperature), and Mount Carmel (32°73'N, high altitude), Israel. The behavior of the populations was followed by measuring the morphophysiological characteristics under well-watered and moderately drought stressed conditions. The experiment was conducted at the Department of Plant Production, University of Helsinki, Finland (60°13'N). The measured traits characterized macro-morphology, transpiration rate, photosynthesis and chloroplast features. The data were subjected to principal component and discriminant analyses and the characteristic combinations that most adequately accounted for the differences among A. barbata populations were established. Differences among the populations were related to adaptation to low water availability and high altitude characterized by special light conditions. The Mount Carmel population (high water availability, high light intensities and increased proportion of UV-light) was characterized by higher tillering, hairy leaf sheaths, high transpiration, high stomatal conductance, slow fluorescence quenching capacity, and less starch granules per chloroplast when compared with populations adapted to lower altitudes. The En Hamifraz population (high mean temperature) was characterized by a high CO₂ exchange rate and both En Hamifraz and Ashqelon populations (both adapted to arid conditions) used water sparingly when moderately drought stressed.