Morphological traits and water use strategies in seedlings of Mediterranean coexisting species

The distribution of plants is associated with their different patterns of response to their environment. Mediterranean plants have evolved a number of morphological and physiological adaptations that determine their ability to survive and grow, being an effective water uptake and use important factors for drought resistance. In this article, we evaluated interspecific differences in morphology, biomass allocation, and architectural traits and their relationship with water use strategies in seedlings of seven co-occurring Mediterranean species (Anthyllis cytisoides L., Genista scorpius L. DC., Myrtus communis L., Pistacia lentiscus L., Rosmarinus officinalis L., Spartium junceum L. and Ulex parviflorus Pourr.). The results showed that morphological root features vary among species and they are significantly correlated with root hydraulic conductance and leaf gas exchange variables. Species with high specific root length (SRL) showed a low hydraulic conductance per root length (K (RRL)) but high specific hydraulic conductance (K (As)). M. communis and P. lentiscus showed the most contrasting water use patterns with respect to the other species studied. The results are not affected when considering phylogenetic relatedness. Thus, the variability observed in root hydraulic properties and leaf gas exchange suggests important mechanisms for understanding species coexistence in water-limited ecosystems.