Is xylem cavitation resistance a relevant criterion for screening drought resistance among Prunus species?

Fruit trees are likely to suffer from the effects of severe drought in the future; however, sound criteria for evaluating the species' ability to survive these extreme conditions are largely missing. Here, we evaluated the feasibility of using xylem cavitation resistance as a tool for screening Prunus species for drought resistance. Ten different Prunus species were selected to cover a large range of water requirements, from hydrophilic to xerophilic types. Shoot cavitation resistance was evaluated with the new Cavitron technique. At this inter-specific level, cavitation resistance was related to species drought resistance, with xerophilic species being less vulnerable to cavitation. The Cavitron technique enabled species characterization that required a short time and small amounts of plant material. This technique could be used to evaluate the drought resistance of a limited number of fruit tree genotypes. Genotype screening on a larger scale, however, would likely require another approach. Out of a number of anatomical traits tested, a significant correlation was found between cavitation resistance and inter-vessel wall thickness across species. This anatomical trait is, therefore, suggested as a possible alternative to direct cavitation estimates and could be included as a screening criterion in breeding programs for drought resistance of Prunus genotypes.