Anatomical characteristics of Prunus domestica vascular tissue and their implications for selection programmes

Knowledge of varieties' morphological and anatomical characteristics could assist in cultivar selection aimed at higher production, better fruit quality and lower orchard maintenance costs. The aim of the study was to evaluate anatomical characteristics of vascular tissue of shoots, petioles and leaf main veins of plum (Prunus domestica L.) cultivars with a particular emphasis on xylem and vessel hydraulic properties. The results singled out the cultivars with the most desirable combination of anatomical characters in terms of moderate vegetative growth, high yield and good fruit quality ('Toptaste' followed by 'Cacanska lepotica'). A possible application of xylem parameters as preselection criteria in early vegetative period was evaluated, and the link between anatomical properties, tree vigour, cropping potential and fruit quality was discussed. Anatomical traits, especially vessel lumen area, vessel frequency and distribution of vessels in size classes, affect vegetative growth as well as fruit production and quality, since they jointly affect water conductivity and vulnerability to cavitation and drought. Lower shoot vessel lumen values and more numerous small-sized vessels indicated lower vegetative growth, whilst higher vessel lumen values in petiole and lamina induced better lamina photosynthetic tissue water supply, which increased productivity and fruit quality parameters. Obtaining information about the key anatomical traits at early vegetative stage could help breeders to predict the ultimate tree vigour.