Tip-to-base conduit widening and spatial distribution of xylem conduits along the stem of Fagus sylvatica L.
- 1School of Agricultural, Forest, Food and Environmental Sciences (SAFE), University of Basilicata, viale dell’Ateneo Lucano 10, 85100 Potenza, Italy
- 2Department of Agricultural Sciences, University of Naples Federico II, via Università 100, 80055 Portici, NA, Italy
- 3Faculty of Science, Department of Physical Geography and Geoecology, Charles University, Albertov 6, 12843 Prague, Czech Republic
- 4Department of Earth and Environmental Sciences, University of Pavia, Via S. Epifanio 14, 27100 Pavia, Italy
Xylem is a multifunctional tissue that allows water transport, mechanical support, and storage of nutrients. These functions are provided by different cells, with different anatomy among species but also within individual trees. For the latter, it is well established that such anatomical disposition does not remain fixed but it is subject to a suite of adaptations induced by physiological constraints driven by both ontogenetic development and environmental characteristics.
For these reasons, in this study, we assessed 1) the spatial distribution of xylem conduits and their aggregation inside Fagus sylvatica L. tree-rings, and 2) the systematic variation of tip-to-base conduit widening and conduit packing occurring during tree growth.
In order to achieve these goals, we quantified the axial and radial xylem conduit patterns through measurement of conduit anatomical characteristics inside every tree-ring along complete radial series taken at different stem heights in eight Fagus sylvatica L. trees, sampled from two different sites in the Italian Apennines.
Our results showed a significant effect of the distance from the tree base and a weak effect of cambial age on the nearest neighbour distance among xylem conduits, suggesting that conduits were closer to each other near the apex, and became progressively more distant toward the base. However, point pattern profiles clearly highlighted a lack of aggregation between conduits along the stems.
In addition, the axial scaling of conduits (β) follows a power trajectory according to the theoretical prediction, while the xylem conduits packing exponent (α) was lower than the predicted Sperry’s packing rule. Furthermore, no consistent trend was found for the scaling exponent (β) during tree ontogeny, confirming that tip-to-base conduit widening is an adaptation, favored by natural selection to minimize the increase in hydraulic resistance when the individual stem grows longer and conductive path length increases.
How to cite: Pericolo, O., Rita, A., Tumajer, J., Ripullone, F., Gentilesca, T., Saracino, A., Nola, P., and Borghetti, M.: Tip-to-base conduit widening and spatial distribution of xylem conduits along the stem of Fagus sylvatica L., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11434, https://doi.org/10.5194/egusphere-egu22-11434, 2022.
