Hydraulic Efficiency and Safety of Xylem Sap Flow in Relation to Water Stress in Woody Plants

Abstract

Additional information is available at the end of the chapter http://dx.doi.org/10.5772/56656 . IntroductionTrees as long-living organisms can be looked as the archives of ecological events recorded in the annual rings of wood. These can play an important role in studying and reconstruction of climate variation. The ability of a tree genotype to adjust the phenotype over the life of a tree is a consequence of short-term to long-term physiological responses to environmental changes, the ability which can be used to link environment with wood structure. The anatomical features of tree rings such as conduits size and density, cell wall thickness and the share of different tissues are sources of information on global environmental changes throughout the last millennium and on the strategies of species responses to the evaluation of the impact of predicted climate change on vegetation dynamics.The aim of this chapter is to present the up to date knowledge about the changes in woody plant hydraulics in response to water stress. The understanding of drought impact on plant water conducting systems structure and functioning and their possible adjustments becomes especially essential in respect to climate change projections for Central Europe predicting lower summer precipitation combined with prolonged drought periods. The issue of structural basis for water flow in wood of woody plants and the methods of its measurement and assessment are presented and the adjustments to water stress in short-and long-time scale as well as at different levels of woody plant organizations discussed. . Structural basis for woody plants hydraulicsWood anatomy can be studied in the view of different disciplines e.g. technical applications, tree pathology, ecology, dendrochronology but also in terms of hydraulics as a specific hydrosystem based on cells with lumina filled with water.© 2013 Marciszewska and Tulik; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.In perennial vascular plants the transport of water is to great extent determined by the hydraulic architecture. This term describes the xylem network within the plant and its variations with wood type, plant age and growth form e.g. liana, shrub vs. tree [ ]. The xylem network integrates all main parts of the plant s body, i.e. roots, branches and leaves. It means that any root in this system is more or less directly connected with any branch and not with a single one. Moreover, the xylem network is redundant in two meanings at a given level of the stem several xylem element are present in parallel and they develop lateral contacts with other tracks of vessels or tracheids.The xylem network is mainly represented by tracheary elements conduits that arise from vascular cambium periodically or continuously. Mature tracheary elements are dead cells with lignified wa...

Origin, activity and environmental acclimation of stem secondary tissues of the polar willow (Salix polaris) in high-Arctic Spitsbergen

“…In dry environment there is a risk of blocked water flow in the conducting elements (vessels) by air bubbles (embolism). The formation of vessels with smaller diameters is thus probably a way to prevent that phenomenon from occurring, although the relationship between the vessel diameter and their vulnerability to embolism is not direct (Carlquist 2012;Marciszewska and Tulik 2013;Hacke et al 2017). The differences in vessel length between willow plants from five tundra vegetation types are similar in terms of patterns to those of vessel diameter but are of a much smaller magnitude and not statistically significant (Fig.…”

Differences in xylem response to drought provide hints to future species selection

“…In conifers, more than 90% of the xylem is composed of tracheids, cells which provide both water transport and mechanical support (Brown et al 1949). Their anatomical characteristics strongly affect water conductance and determine the risk of cavitation during drought (Hacke and Sperry 2001;Pratt et al 2007;Marciszewska and Tulik 2013) and thereby tree vigour and growth. The anatomical characteristics of the tracheids also affect possible utilization of the wood via properties like wood density, microfibril angle and stiffness.…”

“…In temperate climate, cambium activity is seasonal, producing annual rings characterized by thin-walled tracheids with wide diameters in the early season transitioning to thick-walled tracheids with narrow diameters in the late season (Shmulsky and Jones 2011). The various functions of the xylem in the tree are determined by the number and morphology (such as the lumen size and the thickness of the cell wall) of these cells (Tyree and Zimmermann 2002;Marciszewska and Tulik 2013). The formation of tracheids is highly sensitive to environmental factors (Fonti et al 2010).…”

“…Here, we extend this approach for the conifer species by investigating xylem traits that are relevant for both the functioning of this tissue in the living tree and when it is used for wood products after harvesting. Effects of annual variations in summer drought were investigated on selected traits, emphasising two anatomic traits relevant for hydraulic conductivity and safety (Marciszewska and Tulik 2013;Rosner et al 2016;Venturas et al 2017): tracheid lumen area and tracheid wall thickness, and three properties of core importance for wood use: density, microfibril angle and stiffness (Lachenbruch et al 2010;Alves et al 2020).…”