The hydraulic architecture of Juniperus communis L. ssp. communis: shrubs and trees compared

Abstract

Juniperus communis ssp. communis can grow like a shrub or it can develop a tree-like habit. In this study, the hydraulic architecture of these contrasting growth forms was compared. We analysed the hydraulic efficiency (leaf-specific conductivity, kl; specific conductivity, ks; Huber value, HV) and the vulnerability to cavitation (the water potential corresponding to a 50% loss of conductivity, Conduit diameters were correlated with kl and ks. Data indicate that differences in hydraulic architecture correspond to changes in growth form. In some aspects, the xylem hydraulics of tree-like Juniperus communis differs from that of other coniferous tree species.

The Hydraulic Architecture of Conifers

“…In conifers, LSC generally increases greatly with stem diameter (Tyree and Ewers 1991), meaning that branches tend to have lower, LSC than the trunk (Domec et al 2012). In branches of Juniperus communis trees, LSC and K smax were low at the base, increased toward the distal parts and decreased again near the branch tips (Beikircher and Mayr 2008). These patterns are controlled in part by differences in tracheid dimension.…”

The blind men and the elephant: the impact of context and scale in evaluating conflicts between plant hydraulic safety and efficiency

“…The extent to which xylem safety and efficiency are antagonistic features leading to inevitable trade-offs has been debated (Maherali et al 2004(Maherali et al , 2006Willson et al 2008). In woody plants, these attributes are most frequently characterized in terminal branches and less often in other parts of the plant, such as roots (Martinez-Vilalta et al 2002;Domec et al 2004Domec et al , 2006Maherali et al 2006;Pratt et al 2007;Willson et al 2008), main stems (Spicer and Gartner 2001;Domec and Gartner 2003;Domec et al 2005Domec et al , 2006Beikircher and Mayr 2008), and leaves (Sack et al 2003;Brodribb and Holbrook 2004a;Woodruff et al 2008;Johnson et al 2009a, b). Although plant organs can be characterized in terms of their own hydraulic architecture, recognition of the spatial and temporal contexts in which they are being studied is essential for interpretation of their role in plant hydraulic function.…”

Winter peridermal conductance of apple trees: lammas shoots and spring shoots compared

“…About 3 cm long samples were cut out of the shoot under water, de-barked, re-cut with a sharp wood carving knife and sealed under water in the silicone tubes of the measurement system. Measurement pressure was set to 4 kPa and the flow rate was determined with a PC-connected analytical balance (specification see above) by weight registration every 10 s and linear regression over 200 s. For measurements, distilled, filtered (0.22 μm) and degassed water containing 0.005 % (v/v) ‘Micropur Forte MF 1000F’ (a mixture containing Ag+ and sodium hypochlorite sold for water sterilization and preservation; Katadyn Products Inc., Wallisellen, Switzerland) to prevent microbial growth (Sperry et al 1988; Beikircher and Mayr 2008) was used. Between measurements of the flow rate, samples were flushed at 80 kPa for 20 min.…”