How to quantify conduits in wood?

Abstract

Vessels and tracheids represent the most important xylem cells with respect to long distance water transport in plants. Wood anatomical studies frequently provide several quantitative details of these cells, such as vessel diameter, vessel density, vessel element length, and tracheid length, while important information on the three dimensional structure of the hydraulic network is not considered. This paper aims to provide an overview of various techniques, although there is no standard protocol to quantify conduits due to high anatomical variation and a wide range of techniques available. Despite recent progress in image analysis programs and automated methods for measuring cell dimensions, density, and spatial distribution, various characters remain time-consuming and tedious. Quantification of vessels and tracheids is not only important to better understand functional adaptations of tracheary elements to environment parameters, but will also be essential for linking wood anatomy with other fields such as wood development, xylem physiology, palaeobotany, and dendrochronology.

Nutrient-Induced Modifications of Wood Anatomical Traits of Alchornea lojaensis (Euphorbiaceae)

“…To achieve optimal results, Mean group size of non-solitary vessels Scholz et al, 2013;von Arx et al, 2013 it was necessary to count every vessel separately, based on the total xylem area (Wheeler, 1986). Additionally, we evaluated the vessel frequency distribution (absolute and relative) of different vessel group sizes (von Arx et al, 2013).…”

“…But how can those changes of the vascular system be detected or calculated? Scholz et al (2013) provided an overview of different methodological approaches how to quantify vessel or tracheid elements in plants. Numbers of different vessel parameters help comprehending possible adaptations or changes of the xylem structure.…”

Relationships among wood anatomy, hydraulic conductivity, density and shear parallel to the grain in the wood of 24-year-old Handroanthus vellosoi (Bignoniaceae)

“…Hydraulic conductivity was calculated based on vessel diameter, using the following equation: Kh = πD4/128η, where D is the diameter, η is the viscosity index of water (1.002 × 10-9 MPa s at 20 o C), and Kh is the hydraulic conductivity (Scholz et al 2013). …”

Intraspecific variation in embolism resistance and stem anatomy across four sunflower (Helianthus annuus L.) accessions

“…The parameters measured included: total stem cross‐section area ( A stem , μm 2 ); total xylem area ( A Tx , μm 2 ); primary xylem area ( A Px , μm 2 ) and secondary xylem area ( A Sx , μm 2 ); pith area ( A pith , μm 2 ); proportion of pith area per unit stem area ( P p s ); area of the cellular part of the stem ( A cp , μm 2 ) calculated by subtracting A pith from A stem ; lignified area ( A lig , μm 2 ) calculated by adding total xylem area ( A Tx ) and fiber cap area ( A fcap , μm 2 ); proportion of lignified area per stem area ( P lig s ) obtained dividing A lig by A stem ; proportion of lignified area relative to the cellular part of the stem ( P lig cp ) calculated by dividing A lig by A cp ; fiber cell wall area ( A fcw , μm 2 ) in the secondary xylem measured by subtracting fiber lumen area ( A flumen , μm 2 ) from fiber cell area ( A fcell , μm 2 ); proportion of cell wall per fiber cell ( P cw f ) obtained by dividing ( A fcw ) by ( A fcell ); total fiber wall area in the lignified area ( A fcw in A lig , μm 2 ) calculated by multiplying P cw f by A lig ; proportion of fiber wall in the lignified area per stem area ( P fcw in lig s ) measured by dividing A fcw in A lig by A stem . We also calculated the following parameters for both primary and secondary xylem: vessel density ( VD ); vessel lumen area ( A v ); cumulative vessel lumen area ( A cv ); relative vessel lumen area ( A rv ) obtained by dividing cumulative vessel lumen area by the corresponding xylem area; thickness‐to‐span ratio of vessels ( TD − 1 ) obtained by dividing double intervessel wall thickness ( T vw ) by the maximum diameter of the vessel ( D max ); equivalent circle diameter ( D ) and hydraulically weighted vessel diameter ( D h ), respectively, calculated as D = (4A/π) 1/2 where A is vessel cross sectional surface area (μm 2 ), and D h = ∑ D 5 /∑ D 4 (Scholz et al ). A list of all the measured traits, their symbols and units is provided in Table .…”