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Vessel length distribution function for three apple rootstock varieties, as determined by linear regression of the logarithm of wood conductivity on stem segment length. The curves are from equation 10.
Source publication
Studies showing that rootstock dwarfing potential is related to plant hydraulic conductance led to the hypothesis that xylem
properties are also related. Vessel length distribution and other properties of apple wood from a series of varieties were
measured using the ‘air method’ in order to test this hypothesis. Apparatus was built to measure and m...
Contexts in source publication
Context 1
... class 1 represents a rootstock that produces a tree 10±20% the size that an own-rooted tree would produce under similar conditions'. Vessel length distributions for apple varieties 5 of 9 Figure 3 shows the distribution function for vessel lengths as determined from equation 10 for three root- stocks. As noted above, the difference between the distributions is expressed by one parameter, the slope of the relationship between the logarithm of conductivity and length, or its inverse, the mode vessel length. ...
Context 2
... distributions of vessel lengths have been found in many diffuse porous tree species ( Ewers et al., 1990), so the distribution presented here should have considerable utility. Experimentally determined uni-modal vessel length distributions reported in the past all appear to ®t the general form shown in Fig. 3, although some, where the mode is close to zero, do not indicate that they approach zero for very short lengths. The latter condition is a feature of the probability density function found in the current study (equation 10). Additional experimentation will be necessary to clarify this point. One possibility is to see if the log-linear ...
Similar publications
Ions can enhance water flow through the xylem via changes in the hydraulic resistance at border pit membranes. Because flow
between adjacent xylem vessels occurs primarily via bordered pit fields, it is hypothesized that xylem sap ion concentrations
would affect lateral movement of water more than longitudinal flow. Using tomato as a model system,...
Citations
... The shorter the branch was cut, the higher the volume of air sucked by the Pneumatron, as the number of open vessels increased with reduced stem length. The vessel distribution curve and mean vessel length were established according to Cohen et al. (2003). ...
Embolism resistance of xylem tissue varies among species and is an important trait related to drought resistance, with anatomical attributes like pit membrane thickness playing an important role in avoiding embolism spread. Grafted Citrus trees are commonly grown in orchards, with the rootstock being able to affect the drought resistance of the whole plant. Here, we evaluated how rootstocks affect the vulnerability to embolism resistance of the scion using several rootstock/scion combinations. Scions of ‘Tahiti’ acid lime, ‘Hamlin’, ‘Pera’ and ‘Valencia’ oranges grafted on a ‘Rangpur’ lime rootstock exhibit similar vulnerability to embolism. In field‐grown trees, measurements of leaf water potential did not suggest significant embolism formation during the dry season, while stomata of Citrus trees presented an isohydric response to declining water availability. When ‘Valencia’ orange scions were grafted on ‘Rangpur’ lime, ‘IAC 1710’ citrandarin, ‘Sunki Tropical’ mandarin or ‘Swingle’ citrumelo rootstocks, variation in intervessel pit membrane thickness of the scion was found. The ‘Rangpur’ lime rootstock, which is known for its drought resistance, induced thicker pit membranes in the scion, resulting in higher embolism resistance than the other rootstocks. Similarly, the rootstock ‘IAC 1710’ citrandarin generated increased embolism resistance of the scion, which is highly relevant for citriculture.
... Following anatomical indicators were measured in this study: the maximum vessel length (L max ), sapwood area (A sapwood ), vessel lumen area (A lumen ), xylem area (A xylem ), vessel density (VD), vessel diameter (D), hydraulically vessel diameter (D h ), and inter-vessel wall thickness (T W ). Previous studies have shown that L max in apple branches is approximately 0.5 m; therefore, 1-year-old branches of approximately 1 m length were selected (Cohen et al., 2003). The L max was measured by the "air method" (Cohen et al., 2003). ...
... Following anatomical indicators were measured in this study: the maximum vessel length (L max ), sapwood area (A sapwood ), vessel lumen area (A lumen ), xylem area (A xylem ), vessel density (VD), vessel diameter (D), hydraulically vessel diameter (D h ), and inter-vessel wall thickness (T W ). Previous studies have shown that L max in apple branches is approximately 0.5 m; therefore, 1-year-old branches of approximately 1 m length were selected (Cohen et al., 2003). The L max was measured by the "air method" (Cohen et al., 2003). Briefly, long stems were cut with a sharp razor blade and injected with compressed air (0.15 MPa) from the distal side while the basal end was immersed in water. ...
Deep soil water is important for trees to survive droughts in arid and semiarid regions, but often irreversibly decrease as tree age due to limitations in soil infiltration rates and precipitation. How adaptable is the hydraulic system of trees undergoing the depletion of deep soil moisture reserves? To answer this question, we examined 12 traits characterizing the hydraulic structure of apple tree branches along a plantation age gradient (7-26 years) under uniform soil and climatic conditions. We found that almost all deep soil available water was consumed (reduced by up to 98%) as apple trees aged, as a result, the fraction of roots located in water deficit layers increased by up to 70%. Reduced water availability in deep soil significantly increased xylem embolism resistance (P 50) by 8%, without altering xylem-specific hydraulic conductivity, vessel diameter, or vessel density. A distinct adaptive response to permanently reduced deep soil water availability seems to occur primarily by increasing tree hydraulic safety with no reductions in hydraulic efficiency, through which mechanism trees may acclimatize to deep soil water reduction.
... Pneumatic methods have been used to measure the maximum vessel length, to estimate vessel length distribution, and to determine the level of xylem embolism in woody stems (Greenidge, 1952, Zimmermann andJeje, 1981;Cohen et al., 2003;Pereira et al., 2016). However, in the context of plant physiology, no study has comprehensively examined the physics of how gas flows through long, narrow vessels. ...
... Therefore, one purpose of the present study is to provide the theoretical background of air flow and compare it to water flow, as illustrated using the air-injection method for the estimation of vessel length distribution in stems. The theory of vessel length calculation requires the measurement of the air flow rate through stems, Downloaded from https://academic.oup.com/jxb/article/73/16/5612/6584496 by Zhejiang Normal University user on 13 September 2022 calculation of the stem conductivity to air (K air ), and the use of analytical algorithms (Cohen et al., 2003) to estimate the distribution as well as mean and mode values of vessel length. ...
... Vessel length varies greatly both within and between species and even within the same tree, and it is affected by phylogeny, ontogeny, and environment (Tyree and Zimmermann, 2002;Pan et al., 2015). Diverse materials and methods have been used to determine the mean value and distribution of vessel length, including the injection of various substances such as pigments, India ink, paint, or silicone (Handley, 1936;Skene and Balodis, 1968;Zimmermann and Jeje, 1981;Ewers and Fisher, 1989;Sperry et al., 2005); air injection (Greenidge, 1952;Skene and Balodis, 1968;Zimmermann and Jeje, 1981;Cohen et al., 2003); wire insertion (Kanai et al., 1996); cinematographic methods (Huggett and Tomlinson, 2010); X-ray distribution of titanium mixed with paint solution (Middleton, 1989); and high-resolution computed tomography (Bordersen et al., 2011). Detailed information is available in various papers (Scholz et al., 2013;Cai and Tyree, 2014;Williamson and Milburn, 2017); however, all these methods have specific advantages or disadvantages, and inconsistencies exist among the different techniques (Ewers and Fisher, 1989;Tyree, 1993;Comstock and Sperry, 2000). ...
In plants, xylem vessel length is important for long-distance water transport; however, the currently used methods for vessel length measurement are inconvenient and time-consuming. The semi-automated Pneumatron device is based on the pneumatic theory, is similar to the air injection method, and can rapidly estimate vessel length.
Mean vessel length was compared between the newly-developed Pneumatron device and air injection method in seven species with different vessel lengths (2.3 to 78.7 cm). The results were consistent between two methods, regardless of whether the same or different samples were used.
The theory underlying the gas flow in vessels was improved and expanded, and compared to that underlying the water flow to better understand the pneumatic processes within a stem sample. Moreover, a new and simple equation for gas flow in vessels was derived based on the molar gas flow (mol·s -1) rather than volume flow, because the former remains constant with distance throughout the stem axis.
We strongly recommend using the Pneumatron device in future studies owing to its low cost, convenience, rapidity, and simple operation. Nonetheless, several cautions are warranted to avoid artifacts during measurements.
... The cut ends were wrapped with wet tissue papers, and the samples were enclosed in black plastic bags and immediately transported to the laboratory within 20 min. The maximum vessel length (MVL) for the seven species was measured using the air infiltration method (Cohen 2003;Zhang et al. 2021a, b). Five branches were used except for Zenia insignis (three replicates), because the height of this species was too high to harvest enough canopy branches. ...
Key message
Xylem hydraulic safety is a good predictor of long-term growth of the economical tropical timber tree species planted in the degraded tropical karst areas.
Abstract
Planting native economical timber tree species in the degraded dry tropical karst areas has been proven to be an effective restoration way. However, drought is the key limiting factor influencing growth performance of the reforestation tree species in such habitats. In this study, we investigated long-term growth rate of seven precious timber tree species in a tropical rocky desertification area three decades after planting, and measured a series of hydraulic-related traits for these species. By examining hydraulic-growth relationships across the seven species, we aimed to explore whether hydraulic traits can be used to predict tree growth. Our results showed that long-term growth rate was significantly related to xylem water potential causing 88% loss of hydraulic conductivity and hydraulic safety margin under extreme drought. However, it was not associated with hydraulic conductivity, Huber value, wood density, and xylem anatomical traits. Additionally, there was no trade-off between hydraulic efficiency and safety, with several timber tree species showing both high hydraulic conductivity and cavitation resistance. Our results suggest that the hydraulic safety-related traits are good predictor of long-term growth rate of the economical timber tree species planted in degraded dry karst areas, thus providing guidelines to improve the efficiency of future ecological restoration.
... The stem segments were immediately recut under water, transported to a nearby laboratory, kept in water, and rehydrated for 8 h. The maximum vessel length (MVL) was determined by the air injection method (Cohen et al. 2003). Stem segments (0.3-1.0 m) longer than the MVL were used to measure the stem hydraulic conductivity following the method described by Sperry et al. (1988). ...
Resprouting plants are distributed in many vegetation communities worldwide. With increasing resprout age post-severe-disturbance, new stems grow rapidly at their early age, and decrease in their growth with gradually decreasing water status thereafter. However, there is little knowledge about how stem hydraulic strategies and anatomical traits vary post-disturbance. In this study, the stem water potential (Ψstem), maximum stem hydraulic conductivity (Kstem-max), water potential at 50% loss of hydraulic conductivity (Kstem P50), and anatomical traits of Caragana korshinkii resprouts were measured during a 1- to 13-year post-disturbance period. We found that the Kstem-max decreased with resprout age from 1-year-old resprouts (84.2 mol m−1 s−1 MPa−1) to 13-year-old resprouts (54.2 mol m−1 s−1 MPa−1) as a result of decreases in the aperture fraction (Fap) and the sum of aperture area on per unit intervessel wall area (Aap). The Kstem P50 of the resprouts decreased from 1-year-old resprouts (−1.8 MPa) to 13-year-old resprouts (−2.9 MPa) as a result of increases in vessel implosion resistance (t/b)2, wood density (WD), vessel grouping index (GI), and decreases in Fap, and Aap. These shifts in hydraulic structure and function resulted in an age-based divergence in hydraulic strategies i.e., a change from an acquisitive strategy to a conservative strategy, with increasing resprout age post-disturbance.
... Instead of injecting gas into conduits under positive pressure (e.g. Cohen et al., 2003), fast and easy extraction of gas from cut-open vessels (i.e. vessels that have no end wall within a stem segment of given length) has resulted in a pneumatic method for the study of hydraulically weighted vessel length distributions (Pereira et al., 2020b). ...
International online meeting on ‘Plant Pneumatics’, Ulm University and the University of Natural Resources and Life Sciences (BOKU), Ulm (Germany) and Vienna (Austria), 22 April and 29 September 2021
... The air conductivity of cut and open vessels was plotted against the segment length and fitted to the equations of Sperry et al. (2005) to calculate average vessel length (L V ). This method has been validated against the silicon-injection method (Cohen et al. 2003;Pan et al. 2015;Pereira et al. 2020). Vessel length distribution data of leaf petioles of B. pendula, C. betulus, F. sylvatica, L. tulipifera and Q. petraea were retrieved from Guan et al. (2021) By combining anatomical results from LM, SEM and vessel length determinations, we calculated the total pit membrane surface area for a vessel with an average diameter and length (A P , mm 2 ) as A P = F C × F PF × π × D × L V . ...
• Drought events may increase the likelihood that the plant water transport system becomes interrupted by embolism. Yet our knowledge about the temporal frequency of xylem embolism in the field is frequently lacking, as it requires detailed, long-term measurements.
• We measured xylem embolism resistance and midday xylem water potentials during the consecutive summers of 2019 and 2020 to estimate maximum levels of embolism in leaf and stem xylem of ten temperate angiosperm tree species. We also studied vessel and pit membrane characteristics based on light and electron microscopy to corroborate potential differences in embolism resistance between leaves and stems.
• Apart from A. pseudoplatanus and Q. petraea, eight species experienced minimum xylem water potentials that were close to or below those required to initiate embolism. Water potentials corresponding to ca. 12% loss of hydraulic conductivity (PLC) could occur in six species, while considerable levels of embolism around 50% PLC were limited to B. pendula and C. avellana. There was a general agreement in embolism resistance between stems and leaves, with leaves being equally or more resistant than stems. Also, xylem embolism resistance was significantly correlated to intervessel pit membrane thickness (TPM) for stems, but not to vessel diameter and total intervessel pit membrane surface area of a vessel.
• Our data indicate that low amounts of embolism occur in most species during moderate summer drought, and that considerable levels of embolism are uncommon. Moreover, our experimental and TPM data show that leaf xylem is generally no more vulnerable than stem xylem.
... The cut ends were wrapped with wet tissue papers, and the samples were enclosed in black plastic bags and immediately transported to the laboratory within 20 min. The maximum vessel length (MVL) for the seven species was measured using the air infiltration method (Cohen 2003;Zhang et al. 2021a, b). Five branches were used except for Zenia insignis (three replicates), because the height of this species was too high to harvest enough canopy branches. ...
... This is possible by easy modification of the reservoir volume and by running the Pneumatron in a semi-automated way. The data analysis is also straightforward by using an R-script, and thus, makes it feasible to obtain fast measurements of vessel length distributions, and to investigate the non-random distribution of vessel ends near nodes, side branches, stem-petioles transitions, etc. Pneumatic estimations of the hydraulically weighted vessel length have been validated against the silicon-injection method for five species, and the air-injection method of Cohen et al. (2003) for seven species (Yang et al., 2021). ...
The Pneumatron device measures gas diffusion kinetics in the xylem of plants. The device provides an easy, low-cost, and powerful tool for research on plant water relations and gas exchange. Here, we describe in detail how to construct and operate this device to estimate embolism resistance of angiosperm xylem, and how to analyse pneumatic data. Simple and more elaborated ways of constructing a Pneumatron are shown, either using wires, a breadboard, or a printed circuit board. The instrument is based on an open-source hardware and software system, which allows users to operate it in an automated or semi-automated way. A step-by-step manual and a troubleshooting section are provided. An excel spreadsheet and an R-script are also presented for fast and easy data analysis. This manual aims at helping users to avoid common mistakes, such as unstable measurements of the minimum and maximum amount of gas discharged from xylem tissue, which has major consequences for estimating embolism resistance. Major advantages of the Pneumatron device include its automated and accurate measurements of gas diffusion rates, including highly precise measurements of the gas volume in intact, embolised conduits. It is currently unclear if the method can also be applied to woody monocots, gymnosperm species that possess torus-margo pit membranes, or to herbaceous species.
... Maximum vessel length was measured first, using the air-injection method (Cohen et al., 2003), for all species to determine the appropriate technique for measuring hydraulic vulnerability (measurement method is available in Table 2). ...
Globally, forests are facing an increasing risk of mass tree mortality events associated with extreme droughts and higher temperatures. Hydraulic dysfunction is considered a key mechanism of drought triggered dieback. By leveraging the climate breadth of the Australian landscape and a national network of research sites (Terrestrial Ecosystem Research Network), we conducted a continental‐scale study of physiology and hydraulic traits of 33 native tree species from contrasting environments to disentangle the complexities of plant response to drought across communities.
We found strong relationships between key plant hydraulic traits and site aridity. Leaf turgor loss point and xylem embolism resistance were correlated with minimum water potential experienced by each species. Across the dataset, there was a strong coordination between hydraulic traits, including those linked to hydraulic safety, stomatal regulation, and the cost of caron investment into woody tissue.
These results illustrate that aridity has acted as a strong selective pressure, shaping hydraulic traits of tree species across the Australian landscape. Hydraulic safety margins were constrained across sites, with species from wetter sites tending to have smaller safety margin compared with species at driest sites, suggesting trees are operating close to their hydraulic thresholds and forest biomes across the spectrum may be susceptible to shifts in climate that result in the intensification of drought.
