Wood structure and function change with maturity: Age of the vascular cambium is associated with xylem changes in current‐year growth

Xylem vessel structure changes as trees grow and mature. Age‐ and development‐related changes in xylem structure are likely related to changes in hydraulic function. We examined whether hydraulic function, including hydraulic conductivity and vulnerability to water‐stress‐induced xylem embolism, changed over the course of cambial development in the stems of 17 tree species. We compared current‐year growth of young (1–4 years), intermediate (2–7 years), and older (3–10 years) stems occurring in series along branches. Diffuse and ring porous species were examined, but nearly all species produced only diffuse porous xylem in the distal branches that were examined irrespective of their mature xylem porosity type. Vessel diameter and length increased with cambial age. Xylem became both more conductive and more cavitation resistant with cambial age. Ring porous species had longer and wider vessels and xylem that had higher conductivity and was more vulnerable to cavitation; however, these differences between porosity types were not present in young stem samples. Understanding plant hydraulic function and architecture requires the sampling of multiple‐aged tissues because plants may vary considerably in their xylem structural and functional traits throughout the plant body, even over relatively short distances and closely aged tissues.     

Polar auxin transport is implicated in vessel differentiation and spatial patterning during secondary growth in Populus

Premise of the Study

Dimensions and spatial distribution of vessels are critically important features of woody stems, allowing for adaptation to different environments through their effects on hydraulic efficiency and vulnerability to embolism. Although our understanding of vessel development is poor, basipetal transport of auxin through the cambial zone may play an important role.

Methods

Stems of Populus tremula ×alba were treated with the auxin transport inhibitor N‐1‐naphthylphthalamic acid (NPA) in a longitudinal strip along the length of the lower stem. Vessel lumen diameter, circularity, and length; xylem growth; tension wood area; and hydraulic conductivity before and after a high pressure flush were determined on both NPA‐treated and control plants.

Key Results

NPA‐treated stems formed aberrant vessels that were short, small in diameter, highly clustered, and angular in cross section, whereas xylem formed on the untreated side of the stem contained typical vessels that were similar to those of controls. NPA‐treated stems had reduced specific conductivity relative to controls, but this difference was eliminated by the high‐pressure flush. The control treatment (lanolin + dimethyl sulfoxide) reduced xylem growth and increased tension wood formation, but never produced the aberrant vessel patterning seen in NPA‐treated stems.

Conclusions

These results are consistent with a model of vessel development in which basipetal polar auxin transport through the xylem‐side cambial derivatives is required for proper expansion and patterning of vessels and demonstrate that reduced auxin transport can produce stems with altered stem hydraulic properties.     

Xylem sap flow and stem hydraulics of the vesselless angiosperm Drimys granadensis (Winteraceae) in a Costa Rican elfin forest

For decades, botanists have considered Winteraceae as the least modified descendents of the first angiosperms primarily because this group lacks xylem vessels. Because of a presumed high resistance of a tracheid‐based vascular system to water transport, Winteraceae have been viewed as disadvantaged relative to vessel‐bearing angiosperms. Here we show that in a Costa Rican cloud forest, stem hydraulic properties, sapwood area‐ and leaf area‐specific hydraulic conductivities of Drimys granadensis L. (Winteraceae) are similar to several co‐occurring angiosperm tree species with vessels. In addition, D. granadensis had realized midday transpiration rates comparable to most vessel‐bearing trees. Surprisingly, we found that D. granadensis transpired more water at night than during the day, with actual water loss being correlated with wind speed. The failure of stomata to shut at night may be related to the occlusion of stomatal pores by cutin and wax. Our measurements do not support the view that absence of xylem vessels imposes limitations on water transport above those for other vesselled plants in the same environment. This, in turn, suggests that a putative return to a tracheid‐based xylem in Winteraceae may not have required a significant loss of hydraulic performance.     

The mechanism of water-stress-induced embolism in two species of chaparral shrubs

The mechanism of water-stress-induced embolism of xylem was investigated in Malosma laurina and Heteromeles arbutifolia, two chaparral shrub species of southern California. We tested the hypothesis that the primary cause of xylem dysfunction in these species during dehydration was the pulling of air through the pores in the cell walls of vessels (pores in pit membranes) as a result of high tensions on xylem water. First, we constructed vulnerability-to-embolism curves for (i) excised branches that were increasingly dehydrated in the laboratory and (ii) hydrated branches exposed to increasing levels of external air pressure. Branches of M. laurina that were dehydrated became 50% embolized at a xylem pressure potential of -1.6 MPa, which is equal in magnitude but opposite in sign to the +1.6 MPa of external air pressure that caused 50% embolism in hydrated stems. Dehydrated and pressurized branches of H. arbutifolia reached a 50% level of embolism at -6.0 and +6.4 MPa, respectively. Secondly, polystyrene spheres ranging in diameter from 20 to 149 nm were perfused through hydrated stem segments to estimate the pore size in the vessel cell walls (pit membranes) of the two species. A 50% or greater reduction in hydraulic conductivity occurred in M. laurina at perfusions of 30, 42, 64 and 82 nm spheres and in H. arbutifolia at perfusions of 20 and 30 nm spheres. Application of the capillary equation to these pore diameters predicted 50% embolism at xylem tensions of -2.2 MPa for M. laurina and -6.7 MPa for H. arbutifolia, which are within 0.7 MPa of the actual values. Our results suggest that the size of pores in pit membranes may be a factor in determining both xylem efficiency and vulnerability to embolism in some chaparral species. H. arbutifolia, with smaller pores and narrower vessels, withstands lower water potentials but has lower transport efficiency. M. laurina, with wider pores and wider vessels, has a greater transport efficiency but requires a deeper root system to help avoid catastro-phically low water potentials.     

Vulnerability to cavitation differs between current‐year and older xylem: non‐destructive observation with a compact magnetic resonance imaging system of two deciduous diffuse‐porous species

Development of xylem embolism during water stress in two diffuse‐porous hardwoods, Katsura (Cercidiphyllum japonicum) and Japanese white birch (Betula platyphylla var. japonica), was observed non‐destructively under a compact magnetic resonance imaging (MRI) system in addition to conventional quantitation of hydraulic vulnerability to cavitation from excised stem segments. Distribution of white and dark areas in MR images corresponded well to the distribution of water‐filled/embolized vessels observed by cryo‐scanning electron microscopy in both species. Water‐filled vessels were observed in MR images as white areas in Katsura and as white dots in Japanese white birch, respectively, and embolisms could be detected as a change to dark areas. The increase in the relative embolized area (REA: %) in the cross‐sectional area of total xylem during water stress, which was estimated from the binarized MR images, was consistent with the hydraulic vulnerability curves of these species. From the non‐destructive MRI observations, cavitation induced by water stress was shown to develop earlier in 1‐ or 2‐year‐old xylem than in the current‐year xylem in both species; that is, the vulnerability to cavitation differs between vessels in the current‐year xylem and those in older annual rings.     

Xylem hydraulic safety and construction costs determine tropical tree growth

Faster growth in tropical trees is usually associated with higher mortality rates, but the mechanisms underlying this relationship are poorly understood. In this study, we investigate how tree growth patterns are linked with environmental conditions and hydraulic traits, by monitoring the cambial growth of 9 tropical cloud forest tree species coupled with numerical simulations using an optimization model. We find that fast‐growing trees have lower xylem safety margins than slow‐growing trees and this pattern is not necessarily linked to differences in stomatal behaviour or environmental conditions when growth occurs. Instead, fast‐growing trees have xylem vessels that are more vulnerable to cavitation and lower density wood. We propose the growth ‐ xylem vulnerability trade‐off represents a wood hydraulic economics spectrum similar to the classic leaf economic spectrum, and show through numerical simulations that this trade‐off can emerge from the coordination between growth rates, wood density, and xylem vulnerability to cavitation. Our results suggest that vulnerability to hydraulic failure might be related with the growth‐mortality trade‐off in tropical trees, determining important life history differences. These findings are important in furthering our understanding of xylem hydraulic functioning and its implications on plant carbon economy.     

Vessel development and the importance of lateral flow in water transport within developing bundles of current-year shoots of grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis> L.)

In the developing xylem bundles of young stems, the presence of immature living vessel elements can strongly restrict or even block axial hydraulic conductance, especially in newly matured vessels. Lateral connections between vessels may provide an alternative pathway for water movement to bypass these closed, living elements. Using the grapevine as a model system, the present study aimed to demonstrate the effects of living vessel elements on water movement patterns, and the importance of lateral flow for effective water conductivity in the developing bundles. Living vessel elements were detected using dye staining and the pattern of vessel development and maturation was then monitored. The importance of lateral flow was confirmed using several approaches: (1) capacity for lateral flow, (2) effect of increasing the distance of water transport, and (3) effect of ion concentrations. Living vessel elements were found along the developing bundles, they occupied a significant proportion of the distal and peripheral parts of the flow path, forming a substantial barrier to apoplastic water flow. Water in the developing xylem bundles could move easily from vessel to vessel and between secondary and primary xylem. Furthermore, data from increasing the transport length and altering the ion concentrations supported the critical contribution of the lateral flow to the total hydraulic conductance within the developing bundles. The hydraulic architecture of the developing xylem bundles is described. The results are discussed in terms of reliability and efficiency of water transport during shoot growth and development.     

Distribution of xylem hydraulic resistance in fruiting truss of tomato influenced by water stress

In this study xylem hydraulic resistances of peduncles (truss stalk), pedicels (fruit stalk) and the future abscission zone (AZ) halfway along the pedicel of tomato (Lycopersicon esculentum L.) plants were directly measured at different stages of fruit development, in plants grown under two levels of water availability in the root environment. The xylem hydraulic connection between shoot and fruits has previously been investigated, but contradictory conclusions were drawn about the presence of a flow resistance barrier in the pedicel. These conclusions were all based on indirect functional measurements and anatomical observations of water-conducting tissue in the pedicel. In the present study, by far the largest resistances were measured in the AZ where most individual vessels ended. Plants grown at low water availability in the root environment had xylem with higher hydraulic resistances in the peduncle and pedicel segments on both sides of the AZ, while the largest increase in hydraulic resistance was measured in the AZ. During fruit development hydraulic resistances in peduncle and pedicel segments decreased on both sides of the AZ, but tended to increase in the AZ. The overall xylem hydraulic resistance between the shoot and fruit tended to increase with fruit development because of the dominating role of the hydraulic resistance in the AZ. It is discussed whether the xylem hydraulic resistance in the AZ of tomato pedicels in response to water stress and during fruit development contributes to the hydraulic isolation of fruits from diurnal cycles of water stress in the shoot.     

Effect of indole-3-acetic acid (IAA) and sucrose on vessel size and density in isolated stem segments of oak (Quercus robur)

The effects of several concentrations of indole-3-acetic acid (IAA) and sucrose on xylogenic cambial activity and secondary xylem differentiation were investigated in isolated stem segments of Quercus robur L. supplied with liquid medium in aseptic conditions. After 5 weeks of culture auxin controlled cambial cell division and the number and size of vessel elements even without sugar in the medium. Sucrose modified these IAA effects, although little cambial activity occurred without auxin. The xylem increment correlated with changes of auxin concentration with the optimum at 28.5 μ M IAA. The formation of wide vessels was correlated with the optimal concentration of auxin. The frequency of vessel differentiation increased with auxin concentration. High concentrations of sucrose (0.24 M and 0.96 M ) reduced both the number of vessels and their diameter. The frequency of vessel formation was inhibited more than the vessel size by changes of sugar concentration. The vessels formed under low concentrations of IAA were circular in transverse section. With increase in IAA concentration the shape of the vessel cross-section changed to oval with the largest dimension in the radial direction.     

Formation of successive cambia and stem anatomy of Sesuvium sesuvioides (Aizoaceae)

Mature stems of Sesuvium sesuvioides (Fenzl) Verdc. were found to be composed of successive rings of xylem alternating with phloem. Repeated periclinal divisions in the parenchyma outside the primary phloem gave rise to conjunctive tissue and the lateral meristem that differentiate into the vascular cambium on its inner side. After the formation of the vascular cambium, the lateral meristem external to it became indistinct as long as the cambium was functional. As the cambium ceased to divide, the lateral meristem again became apparent prior to the initiation of the next cambial ring. The cambium was exclusively composed of fusiform cambial cells with no rays. In the young saplings, the number of cambial cylinders in the axis varied from the apex to the base, indicating formation of several rings within the year. In each successive ring of the lateral meristem, small segments differentiated into the vascular cambium and gave rise to vessels, axial parenchyma, fibres and fibriform vessels towards the inside, and secondary phloem on the outer side. In the old stems, non‐functional phloem of the innermost rings was replaced by a new set of sieve tube elements formed by periclinal divisions in the cambial segments associated with the non‐functional phloem. In some places the cambial segments completely differentiate into derivatives leaving no cambial cells between the xylem and phloem. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 548–555.     

Ecological significance of wood anatomy in two lianas from arid southwestern Saudi Arabia

The hot and arid lowlands of southwestern Saudi Arabia are home to two common lianas, Cocculus pendulus and Leptadenia arborea. This paper attempts to relate the adaptation of these two climbing woody perennials to such a harsh environment to the anatomy and hydraulic characteristics of their wood. The stems of these lianas have wood with wide xylem vessels and high hydraulic conductivity which should enhance water flow to the upper canopy despite their severe twisting. Hydraulic conductivity is further helped by the simple perforation plates of xylem vessels. The circular thickening of xylem walls gives them strength and reduces the risk of their collapse and the ensuing embolism in the advent of high tension created by severe water deficit and high evapo-transpiration demand. Wide vessels, on the other hand, are more susceptible to embolism. This problem may be overcome by reducing the solute potential of xylem sap by hydrolysis of starch grains which were found to be abundant in the vicinity of the vessels. This should help absorb water by the deep roots from the capillary fringes of the typically shallow water table in this particular habitat. Furthermore, the abundance of ray parenchyma cells between xylem groups of both lianas provides great flexibility with minimum damage to water conduits in the stem during climbing and twisted growth. It was concluded that these wood features in both lianas are crucial for survival under the harsh conditions of arid Tihama plains of southwestern Saudi Arabia.     

Fibre length and gibberellins A1 and A20 are decreased in Eucalyptus globules by acylcyclohexanedione injected into the stem

Trinexapacethyl (TriEt), an acylcyclohexanedionetype inhibitor of gibberellin (GA) biosynthesis, was applied to 3-year-old Eucalyptus globules saplings by localised injection near the base of each stem. The objective was to alter cambial region GA levels and to study the effects on secondary xylem fibre development. Seven weeks later wood samples, with bark and cambial region intact, were removed 10 and 30 cm above the point of injection. Fusiform cambial cell dimensions were compared with those of fibre-tracheids in the most recently formed 100 um of secondary xylem. Increasing TriEt applications from 5 to 5 000 mg active ingredient significantly reduced average fibre length, and to a lesser extent average fusiform cambial cell length. Also reduced was the number of cells in the cambial zone and the number of differentiating fibres with primary walls. However, no trends were evident for changes in fibre diameter, the proportion of vessel elements or the ratio of cambial ray cells to fusiform cambial cells. Two gibberellins (GA₁ and GA₂₀), indole-3-acetic acid (IAA) and abscisic acid (ABA) were quantified in cambial region tissues by gas chromatographymass spectrometry using stable isotope labelled internal standards. Increasing TriEt application reduced both GA₁ and GA₂₀ levels. Effects on IAA and ABA were not significant, although their levels tended to be lower at the highest TriEt application rate. The elongation of secondary xylem fibres was positively correlated with higher levels of endogenous GA₁ (r_s= 0.74, P < 0.01) and GA₂₀ (r_s= 0.72, P < 0.01). These results support a causal role for GA₁ in cambial cell division. They are also consistent with the hypothesis that the elongation of differentiating secondary xylem fibres in woody an–giosperms is dependent on GA₁ levels in the cambial region.     

Single‐vessel flow measurements indicate scalariform perforation plates confer higher flow resistance than previously estimated

During vessel evolution in angiosperms, scalariform perforation plates with many slit‐like openings transformed into simple plates with a single circular opening. The transition is hypothesized to have resulted from selection for decreased hydraulic resistance. Previously, additional resistivity of scalariform plates was estimated to be small – generally 10% or less above lumen resistivity – based on numerical and physical models. Here, using the single‐vessel technique, we directly measured the hydraulic resistance of individual xylem vessels. The resistivity of simple‐plated lumens was not significantly different from the Hagen–Poiseuille (HP) prediction (+6 ± 3.3% mean deviation). In the 13 scalariform‐plated species measured, plate resistivity averaged 99 ± 13.7% higher than HP lumen resistivity. Scalariform species also showed higher resistivity than simple species at the whole vessel (+340%) and sapwood (+580%) levels. The strongest predictor of scalariform plate resistance was vessel diameter (r² = 0.84), followed by plate angle (r² = 0.60). An equation based on laminar flow through periodic slits predicted single‐vessel measurements reasonably well (r² = 0.79) and indicated that Baileyan trends in scalariform plate evolution maintain an approximate balance between lumen and plate resistances. In summary, we found scalariform plates of diverse morphology essentially double lumen flow resistance, impeding xylem flow much more than previously estimated.     

Size‐correlated morpho‐physiology of the aroid vine Rhodospatha oblongata along a vertical gradient in a Brazilian rain forest

In this work, we analyse morpho‐physiological modifications presented during the allomorphic growth of the aroid vine Rhodospatha oblongata Poepp throughout its ascent into the forest canopy. We test the hypothesis that morphological modifications in the root, shoot and leaf are followed by a gradual improvement of the xylem vascular system in order to increase water acquisition and transport as body size increases. The characterisation of these structural modifications was based on 30–35 specimens divided into six size classes. The dimensions of shoots, leaves and roots were quantified and qualified. The transition from the terrestrial to the epiphytic phase was followed by a simultaneous increase of leaf number and lamina area, together with increased length and diameter of the petiole. Furthermore, as the plant grows, the shoot internodes become shorter and thicker. However, occurrence of aerial roots is the most important characteristic in the ascending phase. In taller individuals, the increase in number of roots with wider xylem vessels guarantees an increased theoretical xylem hydraulic conductance for this growth phase. Along an acropetal direction of the same shoot, the diameter of xylem vessels increased, while the number of vessels per stele area decreased, in contrast with such allometric models as that of West, Brown and Enquist, showing that xylem vessel number and diameter taper in a reverse manner along the same direction. Such structural changes of R. oblongata allow improved foraging for light and water, facilitating the survival of bigger‐sized plants of this vine in the canopy.     

WOOD FORMATION IN PROSOPIS: EFFECT OF 2,4-D, 2,4,5-T,AND TIBA

Treatment of erect stems of Prosopis with near phytotoxic levels of 2,4-D or 2,4,5-T causes the formation of an unusual wood with narrow, thick-walled vessels and axial parenchyma in which cell wall thickening is inhibited. Although reduced in diameter, the vessels formed during 2,4-D and 2,4,5-T treatment are so numerous that there is no significant difference between phenoxyacetic acid and control seedling groups with regard to total area of xylem occupied by vessels. The preferential maturation of xylem vessels over parenchyma and the transformation of fusiform initials into septate parenchyma strands in phenoxyacetic acid-treated Prosopis resemble the structural changes reported to occur after girdling in the cambial tissue of other arborescent angiosperms. Bending experiments indicate that tension-wood fibers of Prosopis differentiate in response to an auxin deficiency. However, xylogenesis in erect stems treated with TIBA is affected such that a significantly higher proportion of the cambial cell population becomes axial xylem parenchyma.     

EFFECTS OF TREE AGE ON SECONDARY XYLEM AND PHLOEM ANATOMY IN STEMS OF GREAT BASIN BRISTLECONE PINE (PINUS LONGAEVA)

Xylem and phloem tissue samples were collected from various-aged Great Basin bristlecone pine (Pinus longaeva D. K. Bailey) stems in southern Utah and southeastern California to determine whether the vascular cambia of older trees produce fewer xylem rays, shorter-lived xylem and phloem ray cells, fewer phloem sieve cells, and a thinner phloem. Increment cores were examined to determine whether ‘aged’ cambia produced narrower tracheids that might reduce water translocation. Sapwood thickness was measured and sapwood growth layers were counted on these cores. Regression and Classification and Regression Tree (CART) analyses of sample data found no age-related changes in cambial products. Phloem and xylem production appeared normal at all ages, with no evidence of cambial malfunction.     

Leaf morphology of 40 evergreen and deciduous broadleaved subtropical tree species and relationships to functional ecophysiological traits

We explored potential of morphological and anatomical leaf traits for predicting ecophysiological key functions in subtropical trees. We asked whether the ecophysiological parameters stomatal conductance and xylem cavitation vulnerability could be predicted from microscopy leaf traits. We investigated 21 deciduous and 19 evergreen subtropical tree species, using individuals of the same age and from the same environment in the Biodiversity‐Ecosystem Functioning experiment at Jiangxi (BEF‐China). Information‐theoretic linear model selection was used to identify the best combination of morphological and anatomical predictors for ecophysiological functions. Leaf anatomy and morphology strongly depended on leaf habit. Evergreen species tended to have thicker leaves, thicker spongy and palisade mesophyll, more palisade mesophyll layers and a thicker subepidermis. Over 50% of all evergreen species had leaves with multi‐layered palisade parenchyma, while only one deciduous species (Koelreuteria bipinnata) had this. Interactions with leaf habit were also included in best multi‐predictor models for stomatal conductance (g_s) and xylem cavitation vulnerability. In addition, maximum g_s was positively related to log ratio of palisade to spongy mesophyll thickness. Vapour pressure deficit (vpd) for maximum g_s increased with the log ratio of palisade to spongy mesophyll thickness in species having leaves with papillae. In contrast, maximum specific hydraulic conductivity and xylem pressure at which 50% loss of maximum specific xylem hydraulic conductivity occurred (Ψ₅₀) were best predicted by leaf habit and density of spongy parenchyma. Evergreen species had lower Ψ₅₀ values and lower maximum xylem hydraulic conductivities. As hydraulic leaf and wood characteristics were reflected in structural leaf traits, there is high potential for identifying further linkages between morphological and anatomical leaf traits and ecophysiological responses.     

XYLEM ANATOMY,WATER FLOW,AND HYDRAULIC CONDUCTANCE IN THE FERN CYRTOMIUM FALCATUM

Xylem anatomy and water relations were studied in holly fern (Cyrtomium falcatum, Aspidiaceae) to determine the details of the pathway for water flow through an entire plant and the influence of tracheid number and lumen diameter on water flow. Each leaf has two adaxial traces and an abaxial trace, which are supplied by diarch adventitious roots attached to the dictyostele of the rhizome near the leaf base. Anatomical observations and dye experiments showed that each adaxial bundle vascularizes the approximately seven pinnae on its side of a leaf. An abaxial bundle is intermittently connected to an adaxial bundle as well as other abaxial bundles, forming a minor vascular pathway between the bundles of the leaf axis. Changes in both number and diameter of tracheids result in an acropetal decrease in hydraulic conductance per unit length along the rachis, although tracheid number locally increases when the trace for a pinna is produced in an adaxial bundle. Water flow was determined from the transpiration distal to the point in question or by forcing a solution through an axis with applied pressure. The water potential gradient along the plant axis was quite constant, indicating that hydraulic conductance per unit length varied with leaf area to be supplied. About 40% of the overall water potential drop occurred from the rachis into the pinnae, which reflected factors controlling water potential gradients in the lamina and not a very low conductance in the petiolule xylem. Hydraulic conductances calculated using the Hagen-Poiseuille equation and tracheid diameters were generally double those of measured conductances. Since the values tended to vary by a constant factor, tracheid number and diameter may largely control water flow in the xylem.     

A comparison of two centrifuge techniques for constructing vulnerability curves: insight into the ‘open‐vessel’ artifact

A vulnerability curve (VC) describes the extent of xylem cavitation resistance. Centrifuges have been used to generate VCs for decades via static‐ and flow‐centrifuge methods. Recently, the validity of the centrifuge techniques has been questioned. Researchers have hypothesized that the centrifuge techniques might yield unreliable VCs due to the open‐vessel artifact. However, other researchers reject this hypothesis. The focus of the dispute is centered on whether exponential VCs are more reliable when the static‐centrifuge method is used rather than the flow‐centrifuge method. To further test the reliability of the centrifuge technique, two centrifuges were manufactured to simulate the static‐ and flow‐centrifuge methods. VCs of three species with open vessels of known lengths were constructed using the two centrifuges. The results showed that both centrifuge techniques produced invalid VCs for Robinia because the water flow through stems under mild tension in centrifuges led to an increasing loss of water conductivity. In addition, the injection of water in the flow‐centrifuge exacerbated the loss of water conductivity. However, both centrifuge techniques yielded reliable VCs for Prunus, regardless of the presence of open vessels in the tested samples. We conclude that centrifuge techniques can be used in species with open vessels only when the centrifuge produces a VC that matches the bench‐dehydration VC.