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Enabling better global research outcomes in soil, plant & environmental monitoring.

PSY1 Stem Psychrometer

The PSY1 Stem Psychrometer is a very powerful tool integrating all the ambient environmental parameters acting upon the plant such as solar radiation, temperature, humidity, wind speed and water availability into a single continuously measurable variable.

The PSY1 is a stand-alone instrument for the measurement of stem water potential. It can continuously log changes in plant water status/potential, which directly reflect the energy required to access water or the stress the plant is under.

Optimal logging solution: Plant Water Potential

PSY1 Psychrometer Features

  • Stem, leaf and root water potential
  • Ambient environmental parameters integration
  • Hydraulic conductivity
  • Plant water relations
  • Growth potential




See a list of PSY1 Psychrometer Research Publications here.

See Full Playlist of PSY1 Psychrometer Youtube Videos Here

Introduction Videos

PSY1 Psychrometer Theory of Operation:

PSY1 Psychrometer Principle of Operation:


Installation Videos

PSY1 Psychrometer Installation:


Calibration Videos

PSY1 Psychrometer Calibration Procedure:

About the PSY1 Stem Psychrometer

Thermocouple hygrometers, or psychrometers, of various designs have been used successfully in plant science research since the early 1950’s, most commonly used on a detached leaf sample. The PSY1 Stem Psychrometer developed by Professor Mike Dixon, University of Guelph, measures water potential in-situ and has been validated against Scholander-Hammel pressure bombs with excellent results and used in published research since 1984. Initially published as Dixon, M. A., & Tyree, M. T. (1984). A new stem hygrometer, corrected for temperature gradients and calibrated against the pressure bomb. Plant, Cell & Environment, 7(9), 693-697., the PSY1 Stem Psychrometer has since been used in many other studies.

PSY1-PWSC comparison

PSY1 Stem Psychrometer Comparison to Pressure Bomb – Courtesy George Koch, Northern Arizona University.

All temperature measurements (dT, Wet Bulb depression & chamber temperature) are then used in the determination of plant water potential. It can continuously log (at 10-minute temporal resolution) changes in the plant water status.

When simultaneously combined with the SFM1 Sap Flow Meter and Dendrometry Instrumentation the complete plant water relations and growth potential of the plant can be obtained, continuously monitoring ecophysiological change over time. The PSY1 Stem Psychrometer offers significant benefits over more common leaf psychrometers through the ease of attachment which minimises energy balance disruptions and improves measurement accuracy.

Instrument design

The PSY1 Stem Psychrometer head consists of two welded chromel-constantan thermocouples connected in series within a chromium plated brass chamber that forms a large insulating thermal mass.

Inside the chamber one thermocouple is in contact with the stem sample and the other simultaneously measures the chamber air temperature and subsequent to a Peltier cooling pulse, the set bulb depression. A third soldered copper-constantan thermocouple is located within the sample chamber body to measure the instrument temperature for the purpose of temperature compensation.

Within the chamber, the thermocouples are set so one is slightly above the surface of the sample chamber such that upon installation it is placed in contact with an exposed section of sapwood, while a second thermocouple remains within the sample chamber measuring the chamber air temperature. A Peltier cooling current is then applied to the junction, the differential output of the two junctions is a measure of the temperature gradient between the sample and the dew point measuring junction. By measuring the psychrometric (wet bulb) depression and applying automatic temperature correction of the error induced by temperature gradients within the chamber, precise and repeatable measurements of plant water potential are accurately obtained.

PSY Thermocouples


The PSY1 Stem Psychrometer is attached to the stem using a clamp to hold it in position using moderate pressure, and is then insulated against external temperature influences with additional insulation.

Small Stem PsychrometerWhen installing, insulation will effect the equilibration half-time and the quality of the results.

Equilibration Half-Time

The equilibration half-time for thermocouple psychrometers is varied. The range can extend from several minutes to several hours depending upon the design of the psychrometer. Variability stems from how accurately the differential temperatures are measured, whether the initial measuring junction and sample temperatures are measured or assumed and finally, how well the psychrometer is insulated from thermal gradients. The PSY1 Stem Psychrometer measures all temperatures and assumes nothing. With good insulation, equilibration half-times as short as 60 seconds can be achieved, making it a very rapid, repeatable and reliable instrument.

Instrument Configuration & Operation

All functions of the instrument’s operation and calculations are controlled by the microprocessor which automatically converts the analogue microvolt signals to a calibrated output. Programming variables such as Peltier cooling pulse, duration & wait time, reverse Peltier warming, duration & wait time, Chamber heating duration & period, measurement frequency and data logging options, are all held resident in non-volatile memory.

The PSY1 Stem Psychrometer displays information such as:

  • External Power Status
  • Serial Number
  • Firmware Version
  • SD Card Status
  • Measurement Interval
  • Data File Logging Option
  • Calibration Factors

The utility software enables the instrument to be used in the manual mode. This provides the ability to perform lab based work with destructively sampled material, osmotic potential measurements or to evaluate the cleanliness or reliability of the chamber using the Plot Peltier Cooling Curve recording and plotting function.

Data Analysis

Data can be manually processed using a Spreadsheet such as Excel by opening the Comma Separated Values (CSV) file provided by the PSY1. The user can customise what values are logged in the data file choosing from all raw data parameters, processed stem Water Potential in MPa and the relevant calibration and correction factors used in the data processing. Regardless of the parameters chosen all are pre-processed into engineering units ready for interpretation and analysis.

Calibration Options

The PSY1 Stem Psychrometer requires calibration. Depending upon the level of accuracy required you can choose to utilise a generic batch calibration with coarse generalised accuracy or a specific chamber calibration. The specific chamber calibration can be requested from ICT International at the time of purchase and this calibration is at additional cost to the instrument. Alternatively, ICT International provides detailed calibration instructions and a calibration spreadsheet to enable the user to perform their own calibration at no extra cost.

It is recommended that a full 6-point calibration (0.1, 0.2, 0.3, 0.4, 0.5 and 1.0 Molal NaCl solutions) be performed every 6 to 12 months or immediately following a serious contamination and cleaning of the chamber. The need for a full calibration and/or change of calibration can then be determined using the integrated calibration function of the utility software. Calibrations should be performed both within the range of expected water potentials and at a range of expected temperatures. An extreme environment calibration range (1.2 to 2.0 Molal equivalent to -6 to -10 MPa) is included to facilitate this.

The calibration function automatically records raw wet bulb depressions, chamber temperatures and corrected wet bulb depression values for plotting against known solute potentials. The plot function includes each individual data point, r2 regression analysis and line, and the slope and intercept of the calibration curve. You can also choose to plot the current calibration against a historical calibration evaluating and comparing r2, slope and offsets of each. The calibration function is a very powerful and time saving feature. Multiple calibration files for a Psychrometer or calibration files for multiple Psychrometer chambers can be stored on the MicroSD card of the PSY1 and recalled for use with the specific chamber.


Units MPa
Range -0.1 MPa to -10 Mpa
(1 to 100 Bars)
Resolution 0.01 MPa (0.1 Bar)
Accuracy ±0.1 MPa (1 Bar)
Response Time Measurement mode: 51 seconds
Live mode: 1 second
Sampling Rate 10 Hz


Computer Interface USB, Wireless RF 2.4 GHz
Data Storage MicroSD Card
Memory Capacity Up to 16GB, 8GB MicroSD card included.


Temperature Range -10 to 50°C
R/H Range 0-99%


Logger Length: 170 mm
Width: 80 mm
Depth: 35 mm
Psychrometer Chamber Diameter: 25.5mm
Depth: 20mm
Depth with calibration chamber: 30mm




Analogue Channels 1x Input, (1x Sensor) High precision 24bit ADC circuit
1x Output – PSY Chamber Heater Circuit
Minimum Logging Interval 1 second
Delayed Start Suspend Logging, Customised Intervals
Sampling Frequency 10Hz


Communications USB, Wireless Radio Frequency 2.4 GHz
Data Storage MicroSD Card, SD, SDHC & SDXC Compatible (FAT32 format)
Software Compatibility Windows OS
Data Compatibility FAT32 compatible for direct exchange of SD card with any Windows PC and Mac
Data File Format Comma Separated Values (CSV) for compatibility with all software programs
Memory Capacity Up to 16GB, 8GB MicroSD card included.


Temperature Range -10°C to +50°C
R/H Range 0-100%
Upgradable User Upgradeable firmware using USB boot strap loader function


Internal Battery Specifications
950mAh Lithium Polymer, 4.20 Volts fully charged
External Power Requirements
Bus Power 8-30 Volts DC, non-polarised, current draw is 190mA maximum at 17 volts per logger
USB Power 5 Volts DC
Internal Charge Rate
Bus Power 60mA – 200mA Variable internal charge rate, maximum charge rate of 200mA active when the external voltage rises above 16 Volts DC
USB Power 100mA fixed charge rate
Internal Power Management
Fully Charged Battery 4.20 Volts
Low Power Mode 3.60 Volts – Instrument ceases to take measurements
Discharged Battery 2.90 Volts – Instrument automatically switches off at and below this voltage when no external power connected.
Battery Life varies
  • With a recommended power source connected, operation can be continuous.
  • 3 days at hourly logging interval without chamber heating
  • 1 day with chamber heating
  • Clamps for PSY1-Stem
  • PSY1-Stem Leaf Clamp
    Leaf clamp for use with the PSY1 Stem Psychrometer.
  • PSY1 Installation Kit
  • CH24 - 24 Volt Power Supply
    The CH24 is a 100 - 240Volts AC Mains to 24Volts DC power supply adapter; capable of outputting up to 2.5Amps. For most ICT Instruments.
  • MCC Mini
    The MCC Mini is a simple to use USB Serial to Radio Communications device providing a high level of integrity in data transfers. Its miniature design and minimalist approach make it an attractive solution for portable computers and less intrusive workstation setups where space and weight are of concern.

Compilation of Published Research

The PSY1 Psychrometer is widely used in research into plant water stress; below is a list of over 80 publications that have used the PSY1 Psychrometer in their research.


Lamarque, L. J., Delmas, C. E. L., Charrier, G., Burlett, R., Dell’Acqua, N., Pouzoulet, J., Gambetta, G. A., & Delzon, S. (2023). Quantifying the grapevine xylem embolism resistance spectrum to identify varieties and regions at risk in a future dry climate. Scientific Reports, 13(1), 7724. https://doi.org/10.1038/s41598-023-34224-6
Skelton, R. P., West, A. G., Buttner, D., & Dawson, T. E. (2023). Consistent responses to moisture stress despite diverse growth forms within mountain fynbos communities. Oecologia. https://doi.org/10.1007/s00442-023-05326-9


Avila, R. T., Guan, X., Kane, C. N., Cardoso, A. A., Batz, T. A., DaMatta, F. M., Jansen, S., & McAdam, S. A. M. (2022). Xylem embolism spread is largely prevented by interconduit pit membranes until the majority of conduits are gas-filled. Plant, Cell & Environment, 45(4), 1204–1215. https://doi.org/10.1111/pce.14253
Cecilia, B., Francesca, A., Dalila, P., Carlo, S., Antonella, G., Francesco, F., Marco, R., & Mauro, C. (2022). On-line monitoring of plant water status: Validation of a novel sensor based on photon attenuation of radiation through the leaf. Science of The Total Environment, 152881. https://doi.org/10.1016/j.scitotenv.2021.152881
Gauthey, A., Peters, J. M. R., Lòpez, R., Carins-Murphy, M. R., Rodriguez-Dominguez, C. M., Tissue, D. T., Medlyn, B. E., Brodribb, T. J., & Choat, B. (2022). Mechanisms of xylem hydraulic recovery after drought in Eucalyptus saligna. Plant, Cell & Environment, 45(4), 1216–1228. https://doi.org/10.1111/pce.14265
Gauthey, A., Backes, D., Balland, J., Alam, I., Maher, D. T., Cernusak, L. A., Duke, N. C., Medlyn, B. E., Tissue, D. T., & Choat, B. (2022). The Role of Hydraulic Failure in a Massive Mangrove Die-Off Event. Frontiers in Plant Science, 13. https://www.frontiersin.org/articles/10.3389/fpls.2022.822136
Guan, X., Werner, J., Cao, K.-F., Pereira, L., Kaack, L., McAdam, S. a. M., & Jansen, S. (2022). Stem and leaf xylem of angiosperm trees experiences minimal embolism in temperate forests during two consecutive summers with moderate drought. Plant Biology, n/a(n/a). https://doi.org/10.1111/plb.13384
Johnson, K. M., Lucani, C., & Brodribb, T. J. (2022). In vivo monitoring of drought-induced embolism in Callitris rhomboidea trees reveals wide variation in branchlet vulnerability and high resistance to tissue death. New Phytologist, 233(1), 207–218. https://doi.org/10.1111/nph.17786
Jorda, H., Ahmed, M. A., Javaux, M., Carminati, A., Duddek, P., Vetterlein, D., & Vanderborght, J. (2022). Field scale plant water relation of maize (Zea mays) under drought – impact of root hairs and soil texture. Plant and Soil, 478(1), 59–84. https://doi.org/10.1007/s11104-022-05685-x
Lakmali, S., Benyon, R. G., Sheridan, G. J., & Lane, P. N. J. (2022). Change in fire frequency drives a shift in species composition in native Eucalyptus regnans forests: Implications for overstorey forest structure and transpiration. Ecohydrology, 15(3), e2412. https://doi.org/10.1002/eco.2412
Smith-Marin, C. M., Muscarella, R., Ankori-Karlinsky, R., Delzon, S., Farrar, S. L., Salva-Sauri, M., Thompson, J., Zimmerman, J. K., & Uriarte, M. (2022). Hydraulic traits are not robust predictors of tree species stem growth during a severe drought in a wet tropical forest. Functional Ecology, n/a(n/a). https://doi.org/10.1111/1365-2435.14235
Smith-Martin, C. M., Muscarella, R., Ankori-Karlinsky, R., Delzon, S., Farrar, S. L., Salva-Sauri, M., Thompson, J., Zimmerman, J. K., & Uriarte, M. (2022). Hurricanes increase tropical forest vulnerability to drought. New Phytologist, 235(3), 1005–1017. https://doi.org/10.1111/nph.18175
Sun, X., Li, J., Cameron, D., & Moore, G. (2022). On the Use of Sap Flow Measurements to Assess the Water Requirements of Three Australian Native Tree Species. Agronomy, 12(1), 52. https://doi.org/10.3390/agronomy12010052


Amrutha, S., Parveen, A. B. M., Muthupandi, M., Vishnu, K., Bisht, S. S., Sivakumar, V., & Ghosh Dasgupta, M. (2021). Characterization of Eucalyptus camaldulensis clones with contrasting response to short-term water stress response. Acta Physiologiae Plantarum, 43(1), 14. https://doi.org/10.1007/s11738-020-03175-0
Avila, R. T., Cardoso, A. A., Batz, T. A., Kane, C. N., DaMatta, F. M., & McAdam, S. A. M. (2021). Limited plasticity in embolism resistance in response to light in leaves and stems in species with considerable vulnerability segmentation. Physiologia Plantarum, n/a(n/a). https://doi.org/10.1111/ppl.13450
Benettin, P., Nehemy, M. F., Asadollahi, M., Pratt, D., Bensimon, M., McDonnell, J. J., & Rinaldo, A. (2021). Tracing and Closing the Water Balance in a Vegetated Lysimeter. Water Resources Research, 57(4), e2020WR029049. https://doi.org/10.1029/2020WR029049
Bourbia, I., Pritzkow, C., & Brodribb, T. J. (2021). Herb and conifer roots show similar high sensitivity to water deficit. Plant Physiology, kiab207. https://doi.org/10.1093/plphys/kiab207
Brodribb, T., Brodersen, C. R., Carriqui, M., Tonet, V., Rodriguez Dominguez, C., & McAdam, S. (2021). Linking xylem network failure with leaf tissue death. New Phytologist, 232(1), 68–79. https://doi.org/10.1111/nph.17577
Chen, Y.-J., Maenpuen, P., Zhang, Y.-J., Barai, K., Katabuchi, M., Gao, H., Kaewkamol, S., Tao, L.-B., & Zhang, J.-L. (2021). Quantifying vulnerability to embolism in tropical trees and lianas using five methods: can discrepancies be explained by xylem structural traits? New Phytologist, 229(2), 805–819. https://doi.org/10.1111/nph.16927
Dainese, R., & Tarantino, A. (2021). Measurement of plant xylem water pressure using the high-capacity tensiometer and implications for the modelling of soil–atmosphere interaction. Géotechnique, 71(5), 441–454. https://doi.org/10.1680/jgeot.19.P.153
Dainese, R., Lima Lopes, B. de C. F., Tedeschi, G., Lamarque, L. J., Delzon, S., Fourcaud, T., & Tarantino, A. (2021). Cross-validation on saplings of High-Capacity Tensiometer and Thermocouple Psychrometer for continuous monitoring of xylem water potential. Journal of Experimental Botany, erab412. https://doi.org/10.1093/jxb/erab412
Dainese, R., Lopes, B. de C. F. L., Fourcaud, T., & Tarantino, A. (2021). Evaluation of instruments for monitoring the soil–plant continuum. Geomechanics for Energy and the Environment, 100256. https://doi.org/10.1016/j.gete.2021.100256
Epron, D., Kamakura, M., Azuma, W., Dannoura, M., & Kosugi, Y. (2021). Diurnal variations in the thickness of the inner bark of tree trunks in relation to xylem water potential and phloem turgor. Plant-Environment Interactions, 2(3), 112–124. https://doi.org/10.1002/pei3.10045
Espinosa, C. M. O., Salazar, J. C. S., Churio, J. O. R., & Mora, D. S. (2021). Los sistemas agroforestales y la incidencia sobre el estatus hídrico en árboles de cacao. Biotecnología en el Sector Agropecuario y Agroindustrial, 19(1), 256–267. https://doi.org/10.18684/bsaa.v19.n1.2021.1623
Guan, X., Pereira, L., McAdam, S. A. M., Cao, K.-F., & Jansen, S. (2021). No gas source, no problem: Proximity to pre-existing embolism and segmentation affect embolism spreading in angiosperm xylem by gas diffusion. Plant, Cell & Environment, 44(5), 1329–1345. https://doi.org/10.1111/pce.14016
Hallmark, A. J., Maurer, G. E., Pangle, R. E., & Litvak, M. E. (2021). Watching plants’ dance: movements of live and dead branches linked to atmospheric water demand. Ecosphere, 12(8), e03705. https://doi.org/10.1002/ecs2.3705
Harrison Day, B. L., Carins-Murphy, M. R., & Brodribb, T. J. (2021). Reproductive water supply is prioritized during drought in tomato. Plant, Cell & Environment, n/a(n/a). https://doi.org/10.1111/pce.14206
Holtzman, N. M., Anderegg, L. D. L., Kraatz, S., Mavrovic, A., Sonnentag, O., Pappas, C., Cosh, M. H., Langlois, A., Lakhankar, T., Tesser, D., Steiner, N., Colliander, A., Roy, A., & Konings, A. G. (2021). L-band vegetation optical depth as an indicator of plant water potential in a temperate deciduous forest stand. Biogeosciences, 18(2), 739–753. https://doi.org/10.5194/bg-18-739-2021
Jiang, G.-F., Brodribb, T. J., Roddy, A. B., Lei, J.-Y., Si, H.-T., Pahadi, P., Zhang, Y.-J., & Cao, K.-F. (2021). Contrasting Water Use, Stomatal Regulation, Embolism Resistance, and Drought Responses of Two Co-Occurring Mangroves. Water, 13(14), 1945. https://doi.org/10.3390/w13141945
Mantova, M., Menezes-Silva, P. E., Badel, E., Cochard, H., & Torres-Ruiz, J. M. (2021). The interplay of hydraulic failure and cell vitality explains tree capacity to recover from drought. Physiologia Plantarum, 172(1), 247–257. https://doi.org/10.1111/ppl.13331
Nehemy, M. F., Benettin, P., Asadollahi, M., Pratt, D., Rinaldo, A., & McDonnell, J. J. (2021). Tree water deficit and dynamic source water partitioning. Hydrological Processes, 35(1), e14004. https://doi.org/10.1002/hyp.14004
Nolan, R. H., Gauthey, A., Losso, A., Medlyn, B. E., Smith, R., Chhajed, S. S., Fuller, K., Song, M., Li, X., Beaumont, L. J., Boer, M. M., Wright, I. J., & Choat, B. (2021). Hydraulic failure and tree size linked with canopy die-back in eucalypt forest during extreme drought. New Phytologist, 230(4), 1354–1365. https://doi.org/10.1111/nph.17298
Nuixe, M., Traoré, A. S., Blystone, S., Bonny, J.-M., Falcimagne, R., Pagès, G., & Picon-Cochard, C. (2021). Circadian Variation of Root Water Status in Three Herbaceous Species Assessed by Portable NMR. Plants, 10(4), 782. https://doi.org/10.3390/plants10040782
Prats, K. A., & Brodersen, C. R. (2021). Desiccation and rehydration dynamics in the epiphytic resurrection fern Pleopeltis polypodioides. Plant Physiology, 187(3), 1501–1518. https://doi.org/10.1093/plphys/kiab361
Pritzkow, C., Szota, C., Williamson, V., & Arndt, S. K. (2021). Previous drought exposure leads to greater drought resistance in eucalypts through changes in morphology rather than physiology. Tree Physiology, tpaa176. https://doi.org/10.1093/treephys/tpaa176
Siddiqi, S. A., Al-Mulla, Y. A., McCann, I., AbuRumman, G., Belhaj, M., Zekri, S., Al-Ismaili, A., & Rahman, S. (2021). Smart Monitoring, Sap-Flow, Stem-Psychrometer And Soil-Moisture Measurements Tools For Precision Irrigation And Water Saving Of Date Palm. International Journal of Agriculture and Biology, 26(5), 570–578.
Skelton, R. P., Anderegg, L. D. L., Diaz, J., Kling, M. M., Papper, P., Lamarque, L. J., Delzon, S., Dawson, T. E., & Ackerly, D. D. (2021). Evolutionary relationships between drought-related traits and climate shape large hydraulic safety margins in western North American oaks. Proceedings of the National Academy of Sciences, 118(10). https://doi.org/10.1073/pnas.2008987118
Soland, K. R., Kerhoulas, L. P., Kerhoulas, N. J., & Teraoka, J. R. (2021). Second-growth redwood forest responses to restoration treatments. Forest Ecology and Management, 496, 119370. https://doi.org/10.1016/j.foreco.2021.119370
Suárez, J. C., Casanoves, F., Bieng, M. A. N., Melgarejo, L. M., Di Rienzo, J. A., & Armas, C. (2021). Prediction model for sap flow in cacao trees under different radiation intensities in the western Colombian Amazon. Scientific Reports, 11(1), 10512. https://doi.org/10.1038/s41598-021-89876-z
Williams, C. B., Reese Næsborg, R., Ambrose, A. R., Baxter, W. L., Koch, G. W., & Dawson, T. E. (2021). The dynamics of stem water storage in the tops of Earth’s largest trees—Sequoiadendron giganteum. Tree Physiology, 41(12), 2262–2278. https://doi.org/10.1093/treephys/tpab078
Zhang, F.-P., Zhang, J.-L., Brodribb, T. J., & Hu, H. (2021). Cavitation resistance of peduncle, petiole and stem is correlated with bordered pit dimensions in Magnolia grandiflora. Plant Diversity, 43(4), 324–330. https://doi.org/10.1016/j.pld.2020.11.007


Bourbia, I., Carins-Murphy, M. R., Gracie, A., & Brodribb, T. J. (2020). Xylem cavitation isolates leaky flowers during water stress in pyrethrum. New Phytologist, 227(1), 146–155. https://doi.org/10.1111/nph.16516
Brodribb, T. J., Carriquí, M., Delzon, S., McAdam, S. a. M., & Holbrook, N. M. (2020). Advanced vascular function discovered in a widespread moss. Nature Plants, 6(3), 273–279. https://doi.org/10.1038/s41477-020-0602-x
Cardoso, A. A., Brodribb, T. J., Kane, C. N., DaMatta, F. M., & McAdam, S. A. M. (2020). Osmotic adjustment and hormonal regulation of stomatal responses to vapour pressure deficit in sunflower. AoB PLANTS, 12(4), plaa025. https://doi.org/10.1093/aobpla/plaa025
Corso, D., Delzon, S., Lamarque, L. J., Cochard, H., Torres-Ruiz, J. M., King, A., & Brodribb, T. (2020). Neither xylem collapse, cavitation, or changing leaf conductance drive stomatal closure in wheat. Plant, Cell & Environment, 43(4), 854–865. https://doi.org/10.1111/pce.13722
Creek, D., Lamarque, L. J., Torres-Ruiz, J. M., Parise, C., Burlett, R., Tissue, D. T., & Delzon, S. (2020). Xylem embolism in leaves does not occur with open stomata: evidence from direct observations using the optical visualization technique. Journal of Experimental Botany, 71(3), 1151–1159. https://doi.org/10.1093/jxb/erz474
Deng, L., Li, P., Chu, C., Ding, Y., & Wang, S. (2020). Symplasmic phloem unloading and post-phloem transport during bamboo internode elongation. Tree Physiology, 40(3), 391–412. https://doi.org/10.1093/treephys/tpz140
Gauthey, A., Peters, J. M. R., Carins-Murphy, M. R., Rodriguez-Dominguez, C. M., Li, X., Delzon, S., King, A., López, R., Medlyn, B. E., Tissue, D. T., Brodribb, T. J., & Choat, B. (2020). Visual and hydraulic techniques produce similar estimates of cavitation resistance in woody species. New Phytologist, 228(3), 884–897. https://doi.org/10.1111/nph.16746
Gullo, G., Dattola, A., Vonella, V., & Zappia, R. (2020). Effects of two reflective materials on gas exchange, yield, and fruit quality of sweet orange tree Citrus sinensis (L.) Osb. European Journal of Agronomy, 118, 126071. https://doi.org/10.1016/j.eja.2020.126071
Guo, J. S., Gear, L., Hultine, K. R., Koch, G. W., & Ogle, K. (2020). Non-structural carbohydrate dynamics associated with antecedent stem water potential and air temperature in a dominant desert shrub. Plant, Cell & Environment, 43(6), 1467–1483. https://doi.org/10.1111/pce.13749
Guo, J. S., Hultine, K. R., Koch, G. W., Kropp, H., & Ogle, K. (2020). Temporal shifts in iso/anisohydry revealed from daily observations of plant water potential in a dominant desert shrub. New Phytologist, 225(2), 713–726. https://doi.org/10.1111/nph.16196
Johnson, K. M., Brodersen, C., Carins-Murphy, M. R., Choat, B., & Brodribb, T. J. (2020). Xylem Embolism Spreads by Single-Conduit Events in Three Dry Forest Angiosperm Stems. Plant Physiology, 184(1), 212–222. https://doi.org/10.1104/pp.20.00464
Levionnois, S., Ziegler, C., Jansen, S., Calvet, E., Coste, S., Stahl, C., Salmon, C., Delzon, S., Guichard, C., & Heuret, P. (2020). Vulnerability and hydraulic segmentations at the stem–leaf transition: coordination across Neotropical trees. New Phytologist, 228(2), 512–524. https://doi.org/10.1111/nph.16723
Li, R., Lu, Y., Peters, J. M. R., Choat, B., & Lee, A. J. (2020). Non-invasive measurement of leaf water content and pressure–volume curves using terahertz radiation. Scientific Reports, 10(1), 21028. https://doi.org/10.1038/s41598-020-78154-z
Li, X., He, X., Smith, R., Choat, B., & Tissue, D. (2020). Temperature alters the response of hydraulic architecture to CO2 in cotton plants (Gossypium hirsutum). Environmental and Experimental Botany, 172, 104004. https://doi.org/10.1016/j.envexpbot.2020.104004
Li, X., Smith, R., Choat, B., & Tissue, D. T. (2020). Drought resistance of cotton (Gossypium hirsutum) is promoted by early stomatal closure and leaf shedding. Functional Plant Biology, 47(2), 91–98. https://doi.org/10.1071/FP19093
Liu, N., Deng, Z., Wang, H., Luo, Z., Gutiérrez-Jurado, H. A., He, X., & Guan, H. (2020). Thermal remote sensing of plant water stress in natural ecosystems. Forest Ecology and Management, 476, 118433. https://doi.org/10.1016/j.foreco.2020.118433
Luo, Z., Deng, Z., Singha, K., Zhang, X., Liu, N., Zhou, Y., He, X., & Guan, H. (2020). Temporal and spatial variation in water content within living tree stems determined by electrical resistivity tomography. Agricultural and Forest Meteorology, 291, 108058. https://doi.org/10.1016/j.agrformet.2020.108058
Ocheltree, T., Gleason, S., Cao, K.-F., & Jiang, G.-F. (2020). Loss and recovery of leaf hydraulic conductance: Root pressure, embolism, and extra-xylary resistance. Journal of Plant Hydraulics, 7, e-001. https://doi.org/10.20870/jph.2020.e-001
Pereira, L., Bittencourt, P. R. L., Pacheco, V. S., Miranda, M. T., Zhang, Y., Oliveira, R. S., Groenendijk, P., Machado, E. C., Tyree, M. T., Jansen, S., Rowland, L., & Ribeiro, R. V. (2020). The Pneumatron: An automated pneumatic apparatus for estimating xylem vulnerability to embolism at high temporal resolution. Plant, Cell & Environment, 43(1), 131–142. https://doi.org/10.1111/pce.13647
Powers, J. S., Vargas G., G., Brodribb, T. J., Schwartz, N. B., Pérez-Aviles, D., Smith-Martin, C. M., Becknell, J. M., Aureli, F., Blanco, R., Calderón-Morales, E., Calvo-Alvarado, J. C., Calvo-Obando, A. J., Chavarría, M. M., Carvajal-Vanegas, D., Jiménez-Rodríguez, C. D., Murillo Chacon, E., Schaffner, C. M., Werden, L. K., Xu, X., & Medvigy, D. (2020). A catastrophic tropical drought kills hydraulically vulnerable tree species. Global Change Biology, 26(5), 3122–3133. https://doi.org/10.1111/gcb.15037
Rodriguez-Dominguez, C. M., & Brodribb, T. J. (2020). Declining root water transport drives stomatal closure in olive under moderate water stress. New Phytologist, 225(1), 126–134. https://doi.org/10.1111/nph.16177
Wang, S., Zhan, H., Li, P., Chu, C., Li, J., & Wang, C. (2020). Physiological Mechanism of Internode Bending Growth After the Excision of Shoot Sheath in Fargesia yunnanensis and Its Implications for Understanding the Rapid Growth of Bamboos. Frontiers in Plant Science, 11. https://doi.org/10.3389/fpls.2020.00418


Amrutha, S., Muneera Parveen, A. B., Muthupandi, M., Sivakumar, V., Nautiyal, R., & Dasgupta, M. G. (2019). Variation in morpho-physiological, biochemical and molecular responses of two Eucalyptus species under short-term water stress. Acta Botanica Croatica, 78(2), 125–134. https://doi.org/10.2478/botcro-2019-0021
Caplan, D., Dixon, M., & Zheng, Y. (2019). Increasing Inflorescence Dry Weight and Cannabinoid Content in Medical Cannabis Using Controlled Drought Stress. HortScience, 54(5), 964–969. https://doi.org/https://doi.org/10.21273/HORTSCI13510-18
Iwasaki, N., Hori, K., & Ikuta, Y. (2019). Xylem plays an important role in regulating the leaf water potential and fruit quality of Meiwa kumquat (Fortunella crassifolia Swingle) trees under drought conditions. Agricultural Water Management, 214, 47–54. https://doi.org/10.1016/j.agwat.2018.12.026
Liu, N., Buckley, T. N., He, X., Zhang, X., Zhang, C., Luo, Z., Wang, H., Sterling, N., & Guan, H. (2019). Improvement of a simplified process-based model for estimating transpiration under water-limited conditions. Hydrological Processes, 33(12), 1670–1685. https://doi.org/10.1002/hyp.13430
Lucani, C. J., Brodribb, T. J., Jordan, G. J., & Mitchell, P. J. (2019). Juvenile and adult leaves of heteroblastic Eucalyptus globulus vary in xylem vulnerability. Trees, 33(4), 1167–1178. https://doi.org/10.1007/s00468-019-01851-4
Nehemy, M. F., Benettin, P., Asadollahi, M., Pratt, D., Rinaldo, A., & McDonnell, J. J. (2019). How plant water status drives tree source water partitioning. Hydrology and Earth System Sciences Discussions, 1–26. https://doi.org/10.5194/hess-2019-528


Cuellar-Murcia, C. A., & Suárez-Salazar, J. C. (2018). Sap flow and water potential in tomato plants (Solanum lycopersicum L.) under greenhouse conditions/Flujo de savia y potencial hídrico en plantas de tomate (Solanum lycopersicum L.) bajo condiciones de invernadero. Revista Colombiana de Ciencias Hortícolas, 12, 104–112. https://doi.org/10.17584/rcch.2018v12i1.7316
Johnson, K. M., Jordan, G. J., & Brodribb, T. J. (2018). Wheat leaves embolized by water stress do not recover function upon rewatering. Plant, Cell & Environment, 41(11), 2704–2714. https://doi.org/10.1111/pce.13397
Lamarque, L. J., Corso, D., Torres-Ruiz, J. M., Badel, E., Brodribb, T. J., Burlett, R., Charrier, G., Choat, B., Cochard, H., Gambetta, G. A., Jansen, S., King, A., Lenoir, N., Martin-StPaul, N., Steppe, K., Van den Bulcke, J., Zhang, Y., & Delzon, S. (2018). An inconvenient truth about xylem resistance to embolism in the model species for refilling Laurus nobilis L. Annals of Forest Science, 75(3), 1–15. https://doi.org/10.1007/s13595-018-0768-9
Milliron, L. K., Olivos, A., Saa, S., Sanden, B. L., & Shackel, K. A. (2018). Dormant stem water potential responds to laboratory manipulation of hydration as well as contrasting rainfall field conditions in deciduous tree crops. Biosystems Engineering, 165, 2–9. https://doi.org/10.1016/j.biosystemseng.2017.09.001
Pfautsch, S., Aspinwall, M. J., Drake, J. E., Chacon-Doria, L., Langelaan, R. J. A., Tissue, D. T., Tjoelker, M. G., & Lens, F. (2018). Traits and trade-offs in whole-tree hydraulic architecture along the vertical axis of Eucalyptus grandis. Annals of Botany, 121(1), 129–141. https://doi.org/10.1093/aob/mcx137
Rodriguez-Dominguez, C. M., Murphy, M. R. C., Lucani, C., & Brodribb, T. J. (2018). Mapping xylem failure in disparate organs of whole plants reveals extreme resistance in olive roots. New Phytologist, 218(3), 1025–1035. https://doi.org/10.1111/nph.15079
Skelton, R. P., Dawson, T. E., Thompson, S. E., Shen, Y., Weitz, A. P., & Ackerly, D. (2018). Low Vulnerability to Xylem Embolism in Leaves and Stems of North American Oaks. Plant Physiology, 177(3), 1066–1077. https://doi.org/10.1104/pp.18.00103
Steppe, K., Vandegehuchte, M. W., Van de Wal, B. A. E., Hoste, P., Guyot, A., Lovelock, C. E., & Lockington, D. A. (2018). Direct uptake of canopy rainwater causes turgor-driven growth spurts in the mangrove Avicennia marina. Tree Physiology, 38(7), 979–991. https://doi.org/10.1093/treephys/tpy024
Stoochnoff, J. A., Graham, T., & Dixon, M. A. (2018). Drip irrigation scheduling for container grown trees based on plant water status. Irrigation Science, 36(3), 179–186. https://doi.org/10.1007/s00271-018-0575-y


Brodribb, T. J., Carriqui, M., Delzon, S., & Lucani, C. (2017). Optical Measurement of Stem Xylem Vulnerability. Plant Physiology, 174(4), 2054–2061. https://doi.org/10.1104/pp.17.00552
Charrier, G., Burlett, R., Gambetta, G. A., Delzon, S., Domec, J. C., & Beaujard, F. (2017). Monitoring Xylem Hydraulic Pressure in Woody Plants. Bio-Protocol, 7(20), e2580. https://doi.org/10.21769/BioProtoc.2580
Deng, Z., Guan, H., Hutson, J., Forster, M. A., Wang, Y., & Simmons, C. T. (2017). A vegetation-focused soil-plant-atmospheric continuum model to study hydrodynamic soil-plant water relations. Water Resources Research, 53(6), 4965–4983. https://doi.org/10.1002/2017WR020467
Hodgson-Kratky, K. J. M., Stoffyn, O. M., & Wolyn, D. J. (2017). Recurrent Selection for Improved Germination under Water Stress in Russian Dandelion. Journal of the American Society for Horticultural Science, 142(2), 85–91. https://doi.org/10.21273/JASHS03941-16
Jerszurki, D., Couvreur, V., Maxwell, T., Silva, L. de C. R., Matsumoto, N., Shackel, K., de Souza, J. L. M., & Hopmans, J. (2017). Impact of root growth and hydraulic conductance on canopy carbon-water relations of young walnut trees (Juglans regia L.) under drought. Scientia Horticulturae, 226, 342–352. https://doi.org/10.1016/j.scienta.2017.08.051
Reddy, K. S., Sekhar, K. M., & Reddy, A. R. (2017). Genotypic variation in tolerance to drought stress is highly coordinated with hydraulic conductivity–photosynthesis interplay and aquaporin expression in field-grown mulberry (Morus spp.). Tree Physiology, 37(7), 926–937. https://doi.org/10.1093/treephys/tpx051
Zhang, F.-P., & Brodribb, T. J. (2017). Are flowers vulnerable to xylem cavitation during drought? Proceedings of the Royal Society B: Biological Sciences, 284(1854), 20162642. https://doi.org/10.1098/rspb.2016.2642


Charrier, G., Torres-Ruiz, J. M., Badel, E., Burlett, R., Choat, B., Cochard, H., Delmas, C. E. L., Domec, J.-C., Jansen, S., King, A., Lenoir, N., Martin-StPaul, N., Gambetta, G. A., & Delzon, S. (2016). Evidence for Hydraulic Vulnerability Segmentation and Lack of Xylem Refilling under Tension. Plant Physiology, 172(3), 1657–1668. https://doi.org/10.1104/pp.16.01079
Gonzalez-Fuentes, J. A., Shackel, K., Heinrich Lieth, J., Albornoz, F., Benavides-Mendoza, A., & Evans, R. Y. (2016). Diurnal root zone temperature variations affect strawberry water relations, growth, and fruit quality. Scientia Horticulturae, 203, 169–177. https://doi.org/https://doi.org/10.1016/j.scienta.2016.03.039
Liu, N., Guan, H., Luo, Z., Zhang, C., Wang, H., & Zhang, X. (2016). Examination of a coupled supply- and demand-induced stress function for root water uptake modeling. Hydrology Research, 48(1), 66–76. https://doi.org/10.2166/nh.2016.173
Wang, H., Guan, H., & Simmons, C. T. (2016). Modeling the environmental controls on tree water use at different temporal scales. Agricultural and Forest Meteorology, 225, 24–35. https://doi.org/10.1016/j.agrformet.2016.04.016


Cermák, J., Nadezhdina, N., Trcala, M., & Simon, J. (2015). Open field-applicable instrumental methods for structural and functional assessment of whole trees and stands. IForest - Biogeosciences and Forestry, 8(3), 226. https://doi.org/10.3832/ifor1116-008
Forster, M. (2015). Measuring water stress for irrigation efficiency. Irrigation Australia: The Official Journal of Irrigation Australia. https://search.informit.org/doi/abs/10.3316/INFORMIT.201053890291709


Vandegehuchte, M. W., Guyot, A., Hubau, M., De Groote, S. R. E., De Baerdemaeker, N. J. F., Hayes, M., Welti, N., Lovelock, C. E., Lockington, D. A., & Steppe, K. (2014). Long-term versus daily stem diameter variation in co-occurring mangrove species: Environmental versus ecophysiological drivers. Agricultural and Forest Meteorology, 192–193, 51–58. https://doi.org/10.1016/j.agrformet.2014.03.002
Vandegehuchte, M. W., Guyot, A., Hubeau, M., De Swaef, T., Lockington, D. A., & Steppe, K. (2014). Modelling reveals endogenous osmotic adaptation of storage tissue water potential as an important driver determining different stem diameter variation patterns in the mangrove species Avicennia marina and Rhizophora stylosa. Annals of Botany, 114(4), 667–676. https://doi.org/10.1093/aob/mct311
Wang, H., Guan, H., Deng, Z., & Simmons, C. T. (2014). Optimization of canopy conductance models from concurrent measurements of sap flow and stem water potential on Drooping Sheoak in South Australia. Water Resources Research, 50(7), 6154–6167. https://doi.org/10.1002/2013WR014818

2013 and earlier

Patankar, R., Quinton, W. L., & Baltzer, J. L. (2013). Permafrost-driven differences in habitat quality determine plant response to gall-inducing mite herbivory. Journal of Ecology, 101(4), 1042–1052. https://doi.org/10.1111/1365-2745.12101
Yang, Y., Guan, H., Hutson, J. L., Wang, H., Ewenz, C., Shang, S., & Simmons, C. T. (2013). Examination and parameterization of the root water uptake model from stem water potential and sap flow measurements. Hydrological Processes, 27(20), 2857–2863. https://doi.org/10.1002/hyp.9406
Dixon, M. A., & Tyree, M. T. (1984). A new stem hygrometer, corrected for temperature gradients and calibrated against the pressure bomb. Plant, Cell & Environment, 7(9), 693–697. https://doi.org/10.1111/1365-3040.ep11572454


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