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Plant function and evolutionary biology
RESEARCH ARTICLE

Using the water potential curve to identify the transition from water-consumptive to water-conservative behaviour in Cucumis melo

Heinrich di Santo A , Thorsten Knipfer https://orcid.org/0000-0002-1375-5651 B and Felipe H. Barrios-Masias https://orcid.org/0000-0001-8906-9554 A *
+ Author Affiliations
- Author Affiliations

A Department of Agriculture, Veterinary and Rangeland Sciences, University of Nevada, Reno, Reno, NV 89557, USA.

B Department of Land and Food Systems, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.

* Correspondence to: fbarriosmasias@unr.edu

Handling Editor: Wieland Fricke

Functional Plant Biology 52, FP25048 https://doi.org/10.1071/FP25048
Submitted: 6 February 2025  Accepted: 25 July 2025  Published: 21 August 2025

© 2025 The Author(s) (or their employer(s)). Published by CSIRO Publishing

Abstract

As plants experience drought, transpiration is regulated by decreases in stomatal conductance (gs) that can reduce carbon assimilation, biomass production and yield. The plant water potential (Ψ) provides an estimate of the plant water status, and the relationship between predawn (Ψpd) and midday (Ψmd) water potential (i.e. the water potential curve) could help determine when plants transition from water-consumptive (higher gs) to water-conservative (lower gs) behaviour. In this study, we apply the water potential curve framework (WP curve; i.e. Ψpd ~ Ψmd relationship) to an annual crop (Cucumis melo). The WP curve was evaluated over several dry-down experiments in both greenhouse (GH) and field conditions. Leaf gas exchange and Ψ measurements were taken on the same days. Overall, the WP curve differed between environments and the shift from higher to lower gs occurred earlier (higher Ψpd) under GH conditions, likely driven by a smaller root system, reduced access to soil water availability and a more rapid onset of drought. The WP curve exhibited two phases divided by a breakpoint (Θ) at −0.5 MPa (GH) and −0.72 MPa (field) of Ψpd that coincided with a gs reduction of 55% and 85% respectively. During phase I, plants reduced gs as the drought intensified without significantly compromising carbon assimilation (Pn). Yet, at Θ, Pn decreased by 57% and 61% under GH and field conditions respectively. During phase II, leaves reached the turgor loss point (TLP) at a Ψmd of −0.83 MPa (GH) and −1.3 MPa (field) that were similar to the TLP estimated from bench-top leaf pressure curves. Our results suggest that the WP curve in melons identifies the transition from water-consumptive to water-conservative behaviour and sets a boundary at which plants substantially reduce leaf gas exchange. Hence, the WP curve could be used to select crop varieties able to endure longer periods of drought with minimal impact on carbon assimilation, and better manage irrigation based on estimates of Ψpd to support effective use of water without a yield decrease.

Keywords: drought, leaf gas exchange, melon, osmotic potential, photosynthetic rate, plant water potential, stomatal conductance, turgor, WP curve.

References

Acevedo E, Fereres E, Hsiao TC, Henderson DW (1979) Diurnal growth trends, water potential, and osmotic adjustment of maize and sorghum leaves in the field. Plant Physiology 64, 476-480.
| Crossref | Google Scholar |

Al-Mefleh NK, Abu Salah KK, Abandeh MM (2012) Influence of water quality and harvest times on biomass yield and essential oil of lemon verbena (Aloysia triphylla) under a drip irrigation system. Journal of Herbs, Spices & Medicinal Plants 18(2), 166-177.
| Crossref | Google Scholar |

Allen RG, Pereira LS (2006) ‘Crop evapotranspiration (guidelines for computing crop water requirements).’ FAO Irrigation and Drainage Paper 56, pp. 1–203.

Arndt SK, Irawan A, Sanders GJ (2015) Apoplastic water fraction and rehydration techniques introduce significant errors in measurements of relative water content and osmotic potential in plant leaves. Physiologia Plantarum 155(4), 355-368.
| Crossref | Google Scholar |

Barrios-Masias FH, Knipfer T, McElrone AJ (2015) Differential responses of grapevine rootstocks to water stress are associated with adjustments in fine root hydraulic physiology and suberization. Journal of Experimental Botany 66, 6069-6078.
| Crossref | Google Scholar |

Barrios-Masias FH, Lazcano C, Hernandez-Espinoza LH (2019a) Advances in understanding vegetable physiology: root systems as the next frontier in improving sustainable vegetable production. In ‘Achieving sustainable cultivation of vegetables. Vol. 3’. (Ed. G Hochmuth) pp. 3–34. (Burleigh Dodds Science Publishing)

Barrios-Masias FH, Knipfer T, Walker MA, McElrone AJ (2019b) Differences in hydraulic traits of grapevine rootstocks are not conferred to a common Vitis vinifera scion. Functional Plant Biology 46(3), 228-235.
| Crossref | Google Scholar |

Blum A (2011) ‘Plant breeding for water-limited environments.’ (Springer Science and Business Media)

Bonarota M-S, Toups HS, Bristow ST, Santos P, Jackson LE, Cramer GR, Barrios-Masias FH (2024) Drought response and recovery mechanisms of grapevine rootstocks grafted to a common Vitis vinifera scion. Plant Stress 11, 100346.
| Crossref | Google Scholar |

Bristow ST, Hernandez-Espinoza LH, Bonarota M-S, Barrios-Masias FH (2021) Tomato rootstocks mediate plant-water relations and leaf nutrient profiles of a common scion under suboptimal soil temperatures. Frontiers in Plant Science 11, 618488.
| Crossref | Google Scholar |

Brodribb TJ, Holbrook NM (2003) Stomatal closure during leaf dehydration, correlation with other leaf physiological traits. Plant Physiology 132(4), 2166-2173.
| Crossref | Google Scholar |

Cai G, Carminati A, Abdalla M, Ahmed MA (2021) Soil textures rather than root hairs dominate water uptake and soil-plant hydraulics under drought. Plant Physiology 187(2), 858-872.
| Crossref | Google Scholar |

Cleveland WS, Grosse EH, Shyu MJ (1992) Local regression models. In ‘Statistical models in S’. (Eds JM Chambers, T Hastie) pp. 309–376. (Chapman and Hall)

Condon AG (2020) Drying times: plant traits to improve crop water use efficiency and yield. Journal of Experimental Botany 71(7), 2239-2252.
| Crossref | Google Scholar |

de Dios VR, Roy J, Ferrio JP, Alday JG, Landais D, Milcu A, Gessler A (2015) Processes driving nocturnal transpiration and implications for estimating land evapotranspiration. Scientific Reports 5, 10975.
| Crossref | Google Scholar |

Devi MJ, Reddy VR (2018) Transpiration response of cotton to vapor pressure deficit and its relationship with stomatal traits. Frontiers in Plant Science 9, 1572.
| Crossref | Google Scholar |

di Santo H, Barrios-Masias FH (2024) Melon grafting effects on plant performance and yield in the high desert. HortScience 59(8), 1143-1149.
| Crossref | Google Scholar |

Ding Y, Zhang Y, Zheng Q-S, Tyree MT (2014) Pressure-volume curves: revisiting the impact of negative turgor during cell collapse by literature review and simulations of cell micromechanics. New Phytologist 203(2), 378-387.
| Crossref | Google Scholar |

Domec J-C, Johnson DM (2012) Does homeostasis or disturbance of homeostasis in minimum leaf water potential explain the isohydric versus anisohydric behavior of Vitis vinifera L. cultivars? Tree Physiology 32(3), 245-248.
| Crossref | Google Scholar |

Domec J-C, King JS, Noormets A, Treasure E, Gavazzi MJ, Sun G, McNulty SG (2010) Hydraulic redistribution of soil water by roots affects whole-stand evapotranspiration and net ecosystem carbon exchange. New Phytologist 187(1), 171-183.
| Crossref | Google Scholar |

Du Q, Jiao X, Song X, Zhang J, Bai P, Ding J, Li J (2020) The response of water dynamics to long-term high vapor pressure deficit is mediated by anatomical adaptations in plants. Frontiers in Plant Science 11, 758.
| Crossref | Google Scholar |

Ezzo MI, Mohamed AS, Glala AA, Saleh SA (2020) Utilization of grafting technique for sustaining cantaloupe productivity and quality under deficit irrigation water. Bulletin of the National Research Centre 44(1), 23.
| Crossref | Google Scholar |

Fila G, Zeinalipour N, Badeck F-W, Delshad M, Ghashghaie J (2019) Application of water-saving treatments reveals different adaptation strategies in three Iranian melon genotypes. Scientia Horticulturae 256, 108518.
| Crossref | Google Scholar |

Girona J, Mata M, del Campo J, Arbonés A, Bartra E, Marsal J (2006) The use of midday leaf water potential for scheduling deficit irrigation in vineyards. Irrigation Science 24(2), 115-127.
| Crossref | Google Scholar |

Guan W, Zhao X (2014) Techniques for Melon Grafting: HS1257/HS1257, 12/2014. EDIS 2014,.
| Google Scholar |

Han S, Kim W, Lee HJ, Joyce R, Lee J (2022) Continuous and real-time measurement of plant water potential using an AAO-based capacitive humidity sensor for irrigation control. ACS Applied Electronic Materials 4(12), 5922-5932.
| Crossref | Google Scholar |

Hernandez-Espinoza LH, Barrios-Masias FH (2020) Physiological and anatomical changes in tomato roots in response to low water stress. Scientia Horticulturae 265, 109208.
| Crossref | Google Scholar |

Jones MM, Turner NC (1978) Osmotic adjustment in leaves of sorghum in response to water deficits. Plant Physiology 61(1), 122-126.
| Crossref | Google Scholar |

Knipfer T, Bambach N, Hernandez MI, Bartlett MK, Sinclair G, Duong F, Kluepfel DA, McElrone AJ (2020) Predicting stomatal closure and turgor loss in woody plants using predawn and midday water potential. Plant Physiology 184(2), 881-894.
| Crossref | Google Scholar |

Koehler T, Wankmüller FJP, Sadok W, Carminati A (2023) Transpiration response to soil drying versus increasing vapor pressure deficit in crops: physical and physiological mechanisms and key plant traits. Journal of Experimental Botany 74(16), 4789-4807.
| Crossref | Google Scholar |

Kukal SS, Hira GS, Sidhu AS (2005) Soil matric potential-based irrigation scheduling to rice (Oryza sativa). Irrigation Science 23(4), 153-159.
| Crossref | Google Scholar |

Kusvuran S (2012) Effects of drought and salt stresses on growth, stomatal conductance, leaf water and osmotic potentials of melon genotypes (Cucumis melo L.). African Journal of Agricultural Research 7(5), 775-781.
| Crossref | Google Scholar |

Lamaoui M, Chakhchar A, El Kharrassi Y, Wahbi S, El Modafar C (2018) Morphological, physiological, and biochemical responses to water stress in melon (Cucumis melo) subjected to regulated deficit irrigation (RDI) and partial rootzone drying (PRD). Journal of Crop Science and Biotechnology 21(4), 407-416.
| Crossref | Google Scholar |

Lambers H, Chapin F, Pons TL (2008) ‘Plant physiological ecology.’ 2nd edn. (Springer)

Li X, Smith R, Choat B, Tissue DT (2020) Drought resistance of cotton (Gossypium hirsutum) is promoted by early stomatal closure and leaf shedding. Functional Plant Biology 47(2), 91-98.
| Crossref | Google Scholar |

Luiz Ferraresso Conti Junior J, José de Araujo M, Cesar de Paula R, Barroso Queiroz T, Eiji Hakamada R, Hubbard RM (2020) Quantifying turgor loss point and leaf water potential across contrasting Eucalyptus clones and sites within the TECHS research platform. Forest Ecology and Management 475, 118454.
| Crossref | Google Scholar |

Ma Y, Yuan Z, Mithöfer A, Geilfus C-M, Dodd IC (2024) Decreased irrigation volume, not irrigation placement, promotes accumulation of multiple hormones in cotton leaves during partial rootzone drying. Environmental and Experimental Botany 223, 105781.
| Crossref | Google Scholar |

Martínez-Vilalta J, Poyatos R, Aguadé D, Retana J, Mencuccini M (2014) A new look at water transport regulation in plants. New Phytologist 204(1), 105-115.
| Crossref | Google Scholar |

Mashilo J, Odindo AO, Shimelis HA, Musenge P, Tesfay SZ, Magwaza LS (2018) Photosynthetic response of bottle gourd [Lagenaria siceraria (Molina) Standl.] to drought stress: relationship between cucurbitacins accumulation and drought tolerance. Scientia Horticulturae 231, 133-143.
| Crossref | Google Scholar |

McElrone AJ, Shapland TM, Calderon A, Fitzmaurice L, Paw UKT, Snyder RL (2013) Surface renewal: an advanced micrometeorological method for measuring and processing field-scale energy flux density data. Journal of Visualized Experiments 82, 50666.
| Crossref | Google Scholar |

Medrano E, Lorenzo P, Sánchez-Guerrero MC, Montero JI (2005) Evaluation and modelling of greenhouse cucumber-crop transpiration under high and low radiation conditions. Scientia Horticulturae 105(2), 163-175.
| Crossref | Google Scholar |

Meinzer FC, Woodruff DR, Marias DE, Smith DD, McCulloh KA, Howard AR, Magedman AL (2016) Mapping ‘hydroscapes’ along the iso- to anisohydric continuum of stomatal regulation of plant water status. Ecology Letters 19(11), 1343-1352.
| Crossref | Google Scholar |

Menne D, Hübner C, Trebbels D, Willenbacher N (2022) Robust soil water potential sensor to optimize irrigation in agriculture. Sensors 22(12), 4465.
| Crossref | Google Scholar |

Mohamed FH, Mennat-Allah NH, Abd El-Hamed KE, Elwan MW, Abdel-Salam MM (2021) Response of watermelon plants grafted onto different rootstocks to deficit irrigation. Hortscience Journal of Suez Canal University 10(1), 63-71.
| Crossref | Google Scholar |

Muggeo VMR (2003) Estimating regression models with unknown breakpoints. Statistics in Medicine 22(19), 3055-3071.
| Crossref | Google Scholar |

Muggeo VMR, Atkins DC, Gallop RJ, Dimidjian S (2014) Segmented mixed models with random changepoints: a maximum likelihood approach with application to treatment for depression study. Statistical Modelling 14(4), 293-313.
| Crossref | Google Scholar |

R Core Team (2021) ‘R: a language and environment for statistical computing.’ (R Foundation for Statistical Computing: Vienna, Austria)

Sack L, Pasquet-Kok J (2010) Leaf pressure-volume curve parameters. Available at https://prometheusprotocols.net/ [accessed 2 August 2024]

Sanchez M, Sinclair TR, Pradhan D (2021) Transpiration response to vapor pressure deficit and soil drying among quinoa genotypes (Chenopodium quinoa Willd.). Journal of Crop Improvement 35(2), 291-302.
| Crossref | Google Scholar |

Sarabi B, Fresneau C, Ghaderi N, Bolandnazar S, Streb P, Badeck F-W, Citerne S, Tangama M, David A, Ghashghaie J (2019) Stomatal and non-stomatal limitations are responsible in down-regulation of photosynthesis in melon plants grown under the saline condition: application of carbon isotope discrimination as a reliable proxy. Plant Physiology and Biochemistry 141, 1-19.
| Crossref | Google Scholar |

Savvides A, Fanourakis D, Van Ieperen W (2012) Co-ordination of hydraulic and stomatal conductances across light qualities in cucumber leaves. Journal of Experimental Botany 63(3), 1135-1143.
| Crossref | Google Scholar |

Scholander PF, Bradstreet ED, Hemmingsen EA, Hammel HT (1965) Sap pressure in vascular plants: negative hydrostatic pressure can be measured in plants. Science 148(3668), 339-346.
| Crossref | Google Scholar |

Schultz HR (2003) Differences in hydraulic architecture account for near-isohydric and anisohydric behaviour of two field-grown Vitis vinifera L. cultivars during drought. Plant, Cell & Environment 26(8), 1393-1405.
| Crossref | Google Scholar |

Sepaskhah AR, Ahmadi SH (2010) A review on partial root-zone drying irrigation. International Journal of Plant Production 4(4), 241-258.
| Google Scholar |

Sharma SP, Leskovar DI, Crosby KM (2019) Genotypic differences in leaf gas exchange and growth responses to deficit irrigation in reticulatus and inodorus melons (Cucumis melo L.). Photosynthetica 57(1), 237-247.
| Crossref | Google Scholar |

Sharma G, Brar GS, Knipfer T (2023) Leaf water relations and osmotic adjustment of Canada Western Red Spring wheat cultivars subjected to drought. Functional Plant Biology 50(12), 1037-1046.
| Crossref | Google Scholar |

Turner NC, Long MJ (1980) Errors arising from rapid water loss in the measurement of leaf water potential by the pressure chamber technique. Functional Plant Biology 7(5), 527-537.
| Crossref | Google Scholar |

USDA-NIFA (2015) Description of commercial cucurbit rootstocks. Available at http://www.vegetablegrafting.org/wp/wp-content/uploads/2015/02/usda-scri-cucurbit-rootstock-table-feb-15.pdf [accessed 6 June 2024]

Vieira DA, Mesquita AC, Marinho LB, Souza Vd, Aidar SdT, Carvalho MMP (2019) Gas exchanges of melon under water stress in the submedium region of the São Francisco river valley. Acta Scientiarum Agronomy 41(1), e42686.
| Crossref | Google Scholar |

Weaver JE, Bruner WE (1927) ‘Root development of vegetable crops.’ 1st edn. (McGraw-Hill Book Co: London, UK)

Wijewardana C, Alsajri FA, Irby JT, Krutz LJ, Golden B, Henry WB, Gao W, Reddy KR (2019) Physiological assessment of water deficit in soybean using midday leaf water potential and spectral features. Journal of Plant Interactions 14(1), 533-543.
| Crossref | Google Scholar |

Xu J, Wei Q, Peng S, Yu Y (2012) Error of saturation vapor pressure calculated by different formulas and its effect on calculation of reference evapotranspiration in high latitude cold region. Procedia Engineering 28, 43-48.
| Crossref | Google Scholar |

Yang D, Li J, Ding Y, Tyree MT (2017) Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C. Cheng. 2. Höfler diagrams below the volume of zero turgor and the theoretical implication for pressure-volume curves of living cells. Plant, Cell & Environment 40, 340-350.
| Crossref | Google Scholar |

Yang X, Lu M, Wang Y, Wang Y, Liu Z, Chen S (2021) Response mechanism of plants to drought stress. Horticulturae 7(3), 50.
| Crossref | Google Scholar |

Zegada-Lizarazu W, Monti A (2019) Deep root growth, ABA adjustments and root water uptake response to soil water deficit in giant reed. Annals of Botany 124(4), 605-615.
| Crossref | Google Scholar |

Zhang D, Du Q, Zhang Z, Jiao X, Song X, Li J (2017) Vapour pressure deficit control in relation to water transport and water productivity in greenhouse tomato production during summer. Scientific Reports 7, 43461.
| Crossref | Google Scholar |

Zhang Q, Yang Y, Peng S, Li Y (2021) Nighttime transpirational cooling enabled by circadian regulation of stomatal conductance is related to stomatal anatomy and leaf morphology in rice. Planta 254(1), 12.
| Crossref | Google Scholar |