{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,29]],"date-time":"2026-01-29T14:02:51Z","timestamp":1769695371699,"version":"3.49.0"},"reference-count":32,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2023,1,19]],"date-time":"2023-01-19T00:00:00Z","timestamp":1674086400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"European Union\u2019s Horizon 2020 research","award":["101021894"],"award-info":[{"award-number":["101021894"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Plants"],"abstract":"<jats:p>Potassium (K) is an essential element, which is often supplied to horticultural crops via foliar spraying. Some studies have investigated the effect of different foliar-applied K compounds; however, most studies have focussed on crop quality and yield parameters, or were performed with isolated leaf cuticles. The aim of this study was to evaluate the rates of the foliar ion penetration and leaf surface deposition of 130 mM K sprays of compounds with markedly different point of deliquescence (POD) and efflorescence (POE) values, the rates having been previously estimated in climate chamber trials. Shoots of field-grown, commercial olive trees were sprayed with K-nitrate (KNO3), K-sulphate (K2SO4), K-chloride (KCl), K-phosphate (K3PO4), K-carbonate (K2CO3) and K-bicarbonate (KHCO3), and leaf samples were collected after 3 and 24 h. Cation and anion concentrations were determined in the leaf tissues, and in a preliminary leaf water wash for estimating surface-deposited ion concentrations. No significant leaf tissue K increments were recorded between the K sprays. Olive tissue anion concentrations showed different patterns, and a chloride (Cl\u2212) increase was detected 3 h after the foliar KCl supply. On the other hand, the foliar K applications led to leaf nitrate changes regardless of the K source supplied. High amounts of K and accompanying ions were recovered in the washing liquid of the foliar K-supplied leaves. Some foliar K treatments increased the leaf surface concentration of sulphate and chloride, suggesting a potential effect on leaf cell anion extrusion. Hence, despite no evidence of foliar K uptake, an effect of leaf anion concentrations was observed, indicating that foliar nutrient sprays may influence leaf and leaf surface anion balance.<\/jats:p>","DOI":"10.3390\/plants12030472","type":"journal-article","created":{"date-parts":[[2023,1,19]],"date-time":"2023-01-19T05:50:20Z","timestamp":1674107420000},"page":"472","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":16,"title":["Foliar Application of Potassium Salts to Olive, with Focus on Accompanying Anions"],"prefix":"10.3390","volume":"12","author":[{"given":"H\u00e9ctor A.","family":"Bahamonde","sequence":"first","affiliation":[{"name":"Facultad de Ciencias Agrarias y Forestales, Universidad Nacional de La Plata, Diagonal 113 N_ 469, La Plata 1900, Argentina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5400-9102","authenticated-orcid":false,"given":"Carlos","family":"Pimentel","sequence":"additional","affiliation":[{"name":"Universit\u00e9 Grenoble Alpes, Universit\u00e9 Savoie Mont Blanc, CNRS, IRD, Universit\u00e9 Gustave Eiffel, ISTerre, 38000 Grenoble, France"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Luis Adri\u00e1n","family":"Lara","sequence":"additional","affiliation":[{"name":"Systems and Natural Resources Department, School of Forest Engineering, Universidad Polit\u00e9cnica de Madrid, 28040 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Vikingur","family":"Bahamonde-Fern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Natural Resources Institute, Universidad Nacional de la Patagonia Austral, Lisandro de la Torre 1070, R\u00edo Gallegos 9400, Argentina"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7639-6556","authenticated-orcid":false,"given":"Victoria","family":"Fern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Systems and Natural Resources Department, School of Forest Engineering, Universidad Polit\u00e9cnica de Madrid, 28040 Madrid, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Rengel, Z. (2020). Potassium in Crop Physiology. Achieving Sustainable Crop Nutrition, Burleigh Dodds Science Publishing.","DOI":"10.1201\/9780429275845"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"257","DOI":"10.1111\/ppl.12165","article-title":"Regulation of Potassium Transport in Plants under Hostile Conditions: Implications for Abiotic and Biotic Stress Tolerance","volume":"151","author":"Shabala","year":"2014","journal-title":"Physiol. Plant."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"162","DOI":"10.1016\/j.scienta.2019.01.046","article-title":"Global Warming Effects on Yield and Fruit Maturation of Olive Trees Growing under Field Conditions","volume":"249","author":"Bejaoui","year":"2019","journal-title":"Sci. Hortic."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"385","DOI":"10.1093\/aob\/mcx145","article-title":"On the Origins and Domestication of the Olive: A Review and Perspectives","volume":"121","author":"Besnard","year":"2018","journal-title":"Ann. Bot."},{"key":"ref_5","unstructured":"(2022, December 14). MAFF, (Ministry of Agriculture, Fisheries and Food of Spain) Aceite de oliva. Available online: https:\/\/www.mapa.gob.es\/es\/agricultura\/temas\/producciones-agricolas\/aceite-oliva-y-aceituna-mesa\/aceite.aspx."},{"key":"ref_6","unstructured":"Fern\u00e1ndez, V., Sotiropoulos, T., and Brown, P. (2013). Foliar Fertilization: Scientific Principles and Field Pratices, International Fertilizer Industry Association (IFA)."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"254","DOI":"10.1093\/treephys\/tpaa118","article-title":"Effects of Prolonged Elevated Temperature on Leaf Gas Exchange and Other Leaf Traits in Young Olive Trees","volume":"41","author":"Miserere","year":"2021","journal-title":"Tree Physiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1139","DOI":"10.1093\/jxb\/erp379","article-title":"K+ Starvation Inhibits Water-Stress-Induced Stomatal Closure via Ethylene Synthesis in Sunflower Plants","volume":"61","author":"Romera","year":"2010","journal-title":"J. Exp. Bot."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1080\/07352680902743069","article-title":"Uptake of Hydrophilic Solutes Through Plant Leaves: Current State of Knowledge and Perspectives of Foliar Fertilization","volume":"28","author":"Eichert","year":"2009","journal-title":"Crit. Rev. Plant Sci."},{"key":"ref_10","first-page":"289","article-title":"From Plant Surface to Plant Metabolism: The Uncertain Fate of Foliar-Applied Nutrients","volume":"4","author":"Brown","year":"2013","journal-title":"Front. Plant Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"870","DOI":"10.1111\/tpj.15090","article-title":"Foliar Water and Solute Absorption: An Update","volume":"105","author":"Eichert","year":"2021","journal-title":"Plant J."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1016\/j.scienta.2008.03.004","article-title":"Plant Water Stress and K+ Starvation Reduce Absorption of Foliar Applied K+ by Olive Leaves","volume":"116","author":"Benlloch","year":"2008","journal-title":"Sci. Hortic."},{"key":"ref_13","unstructured":"Elloumi, O., Ghrab, M., and Ben Mimoun, M. (2022, December 01). Responses of Olive Trees (Cv. Chemlali) after Five Years of Experiment to Potassium Mineral Nutrition under Rainfed Condition. The Proceedings of the International Plant Nutrition Colloquium XVI 2009. Available online: https:\/\/escholarship.org\/uc\/item\/2zb9p060."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"1108","DOI":"10.1080\/01904160902943148","article-title":"Leaf Potassium Accumulation in Olive Plants Related to Nutritional K Status, Leaf Age, and Foliar Application of Potassium Salts","volume":"32","author":"Benlloch","year":"2009","journal-title":"J. Plant Nutr."},{"key":"ref_15","first-page":"420","article-title":"Effect of Foliar Sprays with Potassium Nitrate and Mono-Potassium Phosphate on Leaf Mineral Contents, Fruit Set, Yield and Fruit Quality of Picual Olive Trees Grown under Sandy Soil Conditions","volume":"8","author":"Sarrwy","year":"2010","journal-title":"Am. -Eurasian J. Agric. Environ. Sci."},{"key":"ref_16","first-page":"1897","article-title":"Physiological and Biochemical Response of Olive (Olea Europaea L.) Cultivars to Foliar Potassium Application","volume":"18","author":"Zivdar","year":"2016","journal-title":"J. Agric. Sci. Technol."},{"key":"ref_17","first-page":"602","article-title":"Growth and Nutrient Status of Olive Plants as Influenced by Foliar Potassium Applications","volume":"14","author":"Saykhul","year":"2014","journal-title":"J. Soil Sci. Plant Nutr."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"387","DOI":"10.1007\/s10705-018-9954-2","article-title":"Olive Response to Potassium Applications under Different Water Regimes and Cultivars","volume":"112","author":"Ferreira","year":"2018","journal-title":"Nutr. Cycl. Agroecosyst"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1023\/A:1011976727078","article-title":"Cuticular Penetration of Potassium Salts: Effects of Humidity, Anions, and Temperature","volume":"236","author":"Luber","year":"2001","journal-title":"Plant Soil"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1080\/01904168609363431","article-title":"The Foliar Absorption of Potassium from Organic and Inorganic Potassium Carriers","volume":"9","author":"Shafer","year":"1986","journal-title":"J. Plant Nutr."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"728","DOI":"10.1021\/acsagscitech.1c00211","article-title":"Effect of Counterions on the Foliar Absorption and Transport of Potassium in Soybeans [Glycine Max (L.) Merrill]","volume":"1","author":"Diniz","year":"2021","journal-title":"ACS Agric. Sci. Technol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1002\/1522-2624(200104)164:2<225::AID-JPLN225>3.0.CO;2-N","article-title":"Cuticular Penetration of Calcium Salts: Effects of Humidity, Anions, and Adjuvants","volume":"164","year":"2001","journal-title":"J. Plant Nutr. Soil Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/j.foodchem.2015.05.042","article-title":"Comparison of Methods for Determining the Deliquescence Points of Single Crystalline Ingredients and Blends","volume":"195","author":"Allan","year":"2016","journal-title":"Food Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"592","DOI":"10.1002\/jpln.202000168","article-title":"Salt Hydration and Drop Drying of Two Model Calcium Salts: Implications for Foliar Nutrient Absorption and Deposition","volume":"183","author":"Pimentel","year":"2020","journal-title":"J. Plant Nutr. Soil Sci."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Curry, J.A., and Khvorostyanov, V.I. (2014). Deliquescence and Efflorescence in Atmospheric Aerosols. Thermodynamics, Kinetics, and Microphysics of Clouds, Cambridge University Press.","DOI":"10.1017\/CBO9781139060004"},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Parkhurst, D.L., and Appelo, C.A.J. (2013). Description of Input and Examples for PHREEQC Version 3\u2014A Computer Program for Speciation, Batch-Reaction, One-Dimensional Transport, and Inverse Geochemical Calculations. U.S. Geological Survey Techniques and Methods 6, Chap. A43., U.S. Geological Survey Techniques and Methods (USGS).","DOI":"10.3133\/tm6A43"},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Landorfa-Svalbe, Z., Andersone-Ozola, U., and Ievinsh, G. (2023). Type of Anion Largely Determines Salinity Tolerance in Four Rumex Species. Plants, 12.","DOI":"10.3390\/plants12010092"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Aluko, O.O., Li, C., Yuan, G., Nong, T., Xiang, H., Wang, Q., Li, X., and Liu, H. (2022). Differential Effects of Ammonium (NH4+) and Potassium (K+) Nutrition on Photoassimilate Partitioning and Growth of Tobacco Seedlings. Plants, 11.","DOI":"10.3390\/plants11233295"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Bulawa, B., Sogoni, A., Jimoh, M.O., and Laubscher, C.P. (2022). Potassium Application Enhanced Plant Growth, Mineral Composition, Proximate and Phytochemical Content in Trachyandra divaricata Kunth (Sandkool). Plants, 11.","DOI":"10.3390\/plants11223183"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1111\/j.1469-8137.1984.tb04103.x","article-title":"A Hypothesis Relating Critical Potassium Concentrations for Growth to the Distribution and Functions of This Ion in the Plant Cell","volume":"97","author":"Leigh","year":"1984","journal-title":"New Phytol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1007\/BF01869480","article-title":"Potassium Content and Aperture in \u201cIntact\u201d Stomatal and Epidermal Cells of Commelina Communis L","volume":"56","author":"MacRobbie","year":"1980","journal-title":"J. Membrain Biol."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Haynes, W.M. (2014). CRC Handbook of Chemistry and Physics, CRC Press.","DOI":"10.1201\/b17118"}],"container-title":["Plants"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2223-7747\/12\/3\/472\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T18:10:33Z","timestamp":1760119833000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2223-7747\/12\/3\/472"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,1,19]]},"references-count":32,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2023,2]]}},"alternative-id":["plants12030472"],"URL":"https:\/\/doi.org\/10.3390\/plants12030472","relation":{},"ISSN":["2223-7747"],"issn-type":[{"value":"2223-7747","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,1,19]]}}}