{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,11,10]],"date-time":"2025-11-10T21:19:08Z","timestamp":1762809548425,"version":"build-2065373602"},"reference-count":34,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2023,12,29]],"date-time":"2023-12-29T00:00:00Z","timestamp":1703808000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Programa de Desenvolvimento Rural\u2014PDR 2020","award":["MACFERTIQUAL PDR2020-101-031590","UIDB\/04129\/2020"],"award-info":[{"award-number":["MACFERTIQUAL PDR2020-101-031590","UIDB\/04129\/2020"]}]},{"name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia, I.P.","award":["MACFERTIQUAL PDR2020-101-031590","UIDB\/04129\/2020"],"award-info":[{"award-number":["MACFERTIQUAL PDR2020-101-031590","UIDB\/04129\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Horticulturae"],"abstract":"<jats:p>Currently, fertilization decisions in apple orchards are based on soil and leaf analyses while the leaf material is sampled after the growing season, usually in June\u2013July (90\u2013110 days after full bloom). This approach is inefficient, as the information becomes available later than the growing season and is therefore only useful in supporting fertilization decisions for the next year, not the current one. To establish a method that provides useful information for fertilization decisions earlier in the growth cycle, our research focused on the assessment of the nutrient content of petiole sap using different methods, the standard method and the rapid method using a reflectometer. For this study, in 2021, four \u2018Gala\u2019 orchards were fertilized with different N\u2013P\u2013K levels. Macro and micronutrients were determined in leaves and petiole sap at 45 and 90\u2013110 days after full bloom (DAFB) using standard laboratory methods and the reflectometer. When leaf analysis at 45 and 90\u2013110 DAFB was compared with petiole sap analysis at the same time point, no significant correlations were found between the nutrient contents in leaf material and petiole sap, with the exception of calcium. However, positive results were obtained regarding the correlation between reflectometer determination and standard laboratory analyses. The regression analysis revealed high determination coefficients for N-NO3\u2212 (R2 = 0.703), K+ (R2 = 0.705), Ca2+ (R2 = 0.715), and Mg2+ (R2 = 0.780) between standard laboratory methods and the reflectometer. These results suggest that the reflectometer enables a real-time diagnostic tool for monitoring nutrient status throughout the growth cycle, particularly key nutrients related to fruit quality. The N\u2013P\u2013K fertilization strategies had no influence on the nutrient content of leaves or petiole sap. The nutrient content of both sample types varied depending on the orchard.<\/jats:p>","DOI":"10.3390\/horticulturae10010036","type":"journal-article","created":{"date-parts":[[2023,12,29]],"date-time":"2023-12-29T03:28:41Z","timestamp":1703820521000},"page":"36","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Analysis of Petiole Sap Nutrients Using Rapid and Standard Methods and Its Relation to Leaf Analysis of Fertilized Malus domestica cv. Gala"],"prefix":"10.3390","volume":"10","author":[{"given":"Mariana","family":"Mota","sequence":"first","affiliation":[{"name":"LEAF\u2014Linking Landscape, Environment, Agriculture and Food Research Center, Associated Laboratory TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"given":"M. Jo\u00e3o","family":"Martins","sequence":"additional","affiliation":[{"name":"CEF\u2014Centro de Estudos Florestais, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"given":"Layanne","family":"Sprey","sequence":"additional","affiliation":[{"name":"LEAF\u2014Linking Landscape, Environment, Agriculture and Food Research Center, Associated Laboratory TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"given":"Anabela","family":"Maur\u00edcio","sequence":"additional","affiliation":[{"name":"FRUBA\u00c7A-Cooperativa de Horto-Fruticultores, C.R.L. Lugar Acipreste Aptd. 12, 2460-471 Alcoba\u00e7a, Portugal"}]},{"given":"Cristina","family":"Rosa","sequence":"additional","affiliation":[{"name":"GRANFER-Produtores de Frutas, CRL. Rua Principal 167, 2510-772 Usseira, Portugal"}]},{"given":"Jo\u00e3o","family":"Faria","sequence":"additional","affiliation":[{"name":"GRANFER-Produtores de Frutas, CRL. Rua Principal 167, 2510-772 Usseira, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5414-0629","authenticated-orcid":false,"given":"Miguel B.","family":"Martins","sequence":"additional","affiliation":[{"name":"LEAF\u2014Linking Landscape, Environment, Agriculture and Food Research Center, Associated Laboratory TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7218-3745","authenticated-orcid":false,"given":"Miguel L.","family":"de Sousa","sequence":"additional","affiliation":[{"name":"INIAV, I.P., Polo Alcoba\u00e7a, Estrada de Leiria, 2460-059 Alcoba\u00e7a, Portugal"}]},{"given":"Ricardo","family":"Santos","sequence":"additional","affiliation":[{"name":"CAMPOTEC IN-Cons. e Transforma\u00e7\u00e3o de Hortofrut\u00edcolas, SA. EN 9, 2560-393 Torres Vedras, Portugal"}]},{"given":"Rui M.","family":"de Sousa","sequence":"additional","affiliation":[{"name":"INIAV, I.P., Polo Alcoba\u00e7a, Estrada de Leiria, 2460-059 Alcoba\u00e7a, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7914-620X","authenticated-orcid":false,"given":"Henrique","family":"Ribeiro","sequence":"additional","affiliation":[{"name":"LEAF\u2014Linking Landscape, Environment, Agriculture and Food Research Center, Associated Laboratory TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3480-9380","authenticated-orcid":false,"given":"Cristina M.","family":"Oliveira","sequence":"additional","affiliation":[{"name":"LEAF\u2014Linking Landscape, Environment, Agriculture and Food Research Center, Associated Laboratory TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"64","DOI":"10.1007\/s13593-022-00798-0","article-title":"System nutrient dynamics in orchards: A research roadmap for nutrient management in apple and kiwifruit. A review","volume":"42","author":"Gentile","year":"2022","journal-title":"Agron. Sustain. Dev."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Carranca, C., Brunetto, G., and Tagliavini, M. (2018). Nitrogen nutrition of fruit trees to reconcile productivity and environmental concern. Plants, 7.","DOI":"10.3390\/plants7010004"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Esteves, E., Locatelli, G., Bou, N.A., and Ferrarezi, R.S. (2021). Sap Analysis: A Powerful Tool for Monitoring Plant Nutrition. Horticulturae, 7.","DOI":"10.3390\/horticulturae7110426"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1137","DOI":"10.1080\/00103629609369622","article-title":"Factors affecting potato petiole sap nitrate tests","volume":"27","author":"Vitosh","year":"1996","journal-title":"Commun. Soil Sci. Plant Anal."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"23","DOI":"10.1080\/00103629809369926","article-title":"Calibration of a petiole sap nitrate test for irrigated \u201cRusset Burbank\u201d potato","volume":"29","author":"Errebhi","year":"1998","journal-title":"Commun. Soil Sci. Plant Anal."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"835","DOI":"10.1071\/EA9940835","article-title":"Petiole sap nitrate is better than total nitrogen in dried leaf for indicating nitrogen status and yield responsiveness of capsicum in subtropical Australia","volume":"34","author":"Olsen","year":"1994","journal-title":"Aust. J. Exp. Agric."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"218","DOI":"10.21273\/HORTTECH.4.3.218","article-title":"Efficiency ranges for nitrate-nitrogen and potassium for vegetable petiole sap quick tests","volume":"4","author":"Hochmuth","year":"1994","journal-title":"HortTechnology"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1590\/S0103-90162005000100002","article-title":"Calibra\u00e7\u00e3o de medidores de i\u00f5es espec\u00edficos para determina\u00e7\u00e3o da concentra\u00e7\u00e3o de nutrientes na solu\u00e7\u00e3o do solo e na seiva da planta","volume":"62","author":"Folegatti","year":"2005","journal-title":"Sci. Agric."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"200","DOI":"10.5424\/sjar\/2009071-412","article-title":"Evaluation of rapid analysis systems for on-farm nitrate analysis in vegetable cropping","volume":"7","author":"Thompson","year":"2009","journal-title":"Span. J. Agric. Res."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Pe\u00f1a-Fleitas, M.T., Gallardo, M., Padilla, F.M., Rodr\u00edguez, A., and Thompson, R.B. (2021). Use of a portable rapid analysis system to measure nitrate concentration of nutrient and soil solution, and plant sap in greenhouse vegetable production. Agronomy, 11.","DOI":"10.3390\/agronomy11050819"},{"key":"ref_11","doi-asserted-by":"crossref","unstructured":"Llanderal, A., Garc\u00eda-Caparr\u00f3s, P., P\u00e9rez-Alonso, J., Contreras, J.I., Segura, M.L., Reca, J., and Lao, M.T. (2020). Approach to Petiole Sap Nutritional Diagnosis Method by Empirical Model Based on Climatic and Growth Parameters. Agronomy, 10.","DOI":"10.3390\/agronomy10020188"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"56","DOI":"10.1111\/j.1755-0238.1999.tb00152.x","article-title":"A petiole sap test for nitrate and potassium in Sultana grapevines","volume":"5","author":"Nagarajah","year":"1999","journal-title":"Aust. J. Grape Wine Res."},{"key":"ref_13","unstructured":"Cadah\u00eda, C.L. (2008). La Savia Como \u00cdndice de Fertilizaci\u00f3n. Cultivos Agroenerg\u00e9ticos, Hort\u00edcolas, Frutales y Ornamentales, Mundi-Prensa."},{"key":"ref_14","first-page":"37","article-title":"Determination of Leaf Standards for Apple Trees and Grapevines in Northern Italy","volume":"Volume 53","author":"Fragoso","year":"1993","journal-title":"Optimization of Plant Nutrition"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"482","DOI":"10.1590\/S0100-29452012000200022","article-title":"Nutrientes na Seiva de plantas c\u00edtricas fertirrigadas","volume":"34","author":"Quaggio","year":"2012","journal-title":"Rev. Bras. Frutic."},{"key":"ref_16","unstructured":"University of Florida (2023, October 20). Plant Sap Analysis as a Tool to Optimize Fertilizer Application for Sustainable Citrus Production. Available online: https:\/\/projects.sare.org\/sare_project\/os21-148\/."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"363","DOI":"10.1093\/jxb\/4.3.363","article-title":"The use of tracheal sap in the study of apple-tree nutrition","volume":"4","author":"Bollard","year":"1953","journal-title":"J. Exp. Bot."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1071\/BI9570279","article-title":"Composition of the nitrogen fraction of apple tracheal sap","volume":"10","author":"Bollard","year":"1957","journal-title":"Aust. J. BioI. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"778","DOI":"10.1080\/00288233.1965.10423713","article-title":"Chemical changes in apple tree tissues following applications of fertilizer nitrogen","volume":"8","author":"Bollard","year":"1965","journal-title":"N. Z. J. Agric. Res."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1016\/S0044-328X(81)80227-9","article-title":"Spring composition of xylem sap of apple with respect to amino-nitrogen and mineral elements at two root temperatures","volume":"102","author":"Tromp","year":"1981","journal-title":"Z. Pflanzenphysiol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/S0176-1617(85)80097-3","article-title":"Response of young apple trees to time of nitrogen fertilization with respect to the nitrogen, potassium, and calcium levels in xylem sap, new growth, and the tree as a whole","volume":"119","author":"Tromp","year":"1985","journal-title":"J. Plant Physiol."},{"key":"ref_22","first-page":"179","article-title":"Methods of diagnosis of mineral nutrition of plants a critical review","volume":"448","author":"Lucena","year":"1996","journal-title":"Acta Hortic."},{"key":"ref_23","unstructured":"Cadah\u00eda, C. (2005). Fertirrigaci\u00f3n: Cultivos Hort\u00edcolas, Frutales y Ornamentales, Mundi-Prensa."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1693","DOI":"10.1080\/00103624.2020.1791160","article-title":"Rapid Sap Nutrient Analysis Methods in Malus Domestica Borkh Cv","volume":"51","author":"Almeida","year":"2020","journal-title":"\u2018Gala\u2019, Commun. Soil Sci. Plant Anal."},{"key":"ref_25","first-page":"199","article-title":"Untersuchungen \u00fcber die chemische Bodenanalyse als Grundlage f\u00fcr die Beurteilung des N\u00e4hrstoffzustandes der B\u00f6den. II. Chemische Extraktions methoden zur Phosphor und Kaliumbestimmung","volume":"26","author":"Riehm","year":"1960","journal-title":"K. Lant-Bruksh\u00f6gskolans Ann."},{"key":"ref_26","unstructured":"Instituto Portugu\u00eas do Mar e da Atmosfera (IPMA) (2023, November 09). Atlas Clim\u00e1tico Ib\u00e9rico. Available online: https:\/\/www.ipma.pt\/export\/sites\/ipma\/bin\/docs\/institucionais\/pr_atlas.clima.iberico.dmm11.pdf."},{"key":"ref_27","unstructured":"(2023, December 05). Dire\u00e7\u00e3o-Geral de Agricultura e Desenvolvimento Rural (DGADR) Normas T\u00e9cnicas Para a Produ\u00e7\u00e3o Integrada de Pom\u00f3ideas; DGADR: Lisbon, Portugal, Available online: https:\/\/www.dgadr.gov.pt\/images\/docs\/prod_sust\/normas_pi\/i012008.pdf."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Walinga, I., Van Der Lee, J.J., Houba, V.J., Van Vark, W., and Novozamsky, I. (1995). Plant Analysis Manual, Springer Science & Business Media.","DOI":"10.1007\/978-94-011-0203-2"},{"key":"ref_29","unstructured":"Karla, Y.P. (1998). Handbook of Reference Methods for Plant Analysis, CRC Press. Soil and Plant Science Council."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Mota, M., Martins, M.J., Policarpo, G., Sprey, L., Pastaneira, M., Almeida, P., Maur\u00edcio, A., Rosa, C., Faria, J., and Martins, M.B. (2022). Nutrient Content with Different Fertilizer Management and Influence on Yield and Fruit Quality in Apple cv. Gala. Horticulturae, 8.","DOI":"10.3390\/horticulturae8080713"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"493","DOI":"10.1590\/S0103-90162006000500012","article-title":"Seasonality of nutrients in leaves and fruits of apple trees","volume":"63","author":"Nachtigall","year":"2006","journal-title":"Sci. Agric."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1093\/aob\/mcy062","article-title":"Linear relationships between shoot magnesium and calcium concentrations among angiosperm species are associated with cell wall chemistry","volume":"122","author":"White","year":"2018","journal-title":"Ann. Bot."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1016\/j.cj.2020.10.005","article-title":"Synergistic and antagonistic interactions between potassium and magnesium in higher plants","volume":"9","author":"Xie","year":"2021","journal-title":"Crop J."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"409","DOI":"10.1016\/j.scienta.2017.12.057","article-title":"Apple fruit quality: Overview on pre-harvest factors","volume":"234","author":"Musacchi","year":"2018","journal-title":"Sci. Hortic."}],"container-title":["Horticulturae"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2311-7524\/10\/1\/36\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:43:52Z","timestamp":1760132632000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2311-7524\/10\/1\/36"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,29]]},"references-count":34,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2024,1]]}},"alternative-id":["horticulturae10010036"],"URL":"https:\/\/doi.org\/10.3390\/horticulturae10010036","relation":{},"ISSN":["2311-7524"],"issn-type":[{"type":"electronic","value":"2311-7524"}],"subject":[],"published":{"date-parts":[[2023,12,29]]}}}