BACKGROUND Calcium is a preservative and firming agent largely used in the table olive industry. Foliar applications of calcium (CaCl2 ) before harvest have been proposed in other fruits to increase firmness and reduce physiological disorders or internal damage. However, there is still a shortage of information regarding the source, the concentration, the number and the period of calcium application onto the canopy to get an effective response of olive quality. In this study, we aimed to investigate the effect of two concentrations of CaCl2 foliar treatments (0.5% and 1.0%), applied at different stages of fruit development (at the end of fruit set, end of pit hardening, and prior to harvesting) on olive quality for two varieties ('Manzanilla de Sevilla' and 'Ascolanta tenera'), cultivated in two different geographical areas (Spain and Italy, respectively). RESULTS The applied Ca concentrations enhanced the fruit calcium content and decreased sodium and potassium. They also improved the mechanical properties without modifying fruit morphology, cuticle thickness nor causing phytotoxicity. Foliar treatments increased the oil content in the pulp (dry weight basis) and the amount of hydroxytyrosol, tyrosol and oleuropein, among other phenols. CONCLUSION Calcium foliar applications during fruit development effectively increase olive quality. This article is protected by copyright. All rights reserved.

中文翻译：

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在整个果实发育过程中的钙应用可提高橄榄品质、油产量和抗氧化化合物的含量

背景钙是一种防腐剂和固化剂，主要用于食用橄榄工业。已经建议在其他水果中在收获前叶面喷施钙 (CaCl2) 以增加硬度并减少生理障碍或内部损伤。然而，关于钙在树冠上施用的来源、浓度、数量和时间，以获得橄榄质量的有效响应，仍然缺乏信息。在本研究中，我们旨在研究两种浓度的 CaCl2 叶面处理（0.5% 和 1.0%）在果实发育的不同阶段（坐果末期、坑硬化末期和收获前）的效果关于两个品种（'Manzanilla de Sevilla' 和'Ascolanta tenera'）的橄榄质量，在两个不同的地理区域（分别是西班牙和意大利）种植。结果施用的钙浓度提高了果实钙含量并降低了钠和钾。它们还改善了机械特性，而不会改变果实形态、表皮厚度，也不会引起植物毒性。叶面处理增加了果肉中的油含量（干重）和羟基酪醇、酪醇和橄榄苦苷等酚的含量。结论 在果实发育过程中叶面喷施钙剂可有效提高橄榄品质。本文受版权保护。版权所有。表皮厚度也不会引起植物毒性。叶面处理增加了果肉中的油含量（干重）和羟基酪醇、酪醇和橄榄苦苷等酚的含量。结论 在果实发育过程中叶面喷施钙剂可有效提高橄榄品质。本文受版权保护。版权所有。表皮厚度也不会引起植物毒性。叶面处理增加了果肉中的油含量（干重）和羟基酪醇、酪醇和橄榄苦苷等酚的含量。结论 在果实发育过程中叶面喷施钙剂可有效提高橄榄品质。本文受版权保护。版权所有。