20.500.12556/RUL-136038 Metabolic response of 'Topaz' apple fruit to minimal application of nitrogen during cell enlargement stage Nitrogen is an integral element of foliar sprays during apple fruit formation. However, in red cultivars, the application may have adverse effects on color in the second stage of fruit development. The effect of a low-dose foliar application of urea was monitored on ‘Topaz’ apple pomometric (fruit mass, firmness, total solids, starch content, skin color) and biochemical traits (primary metabolites, phenolic compounds, and assimilatory pigments). Three applications (17 July, 27 July, and 18 August) of two different urea doses (N1 = 1.4 kg N ha$^{−1}$; N4 = 4 kg N ha$^{−1}$) and control (N0, only sprayed with water) were used. Low doses of urea did not affect flesh firmness, total soluble, solid, and starch content, but individual fruit mass was significantly higher in N1 treatment compared to the other two treatments. Significantly lower a* parameters and a lower content of anthocyanins were measured on apples subject to N4 treatment. Many secondary metabolites (phenolic acids, flavan-3-ols, flavonols, and chalcones) were also negatively affected by low-dose urea application. Conversely, urea treatments significantly increased total assimilatory pigments in apple skin. Even minor levels of nitrogen, applied directly on the leaf at later stages of red apple fruit development, negatively altered color traits and the composition of metabolites. Malus domestica foliar urea sugars organic acids phenolics anthocyanins assimilatory pigments jablana Malus domestica topaz foliarno gnojenje urea sekundarni metaboliti dušična gnojila sladkorji kemična sestava fenolne spojine pigmenti true false true Angleški jezik Slovenski jezik Članek v reviji 2022-04-08 10:07:03 2022-04-08 10:07:04 2022-09-15 04:13:17 0000-00-00 00:00:00 2021 0 0 10 str. iss. 9, art. 266 Vol. 7 2021 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 634.1/.7 2311-7524 10.3390/horticulturae7090266 77559811 RAZ_Jakopic_Jerneja_2021.pdf RAZ_Jakopic_Jerneja_2021.pdf 1 D7D859CFB26161C8D16A396FA25979AF f0a0fa7c98aafcc5413d845c40616708c7eae587c4aef566e04a208e3d562214 441a24d4-b713-11ec-8aca-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=155468 https://www.mdpi.com/2311-7524/7/9/266 1 d511dbd8-b712-11ec-8aca-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=155467 Biotehniška fakulteta 0 0 0