Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (<i>Allium cepa</i>) Bulbs
Onion (<i>Allium cepa</i>) is one of the world’s most consumed, nutrient-dense foods, low in calories and containing a rich amount of major bioactive compounds, vitamins, and minerals. The purpose of this study was to determine the influence of different nitrogen (N) fertilizer sources o...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-12-01
|
| Series: | Horticulturae |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2311-7524/10/1/10 |
| _version_ | 1827371953157046272 |
|---|---|
| author | Mzwakhile Petros Zakhe Simelane Puffy Soundy Stephen O. Amoo Martin Makgose Maboko |
| author_facet | Mzwakhile Petros Zakhe Simelane Puffy Soundy Stephen O. Amoo Martin Makgose Maboko |
| author_sort | Mzwakhile Petros Zakhe Simelane |
| collection | DOAJ |
| description | Onion (<i>Allium cepa</i>) is one of the world’s most consumed, nutrient-dense foods, low in calories and containing a rich amount of major bioactive compounds, vitamins, and minerals. The purpose of this study was to determine the influence of different nitrogen (N) fertilizer sources on the nutritional and phytochemical qualities of short-day onions. A white-type onion (cv. Texas Grano) was subjected to different fertilizer application treatments, namely (i) pre-plant base application of 80 kg ha<sup>−1</sup> N from CaCN<sub>2</sub>, alone or in combination with (ii) top-dressing with 50 kg ha<sup>−1</sup> N from limestone ammonium nitrate (LAN), or (iii) top-dressing with 50 kg ha<sup>−1</sup> N from urea, (iv) pre-plant base application of 80 kg ha<sup>−1</sup> N from LAN and top-dressing with 50 kg ha<sup>−1</sup> N from LAN, (v) pre-plant base application of 80 kg ha<sup>−1</sup> N from urea and top-dressing with 50 kg ha<sup>−1</sup> N from urea, and (vi) 0 kg ha<sup>−1</sup> N. Pre-plant application of CaCN<sub>2</sub> (80 kg ha<sup>−1</sup> N) outperformed standard onion fertilizers, urea (130 kg ha<sup>−1</sup> N) and LAN (130 kg ha<sup>−1</sup> N), significantly enhancing total phenolic content, antioxidant activity, and calcium (Ca) and potassium (K) content in onion bulbs. Applying 50 kg ha<sup>−1</sup> N from urea as top-dressing with the pre-plant application of CaCN<sub>2</sub> (80 kg ha<sup>−1</sup> N) elevated total phenolics (5.48 mg GAE g<sup>−1</sup>) and flavonoids (0.741 mg CE g<sup>−1</sup>) in the onion bulbs. The highest antioxidant activity (55.9%) and free radical scavenging activity (26.3%) were achieved with top-dressing 50 kg ha<sup>−1</sup> N from LAN following CaCN<sub>2</sub> pre-plant application. Application of CaCN<sub>2</sub> + urea also significantly increased onion bulb potassium (2335 mg kg<sup>−1</sup>) and calcium (828 mg kg<sup>−1</sup>) contents, while CaCN<sub>2</sub> combined with LAN improved magnesium (123.3 mg kg<sup>−1</sup>) content. This study recommends pre-plant CaCN<sub>2</sub>, top-dressed with either LAN or urea, for improved phytochemical components, antioxidant activities, and certain mineral content in onion bulbs. These findings present a practical approach for cultivating nutrient-rich and phytochemically abundant onion bulbs, promoting improved human health. |
| first_indexed | 2024-03-08T10:49:13Z |
| format | Article |
| id | doaj.art-5ac4dd99210c4390a21679f35463d35d |
| institution | Directory Open Access Journal |
| issn | 2311-7524 |
| language | English |
| last_indexed | 2024-03-08T10:49:13Z |
| publishDate | 2023-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Horticulturae |
| spelling | doaj.art-5ac4dd99210c4390a21679f35463d35d2024-01-26T16:49:35ZengMDPI AGHorticulturae2311-75242023-12-011011010.3390/horticulturae10010010Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (<i>Allium cepa</i>) BulbsMzwakhile Petros Zakhe Simelane0Puffy Soundy1Stephen O. Amoo2Martin Makgose Maboko3Department of Crop Sciences, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South AfricaDepartment of Crop Sciences, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South AfricaUnit for Environmental Sciences and Management, Faculty of Natural and Agricultural Sciences, North-West University, Potchefstroom 2520, South AfricaDepartment of Crop Sciences, Tshwane University of Technology, Private Bag X680, Pretoria 0001, South AfricaOnion (<i>Allium cepa</i>) is one of the world’s most consumed, nutrient-dense foods, low in calories and containing a rich amount of major bioactive compounds, vitamins, and minerals. The purpose of this study was to determine the influence of different nitrogen (N) fertilizer sources on the nutritional and phytochemical qualities of short-day onions. A white-type onion (cv. Texas Grano) was subjected to different fertilizer application treatments, namely (i) pre-plant base application of 80 kg ha<sup>−1</sup> N from CaCN<sub>2</sub>, alone or in combination with (ii) top-dressing with 50 kg ha<sup>−1</sup> N from limestone ammonium nitrate (LAN), or (iii) top-dressing with 50 kg ha<sup>−1</sup> N from urea, (iv) pre-plant base application of 80 kg ha<sup>−1</sup> N from LAN and top-dressing with 50 kg ha<sup>−1</sup> N from LAN, (v) pre-plant base application of 80 kg ha<sup>−1</sup> N from urea and top-dressing with 50 kg ha<sup>−1</sup> N from urea, and (vi) 0 kg ha<sup>−1</sup> N. Pre-plant application of CaCN<sub>2</sub> (80 kg ha<sup>−1</sup> N) outperformed standard onion fertilizers, urea (130 kg ha<sup>−1</sup> N) and LAN (130 kg ha<sup>−1</sup> N), significantly enhancing total phenolic content, antioxidant activity, and calcium (Ca) and potassium (K) content in onion bulbs. Applying 50 kg ha<sup>−1</sup> N from urea as top-dressing with the pre-plant application of CaCN<sub>2</sub> (80 kg ha<sup>−1</sup> N) elevated total phenolics (5.48 mg GAE g<sup>−1</sup>) and flavonoids (0.741 mg CE g<sup>−1</sup>) in the onion bulbs. The highest antioxidant activity (55.9%) and free radical scavenging activity (26.3%) were achieved with top-dressing 50 kg ha<sup>−1</sup> N from LAN following CaCN<sub>2</sub> pre-plant application. Application of CaCN<sub>2</sub> + urea also significantly increased onion bulb potassium (2335 mg kg<sup>−1</sup>) and calcium (828 mg kg<sup>−1</sup>) contents, while CaCN<sub>2</sub> combined with LAN improved magnesium (123.3 mg kg<sup>−1</sup>) content. This study recommends pre-plant CaCN<sub>2</sub>, top-dressed with either LAN or urea, for improved phytochemical components, antioxidant activities, and certain mineral content in onion bulbs. These findings present a practical approach for cultivating nutrient-rich and phytochemically abundant onion bulbs, promoting improved human health.https://www.mdpi.com/2311-7524/10/1/10antioxidant capacitymineral compositionflavonoidfree radical scavenging activityphenols |
| spellingShingle | Mzwakhile Petros Zakhe Simelane Puffy Soundy Stephen O. Amoo Martin Makgose Maboko Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (<i>Allium cepa</i>) Bulbs Horticulturae antioxidant capacity mineral composition flavonoid free radical scavenging activity phenols |
| title | Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (<i>Allium cepa</i>) Bulbs |
| title_full | Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (<i>Allium cepa</i>) Bulbs |
| title_fullStr | Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (<i>Allium cepa</i>) Bulbs |
| title_full_unstemmed | Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (<i>Allium cepa</i>) Bulbs |
| title_short | Effects of Nitrogen Source on Mineral Element, Phytochemical Content, and Antioxidant Activity of Short-Day Onion (<i>Allium cepa</i>) Bulbs |
| title_sort | effects of nitrogen source on mineral element phytochemical content and antioxidant activity of short day onion i allium cepa i bulbs |
| topic | antioxidant capacity mineral composition flavonoid free radical scavenging activity phenols |
| url | https://www.mdpi.com/2311-7524/10/1/10 |
| work_keys_str_mv | AT mzwakhilepetroszakhesimelane effectsofnitrogensourceonmineralelementphytochemicalcontentandantioxidantactivityofshortdayonionialliumcepaibulbs AT puffysoundy effectsofnitrogensourceonmineralelementphytochemicalcontentandantioxidantactivityofshortdayonionialliumcepaibulbs AT stephenoamoo effectsofnitrogensourceonmineralelementphytochemicalcontentandantioxidantactivityofshortdayonionialliumcepaibulbs AT martinmakgosemaboko effectsofnitrogensourceonmineralelementphytochemicalcontentandantioxidantactivityofshortdayonionialliumcepaibulbs |