Abstract
The aim of the present study was to evaluate the effect of nitrogen fertigation (0, 200, 400, and 600 ppm of total nitrogen) and harvesting time (9 March 2018 and 19 April 2018) on the plant growth, chemical composition, and bioactive properties of Centaurea raphanina subsp. mixta plants. The highest yield of fresh leaves was observed for the treatment of 200 ppm of N without compromising nutritional value. The increasing nitrogen levels resulted in an increase of α- and total tocopherols and sugars content, especially in the second harvest for tocopherols and in the first harvest for sugars. Similarly, total organic acids and oxalic acid content increased with increasing nitrogen levels in both harvests, while fatty acids composition had a varied response to the tested factors. Pinocembrin neohesperidoside and pinocembrin acetyl neohesperidoside isomer II were the most abundant phenolic compounds with the highest content being observed in the control treatment of the first and second harvest, respectively. The highest antioxidant activity was observed for the control and the 600 ppm treatments of the second harvest for the OxHLIA and TBARS assays, respectively, probably due to the high content of pinocembrin acetyl neohesperidoside isomer II and α-tocopherol, respectively. Finally, cytotoxic effects and antimicrobial properties showed a varied response depending on the treatment. In conclusion, C. raphanina subsp. mixta has low requirements of nitrogen to achieve the highest yield, while a varied response to the tested fertigation treatments and harvesting time was observed in terms of the chemical composition and the bioactive properties.
Highlights
The Mediterranean basin is abounding with numerous wild edible species, which have been widely used for food purposes throughout the centuries as part of the traditional Mediterranean diet [1,2,3,4,5]
The lowest nitrogen level (200 ppm) resulted in the highest fresh weight compared to the rest of the fertilization treatments, a finding which indicates that the species does not require high inputs of nitrogen fertilizers to achieve their full yield potential
The results of our study present new information regarding the response of Centaurea raphanina subsp. mixta plants to nitrogen fertigation and successive harvesting, which are very important cultivation practices for farmers before suggesting the commercial cultivation of the species as a new alternative crop
Summary
The Mediterranean basin is abounding with numerous wild edible species, which have been widely used for food purposes throughout the centuries as part of the traditional Mediterranean diet [1,2,3,4,5]. Molecules 2020, 25, 3175 the commercial cultivation of these species, aiming to increase our knowledge on the best agronomic practices [9,10,11,12]. Considering the wild nature of these species, it is of major importance to establish cultivation protocols that will allow the best agronomic performance under diverse conditions and increase product availability and affordability for consumers. Apart from the achievement of maximum yield, another aspect to be considered is the effect that specific agronomic practices may have on the quality of the edible products, especially in regards to the content of antinutritional factors such as nitrates and oxalic acid, which may accumulate under commercial cultivation conditions [21,22,23]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
