Leaf nitrogen thresholds ensuring high antioxidant features of Vaccinium corymbosum cultivars

Abstract

Deficiency or excess of nitrogen (N) supply can promote formation of reactive oxygen species in plants, inducing oxidative stress. Otherwise, plants may enhance phenolics biosynthesis and antioxidant capacity under N deficiency, but this effect is plant species-dependent. There is no information about influence on phenolics and antioxidant activity in highbush blueberry (Vaccinium corymbosum L.), in which quality and commercial importance depend on high phenolics concentration. We studied the effect of variable N supply (0 to 38 mM) on N uptake and antioxidant responses in two highbush blueberry cultivars (Legacy and Bluegold) hydroponically grown at the long-term. Nitrogen leaves concentration was enhanced for both cultivars at increasing N supply. Bluegold decreased CO 2 assimilation at 0 N treatment, possibly due to both, insufficient N concentration and a decline in superoxide dismutase (SOD) activity. In contrast, SOD was activated in Legacy at 0 N, and interestingly only this cultivar maintained CO 2 assimilation rates across all N treatments. Both cultivars showed higher phenolics and antioxidant activity levels at 9 mM. Despite the differential responses among the cultivars, we propose a threshold of 15 g N kg-1 DW to ensure high antioxidant activity and quality in blueberry leaves.

Applying nitrogen fertilizer increased anthocyanin in vegetative shoots but not in grain of purple rice genotypes

“…Also, 150 kg N ha −1 enhanced flavonoids and antioxidant capacity in stevia . By contrast, the highest anthocyanin concentrations in leaves of blueberry were induced by 0 mmol L −1 N and declined with an increase in N supply . Lastly, a very high rate of N fertilizer (12 mmol L −1 reduced the production of anthocyanins and phenolic acids in red lettuce .…”

“…28 By contrast, the highest anthocyanin concentrations in leaves of blueberry were induced by 0 mmol L −1 N and declined with an increase in N supply. 29 Lastly, a very high rate of N fertilizer (12 mmol L −1 reduced the production of anthocyanins and phenolic acids in red lettuce. 13 From these studies it is apparent that particular fertilizer strategies may need to be developed for each crop species in order to promote the levels of pigments and antioxidants of interest.…”

Distinct physiological and metabolic reprogramming by highbush blueberry (Vaccinium corymbosum) cultivars revealed during long‐term UV‐B radiation

“…Anthocyanins have been previously reported as being induced by stress factors in V . corymbosum (Inostroza‐Blancheteau et al , Rojas‐Lillo et al , Yañez‐Mansilla et al , Reyes‐Díaz et al 2016). In our case, these cultivars did not show a clear induction of anthocyanins under UV‐B radiation.…”

Prospects of N Fertilization in Medicinal Plants Cultivation

“…However, it has been shown in many studies that N efects on plant physiological processes like syntheses of amino acids and phenolics are dependent on tissue N concentration, plant species and other exogenous factors like water availability, temperature and light. Yañez-Mansilla et al [31] hypothesized that there is an optimum N concentration threshold that ensure a high phenolic concentration and antioxidant capacity without detrimental efects on plant performance and proposed a threshold of 15 g N/kg DW as an optimum concentration for ensuring high antioxidant activity and quality in blueberry leaves, based on results obtained in their study. In order to meet requirements of new regulations in the coastal valleys of central California, USA, ield trials were carried out by Botoms [32] to identify commercial ields in which N application could be reduced or eliminated in order to improve nitrogen (N) fertilizer eiciency.…”