Elemental Profile, General Phytochemical Composition and Bioaccumulation Abilities of Selected Allium Species Biofortified with Selenium under Open Field Conditions

Abstract

Allium species are known as a rich source of many compounds with potential healing effects. Biofortification is recognized as an effective agrotechnical measure for raising the level of biogenic elements—especially microelements in the edible parts of these species, so Allium can be considered as a ‘natural dietary supplement’. The aim of this research was to test the effects of foliar application of Se fertilizer (Na2SeO4) in different doses (control—0, 10, 20 and 30 g per ha) on the content of macro, microelements and secondary metabolites (SMs)—free phenolics, flavonoids and hydroxycinnamic acid derivatives in the edible parts, i.e., leaves of two selected Allium species in Serbia (A. odorum and A. schoenoprasum), which grew in open field conditions over the course of two growing seasons. The bioaccumulation factor (BAF), as an indicator of the ability of plants to accumulate biogenic elements, was also determined. Although with no full regularity, the dose of 10 g of Se per ha yielded the highest content for the most biogenic elements for both alliums in the first growing season, i.e., a dose of 20 g of Se per ha for A. schoenoprasum, and a dose of 30 g of Se per ha for A. odorum in the second growing season. The obtained results justified the Se-biofortification of different alliums. The BAF values indicated the ability of both Allium species to accumulate S, K and P in their leaves during both growing seasons. The accumulation of potentially toxic elements was not recorded for either species, emphasizing the safety of the produced plant material for human consumption. Additionally, Se-treated plants had higher SM contents compared to control plants. The growing season also showed an impact on SM content; i.e., in the second season, characterized as drought-stressed, the synthesis of SMs was significantly higher compared to that in the first season. Further research should be directed towards finding the appropriate dose of Se, expanded in the sense of conducting research in controlled conditions, as well as different ways of applying Se fertilizer. The idea of this study was also to popularize the examined Allium species, which are rarely grown in the territory of Serbia.

A detailed survey of agroecological status of Allium ursinum across the republic of Serbia: Mineral composition and bioaccumulation potential

“…Similarly, Sipter et al [ 75 ] investigated the degree of bioaccumulation of some PTEs (As, Pb, Cu, Hg, Zn, Hg and Cd) in the species Rumex acetosa and Allium schoenoprasum from the genus Allium and reported similar effects. In a recent study by Vuković et al [ 6 ] similar bioaccumulation in A. odorum and A. schoenoprasum was found for K (1.07–1.74 and 0.75–0.94); Ca (0.28–0.56 and 0.05–0.07); Mg (0.02–0.03 and 0.01–0.02); Fe (0.0002–0.0004 and 0.0004–0.0007); Mn (0.001–0.002 and 0.001–0.003); Cu (0.011–0.014 and 0.006–0.01); Zn (0.017–0.023 and 0.01–0.025); B (0.07–0.27 and 0.04–0.24); Ni (0.0004–0.002 and 0.0005–0.006); Na (not detected −0.058 and not detected); As (not detected - 0.058 and not detected); Cr (0.001–0.003 and 0.002–0.005); Pb (not detected-0.003 and not detected - 0.002); Al (0.0001–0.0004 and 0.0003–0.001) where the accumulation of other potential toxic elements was not significantly pronounced. The relatively low bioaccumulation abilities of A. ursinum for certain elements may be attributed to local agroecological conditions.…”

“…In addition to organic substances, A. ursinum contains a large number of inorganic components, such as biogenic elements (BEs) like K, Ca, Mg, Na, Ni, and Mn, as well as potentially toxic elements (PTEs) like B, Al, Mn, Ni, Hg, Pb, and Cd [ 5 ]. Vuković et al [ 6 ] stated that other species of the genus Allium have a pronounced ability to accumulate both BEs and PTEs. Biogenic elements, such as iron, zinc, and manganese are considered essential and play important roles in physiological cycles.…”

Allium Species in the Balkan Region—Major Metabolites, Antioxidant and Antimicrobial Properties

“…These compounds possess different characteristics, such as flavor and odor. Other groups of biologically active compounds found in alliums include polyphenols, flavonoids, phenolic acids, anthocyanins (which are responsible for the color characteristics of onion bulbs), phytosterols, fatty acids, and terpenoids [9,10].…”

“…Some essential amino acids such as glutamic acid and arginine are important reserves of nitrogen that contribute to the nutritional value of the onion species. Other complex bioactive compounds include saponins, vitamins (A, C, B6, and B9), and essential elements such as phosphorus, potassium, calcium, magnesium, zinc, manganese, sodium, iron, selenium, and copper [9,10]. It is well known that bioactive substances such as phenolic compounds, phytosterols, and fatty acids are an integral part of many plants and they have attracted great attention from researchers due to their benefits for human health.…”