Boron Biofortification of Portulaca oleracea L. through Soilless Cultivation for a New Tailored Crop

Abstract

Purslane (Portulaca oleracea L.) is a wild edible plant, traditionally consumed in the Mediterranean area and recently proposed as a new ready-to-eat vegetable; it is also called the “vegetable for long life” because of the high contents of several healthy compounds. Although boron (B) is not considered to be essential for humans, a daily intake of about 2 mg to obtain positive effects on aging in adult men and women has been suggested. In this study, two genotypes of purslane (wild collected and commercial variety) are grown by using a hydroponic system with three boron (B) levels in the nutrient solution (NS) (0.3 mg/L—control, 3 mg/L—low level of biofortification, and 6 mg/L—high level of biofortification) in order to increase the B content in the edible parts of the plant. The crop yield, color traits, and content of glucose, fructose, total phenols, chlorophylls, carotenoids, mineral elements (Al, B, Ca, Cr, Fe, K, Mg, Mn, Na, and Zn), nitrate, and oxalate are analyzed. Independent of the genotype, the B content in edible purslane was successfully increased in comparison with the control, obtaining 1.8- to 10.7-fold higher values of B tissue concentrations by using, respectively, 3 and 6 mg/L of B in the NS without affecting crop performances. From a nutritional point of view, the average daily intake of B could be satisfied by consuming about 75 or 48 g of purslane, grown by using 3 and 6 mg/L B level in the NS, respectively. Apart from B and Fe, the content of mineral elements in edible parts of purslane was not strongly influenced by different B levels in the NS but it was affected by genotypes. A lower sugar content was found in wild purslane grown with the highest B level. A higher content of both chlorophylls and carotenoids was found in the control but only for the commercial genotype. No differences in oxalate content were observed among B levels in the NS, while only in the case of wild genotype, we found a lower nitrate content when a B concentration of 3 mg/L was used in the NS. In conclusion, we demonstrated the possibility of using the floating hydroponic system, combined with specific B concentrations in the NS composition, as a method to calibrate the B uptake in edible parts of purslane.

Posidonia Natural Residues as Growing Substrate Component: An Ecofriendly Method to Improve Nutritional Profile of Brassica Microgreens

“…These Authors reported an increase of B contents in leaves, fruits and stems of tomato after application of different concentrations of this element in irrigation water, in a range of 0.028 – 1.48 mol m –3 . In our previous study ( D’Imperio et al, 2020 ) the application of B in the NS allowed to increase the B content in commercial and wild genotypes of purslane ( Portulaca oleracea L.). However, the high increase of B in edible parts of brassica microgreens, in both experiments, did not induce symptoms of plant toxicity, probably related to the typical short growing cycle for microgreens.…”

“…Only for the second experiments the content of total polyphenols was carried out according to the Folin–Ciocalteu method by using the extraction methods reported by D’Imperio et al (2020) . Briefly, 200 mg of lyophilized sample were mixed with 10 mL of solvent mixture (MeOH:H 2 O:CH 3 COOH, 79:20:1% v/v/v).…”

“…A promising approach is biofortification. It consists in increasing the content or the bioavailability of nutrients, e.g., vitamins (mainly folate and vitamin A), minerals (calcium, iron, silicon, boron, iodine, zinc, and selenium) and bioactive compounds (polyphenols and carotenoids) in plant foods, in order to ameliorate their nutritional profile in terms of their contribution to satisfy the Recommended Daily Allowance (RDA) for nutrients ( White and Broadley, 2009 ; D’Imperio et al, 2016 , 2019 , 2020 ; Montesano et al, 2016 ; Smoleń et al, 2017 ; Gonnella et al, 2019 ). This approach allows improving the nutritional quality of different crops by using several strategies, such as genetic engineering, conventional breeding, and agronomic techniques ( Carvalho and Vasconcelos, 2013 ).…”

Smooth Golden Fleece and Prickly Golden Fleece as Potential New Vegetables for the Ready-to-Eat Production Chain

“…[25], Brassica fruticulosa Cyr. [26], Crithmum maritimum L. [27] and Portulaca oleracea L. [28,29] could be cultivated on a large scale. Others could be exploited on a large-scale as new crops expressing agro-biodiversity [9].…”

Natural Boron-Containing Compounds From Herbal Medicinal Resources

“…It is remarkable to underline that the use of soilless systems permits to precisely measure the concentration of each element in the nutrient solution, potentially preventing any excess or deficiency of nutrients in plants. Additionally, by modulating the mineral composition of the nutrient solution, it is possible to increase or reduce the concentration of target ions in plant tissue to obtain tailored vegetables for specific nutritional requirements (D'Imperio et al 2016, Di Gioia et al 2019, Gonnella et al 2019, Montesano et al 2016, Smoleń et al 2019.…”