Selenium Metabolism in Hemp (Cannabis sativa L.)—Potential for Phytoremediation and Biofortification

Abstract

Selenium (Se) deficiency and toxicity affect over a billion people worldwide. Plants can mitigate both problems, via Se biofortification and phytoremediation. Here we explore the potential of hemp (Cannabis sativa L.) for these phytotechnologies. Field surveys in naturally seleniferous agricultural areas in Colorado, United States, found 15−25 μg of Se/g in seed and 5−10 μg of Se/g dry weight (DW) in flowers and leaves. Thus, 4 g of this hemp seed provides the U.S. recommended daily allowance of 55−75 μg of Se. In controlled greenhouse experiments, hemp seedlings grown in Turface supplied with 40−320 μM selenate showed complete tolerance up to 160 μM and accumulated up to 1300 mg of Se/kg shoot dry weight. Mature hemp grown in Turface supplied with 5−80 μM selenate was completely tolerant up to 40 μM selenate and accumulated up to 200 mg of Se/kg DW in leaves, flowers, and seeds. Synchrotron X-ray fluorescence and X-ray absorption spectroscopies of selenate-supplied hemp showed Se to accumulate mainly in the leaf vasculature and in the seed embryos, with predominant Se speciation in C−Se−C forms (57−75% in leaf and more than 86% in seeds). Aqueous seed extracts were found by liquid chromatography mass spectrometry to contain selenomethionine and methyl-selenocysteine (1:1−3 ratio), both excellent dietary Se sources. Floral concentrations of medicinal cannabidiol (CBD) and terpenoids were not affected by Se. We conclude that hemp has good potential for Se phytoremediation while producing Se-biofortified dietary products.

Selenium biofortification in the 21st century: status and challenges for healthy human nutrition

“…Brassicaceae spp ., including broccoli ( Brassica oleracea L.), radish, Chinese cabbage ( Brassica rapa L.), salad rocket and wild rocket can accumulate high amounts of organic Se species, especially SeMet and/or MeSeCys (Bachiega et al 2016 ; Bañuelos et al 2015 ; Ramos et al 2011 ; Schiavon et al 2016 ; Šindelaŕǒva et al 2015 ). The same Se compounds have been identified in hemp ( Cannabis sativa L.), rice ( Oryza sativa L.), and potato ( Solanum tuberosum L.) (Huang et al 2018 ; Stonehouse et al 2020 ; Zhang et al 2019 ). Leguminous plants spp.…”

“…Nanosized biofortification is performed using SeNPs applied to leaves or soil (7). Co-cropping or intercropping practices use Sehyperaccumulators to enrich soil with Se-organic compounds promptly available for uptake by neighboring plants or succeeding crops (8) (Bañuelos et al 2015;Schiavon and Pilon-Smits 2017b;Stonehouse et al 2020). Se-laden plant material derived from plants employed in Se phytoremediation could be recycled as green fertilizer to increase Se content in agricultural soils or as a supplemental fodder for livestock (Bañuelos et al 2009).…”

“…Crop enrichment with Se could also be achieved by combining different types of Se phytotechnologies (Bañuelos et al 2015 ; Schiavon and Pilon-Smits 2017b ; Stonehouse et al 2020 ). Se-laden plant material derived from plants employed in Se phytoremediation could be recycled as green fertilizer to increase Se content in agricultural soils or as a supplemental fodder for livestock (Bañuelos et al 2009 ).…”

Virtual Screening of C. Sativa Constituents for the Identification of Selective Ligands for Cannabinoid Receptor 2

“…Among the many experimental studies regarding cannabinoids, a few studies describing the three compounds selected by us deserve attention [ 39 , 40 , 41 , 42 , 43 ]. What is more, in the last year, many valuable and novel studies on C. Sativa applications in medicine have been published [ 62 , 63 , 64 , 65 , 66 ], thus, we hope that the exploration of the potential use of C. Sativa in pharmacotherapy will continue both experimentally and by using theoretical models.…”

Fertility management for industrial hemp production: Current knowledge and future research needs

“…The majority of research regarding phytoremediation capabilities of hemp have been focused on the extraction of heavy metals from contaminated soils. C. sativa has been found to extract heavy metals including Cu, nickel (Ni), lead (Pb), selenium (Se), chromium (Cr) and cadmium (Cd;Ahmad et al, 2015;Citterio et al, 2003;Husain et al, 2019;Linger et al, 2005;Stonehouse et al, 2020). Aerosol absorption and retention of metals is expected to be a result of the crop's extended flowering period (Angelove et al, 2003), and it is assumed that this could be correlated to nutrient uptake as well.…”