Accumulation and speciation of selenium in Cardamine sp. in Yutangba Se Mining Field, Enshi, China

Abstract

A naturally selenium-accumulating Cardamine sp. is growing in Yutangba Selenium Mining Field, Enshi area, Hubei Province, China, where the geochemical environment is selenium-enriched and endemic selenosis ever occurred in humans. The present study investigated the characteristics of accumulation, speciation and quantity of selenium in Cardamine sp. with HPLC-ICP-MS. Results show that Cardamine sp. can accumulate Se at most 1427 mg/kg in seedling leaves. Even after the biomass incensement of growing up, the plant still could accumulate Se up to several hundred of mg/kg in concentration. Moreover, the biomass enrichment coefficient (BEC) of Se is exceedingly high, in the seedling leaves mostly, higher than 50 mg/kg; in the range of 43.7-68 mg/kg; and the lowest value is higher than 3 mg/kg in mature fronds. Se is present in the plant predominantly in form of SeCys 2 with the highest concentration in seeds; up to 1081 mg/kg as Se. In contrast, SeCys 2 levels are low during early growth period; they are 136.1 mg/kg as Se in seedling fronds and 39.4 mg/kg as Se in mature fronds, respectively. SeMet concentration is comparatively low; 10.6 mg/kg as Se in seedling frond and 5.3 mg/kg as Se in half mature fronds, respectively. This indicates that Cardamine sp. is extremely efficient in extracting Se from soil and translocating it into its above-ground biomass. Therefore, Cardamine sp., found in Yutangba Se Mining Field may be a new Se hyperaccumulator. It is still uncertain whether the Se-accumulation or detoxification of Cardamine sp. happens through the pathway of SeCys methylated to form Se-methylselenoCys or through the formation of Se-carboxymethyl-selenohomocysteine. Indeed, further study should be carried out on the determination of more Se species to explain the high Se hyperaccumulation in Cardamine sp.

Integration analysis of PacBio SMRT- and Illumina RNA-seq reveals candidate genes and pathway involved in selenium metabolism in hyperaccumulator Cardamine violifolia

“…The HG-AFS conditions as follows: negative high voltage 340 V, lamp current 100 mA, temperature of atomization 800 °C, a flow rate of carrier gas 500 mL min − 1 , injection volume 1 mL, KBH 4 concentration 3.5%. The inorganic Se concentration, including SeO 3 2− and SeO 4 2− , was determined via liquid chromatography–HG-AFS (LC-AFS8510, Beijing Haiguang Instrument, China) [ 2 , 58 ]. The standard substances of SeO 3 2− and SeO 4 2− were purchased from the National Institute of Metrology, China.…”

Comparative transcriptomics provides novel insights into the mechanisms of selenium tolerance in the hyperaccumulator plant Cardamine hupingshanensis

“…(2014) measured concentrations of total Se by hydride generation-atomic fluorescence spectrometry (HG-AFS) and HPLC-ICP-MS, respectively. These studies showed that C. hupingshanensis could accumulate Se in excess of 1400 mg Se kg −1 of dry matter in all tissues of seedlings, with most not exceeding 4000 mg Se kg −1 of dry matter in roots 9 , 10 .…”

Structure of Cardamine hupingshanensis No. 2 Polysaccharide (CHP‐2) and Its Effect on Streptozotocin‐induced Diabetic Rats

“…Indeed, its super‐selenium‐rich characteristics have garnered attention in the research community in China. [ 15–19 ] In this study, we report the separation, purification, structural characterization and analysis of C. hupingshanensis polysaccharide no. 2 (CHP‐2) and its effect on diabetes.…”