Distribution and Translocation of Selenium from Soil to Grain and Its Speciation in Paddy Rice (Oryza sativa L.)

Abstract

Selenium, an essential micronutrient for humans, is insufficient in dietary intake for millions of people worldwide. Rice as the most popular staple food in the world is one of the dominant selenium (Se) sources for people. The distribution and translocation of Se from soil to grain were investigated in a Serich environment in this study. The Se levels in soils ranged widely from 0.5 to 47.7 mg kg -1 . Selenium concentration in rice bran was 1.94 times higher than that in corresponding polished rice. The total Se concentrations in the rice fractions were in the following order: straw > bran > whole grain > polished rice > husk. Significant linear relationships between different rice fractions were observed with each other, and Se in the soil has a linear relationship with different rice fractions as well. Se concentration in rice can easily be predicted by soil Se concentrations or any rice fractions and vice versa according to their linear relationships. In all rice samples for Se speciation, SeMet was the major Se species, followed by MeSeCys and SeCys. The average percentage for SeMet (82.9%) and MeSeCys (6.2%) was similar in the range of total Se from 2.2 to 8.4 mg kg -1 tested. The percentage of SeCys decreased from 6.3 to 2.8%, although its concentration elevated with the increase in total Se in rice. This could be due to the fact that SeCys is the precursor for the formation of other organic Se compounds. The information obtained may have considerable significance for assessing translocation and accumulation of Se in plant.

Interactive effects of different inorganic As and Se species on their uptake and translocation by rice (Oryza sativa L.) seedlings

“…For Se speciation in rice shoots and roots, the sample preparation and analysis were conducted as published paper (Sun et al 2010) with minor modification. Briefly finely ground materials (0.1 g) were weighed into a 50 mL centrifuge tube, and protease K (20 mg), lipase VII (10 mg), and 5 mL of 30 mM Tris-HCl buffer solution (pH 7.5) were added.…”

“…The Se species in the supernatants were determined by HPLC-ICP-MS (HPLC, Agilent Technologies 1100 series, ICP-MS, 7500, Agilent Technologies; Sun et al 2010). Selenium species were separated by a precolumn and a Hamilton PRP X-100 anion exchange column (250×4.1 mm, 10 μm).…”

Selenium Biofortification in Rice - A pragmatic perspective

“…These authors found that 10 g of sodium selenate (applied as a foliar spray and at the end of tillering) was enough to increase selenium concentrations in the grain (close to recommended values for human food products) and also improved the proportion of Se-Met, a very bioavailable form of selenium humans. In rice plants grown in a Se-rich environment, Sun et al (2010) further reported that Se concentrations in rice decreased according to the following order rice straw > bran > whole grain > polished rice > husk and that, within the grain, that nutrient mostly accumulated in the bran layer, with concentrations almost twice those of the polished grain. They also found that in the mature grain selenium was primarily present in organic forms, chiefly Se-methionine.…”

Mitigation of cadmium and arsenic in rice grain by applying different silicon fertilizers in contaminated fields

“…The digestion procedure for all plant material samples followed the protocol of Sun et al (2010). Briefly, 0.2 g of rice grain or straw powder was transferred into 50-mL polyethylene centrifuge tubes with HNO 3 (2 mL) added and then incubated overnight at room temperature (∼25°C).…”

“…Three samples of each SRM (GSV-2) for straw, three SRM of rice flour (GSV-1), and three blanks were prepared at the same time for quality control. All samples were microwave digested (MARS, Matthew Inc., USA) using the reported temperature program (Sun et al 2010). Briefly, the temperature was increased to 55°C within 5 min and maintained for 10 min, increased to 75°C within 5 min and maintained for 10 min, and finally increased to 95°C within 5 min and maintained for 30 min.…”