Difference in Selenite Absorption Between High- and Low-Selenium Rice Cultivars and its Mechanism

Zhang, Lianhe; Shi, Weiming; Wang, Xiaochang C.

doi:10.1007/s11104-005-5706-6

Cited by 80 publications

(104 citation statements)

References 36 publications

(31 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…S3). In contrast, sulfate had a comparatively smaller influence on Se accumulation in Se[IV]-exposed roots, which is similar to reports for rice (Zhang et al, 2006) and tomato (Solanum lycopersicum; Asher et al, 1977). Second, for roots supplied with Se[VI], a rapid accumulation of Se occurred within 30 min within the endodermis and cortex, especially in the more proximal root tissues (Fig.…”

Section: Uptake and Distribution Of Sesupporting

confidence: 86%

In Situ Speciation and Distribution of Toxic Selenium in Hydrated Roots of Cowpea

et al. 2013

View full text Add to dashboard Cite

The speciation and spatial distribution of selenium (Se) in hydrated plant tissues is not well understood. Using synchrotronbased x-ray absorption spectroscopy and x-ray fluorescence microscopy (two-dimensional scanning [and associated mathematical model] and computed tomography), the speciation and distribution of toxic Se were examined within hydrated roots of cowpea (Vigna unguiculata) exposed to either 20 mM selenite or selenate. Based upon bulk solution concentrations, selenate was 9-fold more toxic to the roots than selenite, most likely due to increased accumulation of organoselenium (e.g. selenomethionine) in selenate-treated roots. Specifically, uptake of selenate (probably by sulfate transporters) occurred at a much higher rate than for selenite (apparently by both passive diffusion and phosphate transporters), with bulk root tissue Se concentrations approximately 18-fold higher in the selenate treatment. Although the proportion of Se converted to organic forms was higher for selenite (100%) than for selenate (26%), the absolute concentration of organoselenium was actually approximately 5-fold higher for selenate-treated roots. In addition, the longitudinal and radial distribution of Se in roots differed markedly: the highest tissue concentrations were in the endodermis and cortex approximately 4 mm or more behind the apex when exposed to selenate but in the meristem (approximately 1 mm from the apex) when exposed to selenite. The examination of the distribution and speciation of Se in hydrated roots provides valuable data in understanding Se uptake, transport, and toxicity.

show abstract

Section: Uptake and Distribution Of Sesupporting

confidence: 86%

In Situ Speciation and Distribution of Toxic Selenium in Hydrated Roots of Cowpea

et al. 2013

View full text Add to dashboard Cite

show abstract

“…The pH values of most soils in Enshi region are from acidic to neutral, about 4.5-6.5 (17,21), under which condition Se exists predominatly as selenite in well-drained soils (7). Relatively low pH could increase the absorption and accumulation of Se in rice (42). Se concentrations in different fractions of rice plants were rather different.…”

Section: Resultsmentioning

confidence: 99%

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

Sun

Liu

Williams

et al. 2010

Environ. Sci. Technol.

109

View full text Add to dashboard Cite

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.

show abstract

“…In paddy soil, Se is present in the form of selenite. A physiological study showed that selenite uptake by rice roots was inhibited by HgCl 2 and AgNO 3 , suggesting that aquaporin is implicated in the uptake of selenite (Zhang et al, 2006). However, the exact mechanism for selenite uptake has not been understood.…”

mentioning

confidence: 99%

Involvement of Silicon Influx Transporter OsNIP2;1 in Selenite Uptake in Rice

et al. 2010

View full text Add to dashboard Cite

Rice (Oryza sativa) as a staple food, provides a major source of dietary selenium (Se) for humans, which essentially requires Se, however, the molecular mechanism for Se uptake is still poorly understood. Herein, we show evidence that the uptake of selenite, a main bioavailable form of Se in paddy soils, is mediated by a silicon (Si) influx transporter Lsi1 (OsNIP2;1) in rice. Defect of OsNIP2;1 resulted in a significant decrease in the Se concentration of the shoots and xylem sap when selenite was given. However, there was no difference in the Se concentration between the wild-type rice and mutant of OsNIP2;1 when selenate was supplied. A short-term uptake experiment showed that selenite uptake greatly increased with decreasing pH in the external solution. Si as silicic acid did not inhibit the Se uptake from selenite in both rice and yeast (Saccharomyces cerevisiae) at low pHs. Expression of OsNIP2;1 in yeast enhanced the selenite uptake at pH 3.5 and 5.5 but not at pH 7.5. On the other hand, defect of Si efflux transporter Lsi2 did not affect the uptake of Se either from selenite or selenate. Taken together, our results indicate that Si influx transporter OsNIP2;1 is permeable to selenite.

show abstract

Difference in Selenite Absorption Between High- and Low-Selenium Rice Cultivars and its Mechanism

Cited by 80 publications

References 36 publications

In Situ Speciation and Distribution of Toxic Selenium in Hydrated Roots of Cowpea

In Situ Speciation and Distribution of Toxic Selenium in Hydrated Roots of Cowpea

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

Involvement of Silicon Influx Transporter OsNIP2;1 in Selenite Uptake in Rice

Contact Info

Product

Resources

About