A pot experiment was conducted to investigate cadmium(Cd) uptake by different rice cultivars that produce white or dark grains. Four cultivars with white grains(hereafter, white rice) and five cultivars with dark colo...A pot experiment was conducted to investigate cadmium(Cd) uptake by different rice cultivars that produce white or dark grains. Four cultivars with white grains(hereafter, white rice) and five cultivars with dark colors (hereafter dark rice) were selected for this experiment. Three levels of soil Cd concentrations, background(0), 5 and 10 mg/kg, were used. After harvest, plant biomass, tissue concentrations of Cd, Ca, Fe, Cu and Zn were analyzed. The results showed that Cd concentrations are significantly different between different genotypes, but when comparing the Cd concentrations for the two groups, no significant difference was found. For other divalent cations, Ca concentrations in dark rice were higher than those in white ones(P<0.001 for shoots, P=0.037 for roots); Fe concentrations in dark rice were also higher than those in white ones(P=0.001 either in shoot or root); Zn concentrations in shoot of dark rice were higher than those in white ones, but no significant difference in roots. The total molar concentrations of divalent cations in dark rice were also significantly higher than in white rice. The potential benefit of higher Ca and Fe concentrations in dark rice and similar Cd concentrations in both groups is also discussed in this paper.展开更多
Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the d...Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the difference in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil （Entic Haplaquept） with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer （GFAAS） and flame atomic adsorption spectrophotometer （AAS） respectively. Wide variation of Cd content in grain was found in a range of 0.004-0.057 mg/kg, while the Zn content in a range of 10.25-30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods （MOHC and SSC, 2005）, calculated potential risk of food Cd exposure with ＂Zn hungry＂ through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South China using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.展开更多
文摘A pot experiment was conducted to investigate cadmium(Cd) uptake by different rice cultivars that produce white or dark grains. Four cultivars with white grains(hereafter, white rice) and five cultivars with dark colors (hereafter dark rice) were selected for this experiment. Three levels of soil Cd concentrations, background(0), 5 and 10 mg/kg, were used. After harvest, plant biomass, tissue concentrations of Cd, Ca, Fe, Cu and Zn were analyzed. The results showed that Cd concentrations are significantly different between different genotypes, but when comparing the Cd concentrations for the two groups, no significant difference was found. For other divalent cations, Ca concentrations in dark rice were higher than those in white ones(P<0.001 for shoots, P=0.037 for roots); Fe concentrations in dark rice were also higher than those in white ones(P=0.001 either in shoot or root); Zn concentrations in shoot of dark rice were higher than those in white ones, but no significant difference in roots. The total molar concentrations of divalent cations in dark rice were also significantly higher than in white rice. The potential benefit of higher Ca and Fe concentrations in dark rice and similar Cd concentrations in both groups is also discussed in this paper.
基金supported by the Ministry of Science and Technology of China (No. 2006BAD17B06)the Ministry of Education of China (No. B200613).
文摘Enhanced Cd uptake and Zn depletion in rice grains and high potential for food Cd exposure by the high-yielding hybrid cultivars of China had been addressed. A field experiment was conducted in 2006 to determine the difference in grain Cd and Zn between cultivars. Total 110 cultivars including super rice and common hybrid rice cultivars were grown on a single paddy soil （Entic Haplaquept） with a neutral reaction and low total Cd content. Grain Cd and Zn concentrations were determined with graphite atomic adsorption spectrophotometer （GFAAS） and flame atomic adsorption spectrophotometer （AAS） respectively. Wide variation of Cd content in grain was found in a range of 0.004-0.057 mg/kg, while the Zn content in a range of 10.25-30.06 mg/kg among the cultivars. Higher Cd but lower Zn concentration in grains of super rice cultivars was observed compared to the common hybrid ones. A highly significant positive linear correlation of grain Cd/Zn with grain Cd was found for super rice and common hybrid cultivars, meanwhile much higher slope for these hybrid cultivars than the reported non-hybrid cultivars was also observed. Using the limit value of the Chinese chemical guidelines for foods （MOHC and SSC, 2005）, calculated potential risk of food Cd exposure with ＂Zn hungry＂ through diet intake was prominent with all the studied 110 hybrid rice cultivars, possessing high potential health problems for rice production in South China using the super rice cultivars. Breeding of genotypes of rice cultivars with low grain Cd and low Cd/Zn ratio is needed for rice production in acidic red soils where Cd bioavailability is prevalently high.
