Do iron plaque and genotypes affect arsenate uptake and translocation by rice seedlings (Oryza sativa L.) grown in solution culture?

Abstract

The effects of Fe concentrations in the pretreatment solution on the induction of plaque and the differences between genotypes on arsenate uptake by and translocation within rice seedlings grown in nutrient solution in the greenhouse were investigated. After iron plaque on rice roots was induced in solutions containing 20, 40, 60, 80, and 100 mg Fe2+ l(-1), seedlings were transplanted into nutrient solution with 0.5 mg As l(-1). The formation of iron plaque was clearly visible as a reddish coating on the root surface after 12 h induction. Fe2+ concentrations in the pretreatment solution and 0.5 mg As l(-1) in the treatment solutions did not significantly affect rice growth. There was a significant correlation between the concentrations of Fe and As in iron plaque on the root surface for the three genotypes. About 75-89% of total As was concentrated in iron plaque (DCB-extracts). There were no significant differences in As concentrations in the roots between the three genotypes; however, As concentrations in shoots differed significantly between them. Arsenic concentrations in shoots were positively correlated with iron concentrations in the shoots. The results suggest that iron plaque may act as a 'buffer' for As in the rhizosphere.

Assessment of Arsenic Accumulation by Different Varieties of Rice (Oryza sativa L.) Irrigated with Arsenic-contaminated Groundwater in West Bengal (India)

“…This finding is in agreement with the findings by Liu et al [19], Rahman et al [9] and Bhattacharya et al [8]. According to Liu et al [20] the iron oxides or iron plaques formed around root of the rice plant are responsible for the arsenic binding in root. The resultant is the reduction of translocation of arsenic from root to straw, husk, and grain portions of the rice plant.…”

“…The results indicated an appreciable low efficiency (TF = 0.08−0.19) in translocation of arsenic from root to shoot whereas TF values were found to be much higher from shoot to grain (TF = 0.11−0.46) for almost all the analyzed rice varieties. The lower TF values for translocation of arsenic from root to shoot revealed the strong capability of root tissues to hold the arsenic, which was related with the presence of iron plaques [20]. Other than the White Minikit variety, translocation of arsenic from straw to grain (TF = 0.25−0.46) by all other HYVs was evaluated to be much higher than those by the studied local and hybrid rice varieties.…”

Trend of Arsenic Pollution and Subsequent Bioaccumulation in <i>Oryza sativa</i> and <i>Corchorus capsularis</i> in Bengal Delta

“…due to the formation of iron plaques, as reported in a previous study and with synchrony with the present work ). It has also been reported that the accumulation of arsenic in rice plants is highest in the root zones and decrease significantly in the upper parts of the plant (Liu et al 2004). This was verified by the results of the present study, which showed a root > basal stem > median stem > apical stem>leaves>grains trend of arsenic accumulation in O. sativa.…”

Arsenic bioavailability to rice plant in paddy soil: influence of microbial sulfate reduction

“…Arsenic speciation was separated by a PRP-X100 anion exchange HPLC column (150×4.1 mm, Hamilton, Netherlands) under the solution of 7.0 mmol L −1 (NH 4 ) 2 HPO 4 and 7.0 mmol L −1 NH 4 NO 3 (pH=6.2). Roots were incubated in DCB (dithionite-citrate-bicarbonate) solution for the extraction of iron plaques on the root surface (Taylor and Crowder 1983;Liu et al 2004). Arsenic concentration in the iron plaque extraction solution was determined by ICP-MS (Agilent 7500, Agilent Technologies, USA).…”