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Pteris cretica is a native fern in temperate regions known for its ability to hyperaccumulate arsenic (As). However, the uptake and translocation of As in hydroponic conditions have remained poorly understood. In this study, we modified a hydroponic cultivation system, combining 24 plants into one unit, to suppress individual differences among plants and evaluate As uptake and translocation in P. cretica. The 7-day short-term As removal experiment results revealed that the As uptake rate by P. cretica appears to be dependent on the initial As concentration in the hydroponic medium. Furthermore, the rhizomes play a role in regulating As translocation from roots to fronds in P. cretica was observed. In the 27-day long-term continuous flow experiment, approximately 1 mg/d of As was removed by P. cretica with 200 μg/L As applied. Moreover, the long-term translocation factor (TF) between rhizomes and roots and between fronds and rhizomes from the 27-day long-term continuous flow experiment demonstrated the same pattern as the short-term TF from the 7-day short-term As removal experiment, further indicating the role of rhizomes in regulating As translocation from roots to fronds in P. cretica., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Typically, sulfate-reducing bioreactors used to treat acid mine drainage (AMD) undergo an initial incubation period of a few weeks to acclimatize sulfate-reducing bacteria (SRB), although necessity of this preincubation has rarely been evaluated. To reduce time and economic cost, we developed an SRB acclimatization method using the continuous flow of AMD into bioreactors fed with rice bran, and compared with the conventional acclimatization method. We found that the SRB sufficiently acclimatized without the preincubation phase. Furthermore, we examined the performance and SRB communities in bioreactors operated for >200 days under seven different conditions, in which the amount of rice bran added and hydraulic retention times (HRTs) were varied. A comparison of the various bioreactor conditions revealed that the lowest rice bran amount (50 g) and the shortest HRT (6 h) caused a deterioration in reactor performance after day 144 and 229, respectively. In both cases, relatively aerobic environments developed due to the lack of organic matter seemed to inhibit sulfate reduction. Of the conditions tested, operation of the bioreactors with 200 g of rice bran and an HRT of 12.5 h was the most effective in treating AMD, showing a sulfate reduction rate of 20.7-77.9% during days 54-242. DATA AND MATERIALS AVAILABILITY: All data needed to evaluate the conclusions of this study are presented in the paper and/or the appendix., (Copyright © 2021 Elsevier B.V. All rights reserved.)