Coconut-fiber biochar (CFB) was applied at 3% (w/w) to two soils spiked with 250, 2500, 5000 mg kg-1 of lead (Pb), respectively, aiming to explore the effects of CFB and the significance of iron (Fe) plaque on rice roots on the accumulation and translocation of Pb in rice plants using micro-X-ray fluorescence and X-ray absorption spectroscopies. The CFB amendment resulted in a significant decrease in the EDTA-extractable Pb availability in the soils, which might be attributed to the increased amounts of Pb-loaded humic acid and Pb3(PO4)2 formed in the soils. Consequently, the addition of CFB caused a significant decrease in Pb concentrations of the brown rice harvested from the CFB-amended soils under all Pb levels by 14 %-47 %, as compared to those from the unamended soils. Therefore, CFB could be used as an immobilizing agent for Pb in contaminated soils. However, CFB application significantly inhibited the formation of Fe/Mn plaques on rice roots and reduced its interception effect on Pb uptake, which consequently increased the Pb translocation rate from root to shoot. Therefore, the increased translocation rate of Pb in rice plants by CFB should not be ignored when CFB is applied to remediate Pb-contaminated paddy soils.

中文翻译：

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椰子纤维生物炭降低了铅的生物利用度，但提高了水稻植物中铅的转运速度：使用光谱技术阐明了固定机制和根上铁斑块屏障的重要性。

将椰子纤维生物炭（CFB）以3％（w / w）的比例施于两种分别掺有250、2500、5000 mg kg-1铅（Pb）的土壤中，旨在探讨CFB的作用及其重要性。利用X射线荧光光谱和X射线吸收光谱研究水稻根系上铁（Fe）斑对铅在水稻中的积累和转运。CFB修正案导致土壤中EDTA可提取的Pb利用率显着下降，这可能归因于土壤中形成的Pb腐殖酸和Pb3（PO4）2含量的增加。因此，与未改良土壤相比，添加CFB会使从CFB改良土壤中收获的糙米中Pb浓度在所有Pb水平下均显着降低14％-47％。因此，CFB可用作污染土壤中Pb的固定剂。然而，CFB的施用显着抑制了水稻根系上Fe / Mn斑块的形成，并降低了其对Pb吸收的拦截作用，从而提高了Pb从根到芽的易位率。因此，当使用CFB修复受Pb污染的稻田土壤时，CFB在水稻植株中引起的Pb转运速率增加不容忽视。