Sha Zhimin, Chen Zheng, Feng Yanfang, Xue Lihong, Yang Linzhang, Cao Linkui, Chu Qingnan
Graduate School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai, 200240, China.
Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, 215123, Jiangsu, China.
J Hazard Mater. 2020 Nov 5;398:122818. doi: 10.1016/j.jhazmat.2020.122818. Epub 2020 May 20.
Inhibiting reductive transformation of arsenic (As) in flooded paddy soils is fundamentally important for mitigating As transfer into the food chain. In this study, oxygen-nanobubble-loaded-zeolites (ZON) and -vermiculites (VON) were tested as a novel approach for supplying oxygen to paddy soils to inhibit As influx into rice. The dynamic physio- and bio-chemical variations in the rhizosphere and bulk soil were profiled in a rhizobox experiment. Upon adding ZON and VON, the redox potential and dissolved oxygen consistently increased throughout the cultivation period. The improved redox environment inhibited As(III) release into porewater and increased As(V) adsorbed on crystalline Fe (hydr)oxides, following the reduction of arsC and arrA gene abundances and enhancement of the aioA gene. Moreover, adding ZON and VON promoted root iron plaque formation, which increased As retention on iron plaque. Both ZON and VON treatments mitigated As translocation from soil to rice, meanwhile increasing root and shoot biomass. ZON was superior to VON in repressing As transfer and promoting rice growth due to its higher oxygen loading capacity. This study provides a novel and environment-friendly material to both mitigate the As translocation from paddy soil to rice and improve rice growth.
抑制淹水水稻土中砷（As）的还原转化对于减轻砷向食物链的转移至关重要。在本研究中，负载氧纳米气泡的沸石（ZON）和蛭石（VON）作为向水稻土供应氧气以抑制砷进入水稻的新方法进行了测试。在根箱试验中对根际和土体土壤的动态物理和生化变化进行了分析。添加ZON和VON后，整个栽培期的氧化还原电位和溶解氧持续增加。改善的氧化还原环境抑制了As（III）向孔隙水的释放，并增加了吸附在结晶铁（氢）氧化物上的As（V），这伴随着arsC和arrA基因丰度的降低以及aioA基因的增强。此外，添加ZON和VON促进了根表铁膜的形成，这增加了砷在铁膜上的滞留。ZON和VON处理均减轻了砷从土壤向水稻的转运，同时增加了根和地上部生物量。由于ZON具有更高的氧气负载能力，在抑制砷转移和促进水稻生长方面优于VON。本研究提供了一种新型的环保材料，既能减轻砷从水稻土向水稻的转运，又能促进水稻生长。
