Nano-biochar(nano-BC)is one of the most active fractions in the BC continuum and frequently detected in terrestrial ecosystems.However,a paucity of information exists on reactivity and environmental functions of nano-...Nano-biochar(nano-BC)is one of the most active fractions in the BC continuum and frequently detected in terrestrial ecosystems.However,a paucity of information exists on reactivity and environmental functions of nano-BC in the rhizosphere.The present study investigated the potential of nano-BC in transforming silver ions(Ag^(+))to silver nanoparticles(AgNPs)in the rhizosphere of rice.We found that the synergistic effect of nano-BC and dioxygen secreted from rice roots was essential for Ag^(+)reduction to AgNPs.In this process,nano-BC transferred electrons to dioxygen,resulting in the formation of superoxide free radicals,which subsequently donate electrons to Ag^(+).Notably,excess nano-BC was unfavorable to dioxygen secretion from roots and thus inhibited the formation of AgNPs.Our results highlight that although nano-BC significantly decreased the uptake of Ag by rice plants,it contributed to the accumulation of AgNPs in plant tissues.TEM and single-particle ICP-MS analyses confirmed the presence of AgNPs not only in intercellular spaces of leaf tissues but also within the interior of leaf cells.These findings indicate that nano-BC plays a critical role in regulating the chemical species and bioaccumulation of redox-active metals(such as Ag)in the rhizosphere,which has important implications for element cycling from the pedosphere to terrestrial vegetation and warrants further investigation.展开更多
基金Funding Project for Young Backbone Teachers to Visit and Study in China(JNFX2023061)Chuzhou University Research Initiation Fund Project(2023qd49,2023qd44)+4 种基金National Natural Science Foundation of China(42207435,42477263)Natural Science Foundation of Hebei Province(B2023202077,D2022202004)Natural Science Foundation of Tianjin(23JCYBJC00940)China Postdoctoral Science Foundation(2020M680868)Young Scientists Fund-National Science Foundation of China(42207048).
文摘Nano-biochar(nano-BC)is one of the most active fractions in the BC continuum and frequently detected in terrestrial ecosystems.However,a paucity of information exists on reactivity and environmental functions of nano-BC in the rhizosphere.The present study investigated the potential of nano-BC in transforming silver ions(Ag^(+))to silver nanoparticles(AgNPs)in the rhizosphere of rice.We found that the synergistic effect of nano-BC and dioxygen secreted from rice roots was essential for Ag^(+)reduction to AgNPs.In this process,nano-BC transferred electrons to dioxygen,resulting in the formation of superoxide free radicals,which subsequently donate electrons to Ag^(+).Notably,excess nano-BC was unfavorable to dioxygen secretion from roots and thus inhibited the formation of AgNPs.Our results highlight that although nano-BC significantly decreased the uptake of Ag by rice plants,it contributed to the accumulation of AgNPs in plant tissues.TEM and single-particle ICP-MS analyses confirmed the presence of AgNPs not only in intercellular spaces of leaf tissues but also within the interior of leaf cells.These findings indicate that nano-BC plays a critical role in regulating the chemical species and bioaccumulation of redox-active metals(such as Ag)in the rhizosphere,which has important implications for element cycling from the pedosphere to terrestrial vegetation and warrants further investigation.
