Silicon enhances abundances of reducing microbes in rhizoplane and decreases arsenite uptake by rice (Oryza sativa L.). (1st August 2022)

• Record Type: Journal Article
• Authors: Gao, Zixiang; Chen, Hao; Zhang, Xinyuan; Xiao, Zhuoxi; Fan, Xiaoping; Yin, Chang; Tang, Xianjin; Han, Fengxiang X.; Liang, Yongchao
• Is Part Of: Environmental pollution. Volume 306(2022)
• Publication Date: 2022-08-01
• Subjects: Arsenite -- Silicic acid -- Rhizoplane -- Recruitment -- The reducing microorganisms; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.119405
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Although silicon (Si) transporters-mediated uptake of arsenic (As) by rice roots is well-documented, how Si influences As behaviors in rhizosphere and rhizoplane before As entry into roots is still unclear. Here we used three rice genotypes to explore the effect of silicic acid on the root uptake of As as impacted by chemical and microbial changes in bulk soil, rhizosphere, rhizoplane and endosphere. The results show that exogenous Si decreased root arsenite [As(III)] absorption, which was attributed to Si-mediated alteration of traits in chemical plaque and microbial films on the rhizoplane. The pH, Eh, As and Fe in the porewater were not influenced by Si. However, Si enhanced the concentrations of As(III) (16–49%) and Fe (15–80%) in the rhizoplane while decreasing As(III) concentrations in the roots (19–39%) and grains (22–29%). The diversities and richness of microbes in soils and plants were not affected by Si. The microbial connections were negatively influenced by Si in bulk and rhizosphere soils, but positively impacted in rhizoplane and endosphere. Both the abundance of reducing microbes, Anaeromyxobacter and Geobacteraceae, and the level of As(III) and Fe in rhizoplane were significantly increased by the addition of Si, thereby restraining As(III) from uptake into roots. This study provides new insights into the microbial mechanisms of Si-mediated As uptake by rice. Graphical abstract: Image 1 Highlights: Si increased As(III) and Fe in rhizoplane while reducing As(III) contents in roots. Si had no significant influence on microbial richness and diversities. Si affected microbial connections in soils negatively, but positively in roots. Increased As(III) and Fe in rhizoplane was due to enhanced microbial recruitment.