Influences of artificial root exudate components on the behaviors of BDE-28 and BDE-47 in soils: desorption, availability, and biodegradation

Abstract

Behaviors of BDE-28 and BDE-47 in two distinct soils (Phaeozem and Acrisol) as affected by the separate addition of root exudate components (i.e., oxalic acid, glycine, and fructose) were investigated by a soil microcosm incubation experiment. The results showed that root exudate components promoted the desorption of BDE-28 (57.6-235.0 %) and BDE-47 (56.9-223.7 %) from the soils due to the enhancement of their water solubilities. The addition of root exudate components increased the n-butanol extractability of BDE-28 and BDE-47 by 20.3-72.5 and 48.6-169.2 %, respectively, which had a positive correlation with the concentrations of dissolved organic carbon (DOC) in the soils (p < 0.01), suggesting that the increase of DOC in the soils by root exudate components was the major factor to enhance the extractability. Fructose and oxalic acid promoted the desorption and increased the availability of BDE-28 and BDE-47 in the soils more efficiently than glycine. The addition of different root exudate components resulted in distinct shifts in soil microbial community structure (p < 0.05). Oxalic acid caused the greatest impacts on the soil bacterial communities and increased the degradation rates of BDE-28 and BDE-47 most obviously. The findings of this study clarified the roles of root exudate components in affecting the behaviors of polybrominated diphenyl ethers (PBDEs) in soils.

Effects of Selected Root Exudate Components on Nitrogen Removal and Development of Denitrifying Bacteria in Constructed Wetlands

“…Distinct changes in bacterial communities in CWs amended with artificial exudates were revealed by Illumina high-throughput sequencing. These results indicate the potential importance of LMWC compounds in influencing the structure of bacterial communities, in general agreement with other studies [22,29]. Some genera in our study responded positively to the artificial exudates; this result confirms previous studies suggesting that the most common sugars, organic acids, and amino acids associated with root exudate to rhizosphere are nutrient sources, chemoattractant signals, and promoters for microbial growth [30].…”

Plants affect the dissipation and leaching of anilide pesticides in soil mesocosms: Insights from compound-specific isotope analysis (CSIA)

“…Biodegradation was generally more pronounced in leachates from planted than from unplanted mesocosms. Plants can enhance pesticide sorption on SOM or/and minerals within the rhizosphere, while root exudates favour pesticide desorption and availability, thereby increasing biodegradation (Huang et al, 2016;Lefevre et al, 2013;Violante and Caporale, 2015). While microbial (co-)metabolism is a major degradation processes for anilide pesticides (Elsayed et al, 2014;Imfeld et al, 2018), the presence of a plant-root system in the soil can sustain rhizosphere microbial communities through root exudates, mainly consisting of labile organic matter (Mommer et al, 2016).…”

“…The soil-plant system includes the rhizosphere, which is characterized by diverse and intense microbial activity, respiration processes and nutrient uptake, mainly controlled by the water circulation (Bardgett and Van Der Putten, 2014;Hinsinger, et al, 2009;Hinsinger, et al, 2006;Mommer et al, 2016;Zhang et al, 2017). While organic contaminants are hardly adsorbed to organic matter and soil minerals, the root exudates from plants favour their desorption and availability, being directly accessed by macro-and microorganisms and plants (Huang et al, 2016). Plant rhizosphere can enhance pesticide dissipation by sustaining specific microbial communities capable of 4 pesticide transformation (Diez et al, 2017), resulting in shorter pesticide half-lives in the rhizosphere compared to the bulk soil (Hand et al, 2020).…”

Influence of Artificial Root Exudates on Triclosan Removal in Soil under Aerobic and Anaerobic Conditions

“…LeFevre et al have observed that REs could enhance desorption of residual pollutants, thus improving bioavailability and subsequent biodegradation potential. Furthermore, Huang et al have shown the effects of REs components on desorption, availability, and biodegradation of BDE‐28 and BDE‐47 in soils. However, the effect of REs on the removal of TCS is seldom investigated.…”