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8552805 
Journal Article 
接种混合功能细菌降低黑麦草体内菲和芘污染的机理初探 
Sun, K; Li, S; Chen, M; Gao, Y; Si, Y 
2019 
Yes 
Huanjing Kexue Xuebao / Acta Scientiae Circumstantiae
ISSN: 0253-2468 
Science Press 
39 
4 
1303-1311 
Chinese 
Polycyclic aromatic hydrocarbons (PAHs) are a category of persistent organic contaminants extensively found in soil environments. PAHs can be taken up, accumulated, and translocated by plants, which pose a significant risk worldwide to food safety and hence human health due to their high bio-accumulation, carcinogenicity, toxicity, and biodegradation-resistant. It is well documented that inoculation of PAH-degrading bacterium is a simple and effective strategy for mitigating the contamination of PAHs in plants. However, microscopic information is available on inoculation with mixed PAH-degrading bacteria to regulate plant PAH contamination and the activities of related to metabolic enzymes in plants. In this study, the biodegradation kinetics and regularity of phenanthrene and pyrene were respectively investigated using Massilia sp. Pn2 and Mycobacterium flavescens 033 in in vitro. In particular, greenhouse pot experiments of inoculated two PAH-degrading bacteria were conducted to reduce PAHs residues in ryegrass (Lolium multiflorum Lam), and the effect of strains Pn2 and 033 on the activities of polyphenol oxidase (PPO) and peroxidase (POD) was also explored in in vivo. Results indicated that both strains Pn2 and 033 could use phenanthrene and pyrene as the sources of carbon and energy for growth of tested strains. They were effective in biodegrading PAHs in in vitro, and the biodegradation rates of phenanthrene and pyrene were respectively 99.7% and 98.3%, the half-life values were respectively 0.34 d and 0.95 d (R2>0.98). Compared with the mixed dead bacteria control (CRD), inoculation with mixed PAH-degrading strains altered the migration and transformation of PAHs in soil-ryegrass systems, and reduced the concentration and accumulation of PAHs into ryegrass roots and shoots (p<0.05). In addition, inoculation with mixed PAH-degrading bacteria also impacted the activities of PPO (p>0.05) and POD (p<0.05) in plants. Thus, strains Pn2 and 033 could be a useful bacterial resource for reducing PAHs contents via regulating the activity of POD inside plants. These findings provide a novel perspective in utilizing plant-bacteria partnerships to reduce plan PAH residues and regulate the activities of enzymes in plants, with ultimate goal of protecting agricultural products safety and human health. © 2019, Science Press. All right reserved. 
Colonization; Degradation mechanism; Functional bacteria; PAHs; Ryegrass