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 Effects of simulated root exudate carbon inputs on dynamics in microbial community during litter decomposition*(PDF)

Chinese Journal of Applied & Environmental Biology[ISSN:1006-687X/CN:51-1482/Q]

2020 02
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 Effects of simulated root exudate carbon inputs on dynamics in microbial community during litter decomposition*
 HU Kai1 TAO Jianping2 HU ANG Ke 1 HU Jing1&WANG Wei1**
1College of Forestry and Life Science, Institute of Microbial Ecology, Chongqing University of Arts and Sciences, Yongchuan 402168, China
2Key Laboratory of Eco-environments of Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources of Three Gorges Reservoir Region, School of Life Science, Southwest University, Chongqing 400715, China
root exudation leaf litter decomposition microbial community microbial quantity enzyme activities

To understand how root exudates influence litter decomposition in forest ecosystems, a simulation experiment using four different concentrations (0, 0.3, 0.6 and 1.2 mg C/g soil) of carbon (C) compounds often found in root exudates were added to soils to assess how labile C inputs regulate litter decomposition and soil microbial communities i n a 20 d laboratory incubation. The results indicated that a certain concentration of root exudate C inputs (0.6 and 1.2 mg C/g soil) caused a relative increase in the number of microbes, especially fungi, on the surface of leaf litter, obviously changed the composition of microbial communities in the process of litter decomposition, activated some fast-growing fungi, and promoted microbial metabolic activities, which led to the increase of the decomposition rate by 19.0%-26.2%. Root exudate C addition, sampling time, and their interaction had significant effects on the activities of β-glucosidase and β-N-acetylglucosaminidase on the litter surface. With the decomposition prolonging, 0.6 and 1.2 mg C/g soil addition could significantly increase the activities of the two enzymes. The root exudate C addition had no significant effect on the number of archaeal amoA and bacterial amoA on the surface of the litter . However, the treatments of 0.6 mg C/g soil addition could significantly increase the copy number of nifH gene and nosZ gene on 20 th day of decomposition. In summary, a certain concentration of root exudates could change the composition and quantity of microbial communities, increase the extracellular enzyme activities of microbes, and thus accelerate litter decomposition. In addition, the initiation of the priming effect was determined by the interaction of C content added by the substrate and the active microbial communities.




Last Update: 2019-07-30