Chin J Plant Ecol ›› 2018, Vol. 42 ›› Issue (12): 1200-1210.DOI: 10.17521/cjpe.2018.0120

• Research Articles • Previous Articles     Next Articles

Effects of fine root decomposition on bacterial community structure of four dominated tree species in Mount Taishan, China

LU Ying,LI Kun,NI Rui-Qiang,LIANG Qiang,LI Chuan-Rong,ZHANG Cai-Hong()   

  1. Taishan Forest Ecosystem Research Station of the State Forestry Administration, Tai’an, Shandong 271018, China; and Key Labora-tory of State Forestry Administration for Silviculture of the Lower Yellow River, Tai’an, Shandong 271018, China
  • Received:2018-02-21 Revised:2018-10-31 Online:2018-12-20 Published:2019-04-04
  • Contact: Cai-Hong ZHANG
  • Supported by:
    Supported by the National Natural Science Foundation of China(31500362);Supported by the National Natural Science Foundation of China(31570705);the Joint Special Project of Shandong Province(ZR2014CL005);the Funds of Shandong “Double Tops” Program(SYL2017XTTD03)

Abstract:

Aims Microorganisms play a crucial role in the litter decomposition process in terrestrial ecosystems. Understanding the independent and interactive relationship between fine root decomposition and bacteria community related to substrate characteristics can help to predict the consequences of changes on ecosystem function. Therefore, the aim of this study was to identify fine roots’ influences on rhizosphere microbial structure and diversity.

Methods The decomposition of root litters of four dominant tree species of Mount Taishan (Robinia pseudoacacia(RP), Quercus acutissima(QA), Pinus tabulaeformis(PT) and Pinus densiflora(PD)) was tested in a Yaoxiang Forest Farm. Using Illumina high-throughput sequencing of 16S rRNA genes, bacterial community composition was determined. Composition, diversity and relative abundance of bacteria were calculated for per fine root litter.

Important findings (1) Fine root litter decomposition differed significantly among different root types. There was no difference in decomposition rate between broad-leaved species and conifer species. In all species, fine roots of RP and QA were more strongly decomposed than that of PT and PD, and these differences were significant (RP > QA > PT > PD). (2) The number of observed species, operational taxonomic units, Ace index and phylogenetic diversity in broad-leaved species were significantly lower than that in coniferous species. Bacterial community structure differed significantly among four species for root decomposition. Initial carbon (C), lignin:nitrogen (N) and C:N in fine root had a great influence on the bacterial community structure. (3) At the phylum level, a total of 4 phyla were dominant (>5% across all species). Based on the average relative abundance, the most abundant phyla were Proteobacteria, Actinomyces, Bacteroidetes and Acidobacteria. Proteobacteria’s and Acidbacteria’s abundance were significantly different among the four species. Particularly, the Proteobacteria of broad-leaved species was significantly higher than that of coniferous species. At the class level, a wide range of classes dominated. Based on the average relative abundance, the most abundance classes were Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, unidentified-Actinobacteria and Sphingobacteriia. Alphaproteobacteria and unidentified-Actinobacteria had significant differences among the four species. (4) Pearson correlation analysis showed that the relative abundance of dominant phylum and class was affected by the initial properties of root litter, especially the Proteobacteria and Alphaproteobacteria. In addition, there was a significant positive correlation between fine root decomposition rate and relative abundance of Proteobacteria and Alphaproteobacteria. Redundancy analysis (RDA) also demonstrated that the initial properties of fine root litter (initial N, P, C:N) had significant effects on the structures of bacterial community. These results can improve understanding the links between fine root litter decomposition and functional microbial communities.

Key words: decomposition, fine root, bacterial community, diversity