Unravelling the Functional Diversity of the Soil Microbial Community of Chinese Fir Plantations of Different Densities

作   者： Chaoqun Wang , Lin Xue, Yuhong Dong, Yihui Wei and Ruzhen Jiao
期刊名称：Forests
影响因子：1.956
卷 期 号：9(9)
页     码：532
关键词： stand density change drivers; plant-micro-organism interactions; metabolic function; Biolog ECO
论文摘要：
The structure and function of forest ecosystems are directly or indirectly affected by their
stand density. However, what effect the density of Chinese fir plantations has on the functional
diversity of the soil microbial community remains unclear. The microbial metabolic functional
diversity of soils sampled at the topsoil (0–20 cm) of 35-year-old Chinese fir plantations of five initial
densities (D1: 1667 stems hm􀀀2, D2: 3333 stems hm􀀀2, D3: 5000 stems hm􀀀2, D4: 6667 stems hm􀀀2,
and D5: 10,000 stems hm􀀀2) was studied by using Biolog ECO technology. The results showed that
the soil pH, oxidizable organic carbon (SOOC), available N (AN), available P (AP), and available
K (AK) contents all showed a gradual increase from D1 to D4 and a decrease from D4 to D5, while
the number of culturable bacteria and total microorganisms, the average well color development
(AWCD) values for the single carbon substrate and six types of carbon sources used by the microbial
community, as well as the Shannon-Wiener diversity index (H’), Pielou evenness index (J), and
McIntosh Diversity Index (U), were the opposite, suggesting that low-densities favored C and N
mineralization and the nutrient cycle. The density of Chinese fir plantations had a significant effect
on the use of carbohydrates, amino acids, carboxylic acids, and phenolic acids by the soil microbial
community, but it had no significant effect on the use of polymers (p < 0.05). principal component
analysis (PCA) revealed that carbohydrates, polymers, and phenolic acids were sensitive carbon
sources that caused differences in the metabolic functions of soil microbial communities in Chinese
fir plantations. Redundancy analysis (RDA) showed that physicochemical factors have a significant
influence on the metabolic function of soil microbial communities (RDA1 and RDA2 explained >85%
variance). The changes in density affected the soil physicochemical properties, the composition,
and the metabolic functional diversity of microbial communities in Chinese fir plantations, which is
certainly useful for the stand density regulation of Chinese fir plantations.