scholarly journals Response of soil microbial community and hydrothermal environment to nitrogen deposition in Pinus massoniana forest in Central Asia

2019 ◽  
Vol 23 (5 Part A) ◽  
pp. 2551-2559
Author(s):  
Nanjie Li ◽  
Qingping Zeng ◽  
Shuhui Jiang ◽  
Binghui He

In order to demonstrate the response of soil microbial community and hydrothermal environment to nitrogen deposition (low nitrogen N20: 20 kg?hm?2; medium nitrogen N40: 40 kg?hm?2; high nitrogen N60: 60 kg?hm-2, and contrast N0: 0 kg?hm?2), a Pinus massoniana forest in Central Asia was chosen to do the nitrogen deposition simulation experiment. This research is aimed to provide a theoretical evidence for the protection of soil ecosystem under different forest types in china. The results showed that: soil microbes of Pinus massoniana forest were in seasonal changes (spring, autumn, winter, and summer). Differences in different seasons were significant: a very significant quadratic relationship was shown between soil microbes and soil temperature. However, the relationship between soil microbes and the soil water content was not closely related. The N deposition reduced the relationship between microbes and temperature but increased the correlation between microbes and water content: effects of N deposition on soil temperature and soil water content were significant, but the effects were in small scale, and the effects of N deposition on soil microbial community structure were significant.

2019 ◽  
Vol 116 (15) ◽  
pp. 7371-7376 ◽  
Author(s):  
Jenalle L. Eck ◽  
Simon M. Stump ◽  
Camille S. Delavaux ◽  
Scott A. Mangan ◽  
Liza S. Comita

Microbes are thought to maintain diversity in plant communities by specializing on particular species, but it is not known whether microbes that specialize within species (i.e., on genotypes) affect diversity or dynamics in plant communities. Here we show that soil microbes can specialize at the within-population level in a wild plant species, and that such specialization could promote species diversity and seed dispersal in plant communities. In a shadehouse experiment in Panama, we found that seedlings of the native tree species, Virola surinamensis (Myristicaceae), had reduced performance in the soil microbial community of their maternal tree compared with in the soil microbial community of a nonmaternal tree from the same population. Performance differences were unrelated to soil nutrients or to colonization by mycorrhizal fungi, suggesting that highly specialized pathogens were the mechanism reducing seedling performance in maternal soils. We then constructed a simulation model to explore the ecological and evolutionary consequences of genotype-specific pathogens in multispecies plant communities. Model results indicated that genotype-specific pathogens promote plant species coexistence—albeit less strongly than species-specific pathogens—and are most effective at maintaining species richness when genetic diversity is relatively low. Simulations also revealed that genotype-specific pathogens select for increased seed dispersal relative to species-specific pathogens, potentially helping to create seed dispersal landscapes that allow pathogens to more effectively promote diversity. Combined, our results reveal that soil microbes can specialize within wild plant populations, affecting seedling performance near conspecific adults and influencing plant community dynamics on ecological and evolutionary time scales.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Minghui Liu ◽  
Xin Sui ◽  
Yanbo Hu ◽  
Fujuan Feng

Abstract Background The broad-leaved Korean pine mixed forest is an important and typical component of a global temperate forest. Soil microbes are the main driver of biogeochemical cycling in this forest ecosystem and have complex interactions with carbon (C) and nitrogen (N) components in the soil. Results We investigated the vertical soil microbial community structure in a primary Korean pine-broadleaved mixed forest in Changbai Mountain (from 699 to 1177 m) and analyzed the relationship between the microbial community and both C and N components in the soil. The results showed that the total phospholipid fatty acid (PLFA) of soil microbes and Gram-negative bacteria (G-), Gram-positive bacteria (G+), fungi (F), arbuscular mycorrhizal fungi (AMF), and Actinomycetes varied significantly (p < 0.05) at different sites (elevations). The ratio of fungal PLFAs to bacterial PLFAs (F/B) was higher at site H1, and H2. The relationship between microbial community composition and geographic distance did not show a distance-decay pattern. The coefficients of variation for bacteria were maximum among different sites (elevations). Total soil organic carbon (TOC), total nitrogen (TN), soil water content (W), and the ratio of breast-height basal area of coniferous trees to that of broad-leaved tree species (RBA) were the main contributors to the variation observed in each subgroup of microbial PLFAs. The structure equation model showed that TOC had a significant direct effect on bacterial biomass and an indirect effect upon bacterial and fungal biomass via soil readily oxidized organic carbon (ROC). No significant relationship was observed between soil N fraction and the biomass of fungi and bacteria. Conclusion The total PLFAs (tPLFA) and PLFAs of soil microbes, including G-, G+, F, AMF, and Actinomycetes, were significantly affected by elevation. Bacteria were more sensitive to changes in elevation than other microbes. Environmental heterogeneity was the main factor affecting the geographical distribution pattern of microbial community structure. TOC, TN, W and RBA were the main driving factors for the change in soil microbial biomass. C fraction was the main factor affecting the biomass of fungi and bacteria and ROC was one of the main sources of the microbial-derived C pool.


Author(s):  
Yongyong Zhang ◽  
Monika Resch ◽  
Martin Schuetz ◽  
Ziyan Liao ◽  
Beat Frey ◽  
...  

It is generally assumed that there is a relationship between microbial diversity and multiple ecosystem functions. Although it is indisputable that microbial diversity is controlled by stochastic and deterministic ecological assembly processes, the relationship between these processes and soil multifunctionality (SMF) remains less clear. In this study, we examined how different grassland restoration treatments, namely harvest only, topsoil removal and topsoil removal plus propagule addition, affected i) soil bacterial and fungal community stochasticity, ii) SMF, and iii) the relationship between community stochasticity and SMF. Results showed that soil microbial community stochasticity decreased in all the three restoration treatments, while SMF increased. Soil multifunctionality was found to be significantly and negatively correlated with soil microbial community stochasticity. Plant diversity and plant C/N indirectly influenced SMF by regulating the microbial community stochasticity. Our findings provide empirical evidence that when deterministic community assembly processes dominate in soils, then higher microbial functioning is expected.


Author(s):  
Hanchang Zhou ◽  
Anzhou Ma ◽  
Liu Guohua ◽  
Xiaorong Zhou ◽  
Jun Yin ◽  
...  

Ecosystem degradation is a process during which different ecosystem components interact and affect each other. The microbial community, as a component of the ecosystem whose members often display high reproduction rates, is more readily able to respond to environmental stress at the compositional and functional levels, thus potentially threatening other ecosystem components. However, very little research has been carried out on how microbial community degradation affects other ecosystem components, which hampers the comprehensive understanding of ecosystems as a whole. In this study, we investigated the variation in a soil microbial community through the extinction gradient of an ectomycorrhizal species (Tricholomas matsutake) and explored the relationship between microbial community degradation and ectomycorrhizal species extinction. The result showed that during degradation, the microbial community switched from an interactive state to a stress tolerance state, during which the interactivity of the microbial community decreased, and the reduced community interactions with T.matsutake marginalized it from a large central interactive module to a small peripheral module, eventually leading to its extinction. This study highlights the mechanisms of T.matsutake extinction due to the loss of soil microbial community interactivity, offering valuable information about soil microbial community degradation and the plant ectomycorrhizal species conservation.


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