1. Introduction
Soil microbes are crucial for nutrient cycling, organic matter decomposition, and overall soil health, which is vital for the sustainability of terrestrial ecosystems. The role of soil microbial communities in regulating biogeochemical cycles and maintaining ecosystem functions is well-recognized [1,2,3,4]. Notably, microbial communities are more sensitive to environmental fluctuations than plants and animals [5,6]. Variations in factors such as climatic conditions, vegetation patterns, and soil characteristics, especially in environments with altitude gradients, can profoundly alter microbial community structures and functions [7,8]. Despite the importance of soil microbes, the underlying drivers that shape microbial diversity and community composition have not been fully explored, particularly in regions where environmental gradients such as altitude create highly variable conditions. Further exploration of these factors is essential for gaining a deeper insight into the intricate interplay between soil microbial communities and their environment, ultimately contributing to the conservation and restoration of soil health and the sustainability of terrestrial ecosystems.
Altitude is known to be a major determinant of soil microbial diversity, yet its interaction with plant species in shaping these communities has not been sufficiently addressed. Numerous studies have highlighted that changes in altitude induce significant shifts in air temperature, moisture, soil nutrient availability, and biodiversity, which, in turn, affect the structure and function of microbial communities [9,10]. Nevertheless, while altitude is often treated as the primary influencing factor, the pivotal role of plant species—through mechanisms such as root exudation and litter deposition—remains underexplored in these considerations [11]. Deciphering how plant species interact with altitude to influence soil microbes is critical for obtaining a holistic understanding of ecosystem dynamics.
The functional diversity of microbial communities is as important as their taxonomic diversity. Microorganisms facilitate the recycling of organic matter through metabolic activities, thereby enhancing soil structure and fertility [1]. They also enhance stress resistance and promote plant growth and development through processes such as rhizosphere nitrogen fixation and phosphorus solubilization [12,13,14]. Furthermore, microorganisms play a pivotal role in soil remediation and ecological function restoration by degrading pollutants in soil and participating in biochemical processes, such as carbon and nitrogen cycling [15,16]. However, the relationship between microbial functional diversity and influence factors, such as altitude and plant species, is not well understood, impeding our ability to accurately predict how these communities might respond to environmental changes. This knowledge gap highlights the need for research that integrates both taxonomic and functional perspectives, which is crucial for advancing our understanding of plant–microbe interactions. Moreover, it is also essential for developing effective conservation and management strategies for ecosystems vulnerable to environmental changes.
The Qinling Mountains, serving as a vital ecological security barrier in China, are also a transitional and sensitive zone between subtropical and warm temperate climates. They hold a wide range of altitude gradients and abundant biodiversity, yet are also vulnerable to the spread and expansion of invasive plant species. In an earlier risk assessment of 131 exotic plant species recorded in the Qinling Mountains, 4 were identified as extremely high risks, including Galinsoga quadriradiata [17]. Our study focused on the soil microbial communities associated with the invasive G. quadriradiata and the native Artemisia lavandulifolia across various altitudinal regions within the Qinling Mountains. By analyzing soil bacterial α-diversity, community composition, and relationships with environmental factors and plant nutrients and by predicting soil bacterial functional traits, we aimed to fill critical gaps concerning the effects of environmental and biotic drivers on microbial community structure and function. Specifically, the objectives were to (1) compare the composition and diversity of soil bacterial communities along altitude gradients; (2) determine the differences in environmental and plant nutrient factors that influence soil bacterial communities; and (3) clarify the functional characteristics of soil bacterial communities between the two species. This research can help us understand how different plant species shape the structure and function of soil microbial communities, while also revealing the potential damage of invasive plants to the soil environment. Therefore, these findings contribute to conservation efforts or invasive species management in mountainous ecosystems.
2. Materials and Methods
2.1. Study Site and Sample Collection
This study was conducted at Huanghualing (108°52′56.9″ N and 33°47′44.6″ E, 2328 m a.s.l), located in the Niubeiliang National Nature Reserve of eastern Zhashui County, Shaanxi Province. The area is situated 31 km uphill from the Qinling River basin, with a mean annual precipitation (MAP) and annual mean temperature (AMT) of 850–950 mm and 2–10 °C, respectively. The frost-free period lasts for approximately 130 days.
Two plant species were selected for this study: Galinsoga quadriradiata, an invasive species known for its adaptability to diverse environmental conditions, and Artemisia lavandulaefolia, a native species commonly found in the study region. These species were chosen to investigate the effects of different plant traits and ecological strategies on soil microbial communities across an altitudinal gradient.
Soils and plant organs were sampled at 6 altitudes (896, 1056, 1202, 1413, 1713, and 1889 m), with a distribution of the two species. At each altitude, three random individuals of each species were selected in August 2022 to capture peak microbial activity, resulting in a total of 36 individuals (18 per species). After removing apoplastic material from the soil surface, we dug up all the selected individual plants. A sterile, soft-bristled paintbrush was then used to strip away the rhizosphere soil tightly adhered to the root surface. The collected soil samples were divided into two parts: one part was passed through a 2 mm sieve to remove roots and debris, and it was air-dried indoors to determine soil physicochemical properties; the remaining part was stored in an ice box, taken to the laboratory, and then stored at −80 °C for DNA extraction. The plant was divided into three parts, namely roots, stems, and leaves, with each part intact and in a healthy state; then, the parts were stored in a portable ice box for transportation to the laboratory. Next, they were oven-dried at 65 °C to a constant weight, milled, and sifted through a 0.1 mm screen. The obtained powder was used to measure plant physiochemical parameters.
2.2. Determination of Soil and Plant Physiochemical Properties
Soil physiochemical properties included soil organic carbon, nitrogen, phosphorus, potassium, and soil pH. Soil organic carbon was determined via K2Cr2O7 oxidation; the total nitrogen content was analyzed using the Kjeldahl method; total phosphorus was measured using the alkali fusion–Mo-Sb anti-spectrophotometric method; total potassium was quantified via flame photometry; and soil pH was determined using the potentiometric method [18].
Plant physiochemical properties covered the organic carbon, nitrogen, and phosphorus in the root, stem, and leaf, and they were determined via K2Cr2O7 oxidation, the Kjeldahl method, and the molybdenum antimony spectrophotometric method, respectively [18].
2.3. Soil Bacterial Analysis
Soil DNA was extracted from 0.5 g of each soil sample using an E.Z.N.A.® Soil DNA Kit (Omega Bio-Tek, Norcross, GA, USA). The quality and quantity of the extracted DNA were assessed using a NanoDrop 2000 spectrophotometer (Thermo Scientific, Wilmington, DelDEaware, USA) and agarose gel electrophoresis. The V3–V4 hypervariable region of the bacterial 16S rRNA gene was amplified using primers 338F (5′-ACTCCTACGGGAGGCAGCA-3′) and 806R (5′-GGACTACHVGGGTWTCTAAT-3′). Sequencing was performed on an Illumina PE300 platform (Illumina, San Diego, CA, USA) at Shanghai Majorbio Bio-Pharm Technology Co., Ltd. (Shanghai, China) The raw sequencing data were uploaded to the NCBI Sequence Rad Archive (SRA) database (accession number: PRJNA1152501). UPARSE 7.1 software was applied to generate operational taxonomic units (OTUs) of optimized sequences with a similarity of 97%. To minimize the impact of sequencing depth on the soil bacterial diversity analysis, all sample sequences were rarefied, which could still reach an average Good’s coverage of 99.09%. All sequencing data can be found at the Sequence Read Archive (SRA) of the National Center for Biotechnology Information (NCBI, Bethesda, MD, USA) under BioProject number PRJNA1152501 (
2.4. Statistical Analysis
Significant differences in soil bacterial α-diversity and soil and plant physiochemical properties across the six altitudes were examined using a variance analysis (ANOVA), while a paired t-test was applied to investigate the significant differences in these parameters between the two species. SPSS 16.0 (IBM Corp., Armonk, NY, USA) was used for the ANOVA and paired t-test.
Further soil bacterial analysis was carried out using the Majorbio Cloud platform (
3. Results
3.1. Soil Bacterial Alpha Diversity at Different Altitudes
A total of 2,094,818 high-quality soil bacterial sequences were identified from all soil samples, and they were clustered into 10,804 bacterial OTUs based on similarity. A Venn diagram indicated that there were 1494 and 1822 unique bacterial OTUs for G. quadriradiata and A. lavandulifolia, respectively, with 7488 common bacterial OTUs shared between the two species (Figure 1). As the sequencing data increased, the sparsity curves of the soil bacteria of both species basically flattened out (Figure 2). This indicates that the sequencing information was sufficient, and the OTU coverage of the samples could basically reflect the structural composition of the soil microbial communities of G. quadriradiata and A. lavandulifolia at different altitudes in the Qinling Mountains.
We selected Chao diversity and Shannon diversity to represent the soil bacterial α-diversity of G. quadriradiata and A. lavandulifolia. Chao diversity is commonly used to estimate microbial richness, and Shannon diversity indicates microbial diversity. The two indices both showed significant differences among the different altitudes but not between the two species (Table 1). Only at an altitude of 1413 m was the Chao diversity index of A. lavandulifolia significantly higher than that of G. quadriradiata.
3.2. Composition of Soil Bacterial Community Differed with Plant Species
The Bray–Curtis distance algorithm was used to construct an OTU abundance table for a PCoA analysis in order to further analyze the differences in soil bacterial communities between G. quadriradiata and A. lavandulifolia. The results show that there were significant differences (p < 0.01) in the soil bacterial communities (at the OTU level) between the two species (Figure 3).
A total of 40 and 39 bacterial phyla were detected in the soils of G. quadriradiata and A. lavandulifolia, respectively, resulting in 43 bacterial phyla for the two species (Figure 4). The top 10 dominant bacterial phyla were Actinobacteriota, Proteobacteria, Acidobacteriota, Chloroflexi, Bacteroidota, Myxococcota, Gemmatimonadota, Firmicutes, Patescibacteria, and Cyanobacteria. Among them, Actinobacteriota (33.11% and 30.17%), Proteobacteria (31.81% and 30.65%), and Acidobacteriota (10.37% and 14.25%) accounted for relatively high proportions. Other bacterial phyla, such as Chloroflexi and Bacteroidota, accounted for a minor fraction.
The linear discriminant analysis effect size (LefSe) (LDA score > 3) was employed to investigate the differences in the soil bacterial communities between G. quadriradiata and A. lavandulifolia (Figure 5). The results show that Myxococcota, SAR324-cladeMarine-group-B, and Bdellovibrionota were significantly enriched in G. quadriradiata, while Acidobacteriota, Elusimicrobiota, RCP2-54, Methylomirabilota, Latescibacterota, and unclassified-k-norank-d-Bacteria were significantly enriched in A. lavandulifolia. These findings indicate that most of the dominant bacterial phyla in the soil microbial communities of the two species were consistent with the LEfSe analysis results, and they could serve as bacterial indicators most closely related to the microbial communities of G. quadriradiata and A. lavandulifolia.
3.3. Associations of Soil Bacterial Community with Environmental and Plant Factors
The differences in most soil parameters reached statistical significance among all altitudes of the two species, except for soil C/N in A. lavandulifolia (Table S1). However, obvious differences were observed only in several altitudes between the two species. Regarding plant characteristics, significant differences among the different altitudes were found in the stem N and leaf N of both species and the leaf P of G. quadriradiata. Root P, leaf N, and leaf P presented nonsignificant differences between the two species at the same altitude (Table S2).
Relationships between environmental factors (including soil factors and altitude) and plant factors (including roots, stems, and leaves) with bacterial abundance were explored using an RDA analysis (Figure 6). Regarding environmental factors, the first and second axes of RDA explained 57.51% and 44.58% of the variation in bacterial abundance in G. quadriradiata and A. lavandulifolia, respectively. Regarding plant factors, the first and second axes of the RDA respectively explained 43.78% and 40.97%. Compared with plant indicators, environmental factors had a greater impact on plant soil bacterial abundance. Correlation analysis indicated that, for G. quadriradiata, soil pH, C, N, K, C/N, N/P, C/P, altitude, and leaf N significantly affected bacterial community structures. For A. lavandulifolia, the significant factors were soil pH, N, N/P, altitude, root N, P, stem N, and leaf N.
3.4. Functional Analyses of Soil Bacteria
The FAPROTAX database was utilized to predict the functions of the soil bacterial communities, resulting in the identification of 61 functional groups (Figure 7). The relative abundances of the top 15 functional groups accounted for 89.62% and 88.88% of the total relative abundances in G. quadriradiata and A. lavandulifolia, respectively. Chemoheterotrophy and aerobic-chemoheterotrophy, which utilize organic compounds to meet all or primarily carbon demands, were the primary metabolic functional groups of the bacteria in the two species soils.
In the soil of G. quadriradiata, the relative abundances of metabolic functional groups that are correlated to organic matter decomposition and the carbon cycle (such as dark_hydrogen_oxidation, methanol_oxidation, methylotrophy, cellulolysis, cyanobacteria, oxygenic_photoautotrophy, and fermentation) were higher than those in the soils of A. lavandulifolia. Conversely, in the soil of A. lavandulifolia, the relative abundances of various metabolic functional groups related to nitrogen and sulfur cycles (such as anoxygenic_photoautotrophy, anoxygenic_photoautotrophy_S_oxidizing, dark_sulfide_oxidation, photoheterotrophy, chitinolysis, invertebrate_parasites, nitrogen_fixation, chloroplasts, denitrification, and nitrate_denitrification) were higher, with most of them closely related to nitrogen fixation, nitrification, and denitrification processes.
4. Discussion
This study provides a comprehensive analysis of soil bacterial diversity and community composition in relation to plant species and altitude in the Qinling Mountains. By comparing an invasive species G. quadriradiata with a native species and A. lavandulifolia across an altitudinal gradient, we discovered that both plant species and altitude significantly influence the structure and function of soil microbial communities. These findings not only enrich our understanding of plant–microbe interactions in mountainous ecosystems but also offer insights into how these interactions may be influenced by environmental gradients, with implications for ecosystem management and conservation efforts.
4.1. Soil Bacterial Diversity and Composition in Relation to Plant Species and Altitude
This study revealed pronounced differences in soil bacterial diversity and community composition between G. quadriradiata and A. lavandulifolia. Notably, the shared OTUs between the two species indicated that, while the overall microbial pool exhibited similarities, specific environmental conditions and plant traits drove distinct microbial community structures (Figure 1). These findings concur with those of previous studies, which reported altitude as a key factor modulating soil microbial diversity, attributed to variations in temperature, moisture, and nutrient availability [19,20,21]. However, the statistical difference in Chao diversity between the two species was only observed at 1413 m, potentially due to the plant’s physiological adaptations or specific interactions with the soil microbiome (Table 1).
A PCoA analysis showed distinct microbial community structures between the two species (Figure 3), supporting the opinion that plant species could significantly shape soil microbial communities through root exudates, litter inputs, and nutrient cycling processes [22,23]. This coincides with the concept that plants influence microbial communities in ways that could affect plant health and ecosystem functions [1,4,24,25]. However, the current study deeply analyzed the specific bacterial phyla, such as Myxococcota and Acidobacteriota, which exhibited differential enrichment patterns in the soils of G. quadriradiata and A. lavandulifolia, respectively (Figure 4). This observation might reflect the functional specialization of these microbial communities, with potential implications for nutrient cycling and overall soil health. The enrichment of Myxococcota in G. quadriradiata soils might enhance organic matter decomposition (Figure 5) [26,27], whereas the higher abundance of Acidobacteriota in A. lavandulifolia soils could be associated with more acidic conditions, fostering nutrient cycles, such as nitrogen fixation (Figure 5) [28,29]. The results demonstrate that the two species might contribute uniquely to soil ecosystem functions, which could affect plant succession patterns and competition dynamics within the Qinling Mountains ecosystem.
4.2. Environmental and Plant Factors Driving Microbial Communities
An RDA analysis revealed the significant role of altitude in shaping soil microbial communities, which further emphasized the importance of abiotic factors in structuring microbial populations (Figure 6). Among the environmental variables, soil pH and nutrient content emerged as major determinants of microbial community composition. This is in line with previous research that pinpointed soil pH as a primary driver of bacterial community structure due to its profound influence on microbial metabolism and nutrient availability [30,31].
Notably, our study also highlighted the significant influence of plant traits, particularly leaf nitrogen content, on microbial community structure. The correlation between nitrogen content in plant tissues and the abundance of nitrogen-cycling bacteria implies that plants could actively modulate microbial functions to meet their nutritional requirements. This interplay between plant traits and microbial communities underscores the complexity of plant–soil interactions and indicates that managing plant nutrient status could be a key strategy for influencing soil microbial health [32,33].
4.3. Functional Implications of Soil Microbial Communities
Interactions between bacteria and plants are ubiquitous in nature. The rhizosphere, one of the most complex ecosystems on Earth, is a narrow zone rich in bacteria surrounding plant roots [34]. All substances absorbed and released from the soil by plants must traverse the rhizosphere, where their flow, transport, and reaction are also influenced by this specific region [35]. Consequently, the composition and function of rhizosphere bacteria exhibit a close relation [36]. Andreote and Pereira E Silva emphasized that plants are highly dependent on the bacteria surrounding the root system, which can promote plant growth and protect plants under stress conditions [37]. It can be considered that changes in the bacteria community and composition around plant roots have a stronger influence on plant health.
In the current study, the functional predictions from the FAPROTAX database revealed that, for both species, soil bacterial communities were primarily involved in chemoheterotrophy and aerobic chemoheterotrophy (Figure 7), which are crucial for organic matter decomposition and carbon cycling [38]. The relative abundances of bacterial functional groups, including dark_hydrogen_oxidation, methanol_oxidation, methylotrophy, cellulolysis, cyanobacteria, oxygenic_photoautotrophy, and fermentation were significantly higher in the rhizosphere of G. quadriradiata, mainly contributing to energy acquisition, and carbon and nitrogen transformation, as well as serving as primary producers by synthesizing organic matter to provide the foundation for the food chain [39]. In contrast, the bacterial functional groups in the soil of A. lavandulifolia, such as anoxygenic_photoautotrophy, dark_sulfide_oxidation, photoheterotrophy, and nitrite/nitrate respiration/denitrification, played key roles as carbon sources and in energy supply in anoxic or hypoxic environments, as well as nitrogen fixation and denitrification [40,41].
The enhanced nitrogen cycling potential in A. lavandulifolia soils could improve nitrogen availability, which might influence interspecific competition and succession, especially in nitrogen-limited environments [42,43]. Furthermore, the higher rates of organic matter decomposition in G. quadriradiata soils might accelerate carbon turnover, affecting soil organic matter content and long-term soil fertility [44,45]. These functions would undoubtedly increase the growth rate of invasive plants and present a competitive advantage, forming a favorable micro-ecological environment for the invasion and expansion of G. quadriradiata, thereby enhancing its invasiveness [46].
4.4. Implications of Species-Specific Diversity and Function Patterns of Soil Microbial Communities
The distinct microbial communities associated with G. quadriradiata and A. lavandulifolia demonstrated that these species could differentially influence soil health and ecosystem functions, with potential implications for plant community dynamics in the Qinling Mountains. Moreover, altitude, as a crucial environmental factor, can lead to significant changes in climate, vegetation, and soil properties over relatively short distances, impacting soil microbial growth and resource acquisition. The interactions among microorganisms may become more complex and intense, potentially triggering a chain reaction that influences plant health and ecosystem resilience. Understanding these interactions is crucial for controlling invasive species and preserving biodiversity in this region [21,47,48,49]. The study of soil microbial communities and their functions is of great significance for vegetation restoration and reconstruction. Introducing or restoring microbial communities with specific functions would inhibit the spread of invasive plants and promote the recovery of native plants, thereby enhancing the stability and resilience of ecosystems.
However, our study only examined the distribution patterns of the soil bacteria community, lacking an analysis of archaea, fungi, and protists, as well as their interactions. In addition, the seasonal sampling period might also influence the results. Furthermore, research on plants, particularly exotic species, predominantly focuses on a single species. Therefore, future attention should be directed toward the integration of different microbial taxa (e.g., analyses of fungi or archaea) and the impact of community diversity on the spread of single or multiple invasive species in order to further reveal the correlation between specific functional microorganisms and invasion mechanisms.
5. Conclusions
Our study revealed the distribution patterns and driving factors of the soil bacterial communities of an invasive species, G. quadriradiata, and a native species, A. lavandulifolia, at different altitudes. The findings show that the differences in soil bacterial α-diversity were significant at different altitudes but insignificant between invasive and native species. However, at the OTU level, there were obvious differences in soil bacterial communities between the two species. The soil bacterial abundance of both species was influenced by altitude, soil physicochemical properties (e.g., soil pH, N, and N/P), and species-specific factors (e.g., leaf N content). Functional analysis indicated that chemoheterotrophy and aerobic-chemoheterotrophy were the primary metabolic functional groups of the soil bacteria of both G. quadriradiata and A. lavandulifolia. The abundance of metabolic functional groups closely related to nitrogen fixation, nitrification, and denitrification in the soil of A. lavandulifolia was higher than that in the soil of G. quadriradiata. Conversely, the soil bacteria of G. quadriradiata contributed more to organic matter decomposition. The structure and function of bacterial communities play crucial roles in the productivity and health of soil ecosystems. These findings demonstrate that plant species and altitude are key properties of soil bacterial community structure and function, thus providing insights into strategies for managing invasive species and supporting ecosystem resilience. Future research could integrate aboveground vegetation communities and litter with underground microbial communities to deeply understand soil–microbe–plant interactions.
Conceptualization, Y.W., J.L., and M.Y.; investigation and data curation, W.X. and X.W.; formal analysis, Y.L.; writing-original draft, J.L.; writing-review and editing, Y.W. and M.Y. All authors have read and agreed to the published version of the manuscript.
The raw data supporting the conclusions of this article will be made available by the authors upon request.
The authors declare no conflicts of interest.
Footnotes
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Enlarge this image.Figure 1. Venn diagram of soil bacteria of G. quadriradiata and A. lavandulifolia.
Enlarge this image.Figure 2. Sparsity curves of soil bacterial samples at 97% level for G. quadriradiata and A. lavandulifolia.
Enlarge this image.Figure 3. Principal coordinates analysis (PCoA) of the bacterial communities between G. quadriradiata and A. lavandulifolia. Note: red circles are for A. lavandulifolia; blue circles are for G. quadriradiata.
Enlarge this image.Figure 4. Relative abundance of the dominant bacterial phyla (%) in G. quadriradiata and A. lavandulifolia.
Enlarge this image.Figure 5. Indicator bacteria with an LDA score of 3 or greater in bacterial communities associated with soil from the two species.
Enlarge this image.Figure 6. Redundancy analysis (RDA) was conducted to identify the relationships between soil bacteria community and environmental or plant factors. Note: (a,b) represent the RDA analysis performed between the soil bacterial communities and environmental factors; (c,d) represent the RDA analysis performed between the soil bacterial communities and plant factors. The red arrow indicates significant correlations; the green arrow indicates insignificant correlations. C, soil organic carbon; N/P/K soil total nitrogen/phosphorus/potassium; C/N, the ratio of C to N; C/P, the ratio of C to P; N/P, the ratio of N to P; Root/Stem/Leaf-C, root/stem/leaf organic carbon; Root/Stem/Leaf-N/P, root/stem/leaf nitrogen/phosphorus.
Enlarge this image.Figure 7. Relative abundance of predicted biogeochemical functions in soil bacterial communities of G. quadriradiata and A. lavandulifolia.
Differences in bacterial alpha diversity across altitudes in G. quadriradiata and A. lavandulifolia.
| Diversity Indices | Altitude | 896 m | 1056 m | 1202 m | 1413 m | 1713 m | 1889 m | |
|---|---|---|---|---|---|---|---|---|
| Species | ||||||||
| Chao diversity index | G. quadriradiata | 4497.71 ± 96.39 Aab | 3597.99 ± 47.28 Ac | 4363.53 ± 70.73 Aab | 3568.41 ± 59.48 Bc | 4183.72 ± 202.06 Ab | 4635.18 ± 93.27 Aa | |
| A. lavandulifolia | 3890.32 ± 180.09 Aa | 4108.95 ± 449.64 Aa | 4553.25 ± 97.95 Aa | 4026.09 ± 118.66 Aa | 3800.81 ± 292.93 Aa | 4429.89 ± 117.25 Aa | ||
| Shannon-Wiener diversity index | G. quadriradiata | 6.65 ± 0.04 Aa | 5.65 ± 0.32 Ab | 6.63 ± 0.06 Aa | 6.32 ± 0.03 Aa | 6.55 ± 0.07 Aa | 6.72 ± 0.02 Aa | |
| A. lavandulifolia | 6.46 ± 0.10 Aa | 6.47 ± 0.10 Aa | 6.64 ± 0.05 Aa | 6.49 ± 0.06 Aa | 6.34 ± 0.27 Aa | 6.66 ± 0.03 Aa | ||
Note: The data are presented as mean ± standard errors. Different uppercase letters indicate significant differences between the two species at the same altitude (p < 0.05), different lowercase letters indicate significant differences among different altitudes for each species (p < 0.05), and the same letters indicate insignificant differences. Chao diversity is commonly used to estimate microbial richness, and Shannon diversity indicates microbial diversity.
Supplementary Materials
The following supporting information can be downloaded at:
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; Xue, Wenyan 1 ; Wang, Yuchao 3 ; Yang, Li 1 ; Wang, Xue 4 1 Xi’an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, Xi’an 710061, China;
2 Xi’an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, Xi’an 710061, China;
3 Xi’an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, Xi’an 710061, China;
4 Xi’an Botanical Garden of Shaanxi Province, Institute of Botany of Shaanxi Province, Xi’an 710061, China;