Moso bamboo (Phyllostachys edulis) expansion enhances soil pH and alters soil nutrients and microbial communities.

Amid global environmental concerns, the issue of bamboo expansion has garnered significant attention due to its extensive and profound impacts on the ecosystems. Bamboo expansion occurs in native and introduced habitats worldwide, particularly in Asia. However, the effects of bamboo expansion on soil pH, nutrient levels, and microbial communities are complex and vary across different environments. To address this knowledge gap, we conducted a meta-analysis with 2037 paired observations from 81 studies. The results showed that soil pH increased by 6.99 % (0-20 cm) and 4.49 % (20-40 cm) after bamboo expansion. Notably, soil pH increased more in the coniferous forest with bamboo expansion than in the broadleaf forest. Soil pH progressively increased over time since the establishment of bamboo stands. The extent of soil pH elevation was significantly positively correlated with the proportion of bamboo within the forest stand and mean annual solar radiation. In contrast, it was significantly negatively correlated with the mean annual temperature. The elevation of pH is closely related to expansion stage and expanded forest type rather than primarily shaped by climatic factors across a large scale. We also found that bamboo expansion into coniferous forests brought about a notable 14.14 % reduction in total nitrogen (TN). Varied expansion stages resulted in TN reductions of 6.88 % and 7.99 % for mixed forests and bamboo stands, respectively, compared to native forests. Pure bamboo stands exhibited a remarkable 30.39 % increase in ammonium nitrogen and a significant 21.12 % decrease in nitrate nitrogen compared to their native counterparts. Furthermore, bamboo expansion contributed to heightened soil fungal diversity. Taken together, our findings highlight that bamboo expansion leads to an increase in soil pH and alters soil N components and fungal microbial communities, providing valuable insights for future ecological conservation and resource management.

Leaf stomatal traits rather than anatomical traits regulate gross primary productivity of moso bamboo (Phyllostachys edulis) stands.

Leaf stomatal and anatomical traits strongly influence plant productivity. Understanding the environmental adaptation mechanisms of leaf stomatal and anatomical traits and their relationship with ecosystem productivity is essential to better understand and predict the long-term adaptation strategies to climate change of moso bamboo forests. Here, we selected 6 sites within the moso bamboo distribution area, measured 3 leaf stomatal traits and 10 leaf anatomical traits of unmanaged moso bamboo stands. We explored the spatial variation characteristics of these traits and their response to environmental changes, assessed the relationships among these traits at regional scales through network analysis, and tested the direct and indirect effects of environmental, leaf stomatal and anatomical traits on gross primary productivity (GPP) of bamboo stands using structural equation modeling (SEM). The results showed that both climate and soil factors significantly affected leaf stomatal and anatomical traits of moso bamboo. Solar radiation (SR) and mean annual precipitation (MAP) out of the climatic factors were the key drivers of variation in leaf stomatal and anatomical traits, respectively. Soil moisture and nutrients out of the soil properties significantly affected both leaf stomatal and anatomical traits of moso bamboo. Network analysis further indicated that there was a significant correlation between leaf stomata and anatomical traits. Stomatal size (SS) showed the highest centrality value at the regional scale, indicating that it plays a key role in adjusting the adaptation of plants to external environmental conditions. SEM analysis showed that environment did not directly but indirectly affect GPP via stomatal performance. The environment explained 53.3% and 39.2% of the variation in leaf stomatal and anatomical traits, respectively, and leaf stomatal traits explained 20.8% of the regional variation in GPP. Our results demonstrate a direct effect of leaf stomatal traits rather than leaf anatomical traits on bamboo ecosystem productivity, which provides new insights into model predictions of bamboo forests under global climate change.

Soil fungal community characteristics vary with bamboo varieties and soil compartments.

Soil fungi play an important role in nutrient cycling, mycorrhizal symbiosis, antagonism against pathogens, and organic matter decomposition. However, our knowledge about the community characteristics of soil fungi in relation to bamboo varieties is still limited. Here, we compared the fungal communities in different soil compartments (rhizosphere vs. bulk soil) of moso bamboo (Phyllostachys edulis) and its four varieties using ITS high-throughput sequencing technology. The fungal α diversity (Shannon index) in bulk soil was significantly higher than that in rhizosphere soil, but it was not affected by bamboo variety or interactions between the soil compartment and bamboo variety. Soil compartment and bamboo variety together explained 31.74% of the variation in fungal community diversity. Soil compartment and bamboo variety were the key factors affecting the relative abundance of the major fungal taxa at the phylum and genus levels. Soil compartment mainly affected the relative abundance of the dominant fungal phylum, while bamboo variety primarily influenced the dominant fungal genus. Network analysis showed that the fungal network in rhizosphere soil was more complex, stable, and connected than that in bulk soil. A FUNGuild database analysis indicated that both soil compartment and bamboo variety affect fungal functions. Our findings provide new insights into the roles of both soil compartments and plant species (including variety) in shaping soil fungal communities.

Secondary Succession Altered the Diversity and Co-Occurrence Networks of the Soil Bacterial Communities in Tropical Lowland Rainforests.

The characteristics of plant and soil bacterial communities in forest ecosystems have been reported, but our understanding of the relationship between plant communities and soil bacteria in different stages of secondary tropical rainforest succession is still poor. In June 2018, three different natural successional stages of tropical lowland rainforests, early (33 years), early-mid (60 years), and mid successional stage (73 years), in Hainan Island, China, were selected for this study. By conducting field investigation and 16S rRNA gene high-throughput sequencing, the composition and diversity of tree communities, the niche overlap of tree species with legumes among tree species, and the diversity and composition of soil bacterial communities and co-occurrence networks within communities across the successional stages were investigated. The results showed that plant richness and species diversity increased significantly during the secondary succession of tropical lowland rainforests. The order of positive correlations between nitrogen-fixing legumes and other species in plant communities was early-mid > mid > early successional stage. Soil nutrient content and soil bacterial richness were highest in the early-mid stages of succession, followed by mid and early stages of succession. Organic matter (OM), total nitrogen (TN), alkali nitrogen (AN), and available phosphorus (AP) had a stronger positive impact on soil bacterial communities. Co-occurrence network analysis showed that with the advancement of rainforests succession, the negative correlation between soil bacterial species decreased, and the community stability increased. Overall, as a result of tropical lowland rainforest secondary natural succession, the richness and diversity of plant communities increased, which altered the living conditions of nitrogen-fixing legumes and the soil properties, and the network complexity of soil bacterial communities increased with the rising of rainforest soil nutrient content.

Announcing the Genome Atlas of Bamboo and Rattan (GABR) project: promoting research in evolution and in economically and ecologically beneficial plants.

Bamboo and rattan are widely grown for manufacturing, horticulture, and agroforestry. Bamboo and rattan production might help reduce poverty, boost economic growth, mitigate climate change, and protect the natural environment. Despite progress in research, sufficient molecular and genomic resources to study these species are lacking. We launched the Genome Atlas of Bamboo and Rattan (GABR) project, a comprehensive, coordinated international effort to accelerate understanding of bamboo and rattan genetics through genome analysis. GABR includes 2 core subprojects: Bamboo-T1K (Transcriptomes of 1000 Bamboos) and Rattan-G5 (Genomes of 5 Rattans), and several other subprojects. Here we describe the organization, directions, and status of GABR.

Transcriptome-based investigation of cirrus development and identifying microsatellite markers in rattan (Daemonorops jenkinsiana).

Rattan is an important group of regenerating non-wood climbing palm in tropical forests. The cirrus is an essential climbing organ and provides morphological evidence for evolutionary and taxonomic studies. However, limited data are available on the molecular mechanisms underlying the development of the cirrus. Thus, we performed in-depth transcriptomic sequencing analyses to characterize the cirrus development at different developmental stages of Daemonorops jenkinsiana. The result showed 404,875 transcripts were assembled, including 61,569 high-quality unigenes were identified, of which approximately 76.16% were annotated and classified by seven authorized databases. Moreover, a comprehensive analysis of the gene expression profiles identified differentially expressed genes (DEGs) concentrated in developmental pathways, cell wall metabolism, and hook formation between the different stages of the cirri. Among them, 37 DEGs were validated by qRT-PCR. Furthermore, 14,693 transcriptome-based microsatellites were identified. Of the 168 designed SSR primer pairs, 153 were validated and 16 pairs were utilized for the polymorphic analysis of 25 rattan accessions. These findings can be used to interpret the molecular mechanisms of cirrus development, and the developed microsatellites markers provide valuable data for assisting rattan taxonomy and expanding the understanding of genomic study in rattan.

[Effects of land use change on soil labile organic carbon in Central Jiangxi of China].

Selecting the 15-year abandoned land (AL) and three forest lands [Phyllostachys edulis plantation (PE), Schima superba secondary forest (SS), and Cunninghamia Lanceolata plantation (CL)] in Anfu County of Jiangxi Province as test objects, this paper studied the effects of land use change on the soil organic carbon (SOC) pool and soil labile organic carbon (SLOC) contents. The soil organic carbon (SOC), microbial biomass carbon (MBC), hot- water extractable carbon (HWC), and readily oxidizable carbon (ROC) contents in the test lands were all in the order of PE>CL>SS>AL. As compared with those in AL, the SOC content, soil carbon stock, and soil labile organic carbon (SLOC) contents in the three forest lands all decreased with increasing soil depth, and had an obvious accumulation in surface soil. The proportions of different kinds of SLOC to soil total organic carbon differed markedly, among which, ROC had the highest proportion, while MBC had the smallest one. There existed significant relationships between SOC, MBC, HWC, and ROC. The MBC, HWC, and ROC contained higher content of active carbon, and were more sensitive to the land use change, being able to be used as the indicators for evaluating the soil quality and fertility in central Jiangxi Province.

[Soil microelements under different vegetation restoration patterns in yellow soil slope region of mid-subtropics].

With the Nüerzhai watershed in Wuling Mountain as a case, this paper studied the contents and availabilities of soil microelements and their relationships with soil organic matter and pH value in yellow soil slope region of mid-subtropics under seven typical vegetation restoration patterns, i. e., Pinus massoniana natural forest (I), Cunninghamia lanceolata plantation (II), Eucommia ulmoides plantation (III), Vernicia fordii plantation (IV), Machilus pingii secondary forest (V), Phyllostachys edulis - C. lanceolata mixed forest (VI), and wasteland-shrub community (VII). It was found that in 0-20 cm soil layer, the contents of B and Mn, Mo and Cu, Zn, and Fe reached the peaks under VII, IV, III and VI; while in 20-40 cm soil layer, III, IV, Vand VII had the highest contents of Cu, Zn, B, and Fe and Mn, Mo, respectively. In both two soil layers under VI, the contents of B, Mo, Cu and Mn were the lowest. Mn had the biggest single element available index, while Cu had the smallest one. The biggest and smallest total available index of soil microelements was 12.28 for VII and 2.95 for VI, respectively. There existed the regularities of Mn > Zn > Fe > Mo > B > Cu for single microelement available index and VII > V > III > IV > I > II > VI for comprehensive microelement available index under different vegetation patterns. A good linear relationship was observed between soil organic matter and B and Zn availabilities, and the relationship of soil organic matter with available Mn could be described by a quadratic equation. Soil pH was highly positively correlated with soil Cu and Zn contents, correlated with soil Mo and Mn contents, slightly correlated with soil B content, and slightly negatively correlated with soil Fe content.

[Research advances in ecosystem flux].

To develop the long-term localized observation and investigation on ecosystem flux is of great importance. On the basis of generalizing the concepts and connotations of ecosystem flux, this paper introduced the construction and development histories of Global Flux Networks, Regional Flux Networks (Ameri-Flux, Euro-Flux and Asia-Flux) and China-Flux, as well as the main methodologies, including micrometeorological methods (such as eddy correlation method, mass balance method, energy balance method and air dynamic method)and chamber methods (static and dynamic chamber methods), and their basic operation principles. The research achievements, approaches and advances of CO2, N2O, CH4, and heat fluxes in forest ecosystem, farmland ecosystem, grassland ecosystem and water ecosystem were also summarized. In accordance with the realities and necessities of ecosystem flux research in China, some suggestions and prospects were put forward.