Main Environmental Factors Research Articles

A comprehensive review of factors affecting growth and secondary metabolites in hydroponically grown medicinal plants.

Optimizing environmental factors can significantly increase the growth and secondary metabolite synthesis of hydroponically grown medicinal plants. This approach can help increase the quality and quantity of pharmacologically important metabolites to enhance therapeutic needs. Medicinal plants are key therapeutic sources for treating various ailments. The increasing demand for medicinal plants has resulted in the overharvesting of these plants in their natural habitat, which can lead to their extinction in the future. Soil-based cultivation faces challenges, such as a lack of arable land, drastic climatic changes, and attacks by soil-borne pathogens. To overcome these challenges, hydroponic cultivation, known as soilless cultivation, is a sustainable method. The yield and quality of medicinal plants depend on environmental factors, such as nutrients, pH, electrical conductivity, temperature, light, nanoparticles, phytohormones, and microorganisms. This article explores the impact of these environmental factors on the growth and secondary metabolite content of hydroponically grown medicinal plants. Our review reveals how environmental factors qualitatively and quantitatively influence the growth and secondary metabolites of medicinal plants grown in hydroponic systems and how these factors can be integrated into the enhancement of therapeutic compounds.

Environmental Factors Affecting the Phytoplankton Composition in the Lake of Tibetan Plateau

Due to the high altitude, unique geographical location, difficult accessibility and low temperature, the environmental factors influencing phytoplankton composition have rarely been investigated in the Selin Co Lake, which is the largest lake in the Tibetan Plateau. Phytoplankton composition can indicate aquatic ecosystem conditions, which may be sensitive to environmental factors in the Tibetan Plateau. In this study, we investigated the main environmental factors that influence phytoplankton species in the Selin Co Lake by analyzing the spatial distribution and applying statistical analyses. We also compared the influential environmental factors in this lake with other lakes around the world. The results suggest that the eleven environmental variables can explain about 46.78% of the phytoplankton’s composition. DO and fluoride were the most significant environmental variables, followed by arsenic and COD, and the other variables had comparatively smaller and more insignificant influences on phytoplankton composition. There were five dominant phytoplankton species in the Selin Co Lake, namely, Microcystis sp., Navicula spp., Chlorella vulgaris, Ankistrodesmus falcatus, and Westella sp. Some of these dominant species were also found in other tropical lakes, suggesting that the phytoplankton community could adapt to environmental changes. A clear understanding of the influential environmental variables affecting phytoplankton composition could help us to make proper water quality protection strategies in future climate change scenarios.

Continuous cropping of Patchouli alters soil physiochemical properties and rhizosphere microecology revealed by metagenomic sequencing.

Continuous cropping (CC) profoundly impacts soil ecosystems, including changes in soil factors and the structure and stability of microbial communities. These factors are interrelated and together affect soil health and plant growth. In this research, metagenomic sequencing was used to explore the effects of CC on physicochemical properties, enzyme activities, microbial community composition, and functional genes of the rhizosphere soil of patchouli. We found that this can lead to changes in various soil factors, including the continuous reduction of pH and -N and the unstable changes of many factors. In addition, S-PPO enzyme activity increased significantly with the cropping years, but S-NAG increased in the first 2 years and decreased in the third cropping year. Metagenomic sequencing results showed that CC significantly changed the diversity and composition of rhizosphere microbial communities. The relative abundance of Pseudomonas and Bacteroides decreased substantially from the phylum level. At the genus level, the number of microbial genera specific to the zero-year cropping (CK) and first (T1), second (T2), and third (T3) years decreased significantly, to 1798, 172, 42, and 44, respectively. The abundance of many functional genes changed, among which COG0823, a gene with the cellular process and signaling functions, significantly increased after CC. In addition, -N, S-CAT, S-LAP, and SOC were the main environmental factors affecting rhizosphere-dominant microbial communities at the phylum level, while pH, SOC, and AK were the key environmental factors affecting rhizosphere functional genes of Pogostemon cablin. In summary, this study showed the dynamic changes of soil factors and rhizosphere microorganisms during CC, providing a theoretical basis for understanding the formation mechanism and prevention of CC obstacles and contributing to the formulation of scientific soil management and fertilization strategies.

Integrative Transcriptomic and Small RNA Analysis Uncovers Key Genes for Cold Resistance in Rice.

Cold stress is the main environmental factor that affects the growth and development of rice, leading to a decrease in its yield and quality. However, the molecular mechanism of rice's low-temperature resistance remains incompletely understood. In this study, we conducted a joint analysis of miRNA and mRNA expression profiles in the cold-resistant material Yongning red rice and the cold-sensitive material B3 using high-throughput sequencing. 194 differentially expressed miRNAs (DEMIs) and 14,671 differentially expressed mRNAs (DEMs) were identified. Among them, 19 DEMIs, including miR1437, miR1156, miR166, miR1861, and miR396_2 family members, showed opposite expression during the early or late stages of low-temperature treatment in two varieties, while 13 DEMIs were specifically expressed in Yongning red rice, indicating that these miRNAs are involved in rice's resistance to low temperature. In the transcriptome analysis, 218 DEMs exhibited opposite expressions during the early or late stages of low-temperature treatment in two varieties. GO enrichment analysis indicated that these DEMs were enriched in biological processes such as a defense response to fungi, a defense response to bacteria, a plant-type cell wall modification, single-organism cellular processes, a response to chitin, and the regulation of a plant-type hypersensitive response, as well as in cellular components such as the apoplast, nucleus, vacuole, plasma membrane, and plasmodesma. Twenty-one genes were further selected as potential candidates for low-temperature resistance. The joint analysis of miRNA and mRNA expression profiles showed that 38 miRNAs corresponding to 39 target genes were candidate miRNA-mRNA pairs for low-temperature resistance. This study provides valuable resources for determining the changes in miRNA and mRNA expression profiles induced by low temperatures and enables the provision of valuable information for further investigating the molecular mechanisms of plant resistance to low temperatures and for the genetic improvement of cold-resistant varieties.

ƏTRAF MÜHİTİN ÇİRKLƏNMƏSİNİN QARŞISININ ALINMASI YOLLARININ ŞAGİRDLƏRƏ AŞILANMASI

Instilling in students the right attitude to nature and the use of its resources is the basis of environmental education and upbringing. The promotion of anthropogenic impact on the atmosphere plays an important role in this work. A creative teacher can form and develop ecological knowledge and responsible behavior towards nature in students by using various teaching methods (discussion, dispute, round table, preparation of environmental projects and essays, etc.). Thus, the atmosphere, which is considered the main environmental factor for the activity of the biosphere and its entire living world, is subject to severe pollution as a result of the waste emitted by industries and vehicles operating in cities. Atmospheric air pollution does not affect the natural environment and human health. The issue of anthropogenic impact on the atmosphere is the focus of attention of experts and ecologists all over the world. The anthropogenic factors that make up the preamble of the article are among the causes of desertification land degradation, along with natural factors, anthropogenic effects are also one of the main attention-grabbing issues. Anthropogenic factors combine various forms of human activity that affect the environment, including the soil. The spontaneous attitude of people to the land in various forms accelerates the development of erosion processes in the area and creates wetlands in many cases.

Temperature alters bacterial community structure in sediment of mountain stream

Temperature and nutrients are known as crucial drivers for the variations of bacterial community structure and functions in oceans and lakes. However, their significance and mechanisms in influencing the bacterial community structure and function in mountain stream remain unclear. In this study, we investigated the spatiotemporal patterns of the bacterial communities and the main environmental factors in the Taizicheng River, a high-latitude mountainous stream, to reveal the main driving factors for sedimental bacterial communities. Our findings identified that the phyla Acidobacteriota and Bacteroidota served as the strong discriminant for sedimental bacterial community in the non-freezing and freezing periods, respectively. In contrast, no significant difference was detected in bacterial functional composition. Mantel test and Redundancy analysis showed that temperature and nutrients played significant roles in determining the bacterial community structure and temperature critically influenced the bacterial metabolic processes. The results of partial least squares path model demonstrated that temperature affected the bacterial community structure in both directly (43.70%) and indirectly pathways (41.10%) by affecting the sediment parameters. However, the functional composition was not significantly affected by temperature and nutrients. Our results highlight that the change of temperature can significantly alters the structure of bacterial communities rather than functional composition and provides new insights into the response mechanisms of bacterial communities to environmental factors which contributes to the deep understanding of the driving factors as well as the protection strategies for microbial communities in mountain stream and aquatic ecosystem.

Seasonal Dynamics of Planktonic Algae in the Volzhsky Reach of the Kuibyshev Reservoir in 2017

Studies were carried out on the seasonal dynamics of phytoplankton in the Volga r each of the Kuibyshev r eservoir in 2017. At the same time, the seasonal values of the main abiotic environmental factors influencing the dynamics of phytoplankton (level regime, intensity of incident solar radiation, a number of basic hydrochemical and hydrophysical indicators, etc.) were analyzed. The dominant phytoplankton complex consists of blue-green, green volvox, centric diatoms and dinophytes. The studied area is subject to extremely intense processes of “blooming” of water due to the mass reproduction of blue-green algae species Microcystis, Aphanizomenon and Anabaena , and the waters of the studied area during most of the growing season corresponded to the mesosaprobic type and a moderately polluted zone.

The use of Chat GPT for Obesity Management in Greece: A PESTEL Analysis

The treatment of obesity in Greece, which has undesired health, economic and social impacts, requires a holistic approach while the use of strategic management tools such as SWOT and PESTEL analysis can facilitate the fight against the pandemic. The use of Artificial Intelligence in several sectors has increasing applications nowadays. A PESTEL analysis has been realized using the Chat GPT instead of asking the opinion of experts and stakeholders of the healthcare industry. Chat GPT was asked to identify the main political, economic, social, technological, environmental and legal factors affecting obesity management in Greece. It was found that its quick answers were satisfactory although some additional factors which were not identified by Chat GPT have been proposed. Taking into account that the use of Chat GPT has various limitations related with its training in recent scientific advancements and information it is suggested that it should be used combinedly with human analysis for the achievement of optimum results. Our findings could be used by policy makers, experts and several stakeholders of the obesity management industry in Greece for the improvement of the policies used for treating the contemporary pandemic of obesity.

Effects of Underwater Lighting Time on the Growth of Vallisneria spinulosa Yan and Its Water Restoration Process

Submerged macrophytes play a crucial role in the ecological restoration of water bodies, and their restoration capacity is closely related to the underwater lighting conditions. This study explored the effects of underwater lighting time on the growth characteristics of Vallisneria spinulosa Yan (V. spinulosa) and its water restoration process. V. spinulosa achieved a higher Fv/Fm (0.64), ETRmax (10.43), chlorophyll content (0.85 mg/g), and removal efficiency of total phosphorus (0.37 × 10−3 g m−3 d−1) and a lower algal abundance with a longer lighting time (18 h every day). However, a higher removal efficiency of NH4+–N and TN was obtained with a shorter lighting time (6–12 h every day). The lighting time showed a significance influence on the microbial community of the V. spinulosa growth system, and the influence was significantly different in different regions. Temperature and electrical conductivity were the main environmental impact factors for the microbial community under different lighting times. The abundances of Proteobacteria, Bacteroidota, and Verrucomicrobia exhibited a great positive correlation with each other and a strong positive correlation with the two factors. In addition, the lighting time had a strongly significant correlation with the physical and chemical characteristics of the water environment (p < 0.001) and a significant correlation with the growth characteristics of V. spinulosa (p < 0.05).

Effects of the Application of Pseudomonas cedrina DY1-3 on the Growth of Maize Plants and the Structure of Soil Bacterial Community.

Against the background of increasing salinisation of land, the use of environmentally friendly plant growth-promoting bacteria (PGPB) resources for soil improvement is particularly important. The aim of this study was to investigate the effects of Pseudomonas cedrina DY1-3 on maize seedling growth, soil physico-chemical properties, and bacterial community structure. The study also evaluates the effects of this microbial agent on plant growth and saline soil improvement, providing theoretical references for microbial agents in promoting plant growth and improving saline soils. We found that there were significant differences between arable and saline soils in terms of soil physico-chemical properties and bacterial community structural composition, and that total salt was the main environmental factor influencing microbial communities. In both arable and saline soils, the application of DY1-3 bacterial suspension had a significant positive effect on the growth of maize plants and bacterial community richness. In arable soil, it could promote the growth of maize seedlings and significantly increase the Shannon and Simpson index, and AK was a key factor influencing the bacterial community. In saline soil, it could alleviate the mitigation stress and promote the growth of maize seedlings and cause a significant increase in Shannon's and Chao1 index, and the application of DY1-3 and potting could cause a significant decrease in total salt. In addition, DY1-3 and maize plants acting together in the soil can better improve the saline soil. The above results indicate that DY1-3 has potential for saline soil improvement and crop yield enhancement.

Cordycepin Ameliorates Spaceflight-Induced Osteoporosis by Preventing BMSCs Oxidative Stress and Senescence via Interacting with PI3K p110α and Regulating PI3K/Akt/FOXO3 Signalling.

Spaceflight-induced osteoporosis (SFOP) is a detrimental healthcare consequence during spaceflight. Weightlessness and ionizing radiation were main environmental factors that contribute to SFOP, especially in the manned deep space voyages. However, currently there is scarce effective method to treat SFOP. This study aims at discovering the role and mechanism of cordycepin (COR) in treating SFOP. A combined ionizing radiation and tail suspension (IR/IS) model is constructed in mice to simulate SFOP. COR injection exhibits certain dose-dependent therapeutic effects including better imageological bone index and improved histological bone regeneration in treating SFOP, which is most prominent at a dose of 20 mg/kg. A combined radiation and microgravity (R/M) model is established to treat BMSCs in vitro. 10 μM COR alleviates oxidative stress and cellular senescence of BMSCs. Through high-throughput sequencing, molecular docking and microscale thermophoresis (MST), we reveal a novel mechanism that COR interacts with p110α subunit in PI3K isoform α (PI3Kα) and inhibits PI3K kinase activity, which then regulates the PI3K/Akt/FOXO3 signalling. To elevate the bioavailability of COR in the SFOP treatment, a BMSCs-targeted delivery system that uses exosomes (Exos) modified with BMSC-affinity peptide E7 (E7-Exos) is constructed and loaded with COR. E7-Exos loaded COR reduces the dosage of COR to 5 mg/kg while enhancing the therapeutic effect than using 20 mg/kg COR alone in treating SFOP. In conclusion, COR shows promise as a potential agent in SFOP therapy.

Impacts of Climate Change Conditions on the Potential Distribution of Anoplophora glabripennis and Its Host Plants, Salix babylonica and Salix matsudana, in China.

The Anoplophora glabripennis (Motschulsky) is a phytophagous pest that is seriously endangering Salix babylonica Linn. and S. matsudana Koidz. Poor control can damage local ecosystems, resulting in economic losses and management risks. In the context of climate change, the climatic ecological niche of organisms is no longer compatible with the surrounding environment. To mitigate the effects of climate change, some organisms respond adaptively to climate change through different mechanisms and in different ways. In this study, an optimized MaxEnt model was used to explore the potential distribution areas of A. glabripennis and its host plants, S. babylonica and S. matsudana, in response to current and future climate and to determine their movement routes and relative dynamics. The results show that the optimized model exhibits the lowest complexity and excellent prediction accuracy. It is important to note that both temperature and precipitation are the main environmental factors affecting the distribution of suitable habitats for A. glabripennis and its host plants. This is evidenced by the mean temperature of the warmest quarter and precipitation of the wettest month being the main environmental factors affecting the distribution of suitable habitats for the host plants. Similarly, the minimum temperature of the coldest month and precipitation seasonality are the primary bioclimatic variables constraining the dispersal of A. glabripennis. Under climate change, the suitable areas of both S. babylonica and S. matsudana are declining, while the suitable areas of A. glabripennis are expanding in future climates. Furthermore, three species exhibited a proclivity for migration to higher latitudes in response to climate change. In conclusion, this study contributes to our understanding of the biogeographic characteristics of these A. glabripennis, S. babylonica, and S. matsudana and provides a basis for the formulation of timely conservation strategies to reduce the potential impacts of climate change. This is of great significance for the rational management, utilization, and protection of forest ecosystems in China.

Экологические условия и лимитирующие факторы возделывания мандарина (Citrus reticulata Blan. var. unshiu Tan.) в субтропиках черноморского побережья России

Abstract. The main environmental factors determining the optimal conditions for the growth of the main species of the genus Citrus on the example of mandarin (Citrus reticulata Blan. var. unshiu Tan.) and limiting factors of environmental impact on plants are considered. The most informative sources in this case are: temperature (minimum, average, maximum) and the amount of precipitation). The study of weather conditions of five growing seasons (2019-2023) revealed the main environmental factors that expose early-maturing (Kawano-Wase) and late-maturing (Unshiu) citrus varieties in the subtropical zone of Russia to waterthermal stresses. The likelihood of devastating frosts (-5 °C for lemon and -12 °C for mandarin and orange) pose a threat to citrus farming in this region. The relationship between precipitation and HTC is shown. The correlation coefficient is statistically significant r = 0.98. The connection is strong and direct. The largest number of temperature stressors (seven) has been established in 2020, 2022, and 2023. At the same time, the maximum temperature reached from 26.9 °C – 2.10.2022, to 35.9 °C – 6.08.2023. Frosts were not critical, the minimum temperature reached -7.2 °C (09.02.2020) and -4.3 °C (23.12.2021). The last frost – -2.4 °C was observed late on March 18, 2022, but was no longer dangerous for plants. The lack of precipitation creates a stressful situation along with the temperature. 2020 was the most critical year due to the values of this indicator. Precipitation was distributed: 25 mm in June, 11 mm in August and 30 mm in September, that is only 66 mm (19 %) with a norm of 341 mm. Water deficiency affects the growth, generative processes and metabolism of mandarin plants. Mandarin plants exposed to stress exhibit adaptive responses to stressors regardless of the biological characteristics of low-growing (Kawano-Wase) or strong-growing (Unshiu) plants varieties. Keywords: vegetation, environment, stress, adverse effects, temperature

The Role of Underwater Soundscapes in Shaping the Distribution of Cobitidae Fish: Insights From Multiple Environmental Factors

ABSTRACTSound is critical in fish behaviours, including reproduction, feeding, predator avoidance and habitat selection. To investigate the impact of underwater soundscape on the distribution of Cobitidae fishes, we surveyed the status of Cobitidae fish resources and the underwater soundscape along with related environmental factors at 12 sampling sites downstream of the Songxin Hydropower Station in the Heishui River, a major tributary of the Jinsha River in China. Generalised additive models (GAMs) were employed to identify the primary environmental factors influencing the distribution of Cobitidae fishes and we analysed the correlation between the abundance of Cobitidae fish and primary environmental factors. The study revealed that the water depth, flow velocity, water temperature and sound pressure level (SPL) all had highly significant effects on the distribution of Cobitidae fishes (p < 0.001), with SPL showing the lowest relative importance among these factors. Water depth positively correlated with Cobitidae fish abundance, whereas water temperature, SPL and flow velocity showed negative correlations. This study preliminarily explored the response relationship between the distribution of Cobitidae fish and four main environmental factors, offering a technical foundation for predicting the distribution of Cobitidae fishes in rivers and for implementing conservation measures of fish such as suitable habitat creation.

EDNA metabarcoding reveals differences in fish diversity and community structure in Danjiang River

Fish diversity, an important indicator of aquatic ecosystem health, is declining due to water pollution, overfishing, climate change, and invasive species. Effective surveying and monitoring are required to protect fish diversity. Here, a high-sensitivity environmental DNA (eDNA) metabarcoding technique was used to investigate fish diversity in the Danjiang River, Shaanxi Province, China. In total, 59 species were identified in eight orders, 19 families, and 40 genera. Cypriniformes and Perciformes were the main groups in the survey area, while Cyprinidae accounted for 50.85% of the total fish species. Rhinogobius similis (19%), Hemibarbus umbrifer (11%), Gnathopogon herzensteini (10%), Triplophysa stewarti (8%), and Zacco platypus (7%) were the dominant species. Eight rare and two exotic fish species were identified. Combined with analysis of historical data, the richness of fish identified using eDNA metabarcoding was significantly higher than that of fish captured in ground cages. Temperature, pH, and oxidation-reduction potential are the main environmental factors that affect the spatial distribution of fish communities. These results suggest that eDNA metabarcoding could be a new tool with broad application prospects; however, local databases must be improved. This study provides theoretical data and a methodological reference for protecting and managing fish diversity in the Qinling Mountains.

Effects of a Vegetable Eel Co-Culture System on the Soil Ammonia-Oxidizing Microbial Community

(1) Background: A vegetable eel co-culture system is an economically efficient way of agricultural cultivation, which can have an impact on the soil microbial environment and play a pivotal role in the soil nutrient cycle, but there is little research on its impact on soil ammonia-oxidizing microorganisms. (2) Methods: NovaSeq platform sequencing was employed to investigate the richness, structure, and diversity of soil ammonia-oxidizing microbial communities, exploring the effects of a vegetable eel co-culture system on soil nitrogen cycling. Four different planting treatments were set up: unfertilized without vegetable eel (CCK), fertilized without vegetable eel (CRT), unfertilized with vegetable eel (ICK), and fertilized with vegetable eel (IRT). (3) Results: A vegetable eel co-culture system significantly increased soil pH and decreased bulk density under fertilization conditions. The soil nitrification potential rate was enhanced by a vegetable eel co-culture system to an average of 26.3%. A vegetable eel co-culture system significantly altered the community structure of all ammonia-oxidizing microorganisms, with a significant increase in the richness and diversity of ammonia-oxidizing bacteria (AOB) and comammox clade-A, while fertilization significantly increased the diversity of all ammonia-oxidizing microbial communities. Structural equation modeling (SEM) analysis showed that the main environmental factors affecting the structure of the ammonia-oxidizing microbial community were nitrate and total nitrogen. The number of amoA genes in AOB and comammox clade-B was significantly positively correlated with the soil potential N nitrification rate (PNR), which played a leading role in the nitrification of alkaline vegetable soil. The network analysis revealed that a vegetable eel co-culture system improved the modularity of AOB and comammox clade-B by 13.14% and 5.66%. (4) Conclusions: This study showed that the vegetable eel co-culture system stimulated the evolution of ammonia-oxidizing microbial communities by changing the physicochemical properties, which in turn promoted the soil nitrification reaction.

Enhancing Morchella Mushroom Yield and Quality Through the Amendment of Soil Physicochemical Properties and Microbial Community with Wood Ash.

Morchella mushroom is a nutritionally rich and rare edible fungus. The traditional cultivation model, which relies on expanding the cultivation area to meet market demand, is no longer sufficient to address the rapidly growing market demand. Enhancing the yield and quality of Morchella without increasing the cultivation area is an intractable challenge in the development of the Morchella mushroom industry. Against this backdrop, this study investigates the effects of different amounts of wood ash (WA) application on the yield and quality of Morchella, and conducts an in-depth analysis in conjunction with soil physicochemical properties and microbial communities. The results indicate that the application of WA improves both the yield and quality of Morchella, with the highest yield increase observed in the WA2 treatment (4000 kg/hm2), which showed a 118.36% increase compared to the control group (CK). The application of WA also modified the physicochemical properties of the soil, significantly improving the integrated fertility index of the soil (IFI, p < 0.05). The soil microbial community structure was altered by the addition of WA. Redundancy analysis (RDA) revealed that pH and total potassium (TK) were the main environmental factors influencing the bacterial community, while pH, TK, and total nitrogen (TN) were the main factors influencing the fungal community structure. In addition, bacterial community diversity tended to increase with higher WA application rates, whereas fungal community diversity generally showed a decreasing trend. Furthermore, the relative abundance of beneficial microbial communities, such as Acidobacteriota, which promote the growth of Morchella, increased with higher WA application, while the relative abundance of detrimental microbial communities, such as Xanthomonadaceae, decreased. Partial least squares path model (PLS-PM) analysis of external factors affecting Morchella yield and quality indicated that WA application can alter soil physicochemical properties and soil microbial communities, thereby improving Morchella yield and quality. Among these factors, soil fertility was identified as the most important determinant of Morchella yield and quality.

Structural characteristics of plankton community in Dongting Lake and its relationship with water environmental factors

The plankton community structure and environmental factors in Dongting Lake were investigated during four seasons from September 2020 to August 2021. The results revealed 147 species from 58 genera and 7 phyla of phytoplankton and 84 species from 56 genera and 4 phyla of zooplankton in Dongting Lake. The characteristics of plankton communities varied with time and space. The temporal variation of phytoplankton abundance ranged from 43.5201 × 104 to 120.7968 × 104 cells/L and the spatial variation ranged from 18.6707 × 104 to 247.5542 × 104 cells/L. The temporal variation of zooplankton abundance ranged from 18 to 42 ind/L and the spatial variation ranged from 19 to 62 ind/L. The temporal and spatial variations of the abundance range values were much larger for phytoplankton than for zooplankton, with phytoplankton dominating. However, environmental factors in Dongting Lake vary more temporally than spatially, and drive more temporal than spatial variations in planktonic organisms. Based on the redundancy analysis WT, DO, and CODMn were the main environmental factors affecting the distribution of phytoplankton, while WT, CODMn, NO2–N, and Chl-a were the main factors affecting the distribution of zooplankton. WT and CODMn were the common key influencing factors.

Characteristics of soil organic carbon fractions and influencing factors in different understory mosses in karst urban parks

The impact of different vegetation types on soil organic carbon (SOC) is a key focus in global warming research. Bryophytes, commonly found in karst urban forests, significantly contribute to carbon accumulation in surface soil. However, the changes in soil organic carbon fractions under moss and the influencing factors remain unclear. To address this knowledge gap, the study examined the organic carbon content, soil physicochemical properties, and associated environmental factors in both moss-covered soil and bare soil under six different forest species within an urban park. The results showed that the SOC contents under moss cover in evergreen coniferous forest (127.28 g/kg), bamboo forest (144.70 g/kg), deciduous broad-leaved forest (87.63 g/kg), and evergreen shrub (109.28 g/kg) were significantly higher compared to bare soil. Moss cover also had a significant impact on soil readily oxidizable carbon (ROC), particulate organic carbon (POC), mineral-associated organic carbon (MOC), and heavy fraction organic carbon (HFOC) (P < 0.01). The soil under moss had a higher content of stable organic carbon fraction, which is conducive to the stability of the soil organic carbon pool. The interaction between moss cover and stand type had the most significant effect on soil organic carbon, especially in bamboo forests. Canopy density, moss biomass, and soil moisture were the main environmental factors affecting the content of soil organic carbon and its fractions, while soil organic carbon content was mainly affected by soil nitrogen and phosphorus. This study establishes a theoretical framework for investigating the carbon cycle in karst urban underforest ecosystems, offering a scientific basis for the management and preservation of urban green space ecosystems. Future studies should include bryophytes in the assessment of dynamic factors affecting the soil carbon pool under forest cover and further explore the function and ecological significance of bryophytes in understory ecosystems.

Response of Alfalfa Leaf Traits and Rhizosphere Fungal Communities to Compost Application in Saline-Sodic Soil.

Soil salinization is considered a major global environmental problem due to its adverse effects on agricultural sustainability and production. Compost is an environmentally friendly and sustainable measure used for reclaiming saline-sodic soil. However, the responses of the physiological characteristics of alfalfa and the structure and function of rhizosphere fungal communities after compost application in saline-sodic soil remain elusive. Here, a pot experiment was conducted to explore the effect of different compost application rates on soil properties, plant physiological traits, and rhizosphere fungal community characteristics. The results showed that compost significantly increased soil nutrients and corresponding soil enzyme activities, enhanced leaf photosynthesis traits, and ion homeostasis compared with the control treatment. We further found that the rhizosphere fungal communities were dominated by Sodiomyces at the genus level, and the relative abundance of pathogenic fungi, such as Botryotrichum, Plectosphaerella, Pseudogymnoascus, and Fusarium, declined after compost application. Moreover, the α-diversity indexes of the fungal community under compost application rates of 15% and 25% significantly decreased in comparison to the control treatment. The soil SOC, pH, TP, and TN were the main environmental factors affecting fungal community composition. The leaf photosynthetic traits and metal ion contents showed significantly positive correlations with Sodiomyces and Aspergillus. The fungal trophic mode was dominated by Pathotroph-Saprotroph-Symbiotroph and Saprotroph. Overall, our findings provide an important basis for the future application of microbial-based strategies to improve plant tolerance to saline-alkali stress.