Ecology explores the fundamental principles and dynamics of macro living-systems and provides the scientific foundation of ecological civilization. China has separated the ecology as an independent subject from the biology subject to better promote its development. This transition calls for a broader conceptual framework for the subject of ecology. In this article, we define “ecology” as “the science that studies the structures, functions and dynamics of macro living-systems”, which provides a theoretical guidance and practical solutions for maintaining sustainable biosphere. Current ecology encompasses multiple living-system levels from molecules to the biosphere, with its core focus on five key levels: individual, population, community, ecosystem, and landscape. The sub-subject system of ecology comprises seven core disciplines: Plant Ecology, Animal Ecology, Microbial Ecology, Ecosystem Ecology, Landscape Ecology, Restoration Ecology, and Sustainable Ecology. Over nearly 160 years, ecology has generated seminal concepts and landmark theories that have profoundly influenced natural science advancement and human civilization. Current ecology is characterized with four distinctive features: (1) expansion of research scope to both macro- and micro-scales; (2) broad adoption of methodologies from other fields such as molecular biology or information science; (3) increased attention to field-based experiments and observational networks, with plat-forms now established at regional and global scales; and (4) enhanced emphasis on applied ecology to address ecological challenges of human society. Serving as both a natural philosophy for comprehending the living world and a praxeology for conserving and utilizing nature, ecology can be framed through five core perspectives: (1) hierarchical perspective (recognizing the multiple structural levels of living systems), (2) holistic perspective (approaching ecological phenomena from an integrative viewpoint), (3) systematic perspective (viewing the living world as interconnected networks), (4) evolutionary perspective (understanding life systems as dynamic and evolving), and (5) practical perspective (developing solutions for sustainable stewardship of nature). Methodo-logically, ecological research relies on four principal approaches: field investigations, laboratory and in-situ con-trolled experiments, model simulations, and meta-analyses. Although ecology and its branches possess robust theoretical frameworks, they lack their own technological systems. Consequently, the development of core eco-logical technologies is essential to promote continued vitality and progression of the ecology discipline.

Aims Microbial nitrogen use efficiency (NUE) refers to the ratio of nitrogen used by microorganisms for growth to total organic nitrogen absorbed, which is a key regulator of the soil nitrogen cycle. The 18O-H2O method and eco-enzyme stoichiometric model are the most common techniques employed to estimate microbial NUE. However, the impact of nitrogen enrichment on microbial NUE in forest soils remains to be elucidated, which would siginificantly impede the accurate prediction of soil nitrogen supply. Methods In this study, we sampled the soils from subtropical Castanopsis faberi forests and used urea to simulate atmospheric nitrogen deposition. In total, three levels of nitrogen additions were set up, including control (CK, 0 kg N·hm–2·a–1), low nitrogen (40 kg N·hm–2·a–1), and high nitrogen (HN, 80 kg N·hm–2·a–1) treatment. The 18O-H2O method and eco-enzyme stoichiometric model were used to compare the differences in soil microbial NUE under different nitrogen enrichment levels. Furthermore, soil physicochemical properties, microbial biomass, extracellular enzyme activity, and stoichiometric imbalance were also measured to explore the factors that influence the response of microbial NUE to nitrogen enrichment. Important findings The results showed that the microbial NUE, as determined by two different methods, exhibited a decline with the increase of nitrogen enrichment. The vector angle values of different nitrogen treatments were all greater than 55°, indicating that soil microorganisms in this study area were generally phosphorus limited, but nitrogen enrichment did not exacerbate the phosphorus limitation. On the contrary, nitrogen enrichment has a significant negative effect on microbial carbon and nitrogen imbalance, and a positive correlation was observed between microbial NUE and microbial carbon and nitrogen imbalance. In summary, the nitrogen enrichment may have a detrimental effect on soil nitrogen storage in subtropical forests, highlighting the necessity to enhance soil nitrogen storage by means of regulating the soil stoichiometric balance to in these forests.

Aims Soil nitrogen mineralization, nitrification and microbial nitrogen immobilization are key processes in soil nitrogen cycle, which have an important impact on soil nitrogen supply. Exploring the spatial variations in soil nitrogen transformation rates of forest may contribute to in-depth understanding of forest soil nitrogen dynamics and forest ecosystem productivity. Methods In this study, we integrated and analyzed 685 observations from 78 published papers, and aimed to analyze the rate characteristics of soil gross nitrogen mineralization, gross nitrification and microbial nitrogen immobilization of forest ecosystem and the main influencing factors. Important findings The results showed that: (1) The average rate of soil gross nitrogen mineralization, gross nitrification and microbial nitrogen immobilization of forest ecosystem were 6.65±0.61、1.99±0.21 and 8.10±1.45 mg N kg-1d-1, respectively. (2) The soil gross nitrogen mineralization rate and gross nitrification rate differed significantly among various forest types. Higher gross nitrogen mineralization rates were observed in tropical forest and temperate coniferous forest, while lower rates in subtropical broad-leaved forest and subtropical coniferous forest. The microbial nitrogen immobilization rates were higher in temperate coniferous and broad-leaved mixed forest, but was lower in subtropical coniferous and broad-leaved forest. (3) Soil gross nitrification rates exhibited no significant differences among various forest types. (4) The spatial variations in soil gross nitrogen transformation rates were main regulated by soil total nitrogen content and microbial biomass. Overall, the gross nitrogen transformation rates exhibited large spatial variability across global forest, and they were mainly affected by substrate supply and microbial biomass.

Aims Ecosystem reactive nitrogen (N) and phosphorus (P) inputs induced by recent industrial and agricultural development can alter soil carbon (C) storage capacity by affecting soil aggregate structure and stabilization. Currently, there is a lack of observational studies on soil aggregates modeling N deposition in the subtropics, and less attention has been paid to P-N interactions. Methods In order to investigate how ecosystem N enrichment and its interactions with P deposition affect C sequestration mechanisms in soil aggregates, N and P addition experiments were conducted for 7 consecutive years in a subtropical forest in southern China. Sample plots of four N addition types were established (control: CK, 0 kg N·hm-2a-1; N addition: LN，50 kg N·hm-2a-1; N addition: N, 100 kg N·hm-2 a-1; N and P: N+P，100 kg N·hm-2 a-1+50 kg P·hm-2 a-1). Soil properties, soil aggregates and their C, N fractions, and C, N stable isotopes of aggregates at each aggregate level were determined. Important findings Evergreen broadleaf forest macroaggregates (>250 μm) were the dominant soil aggregate size accounting for 83-87% of the total soil weight, and LN treatment increased macroaggregate formation, mean mass diameter (MWD) and mean geometric diameter (MGD), while N and N+P treatments marginally reduced soil aggregate stability (p>0.05). N enrichment in this region mainly increased aggregate C and N content by increasing aggregate C and N concentration at each grain level, and the added organic matter was mainly enriched in macroaggregates. The macroaggregates mainly added organic matter with high C to N ratio and rich δ13C abundance. Compared with low N addition, excessive N input was detrimental to soil aggregate structure stabilization and C sequestration. Under N treatment conditions, the addition of P did not significantly change the stability of local aggregates and their C, N components (p>0.05). Total soil C, N, and P contents of broad-leaved evergreen forests under N addition did not promote soil aggregate formation, and the decrease of pH significantly promoted the increase of C and N contents of aggregates (p<0.05). The results of this study increase our understanding of the mechanisms of aggregate change, and thus are important references for predicting the potential of soil C sinks in broadleaf evergreen forests and other areas with similar conditions under future N and P deposition.

Aims Under the background of global climate change, this study investigated the dynamic characteristics of energy fluxes in Jinyun Mountain's coniferous-broadleaf mixed forest across different temporal scales and their responses to environmental factors. Methods We selected the mixed coniferous and broad-leaved forests in Jinyun Mountains as the study area, and analyzed the long time series flux data of the mixed coniferous and broad-leaved forests in Jinyun Mountains for the years 2020, 2021, and 2023 (data for 2022 are missing) using correlation factor analysis and structural equation modeling based on the data measured by eddy correlation technique. Important findings (1) At the diurnal scale, net radiation (Rn), sensible heat flux (H), and latent heat flux (LE) exhibited unimodal trends, with their peak values occurring at 14:00 local time, and approaching near-zero values after 19:00. In contrast, soil heat flux (G) displayed a bimodal pattern, reaching its daily minimum prior to sunrise and attaining its daily maximum at 14:00 local time. (2) At the monthly scale, the influence of Rn on energy fluxes increased from April, reached its maximum in July and August, then gradually decreased. The influence of Gs on LE followed the same trend. (3) At the growing season scale, Rn was the primary influencing factor for energy flux variations. Correlation factor analysis indicated that canopy conductance (Gs) had a slight limiting effect on H but a significant limiting effect on LE. However, the plant water balance mechanism exerted the strongest influence. (4) The annual mean Bowen ratios (β) for the three years were 0.69, 0.63, and 0.76, respectively. (5) Influenced by extreme drought, the sensible heat flux at the annual scale exhibited a bimodal trend. This study analyzed the characteristics and influencing factors of energy fluxes in the Jinyun Mountain coniferous-broadleaf mixed forests, revealing the dynamic processes of energy fluxes, quantifying the impacts of environmental factors, and providing a scientific basis for assessing the response of subtropical forest ecosystems to climate change and forest conservation.

Aims Accurate estimation of crop yield is important for agricultural policy formulation. Vegetation canopy reflectance spectra and carbon fluxes are the primary data for monitoring crop growth status. However, there are fewer studies comparing their performance in predicting crop yield. Methods Here, we explored the capability of various parameters to predict rice (Oryza sativa) grain yield and aboveground biomass using synchronized observations of vegetation canopy reflectance spectra and gas exchange. Important findings Results showed that vegetation reflectance index outperformed carbon flux parameters in estimating rice grain yield and aboveground biomass, in which the optimal estimation parameter was the near-infrared reflectance of vegetation (NIRv). The vegetative phase was the optimal estimation phase of rice grain yield and aboveground biomass. Our results could provide critical guidances for cropland yield estimation based on remote sensing data and ground flux data.

Abstract Aims This study aims to reveal the effects of climate warming on the growth and morphological characteristics of fine roots in subtropical evergreen broad-leaved forests in China. Methods An in-situ soil warming experiment was conducted at the Fujian Sanming Forest Ecosystem National Observation and Research Station. The effect of soil warming on the growth and morphological characteristics of absorptive and transport roots in evergreen broad-leaved natural forests during the rainy season (May) and dry season (November) were investigated by using the in-growth core method. Imortant findings Compared with the control, during the rainy season, the warming treatment significantly reduced the growth of absorptive roots by 41.2%, and there was no significant change in the growth of transport roots. There was no significant change in the diameter and length of absorptive and transport roots. The absorptive roots SRL and SRA were significantly reduced by 53.2% and 42.9%, respectively, and the absorptive roots RTD was significantly increased by 28.8%; During the dry season, warming treatment significantly increased the growth of absorptive roots, transport roots and fine roots. The length of absorptive and transport roots increased by 38.5% and 33.5%, respectively. However, there were no significant changes in the diameter, SRL, SRA, and RTD of absorptive and transport roots. Evergreen broad-leaved forests in mid-subtropical areas show strong adaptability to future warming. During the rainy season, fine roots exhibit higher plasticity, mainly by adjusting the characteristics of absorptive roots to reduce the effect of warming on the resource absorption and growth of fine root; during the dry season, fine roots adopt a relatively conservative defense strategy, mainly by increasing the length of absorptive and transport roots to expand resource absorption space. This study provides a scientific basis for investigating the ecological adaptation mechanisms and resource acquisition strategies of fine roots with different functions in subtropical forest ecosystems under global warming scenarios.

Evergreen broad-leaved forest (EBLF) is one of the most typical vegetation types in China, with wide geographical distributions, complex species composition, and diverse community types. The EBLF classification is challenging and hasn’t reached a consistent scheme. Here the recently developed “Ecophysiognomic-floristic vegetation classification system (EcoFloVCS)” was used to the EBLF classification. The high-level units of EcoFloVCS are mainly based on ecophysiognomy, with some considerations of floristic characteristics, including five units (Formation Class, Formation Subclass, Formation Group, Formation, and Division). The middle- and low-levels are mainly based on floristic characteristics, with some considerations of ecophysiognomy and geographical distributions, including four units (Community Class, Order, Alliance and Association). Following the previous EBLF classification in 2013, we had an update and revised classification system using the EcoFloVCS and the 4th edition of The International Code of Phytosociological Nomenclature. Currently, the EBLF is classified into 3 formations, 3 divisions, 9 community classes, 23 orders, and 58 alliances. For three formations, we introduced shortly their geographic distributions, the dominant species of dominant layers, diagnostic species, and the classifications of the low-level units. Furthermore, we classified the alliances into 70 associations and 323 communities using the currently available plant vegetation data. More information have been added into the EBLF website (http://EBLF.info), and we will keep updates of the EBLF classification system through this website.

Aims Climate change has significantly influenced the evolutionary history of various biological groups. Among these, the succulents are special plant groups adapted to arid climate conditions. Didiereaceae, a small family circumscribed within Caryophyllales, consist of about 20 species representing 6 genera and 3 subfamilies. Species of the family are succulent plants and are distributed in the arid regions of the southern to eastern African continent and Madagascar. However, the link between the family’s evolution and the establishment of drought climates in its habitats remains unclear. Methods In this study, the phylogenetic relationships among Didiereaceae speceis were reconstructed based on analyses of six plastid DNA markers (viz. rps16, rpl16, trnL-F, trnT-trnL, trnG-S, trnQ-rps16). Additionally, molecular dating and diversification analyses of the family were conducted. Important findings The monophyly of Didiereaceae was strongly supported, and a robust phylogenetic framework for the family was established. The crown age of the family was estimated to be approximately 62.3 million years ago (Ma) in the middle Paleocene. However, the two subfamilies (viz. Didiereoideae and Portulacarioideae) with multiple species began to diverge around 11.1 Ma and 14.9 Ma, respectively, during the mid-late Miocene. Result from diversification analysis further revealed that an increased diversification rate shift in the family may have occurred around 11 Ma. These findings align closely with the timing of the establishment of arid climates (15–10 Ma) in the regions where the family is distributed. Therefore, we suggest that the establishment of arid conditions in southern to eastern Africa and Madagascar during the mid-late Miocene likely played a significant role in driving species diversification within the succulent family Didiereaceae. This study not only enhances our understanding of the evolutionary history of Didiereaceae, but also contributes to the broader knowledge of species diversification patterns in succulent plants.

Aim Goosegrass (Eleusine indica (L.) Gaertn.) is one of the world's malignant weeds, a dominant weed in the cotton fields along the Yangtze River in Anhui Province. Cotton is highly sensitive to weed competition. This article aims to clarify the density competition effect of goosegrass on cotton and identifies its critical period for control, providing a theoretical basis for the integrated weed management of goosegrass in cotton fields. Methods From 2010 to 2012, two experiments were conducted at an experimental site in Anqing City, Anhui Province: the goosegrass density competition experiment and the critical control period experiment. In the density competition experiment, the cotton density was kept constant while eight different densities of goosegrass (0, 0.125, 0.25, 0.5, 1, 2, 3, and 4 plants per meter) were tested to evaluate their competition with cotton throughout its growth period. This aimed to determine the effects of varying goosegrass densities on cotton growth and yield. The critical control period experiment involved different durations of weed interference and weed-free periods (0, 2, 4, 6, 8, 10, 12, and 14 weeks after crop emergence) to gather information on how goosegrass affects cotton. Important findings As the density of goosegrass increased, the plant height gradually decreased. Compared to 0.125 plants m-1 goosegrass, the plant height of goosegrass at densities of 3 plant m-1 and 0.25 plant m-1 was significantly decreased. On average over three years, the biomass of goosegrass per unit area increased from 715 kg ha-1 (0.125 plants m-1) to 4148 kg ha-1 (4 plants m-1). This indicates that intraspecific competition among goosegrass becomes more pronounced at higher densities. In 2012, the number of tillers and biomass per plant of goosegrass gradually increased, and the height of goosegrass exceeded that of cotton during the first 12 weeks after crop emergence. With the increasing weed density, the plant height and stem diameter of cotton decreased, while the number of fruit branches and bolls per plant was significantly reduced. The single boll weight was also reduced at high densities of goosegrass, however, there is no significant change in the lint percentage. In 2012, the plant height of cotton significantly decreased at densities of 2 plant m-1 or more. The cotton stem diameter was remarkably reduced at densities of 3 plant m-1 or more in 2011 and 4 plant m-1 in 2012, respectively. Specifically, at the density of 1 plant m-1, the fruit branch numbers, the boll number per plant and single boll weight was reduced by 8.7% to 11.6%, 18.6% to 35.2% and 0.1% to 4.6%, respectively. The seed cotton yields were significantly reduced at density of 0.125 plant m-1 (2010 and 2012) and 0.25 plant m-1 (2011), with reductions ranging from 10% to 18%. The boll number per plant of cotton and the loss rate of seed cotton yields were affected by the goosegrass densities, following a hyperbolic model. It is predicted that goosegrass densities of 2.3 to 3.7 plants m-1 would result in a 50% reduction in the number of bolls per plant, while densities of 0.05 to 0.09 plants m-1 would lead to a 5% reduction in seed cotton yield. As weed infestation increased, the experiment demonstrated a gradual decline in the height and stem diameter of cotton plants. Additionally, there was a significant reduction in the number of fruit branches and bolls per plant, which led to a marked decrease in seed cotton yields, fitting well with a logistic model. Conversely, With an increasing weed-free duration, cotton plants exhibited greater height and stem diameter, along with a notable rise in the number of fruit branches, bolls per plant, and seed cotton yield. The increase in seed cotton yield with prolonged weed-free duration followed a Gompertz model. The critical period for controlling goosegrass at a density of 2.5 plants m-1 is between 35 and 83 days after cotton planting, based on a 5% yield-loss threshold.

Aims Plant sexual systems is an important reproductive role that affects plant mating, genetics, evolution, and species distribution. They are classified into three categories based on the floral organ's pistil and stamen arrangement: hermaphroditism, dioecy, and monoecy. Methods This article takes forest communities in Daiyun Mountain (elevation 900-1600 m) as the research object, analyzing changes in the quantitative characteristics of woody plant sexual systems and investigating their correlation with environmental factors via Mantel correlation analysis. Important findings The study area encompassed 85 woody plant species, with 49 hermaphroditic (57.6%), 26 dioecious (30.6%), and 10 monoecious (11.8%) species. Altitudinal increase led to a significant rise in the number of hermaphroditic and dioecious individuals, with no significant change in their species ratio, while monoecious individuals' number and species ratio significantly declined. The Shannon Wiener index and Pielou evenness index for sexual systems generally decreased with altitude, whereas the Simpson dominance index remained stable. Effective phosphorus and soil temperature were identified as the primary drivers of altitudinal changes in sexual systems characteristics. In conclusion, the quantitative characteristics of the sexual systems of woody plants on the altitudinal gradient of Daiyun Mountain showed significant differences, and the altitudinal distribution of the sexual systems was highly sensitive to environmental changes, indicating that plants adapt to environmental changes by regulating the composition of their reproductive systems, thereby ensuring the continuous survival and reproduction of their populations.

Abstract Aims Our purpose is to explore the radial variation patterns and their influencing factors under different tree species and different environmental conditions, and to lay a foundation for quantifying and evaluating forest carbon sinks and their carbon fixation processes. Methods We used dendrometers to continuously monitor the dynamic changes in trunk radials of Fraxinus mandshurica and Larix gmelinii for three years, and to analyze the intra-annual and inter-annual variability, as well as the effects of environmental factors on stem radial variation. Important findings Intra-annual stem radial variation in both Fraxinus mandshurica and Larix gmelinii conformed to the Gompertz model, but were not fully synchronized on seasonal scales, and the annual cumulative radial increment and annual mean daily rate of change in the fracture area of the two species were significantly different between species. During the three years from 2020 to 2022, the stem radial variation of Fraxinus mandshurica started earlier than that of Larix gmelinii, and the annual cumulative radial increment of Fraxinus mandshurica reached 25% (DOY₂₅) 3 to 17 days earlier than that of Larix gmelinii, and the peak growth season length (L_PGS) of Fraxinus mandshurica in 2021 was 28 days longer than that of Larix gmelinii, while the radial variation termination time of the two species was consistent. The daily rate of radial variation for both tree species showed a unimodal trend of increasing and then decreasing, reaching the peak in early summer (147-157 days). Important time nodes (DOY₂₅, DOY₅₀, DOY₇₅) and L_PGS of radial variation of the two tree species are affected by interannual environmental factors. The daily stem radial variation of the two tree species during the growing season showed different trends depending on weather conditions, with a sinusoidal function type of fluctuation on sunny days. Daily amplitudes of Fraxinus mandshurica and Larix gmelinii at the peak period of stem radial growth was significantly negatively correlated with volumetric soil water content (P < 0.001) and significantly positively correlated with photosynthetically active radiation (P < 0.05). The amount of daily stem radial variation was negatively correlated with VPD for both species during the peak period of stem radial growth. This shows that stem radial seasonal dynamics are influenced by the characteristics of tree species, while the daily variation pattern is influenced by environmental factors such as volumetric soil water content, light conditions, etc. Moisture conditions are an important factor influencing the radial growth of Fraxinus mandshurica and Larix gmelinii.

Aim: In recent years, the ever increasing greenhouse gas (GHG) emissions and extreme weather events had significantly impacted plant photosynthesis. Photosynthesis is closely related to plant growth and development, with photosynthetic rate is a key indicator of plant health, which has been widely used in predicting global carbon cycle dynamics. The net photosynthesis rate is also an important parameter in calibrating agriculture facility. Therefore, accurate prediction of plant photosynthesis rate is important to agriculture, forestry and grassland research. Methods: We used photosynthesis meter to obtain photosynthetic data of common reed (Phragmites australis) and smooth cordgrass (Spartina alterniflora) under different environmental conditions, we then fitted seven single-factor photosynthetic response models, and developed a multifactorial photosynthetic rate prediction model using theoretically-guided neural network (TgNN). Important findings: The multifactor photosynthetic model outperformed single-factor photosynthetic response models. All existing single-factor light response models show good performances in fitting photosynthetic data but lack theoretical research value; whereas the multifactor photosynthetic model based on TgNN shows good predictability and generality. Our contribution provides a new avenue for calibrating more accurate and reliable models for predicting plant photosynthetic rate.

Aims As a crucial coupling agent linking plant roots, soil, and microorganisms, root exudates serve not only as an important vector for information transformation, but also as the core carrier for energy input, playing a significant role in shaping responses of plants to environmental changes. However, the effects of mixed-species on the metabolite compositions of root exudates remain unclear. Our objective is to explore the differences in metabolite compositions of root exudates between mixed-species stands and corresponding pure stands, and the implications on sustainable management of subtropical plantations. Methods In this study, we used in-situ collection devices to sample root exudates of Pinus massoniana and Erythrophleum fordii in their pure and mixed (P. massoniana×E. fordii) stands in southern subtropial China. The metabolite compositions of root exudates of each species were analyzed using LC-MS/MS. Important findings (1) The relative quantitative values of lipids, organicheterocyclic, organic acid and organic oxygen compounds in root exudates of Pinus massoniana and Erythrophleum fordii were significantly higher in pure stands than in mixed stands. (2) Comparative analysis of differential metabolites between pure and mixed stands revealed that P. massoniana had 208 differential metabolites, with glycerophospholipids exhibiting significant up-regulation in the P. massoniana pure stand. E. fordii had 106 differential metabolites, with p-Mentha-1,8-dien-7-ol, chavicol, isobutyric acid and diplodiatoxin exhibiting significant up-regulation in the E. fordii pure stand. (3) KEGG annotation and enrichment analysis showed that lipid metabolism pathways were significantly up-regulated in both P. massoniana and E. fordii pure stands compared to the mixed stand. Lipid metabolism was correlated with plant defense strategies.

Aims The objective of this study is to elucidate the response mechanism of amino acids and their derivatives secreted by the roots of salt-tolerant plants under salt stress. Methods This study selected Elytrigia elongata as the research subject. Four levels of salt stress (control, mild, moderate, and severe) were established by adding varying concentrations of NaCl. Non-targeted metabolomics analysis based on liquid chromatography-mass spectrometry (LC-MS) was employed to investigate the changing trends of root-secreted amino acids and derivatives in response to increasing salt stress intensity, as well as their relationships with root characteristics and the rhizosphere soil properties. Important findings The results indicated that with escalating salt stress, the secretion of L-Arginine, L-Dopachrome, 2,3,4,5-tetrahydrodipicolinic acid, N-Acetylaspartic acid, L-Phenylalanine, L-Methionine, Trans-3-hydroxy-L-proline, and N-Acetyl-L-phenylalanine significantly decreased. In contrast, Betaine and N-Jasmonic acid isoleucine exhibited significant increases, although no significant differences were observed in the mild, moderate, and severe salt stress treatments. The secretion amounts of the other amino acids and derivatives showed no significant changes. These findings suggest that Elytrigia elongata adapts to salt-stressed environments by modulating the secretion of specific amino acids and derivatives. Soil salinity, electrical conductivity, volumetric water content, total root volume, and total root surface are keys factors influencing the upregulation of betaine and N-jasmonic acid isoleucine. Soil electrical conductivity serves as a key influencing factor for the secretion of eight down-regulated amino acids and their derivatives. Path analysis indicates that both the up-regulated and down-regulated groups of ten amino acids and their derivatives are regulated by soil electrical conductivity and pH.Collectively, these results provide a scientific foundation for understanding the physiological mechanisms underlying how plants adapt to salt stress.

Abstract Aims Root water absorption and leaf transpiration work together to maintain the dynamic balance of water in plants. The driving forces of water transport in the long distance of plant xylem are transpiration pull and root pressure. It is generally believed that the transpiration pull plays a major role, and the root pressure is small and only works at night or when the transpiration rate is low. Some rattan and herbaceous plants have high root pressure. However, because transpiration pull may also play a role, whether the change of root pressure would directly affect transpiration rate and the response speed and mode of transpiration to the change of root pressure are not clear. Methods In this paper, the effect of low temperature(0℃), high temperature(35℃), salt stress(200 mmol·L-1 NaCl), drought(20% PEG 6000), fibrous root removal and in vitro on root pressure and transpiration of Dracaena sanderiana were studied to explore the feedback of transpiration on root pressure. Important findings (1) The root pressure of D. sanderiana was relatively high. Under non-stress conditions, the root pressure could maintain positive throughout the day and act alone to push water to the top of the stem. The maximum transpiration rate of D. sanderiana was only 0.37 mmol·m?2·s?1, which might be the reason why the root pressure can remain positive throughout the day. (2) After low temperature treatment, both root pressure and transpiration decreased, while increased after high temperature treatment, indicating that the root system was affected by temperature, which in turn affected the production of root pressure, and the changes in root pressure quickly affected transpiration. (3) After salt, drought, fibrous root removal and in vitro treatment, root pressure decreased to a negative value in one day and then gradually recovered to around 0, while transpiration rate decreased slightly after several hours of short time treatment, and decreased to 18-72% of the pre-treatment in the next day, and then decreased to 0 after 4-12 days of long-term treatment, indicating that the transpiration rate and stomatal conductance of D. sanderiana fed back rapidly to the change of root pressure. In conclusion, after the root pressure disappeared, the transpiration pull did not appear to maintain the previous transpiration rate, indicating that the long-distance water transport in the xylem of D. sanderiana has a root pressure driven mechanism, which is different from that of most plants. This study provides theoretical support and guidance for water management in D. sanderiana cultivation.

Abstract Aims Aiming at the problems of expanding saline and alkaline land area and decreasing yield of planted maize in Yinhuang Irrigation District of Ningxia, this study aimed to investigate the effects of vertical deep rotary tillage with organic fertilizer on the senescence characteristics and yield of maize leaves, and to provide a theoretical basis for delaying senescence and increasing the yield of maize in saline and alkaline land in this area. Methods A split-zone trial was conducted in Pingluo County, Ningxia from 2021 to 2022. Two types of tillage methods, conventional tillage (TF, tilling depth 25-30 cm) and vertical deep rotary tillage (DT, depth 40-45 cm), were set as the main zone, and four levels of organic fertilizer consumption, namely, 0 kg·hm-2 (M0), 7,500 kg·hm-2 (M1), 15,000 kg·hm-2 (M2) and 22,500 kg·hm-2 (M3), were set as the sub-zones. (M2), 7,500 kg·hm-2 (M1), 15,000 kg·hm-2 (M2) and 22,500 kg·hm-2 (M3) levels of organic fertilizer were used as sub-zones to analyze the yield and leaf senescence characteristics of maize in saline soil. Important findings (1) Corn yield was significantly increased when vertical deep rotary tillage was applied with 15000 kg·hm-2 organic fertilizer (M2 treatment), and the yield could be maximized by keeping the amount of organic fertilizer in the range of 14505~16710 kg·hm-2; under this treatment, the leaf area index (LAI), relative chlorophyll content The leaf area index (LAI) and relative chlorophyll content (SPAD) of maize were significantly increased under this treatment, and the onset of leaf senescence was delayed by 2.9~13.9 d. (2) Vertical deep rotary tillage with organic fertilizers decreased soil pH and EC, increased alkaline nitrogen (AN), effective phosphorus (AP), quick-acting potassium (AK) and organic matter (OM), significantly increased superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities and decreased proline (Pro) and malondialdehyde (MDA) contents, and significantly increased soluble sugar (SS) accumulation compared with other treatments. (MDA) and significantly increased soluble sugar (SS) content. The M2 treatment was the best, compared with the M3 treatment, where excessive organic fertilizer inputs increased soil pH and EC, reduced nutrients, decreased SOD, POD, CAT, SS, and Pro, and increased MDA accumulation, which inhibited maize growth and sustained yield improvement. (3) Pearson correlation analysis showed that maize yield was significantly or highly significantly positively correlated with LAI, SPAD, SOD, POD, CAT, Pro, and SS of leaves and AN, AK, and OM of soil, and significantly or highly significantly negatively correlated with MDA and EC. (4) The principal component analysis showed that the composite score under vertical deep rotary tillage with organic fertilizer treatment showed the trend of M2＞M3＞M1＞M0. In this study, vertical deep rotary tillage with 15000 kg·hm-2 organic fertilizer (M2) effectively improved saline soil environment, delayed leaf senescence, increased leaf antioxidant enzyme activities, and reduced MDA accumulation, which in turn increased maize yield.