Search Results (91)

The regulatory mechanisms by which AMF modulate the integrated carbon (C)-nitrogen (N)-phosphorus (P) metabolic network in woody plant leaves remain unclear. We investigated how varying nitrate (NO₃⁻) and phosphate (Pi) supply, with or without AMF inoculation, reshapes the leaf metabolic network in poplar seedlings. Key findings reveal that AMF acts as a central metabolic hub, optimizing C-N-P coordination in an environment-dependent manner. Under low Pi, NO₃⁻ supply enhanced P remobilization and photosynthetic efficiency, boosting growth. AMF further optimized low-Pi adaptation by promoting P storage and buffering, significantly improving photosynthesis and biomass. Under high Pi, NO₃⁻ supply shifted focus towards enhancing Rubisco-mediated carbon assimilation. AMF synergistically improved carbon assimilation efficiency and suppressed non-essential P recycling. N metabolism effects of Pi were contingent on NO₃⁻ availability, and AMF reprogrammed N assimilation pathways accordingly, balancing uptake and utilization under different N regimes. Critically, AMF orchestrated environment-specific metabolic adjustments, reinforcing P buffering and photosynthetic gain under Pi limitation, and enhancing C assimilation efficiency while minimizing P waste under Pi sufficiency. This study demonstrates that poplar leaf C-N-P networks are reconfigured through N-P synergisms modulated by AMF, positioning AMF as a pivotal integrator of nutrient acquisition and allocation. These insights provide a physiological foundation for developing efficient forestry nutrient management and mycorrhizal application strategies. Full article

Nanofertilizers have attracted increasing attention as an approach to improve the low nutrient use efficiency of conventional fertilizers, in which only a limited fraction of applied nitrogen, phosphorus, and potassium is ultimately taken up by crops. Beyond their capacity to minimize nutrient losses, nanofertilizers have attracted increasing attention for their possible role in addressing environmental issues, including soil eutrophication and the contamination of groundwater systems. Owing to their nanoscale characteristics, including large specific surface area and enhanced adsorption capacity, these materials enable more precise nutrient delivery to the rhizosphere and sustained release over extended periods, while also influencing soil–plant–microbe interactions. In this review, nanofertilizers are classified into six major categories—macronutrient-based, micronutrient-based, organic, controlled-release, composite, and nano-enhanced formulations—and representative examples and preparation routes are summarized, including green synthesis approaches and conventional chemical methods. The agronomic mechanisms associated with nanofertilizer application are discussed, with emphasis on enhanced nutrient uptake, modification of soil physicochemical properties, and shifts in microbial community composition. Reported studies indicate that nanofertilizers can increase crop yield across different crop species and formulations, while also contributing to improved nutrient cycling. Despite these advantages, several limitations continue to restrict their broader adoption. These include uncertainties regarding long-term environmental behavior, relatively high production costs compared with conventional fertilizers, and the absence of well-defined regulatory and safety assessment frameworks in many regions. Overall, this review highlights both the opportunities and challenges associated with nanofertilizer application and points to the need for further development of cost-effective formulations and standardized evaluation systems that account for their distinct environmental interactions. Full article

Cotton is an important cash crop globally. Cotton fiber is the main economic product of cotton plants. Phosphorus, as one of the essential nutrients, plays an important role in plant growth and development. However, few studies focus on phosphorus regulating fiber elongation. In this study, we used the cotton ovule culture system in vitro to explore the effects of various phosphorus levels on fiber and ovule growth, and screened for phosphorus-responsive factor, as well as revealed its action mechanism. The results indicated that fiber elongation was more sensitive than ovule growth to phosphorus deficiency. GhPHR1, a homolog of phosphate starvation response 1 (PHR1) in upland cotton, was significantly upregulated in fibers and ovules under phosphorus-deficient conditions. GhPHR1 directly binds to the promoter of the glucosylceramide synthase gene in cotton (GhGCS1) and positively regulates its expression. Overexpressing GhGCS1 enhanced phosphorus uptake and transport in cotton, increased phosphorus content in fiber cells, and promoted fiber cell elongation. Conversely, downregulating GhGCS1 reduced phosphorus content in fiber cells and suppressed fiber elongation. These findings demonstrate the importance of the GhPHR1-GhGCS1 molecular module in regulating fiber cell elongation and elucidate the molecular mechanism by which phosphorus influences fiber elongation. Full article

Ectomycorrhizal (ECM) fungi form key symbioses with forest trees, strongly regulating plant nutrition and stress tolerance. This review synthesizes how ECM fungi redistribute plant-fixed carbon (C) in soil, interact with soil organic matter (SOM), and mediate the uptake and allocation of nitrogen (N), phosphorus (P) and other macro- and micronutrients. We highlight mechanisms underlying ECM enhanced organic and mineral N and P mobilization, including oxidative decomposition, enzymatic hydrolysis, and organic acid weathering. Beyond C-N-P dynamics, ECM fungi also enhance acquisition and homeostasis of elements such as K, Ca, Mg, Fe, and Zn, reshaping host nutrient stoichiometry, productivity, and soil microbial community composition. We further summarize multi-layered mechanisms by which ECM improve host plant resistance to pathogens, drought, salinity–alkalinity, and heavy metal stresses via physical protection, ion regulation, hormonal signaling, aquaporins, and antioxidant and osmotic adjustment. Finally, we outline research priorities, such as using trait-based, multi-omics, and microbiome-integrated approaches to better harness ECM in forestry and ecosystem restoration. Full article

Nutrient additions including nitrogen (N) and phosphorus (P) are widely considered as an important strategy for enhancing grassland productivity. However, the effects of these nutrients additions on soil nitrous oxide (N₂O) emissions and the underlying mechanisms remain debated. We conducted a two-year field experiment in an alpine grassland on Kunlun Mountain in northwestern China to assess the effects of N and P additions on N₂O emissions, in relation with nitrifying enzyme activity (NEA), denitrifying enzyme activity (DEA), and key functional genes abundance responsible for nitrification (amoA and Nitrobacter-like nxrA) and denitrification (narG, nirS, nirK and nosZ). Compared to the Control without nutrient addition (CK), N addition alone substantially increased cumulative N₂O emission (ƩN₂O) by 2.0 times. In contrast, P addition or combined N and P (N+P) addition did not significantly affect ƩN₂O, though both treatments significantly increased plant aboveground biomass. Such results indicate that P addition may mitigate N-induced N₂O emission, likely by reducing soil N availability through enhanced plant and microbial N uptake. Compared to CK, N or N+P addition significantly elevated NEA but did not affect DEA. Structural equation modeling (SEM) indicated that NEA was directly influenced by the gene abundances of ammonia-oxidizing bacteria (AOB) and Nitrobacter-like nxrA but not by ammonia-oxidizing archaea (AOA). However, SEM also revealed that soil environmental variables including soil temperature, pH, and water-filled pore space (WFPS) had a stronger direct influence on N₂O emissions than the abundances of nitrifiers. These results demonstrate that soil environmental conditions play a more significant role than functional gene abundances in regulating N₂O emissions following N and P additions in semi-arid alpine grasslands. This study highlights that the N+P application can potentially decrease N₂O emissions than N addition alone, while increasing productivity in the alpine grassland ecosystems. Full article

This study systematically analyzes the multi-layered regulatory mechanisms of grazing on soil nitrogen and phosphorus cycling functions, based on the combined effects of different grazing strategies and plant community spatial patterns in alpine grasslands. A controlled mixed grazing experiment with moderate intensity was conducted on a livestock system adaptive management platform in the region surrounding Qinghai Lake on the Qinghai–Tibet Plateau, China. The experimental treatments included yak-only grazing (YG), Tibetan sheep-only grazing (SG), mixed grazing of yak and Tibetan sheep (MG), and no grazing (CK). The study quantitatively assessed the soil microbial nitrogen and phosphorus cycling functional genes in the rhizosphere of dominant species, including the Carex alatauensis and Potentilla acaulis, under different grazing intensities. The aim was to explore the effects of grazing strategy and clusters of dominant species on soil nitrogen and phosphorus cycling and their regulatory mechanisms. The results of this study show that, in the nitrogen cycle, grazing led to a decrease in total nitrogen (TN) content and an increase in ammonium nitrogen content in the dominant species communities. The MG treatment significantly enhanced the abundance of key nitrogen metabolism genes, such as ureC and gs. In the phosphorus cycle, most grazing treatments increased total phosphorus content, but changes in available phosphorus were variable among plant clusters. The MG and SG treatments significantly increased the abundance of functional genes such as aphA, ugpB, and phnW. Compared to the relatively stable soil nitrogen and phosphorus content, the abundance of functional genes exhibited significantly higher variability across different grazing treatments. The clusters of Potentilla acaulis maintained nutrient stability by enhancing nitrogen assimilation and phosphorus uptake, while the clusters of Carex alatauensis promoted ammonium nitrogen accumulation through a conservative strategy. The results indicate that grazing influences nitrogen and phosphorus availability by altering nutrient input and disturbance modes, while plant clusters optimize cycling through differential regulation of microbial functional genes in the community. Both factors jointly regulate nitrogen and phosphorus cycling in Alpine Grassland soils. Mixed grazing exhibited significant advantages in promoting nitrogen retention, enhancing phosphorus activation, and improving plant-microbe interactions, reflecting a comprehensive facilitation of nutrient cycling stability in alpine grasslands. These findings provide important theoretical insights for nutrient cycling management and sustainable grazing practices in alpine grasslands. Full article

Cadmium (Cd), a pervasive and highly phytotoxic metal pollutant, poses severe threats to agricultural productivity, ecosystem stability, and human health through its entry into the food chain. Plants have evolved intricate defense mechanisms, among which the strategic manipulation of nutrient elements emerges as a critical physiological and biochemical strategy for mitigating Cd stress. This comprehensive review delves deeply into the multifaceted roles of essential macronutrient elements (nitrogen, phosphorus, potassium, calcium, magnesium, sulfur), essential micronutrient elements (zinc, iron, manganese, copper) and non-essential beneficial elements (silicon, selenium) in modulating plant responses to Cd toxicity. We meticulously dissect the physiological, biochemical, and molecular underpinnings of how these nutrients influence Cd bioavailability in the rhizosphere, Cd uptake and translocation pathways, sequestration and compartmentalization within plant tissues, and the activation of antioxidant defense systems. Nutrient elements exert their influence through diverse mechanisms: competing with Cd for root uptake transporters, promoting the synthesis of complexes that reduce Cd mobility, stabilizing cell walls and plasma membranes to restrict apoplastic flow and symplastic influx, modulating redox homeostasis by enhancing antioxidant enzyme activities and non-enzymatic antioxidant pools, regulating signal transduction pathways, and influencing gene expression profiles related to metal transport, chelation, and detoxification. The complex interactions between nutrients themselves further shape the plant’s capacity to withstand Cd stress. Recent advances elucidating nutrient-mediated epigenetic regulation, microRNA involvement, and the role of nutrient-sensing signaling hubs in Cd responses are critically evaluated. Furthermore, we synthesize the practical implications of nutrient management strategies, including optimized fertilization regimes, selection of nutrient-efficient genotypes, and utilization of nutrient-enriched amendments, for enhancing phytoremediation efficiency and developing low-Cd-accumulating crops, thereby contributing to safer food production and environmental restoration in Cd-contaminated soils. The intricate interplay between plant nutritional status and Cd stress resilience underscores the necessity for a holistic, nutrient-centric approach in managing Cd toxicity in agroecosystems. Full article

This study explores the complex regulatory mechanisms of nitrogen (N) and phosphorus (P) supply interactions on the growth, root architecture, and nutrient uptake of Populus × euramericana ‘Neva’ seedlings. It shows that these responses depend on nutrient concentrations and exhibit organ-specific patterns. Low P (0 mM) and sufficient N (15–30 mM) enhances plant height and aboveground biomass by promoting P acquisition processes. At moderate N levels (5–15 mM), P supply is sufficient (0.5–1.5 mM) for root and stem growth. Nitrogen application prioritizes aboveground biomass, reducing the root-to-shoot ratio. Root architecture also responds organ-specifically: sufficient N under low P promotes fine root growth to increase P absorption; under moderate P (0.5 mM), balanced N optimizes branching; and under sufficient P (1.5 mM), N increases root thickness while reducing fine root investment. In terms of P metabolism, moderate N under low P increases P concentrations by upregulating phosphate transporter genes, while sufficient N maintains P use efficiency (PUE). For N metabolism, added P under low N (0 mM) maintains N use efficiency (NUE), while higher N levels (15–30 mM) reduce NUE due to interference in nitrogen transport and enzyme activity. This study highlights the importance of organ-specific resource allocation in adapting to N–P interactions and suggests optimizing fertilization strategies based on soil nutrient status to avoid physiological imbalance. Full article

Organic amendments, such as straw, biochar, and animal manure, have been demonstrated to enhance soil phosphorus (P) availability effectively; however, the long-term impacts and underlying mechanisms require further study. Based on a long-term field experiment, this research systematically analyzed the effects of biochar (BIO), biochar-based fertilizer (BF), straw-returning (CS), and pig manure compost (PMC) on soil phosphorus transformation and crop phosphorus uptake. Results showed that biochar significantly boosted soil available phosphorus (AP) by releasing soluble phosphorus, raising soil pH, reducing phosphorus fixation by iron and aluminum oxides, and enhancing soil cation exchange capacity (CEC) to promote phosphorus dissolution and transformation. Notably, biochar increased the proportion of NaOH-P, facilitating phosphorus accumulation in peanut grains and improving the phosphorus harvest index and utilization efficiency. Straw-returning primarily elevated soil AP by promoting organic phosphorus mineralization and inorganic phosphorus release; however, its acidification of the soil impaired phosphorus translocation to grains, resulting in lower phosphorus-use efficiency compared to biochar. Pig manure compost reduced soil phosphorus fixation and increased soil total organic carbon (TOC), thereby boosting phosphorus transformation. Despite enhancing phosphorus dry-matter production in plants, most phosphorus remained in stems and leaves, with limited translocation to grains, leading to lower phosphorus-use efficiency than biochar. In conclusion, biochar was most effective in enhancing soil phosphorus availability and crop phosphorus-use efficiency, highlighting its potential in sustainable soil fertility management and optimized crop production. Full article

Liriope muscari is a medicinal and ornamental herbaceous plant with significant economic value, as its tuberous roots are used for medicinal purposes. However, the current production of medicinal plants is characterized by wasteful use of resources and ecological risks caused by the unreasonable application of nitrogen fertilizers. In this study, based on uniform application of phosphorus and potassium fertilizers, six nitrogen application levels were set in pot experiments (expressed as N): N0: 0 kg/ha, N1: 208.33 kg/ha, N2: 416.66 kg/ha, N3: 625 kg/ha, N4: 833.33 kg/ha, N5: 1041.66 kg/ha). The morphological characteristics, photosynthetic physiology, tuber yield and quality, and seven nitrogen fertilizer utilization indices of L. muscari were analyzed and measured. Correlation analysis and structural equation modeling (SEM) were employed to investigate the mechanism by which nitrogen influences its growth and development, photosynthetic characteristics, tuber yield and quality, and nitrogen fertilizer utilization efficiency. The results showed that (1) nitrogen significantly promoted plant height, crown width, tiller number, and chlorophyll synthesis, with the N3 treatment (625 kg/ha) reaching the peak value, and the crown width and tiller number increasing by 26.44% and 38.90% compared to N0; the total chlorophyll content and net photosynthetic rate increased by 39.67% and 77.04%, respectively, compared to N0; high nitrogen (N5) inhibited photosynthesis and increased intercellular CO₂ concentration; (2) Fresh weight of tuberous roots, polysaccharide content, and saponin C content peaked at N3 (34.67 g/plant, 39.89%, and 0.21%), respectively, representing increases of 128.69%, 28.37%, and 33.66% compared to N0; (3) Nitrogen uptake, nitrogen fertilizer utilization efficiency, agronomic utilization efficiency, and apparent utilization efficiency were optimal at N3, while high nitrogen (N4–N5) reduced nitrogen fertilizer efficiency by 40–60%; (4) SEM analysis indicated that tiller number and transpiration rate directly drive yield, while stomatal conductance regulates saponin C synthesis. Under the experimental conditions, 625 kg/ha is the optimal nitrogen application rate balancing yield, quality, and nitrogen efficiency. Excessive nitrogen application (>833 kg/ha) induces photosynthetic inhibition and “luxury absorption”, leading to source-sink imbalance and reduced accumulation of secondary metabolites. This study provides a theoretical basis and technical support for the precise management of nitrogen in Liriope-type medicinal plants. It is expected to alleviate the contradictions of “high input, low output, and heavy pollution” in traditional fertilization models. Full article

Manganese (Mn) excess and low pH often coexist in some citrus orchard soils. Little information is known about the underlying mechanism by which raising pH reduces Mn toxicity in citrus plants. ‘Sour pummelo’ (Citrus grandis (L.) Osbeck) seedlings were treated with 2 (Mn2) or 500 (Mn500) μM Mn at a pH of 3 (P3) or 5 (P5) for 25 weeks. Raising pH mitigated Mn500-induced increases in Mn, iron, copper, and zinc concentrations in roots, stems, and leaves, as well as nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, copper, iron, and zinc distributions in roots, but it mitigated Mn500-induced decreases in nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, and boron concentrations in roots, stems, and leaves, as well as nutrient imbalance. Raising pH mitigated Mn500-induced necrotic spots on old leaves, yellowing of young leaves, decreases in seedling growth, leaf chlorophyll concentration, and CO₂ assimilation (A_CO2), increase in root dry weight (DW)/shoot DW, and alterations of leaf chlorophyll a fluorescence (OJIP) transients and related indexes. Further analysis indicated that raising pH ameliorated Mn500-induced impairment of nutrient homeostasis, leaf thylakoid structure by iron deficiency and competition of Mn with magnesium, and photosynthetic electron transport chain (PETC), thereby reducing Mn500-induced declines in A_CO2 and subsequent seedling growth. These results validated the hypothesis that raising pH reduced Mn toxicity in ‘Sour pummelo’ seedlings by (a) reducing Mn uptake, (b) efficient maintenance of nutrient homeostasis under Mn stress, (c) reducing Mn excess-induced impairment of thylakoid structure and PEPC and inhibition of chlorophyll biosynthesis, and (d) increasing A_CO2 and subsequent seedling growth under Mn excess. Full article

Calcareous soils, characterized by high pH and calcium carbonate content, often limit the availability of essential nutrients for crops such as rice (Oryza sativa L.), reducing yield and nutritional quality. In this study, we evaluated the effect of the halotolerant yeast Debaryomyces hansenii on the growth, nutrient uptake, and phosphorus acquisition mechanisms of rice plants cultivated in calcareous soil under controlled greenhouse conditions. Plants inoculated with D. hansenii, particularly via root immersion, exhibited significantly higher SPAD chlorophyll index, plant height, and grain yield compared to controls. A modest increase (~4%) in dry matter content was also observed under sterilized soil conditions. Foliar concentrations of Fe, Zn, and Mn significantly increased in plants inoculated with D. hansenii via root immersion in non-sterilized calcareous soil, indicating improved micronutrient acquisition under these specific conditions. Although leaf phosphorus levels were not significantly increased, D. hansenii stimulated acid phosphatase activity, as visually observed through BCIP staining, and upregulated genes involved in phosphorus acquisition under both P-sufficient and P-deficient conditions. At the molecular level, D. hansenii upregulated the expression of acid phosphatase genes (OsPAP3, OsPAP9) and a phosphate transporter gene (OsPTH1;6), confirming its influence on P-related physiological responses. These findings demonstrate that D. hansenii functions as a plant growth-promoting yeast (PGPY) and may serve as a promising biofertilizer for improving rice productivity and nutrient efficiency in calcareous soils, contributing to sustainable agricultural practices in calcareous soils and other nutrient-limiting environments. Full article

Stormwater pollution from residual chlorine after outdoor disinfection with sodium hypochlorite is an increasing environmental challenge due to its potential negative impact on aquatic ecosystems. Even at low concentrations, residual chlorine can disrupt the stability of water ecosystems. In this regard, stormwater treatment requires innovative and green solutions such as green infrastructure (rain gardens) using the plant phytoremediation technique to reduce the amount of residual chlorine. This study explores the interactions between residual chlorine retained by plants in a rain garden and different microelements. Selected plants were analyzed via spectroscopy, and possible interactions with elements such as chlorine (Cl), phosphorus (P), zinc (Zn), iron (Fe), calcium (Ca), potassium (K), nickel (Ni), silicon (Si), manganese (Mn), magnesium (Mg), chromium (Cr), and cadmium (Cd) were determined using Python-based analysis. Chlorine presented significant positive correlations with cadmium (0.39–0.53) and potassium (0.51–0.55), while negative correlations were found between silicon and chlorine (−0.48–−0.54) and chlorine and iron (−0.45–−0.51). The correlations between chlorine and microelements suggest both common uptake mechanisms and mutual interactions. These results provide a better understanding of the behavior of chlorine in rain gardens and its interactions with other materials, which is especially valuable for designing green infrastructure. This research can help to develop sustainable solutions that reduce environmental pollution and strengthen urban adaptation to climate change. Full article

Modified biochar can effectively improve the quality and environment of coastal saline–alkali soil, but its effects on the growth and development of halophytes and its mechanism are still unclear. This study systematically evaluated the growth-promoting effects and preliminary mechanisms of H₃PO₄-modified biochar (HBC) and H₃PO₄–kaolinite–biochar composite (HBCK) on the economically important halophyte Kosteletzkya virginica. The results demonstrated that the application of HBC/HBCK significantly enhanced plant growth, resulting in increases of over 55% in plant height and greater than 100% in biomass relative to the control. Multidimensional mechanistic analysis revealed the following: (1) accumulation of nitrogen (N), phosphorus (P), and potassium (K) increased by at least 40%, significantly enhancing nutrient uptake; (2) increases in the activities of superoxide dismutase (SOD) and peroxidase (POD) by over 100% and 70%, respectively, markedly boosting antioxidant capacity and effectively alleviating oxidative stress; (3) molecular regulation via the activation of transcription factor networks (HSP, MYB, TCP, AP2/ERF, bZIP, and NLP) and modulation of key genes in ABA, BR, and JA signaling pathways (CYP707A, CYP90, and OPR2), establishing a multi-layered stress adaptation and growth promotion system. Beyond assessing the growth-promoting effects of modified biochars, this study provides novel insights into the regulatory transcription factor networks and phytohormone signaling pathways, offering theoretical foundations for the molecular design of biochars for saline–alkali soil remediation. Full article

Drought stress substantially impacts the development and viability of Populus spp., which are essential for forestry and bioenergy production. This review summarizes and describes the functions of phytohormones, such as abscisic acid, auxins, and ethylene, in modulating physiological and molecular responses to water scarcity. Drought-induced ABA-mediated stomatal closure and root extension are essential adaptation processes. Furthermore, auxin–ABA (abscisic acid) interactions augment root flexibility, whereas ethylene regulates antioxidant defenses to alleviate oxidative stress. The advantageous function of endophytic bacteria, specifically plant growth-promoting rhizobacteria (PGPR), can augment drought resistance in spruce trees by enhancing nutrient absorption and stimulating root development. Structural adaptations encompass modifications in root architecture, including enhanced root length and density, which augment water uptake efficiency. Similarly, Arbuscular Mycorrhizal Fungi (AMF) significantly enhance stress resilience in forest trees. AMF establishes symbiotic relationships with plant roots, improving water and nutrient uptake, particularly phosphorus, during drought conditions. Furthermore, morphological alterations at the root–soil interface enhance interaction with soil moisture reserves. This review examines the complex mechanisms by which these hormones influence plant responses to water shortage, aiming to offer insights into prospective techniques for improving drought tolerance in common tree species and highlights the importance of hormone control in influencing the adaptive responses of prominent trees to drought stress, providing significant implications for research and practical applications in sustainable forestry and agriculture. These findings lay the groundwork for improving drought tolerance in Populus spp. by biotechnological means and by illuminating the complex hormonal networks that confer drought resistance. Full article