Search Results (70)

Ecological stoichiometry offers critical insights into nutrient dynamics and soil–plant interactions in agroecosystems. To explore the effects of long-term fertilization on soil–cotton C, N, P stoichiometry and stoichiometric homeostasis in arid gray desert soils, this study was conducted at a national gray desert soil monitoring station in Xinjiang (87°28′27″ E, 43°56′32″ N, elevation: 595 m a.s.l.)—an arid and semi-arid region with an annual mean temperature of 5–8 °C and annual precipitation of 100–200 mm. Established in 1989, the 31-year experiment adopted a wheat–maize–cotton annual rotation system with six treatments: CK (control, no fertilizer), N (nitrogen fertilizer alone), NK (nitrogen + potassium fertilizer), NP (nitrogen + phosphorus fertilizer), PK (phosphorus + potassium fertilizer), and NPK (nitrogen + phosphorus + potassium fertilizer). Key results showed that balanced NPK fertilization significantly increased soil organic carbon (SOC) by 22.7% and soil total phosphorus (STP) by 48.6% compared to CK, while the N-only treatment elevated soil N:P to 3.2 (a 68.4% increase vs. CK), indicating severe phosphorus limitation. For cotton, NPK increased seed phosphorus content by 68.2% (vs. N treatment) but reduced straw carbon content by 10.2% (vs. PK treatment), reflecting a carbon allocation trade-off from vegetative to reproductive organs under nutrient sufficiency. Stoichiometric homeostasis differed between organs: seeds maintained stricter carbon regulation (1/H = −0.40) than straw (1/H = −0.64), while straw exhibited more plastic N:P ratios (1/H = 1.95), highlighting organ-specific adaptive strategies to nutrient supply. Redundancy analysis confirmed that soil available phosphorus (AP) was the primary driver of cotton P uptake and yield formation. The seed cotton yield of NPK (5796.9 kg ha⁻¹) was 111.7% higher than CK, with NP (N-P co-application) achieving a 94.7% yield increase vs. CK—only 7.9% lower than NPK, whereas single N application showed the lowest straw yield (5995.0 kg ha⁻¹) and limited yield improvement. These findings demonstrate that long-term balanced NPK fertilization optimizes soil C-N-P stoichiometric balance by enhancing SOC sequestration and phosphorus retention, regulating cotton organ-specific stoichiometric homeostasis, and promoting efficient nutrient uptake and assimilate translocation. The study confirms that phosphorus is the key limiting factor in arid gray desert soil cotton systems, and balanced NPK supply is essential to mitigate stoichiometric imbalances and sustain soil fertility and productivity. This provides targeted practical guidance for rational fertilization management in arid agroecosystems, emphasizing the need to prioritize phosphorus supply and avoid single-nutrient application to maximize resource use efficiency. Full article

Arbuscular mycorrhizal (AM) fungi establish mutualistic symbioses with plant roots, enhancing plant growth and improving soil fertility through nutrient exchange. Among these, soil nitrogen (N) and phosphorus (P) are critical for symbiosis formation, directly influencing nutrient uptake and translocation within the symbiotic system. This study aimed to examine the regulatory roles of N and P levels on AM fungal development and associated bacterial communities in culture. Sorghum was used as the host plant in pot experiments with two AM fungi, Rhizophagus irregularis and Funneliformis mosseae, under varying N and P concentrations. The analyzed parameters included mycorrhizal colonization, propagule production, plant biomass, nutrient contents (N, P, and K), and bacterial community diversity. N3P1 treatment (150 mg/L N, 30 mg/L P) yielded the highest colonization rate, spore production, and arbuscule abundance in both AM fungal symbionts. At equivalent N and P concentrations, the N, P, and K contents in inoculated plants were significantly higher than those in controls. AM fungal inoculation markedly increased the bacterial diversity in the culture (Shannon index raised by 15.2–28.7%) and enriched beneficial taxa, such as Bradyrhizobium and Pseudomonas. N and P concentrations substantially influenced AM fungal symbiosis, with optimal development observed under N3P1 conditions. By regulating AM symbiotic establishment, N and P levels reshaped microbial community composition, providing theoretical guidance for industrialized AM fungal cultivation and inoculant production. Full article

Phosphorus (P) is essential to life yet constrained by finite reserves, heterogeneous distribution, and strong chemical binding to soil minerals. Pedogenesis progressively alters the availability of P: in ‘young’ soils, P associated with Ca and Mg is relatively labile, while in ‘old’ soils, acidification and leaching deplete base cations, shifting P into organic matter and recalcitrant Al- and Fe-bound pools. Podzolized soils (Spodosols) provide a unique lens for studying this transition because podzolization vertically segregates these dynamics into distinct horizons. Organic cycling dominates the surface horizon, while downward translocation of Al, Fe, and humus creates a spodic horizon that immobilizes P through sorption and co-precipitation in amorphous organometal complexes. This spatial separation establishes two contrasting P pools—biologically dynamic surface P and mineral-stabilized deep P—that may be variably accessible to plants and microbes depending on depth, chemistry, and hydrology. We synthesize mechanisms of spodic P retention and liberation, including redox oscillations, ligand exchange, root exudation, and physical disturbance, and contrast these with strictly mineral-driven or biologically dominated systems. We further propose that podzols serve as natural experimental models for ecosystem aging, allowing researchers to explore how P cycling reorganizes as soils develop, how vertical stratification structures biotic strategies for nutrient acquisition, and how deep legacy P pools may be remobilized under environmental change. By framing podzols as a spatial analogue of long-term weathering, this paper identifies them as critical systems for advancing our understanding of nutrient limitation, biogeochemical cycling, and sustainable management of P in diverse ecosystems. 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

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

SPX (SYG1/Pho81/XPR1) family genes play a pivotal role in phosphorus signaling, phosphorus uptake, and phosphorus translocation in plants. However, to date, the SPX family genes have not been systematically investigated in cotton. In this study, we conducted a genome-wide analysis and identified 44 SPX family genes in Gossypium hirsutum, classifying them into four subfamilies (SPX, SPX-MFS, SPX-EXS, and SPX-RING) based on conserved domains. An expression analysis revealed that the majority of SPX family genes were highly expressed in the root and stem. We identified hormone response, stress response, low-temperature response, and PHR1 binding sequence (P1BS) cis-elements in the promoters of the SPX genes. Additionally, the expression of GhPHO1-4, GhSPX1-1/1-2/1-3, and GhSPX-MFS2-1/2-2 was significantly altered under phosphorus-deficient conditions and may be involved in the regulation of Pi response. A Y2H assay suggested that GhSPX1-1 interacts with GhPHR1A and GhSPX1-2 interacts with GhPHL1A. Our findings provide a basis for further cloning and functional verification of genes related to the regulatory network of low phosphorus tolerance in cotton. Full article

To investigate the remediation efficiency of different plant species on cadmium (Cd)-contaminated soil, this study conducted a pot experiment with two woody species (Populu adenopoda and Salix babylonica) and two herbaceous species (Artemisia argyi and Amaranthus hypochondriacus). Soils were collected from an abandoned coal mine and adjacent pristine natural areas within the dam-adjacent section of the Three Gorges Reservoir Area to establish three soil treatment groups: unpolluted soil (T1, 0.18 mg·kg⁻¹ Cd), a 1:1 mixture of contaminated and unpolluted soil (T2, 0.35 mg·kg⁻¹ Cd), and contaminated coal mine soil (T3, 0.54 mg·kg⁻¹ Cd). This study aimed to investigate the growth status of plants, Cd accumulation and translocation characteristics, and the relationship between them and soil environmental factors. Woody plants exhibited significant advantages in aboveground biomass accumulation. Under T3 treatment, the Cd extraction amount of S. babylonica (224.93 mg) increased by about 36 times compared to T1, and the extraction efficiency (6.42%) was significantly higher than other species. Among the herbaceous species, A. argyi showed the maximum Cd extraction amount (66.26 mg) and extraction efficiency (3.11%) during T2 treatment. While A. hypochondriacus exhibited a trend of increasing extraction amount but decreasing extraction efficiency with increasing concentration. With the exception of S. babylonica under T1 treatment (BCF = 0.78), the bioconcentration factor was greater than 1 in both woody (BCF = 1.39–6.42) and herbaceous species (BCF = 1.39–3.11). However, herbaceous plants demonstrated significantly higher translocation factors (TF = 1.58–3.43) compared to woody species (TF = 0.31–0.87). There was a significant negative correlation between aboveground phosphorus (P) content and root Cd (p < 0.05), while underground nitrogen (N) content was positively correlated to aboveground Cd content (p < 0.05). Soil total N and available P were significantly positively correlated with plant Cd absorption, whereas total potassium (K) showed a negative correlation. This study demonstrated that woody plants can achieve long-term remediation through biomass advantages, while herbaceous plants, with their high transfer efficiency, are suitable for short-term rotation. In the future, it is suggested to conduct a mixed planting model of woody and herbaceous plants to remediate Cd-contaminated soils in the tailing areas of reservoir areas. This would synergistically leverage the dual advantages of root retention and aboveground removal, enhancing remediation efficiency. Concurrent optimization of soil nutrient management would further improve the Cd remediation efficiency of plants. Full article

Replacing chemical fertilizers with organic alternatives represents a viable strategy for enhancing agricultural productivity. The optimized integration of both fertilizer types can reduce the chemical input while improving soil conditions. However, the specific impacts of combined organic and inorganic fertilization on soil quality and crop performance require further investigation. To address this, a two-year field experiment was conducted to examine the effects of varying ratios of organic fertilizer substitution on wheat growth, grain yield, nutrient uptake, and soil quality. The results showed that the application of a 100% organic fertilizer combined with a 90% chemical fertilizer significantly increased the wheat biomass and grain yield. In terms of the nutrient uptake efficiency, the aboveground uptake of nitrogen (N), phosphorus (P), and potassium (K) increased significantly by 29.2%, 29.0%, and 56.5%, respectively. The nutrient use efficiency was also improved, with increases of 30.4% for N, 21.1% for P, and 47.7% for K. The partial factor productivity, total nutrient uptake, and the translocation efficiency of N, P, and K were all significantly enhanced. The soil quality was also markedly improved, with increases in both the soil organic matter and nutrient content. In conclusion, substituting chemical fertilizers with organic fertilizers improves the soil moisture and organic matter content, thereby enhancing the total uptake and translocation efficiency of nitrogen, phosphorus, and potassium. This leads to increased nutrient content in wheat grains, resulting in higher yields and improved grain quality. Moreover, this study provides practical guidance for wheat production and supports policy objectives related to sustainable agriculture, reduced chemical fertilizer use, and improved food security. Full article

The nitrogen (N) and phosphorus (P) additions were commonly used to improve plantation quality. However, the balance between nutrient uptake in the underground part and nutrient utilization in the aboveground part of Pinus elliottii (Slash pine) plantation in subtropical regions after N and P addition is still unclear. We conducted the experiment using a randomized complete block design with four treatments: N (50 kg N ha⁻² yr⁻¹, P (100 kg P ha⁻² yr⁻¹), NP (N + P), and a control (CK). Nutrient transport dynamics of underground (rhizosphere soil and roots) and aboveground (twigs and needles) parts of a 10-year-old Pinus elliottii plantations were evaluated. The trial was maintained for three consecutive growing seasons. The results showed that N and P additions significantly increased the N, P, and potassium (K) contents of soils and plant tissues in subtropical slash pine plantation forests, and showed a significant and gradual increase in interannual variations over the observation period (except for TN in soils, which increased first and then decreased). In terms of nutrient transport and reabsorption efficiency, N addition promoted the transport of elemental P from the translocating root system to the twigs, whereas P addition inhibited this process. P addition significantly increased the nitrogen reabsorption efficiency (NRE) of the needles, but decreased the phosphorus reabsorption efficiency (PRE), showing an element-specific response to the nutrient reabsorption process. Structural equation modeling further revealed that N or P addition had direct positive effects on soil N, P, and K content (path coefficients r: 0.54, 0.71, 0.41). N addition indirectly negatively affected N resorption efficiency (NRE) and K resorption efficiency (KRE) (r: −0.62, −0.51) but positively affected PRE (r: 0.44). Conversely, P addition had an indirect negative effect on PRE (r: −0.59). These results reveal that in subtropical regions, slash pine plantations adapt to N or/and P addition by adjusting nutrient absorption, transport, and resorption efficiency. This provided new insights into nutrient transport and distribution strategies in underground and aboveground parts of plants under N or/and P additions. Full article

Nitrogen (N) and phosphorus (P) are key factors affecting rice yield. To study the effects of single application of nitrogen, phosphorus and their combined application on dry matter accumulation and yield of rice, two types of indica rice with contenting amylose contents, low amylose content (LAC) and high amylose content (HAC) were used as the test materials. Four different levels of nitrogen and phosphorus were applied (N0: 0, N1: 90, N2: 150, N3: 270 kg/hm²) and (P0: 0, P1: 15, P2: 30, P3: 60 kg/hm²). The application of N fertilizer alone and in combination with P effectively promote dry matter accumulation, translocation and increase yield. Under the N3P0 and N3P1 treatments, LAC and HAC achieved their highest yield of 10.03 t/hm² and 11.24 t/hm², respectively. representing increased of 46.19% and 29.05% compared to N0P0 treatment. Phosphorus application influenced dry matter accumulation at maturity and stem and leaf dry matter translocation to the panicle, translocation rates, and their contribution to the panicle, there by increasing yield. Effective panicles, spikelets per panicle, grain filling, stem and leaf dry matter translocation, stem and leaf dry matter translocation rate were significantly or highly significantly positively correlated with yield, and 1000-grain weight was highly significantly negatively correlated with yield, which were mainly increased by increasing panicle dry matter accumulation at maturity, the increase in the amount of increase in dry matter of panicle, the contribution rate of stem and leaf dry matter translocation to the panicle, the amount of stem and leaf dry matter translocation, and the rate of stem and leaf dry matter translocation to increase spikelets per panicle and the grain filling, and then to improvement of yield. Full article

Scallions are a highly valued leafy vegetable and are enjoyed worldwide due to their appealing taste and nutritional benefits. A combination of short cultivation cycles and high market demand not only enhances food security but also offers a profitable opportunity for growers. In our study, we aim to evaluate the effect of increasing boron (B) applications, specifically 0, 0.2, 0.4, 0.8, 1.2, and 1.6 mM B supplied as boric acid (H₃BO₃) in the nutrient solution, on several key physiological and agronomic parameters in scallions. Results showed that the effects of increasing B levels on biomass production were insignificant, but the root fresh weight (FW) significantly decreased with all B levels. Higher B levels (1.2 and 1.6 mM) caused decreases of 22.9% and 29.6%, respectively. The effects of all B levels on photosynthetic pigment contents [chlorophyll (Chl) a, b, a + b, and carotenoid (Car)], root and shoot membrane permeability (MP), and root, shoot, and leaf nutritional status [phosphorus (P), potassium (K), calcium (Ca), and sodium (Na) concentrations] were found insignificantly. However, all B levels caused a significant increase in the B concentrations of the root, shoot, and leaf of scallions and plants translocated the majority of applied B into their leaves. The translocation factor (TF) of B from the root to the leaf was found to be 138.2%, 133.3%, and 107.3% with 0.8, 1.2, and 1.6 mM B levels, respectively. Moreover, plants exposed to high levels of B showed no significant response or toxicity symptoms. We concluded that B is a phloem mobile element in onion, a non-graminaceous monocotyledonous plant, and therefore accumulates in the upper organs but illustrates partial toxicity symptoms in leaves. Studies with higher B concentrations could be recommended to determine critical B levels for green onion production in B-contaminated areas. Full article

Biochar, an eco-friendly soil amendment, holds promise for remediating contaminated soils, yet its impacts on coastal wetland soils under combined microplastic (MP) and heavy metal (HM) pollution remain underexplored. This study examined the efficacy of 2% Spartina alterniflora-derived biochar (BC) in rehabilitating soils co-contaminated with cadmium (Cd) and two MPs—polyethylene (PE) and polylactic acid (PLA)—at 0.2% and 2% (w/w). The results indicated that biochar significantly elevated soil pH (8.35–8.43) and restored electrical conductivity (EC) to near-control levels, while enhancing organic matter content (up to 130% in PLA-contaminated soils), nutrient availability (e.g., phosphorus, potassium), and enzyme activity. Biochar reduced bioavailable Cd by 14–15% through adsorption and ion exchange. Although bacterial richness and diversity slightly declined, biochar reshaped microbial communities, enriching taxa linked to pollutant degradation (e.g., Proteobacteria, Bacteroidota) and upregulated functional genes associated with carbon, nitrogen, and sulfur cycling. Additionally, biochar boosted Suaeda salsa (S. salsa) biomass (e.g., 0.72 g/plant in A1B) and height (e.g., 14.07 cm in E1B) while reducing Cd accumulation (29.45% in shoots) and translocation. Remediation efficiency was most pronounced in soils with 0.2% PLA. These findings bridge critical knowledge gaps in biochar’s role in complexly polluted coastal wetlands and validate its potential for sustainable soil restoration. Full article

Accumulating evidence suggests that the plasma membrane-localized phosphate transporter 1 (PHT1) family plays a fundamental role in the absorption, translocation, and re-mobilization of phosphorus in plants. Buckwheat (Fagopyrum spp.) exhibits high efficiency in phosphate uptake and wide adaptability to grow in under-fertilized soils. Despite their physiological importance, a systematic analysis of PHT1 genes in buckwheat has not been conducted yet. In this study, we performed a genome-wide identification and expression profile of the PHT1 gene family in Tartary buckwheat (Fagopyrum tataricum Gaertn). A total of eleven putative PHT1 genes (FtPHT1;1 to 1;11) were identified with an uneven distribution on all the F. tataricum chromosomes except for chromosomes 2, 3, and 5. All the FtPHT1s share the conserved domain GGDYPLSATIxSE, a typical signature of PHT1 transporters. A phylogenetic analysis indicated that FtPHT1 proteins could be clustered into four distinct subgroups, well supported by the exon–intron structure, consensus motifs, and the domain architecture. A gene duplication analysis suggested that tandem duplication may largely contribute to the expansion of the FtPHT1 gene family members. In silico predictions of cis-acting elements revealed that low-phosphate-responsive elements, such as W-box, P1BS, and MBS, were enriched in the promoter regions of FtPHT1 genes. Quantitative real-time PCR assays showed differential but partially overlapping expression patterns of some FtPHT1 genes in various organs under limited Pi supply and hormone stimuli, implying that these FtPHT1 transporters may be essential for Pi uptake, translocation, and re-mobilization, possibly through signaling cross-talk between the low phosphate and hormones. These observations provide molecular insights into the FtPHT1 gene family, which paves the way to a functional analysis of FtPHT1 members in the future. Full article

Phytoremediation technology is viewed as a potential solution for addressing soil uranium contamination. Sudan grass (Sorghum sudanense (Piper) Stapf.), noted for its robust root structure and resilience to heavy metals, has garnered significant attention. This paper investigates a strain of uranium-tolerant bacterium, B6, obtained from the inter-root environment of native plants in soil contaminated with uranium tailings. The bacterium was identified as Bacillus cereus. Genomic analyses and assessment of uranium tolerance-promoting properties showed that strain B6 not only exhibited high uranium tolerance, but also possessed beneficial properties such as phosphorus solubilization and iron-producing carriers. In this study, we used strain B6 as an inoculant in combination with Sudan grass for germination and potting experiments. The findings demonstrated that Bacillus cereus B6 could substantially mitigate the adverse effects of uranium stress on Sudan grass, boost the plant’s antioxidant response, significantly increase the root length and dry biomass of Sudan grass, and facilitate the accumulation of uranium in the roots, as well as its translocation to the aboveground portions. The study showed that PGPB strain B6 can significantly enhance the effect of plant accumulation of uranium and increase the potential of Sudan grass to become a uranium-rich plant, which provides an important scientific basis and application prospect for the use of microbial-assisted Sudan grass remediation technology to treat uranium-contaminated soil. Full article

Soil in the karst region usually features high geogenic cadmium (Cd) and limited available phosphorus (P). Appropriate phosphate amendment is crucial for alleviating Cd accumulation in food crops and reducing health risks. However, the interaction of Cd and P in geogenic Cd-rich soil-plant systems is poorly understood. In this study, a pot experiment was conducted to investigate the translocation of Cd in the soil-pepper system under different amendment rates of Ca(H₂PO₄)₂. The results showed that the biomass of pepper was not affected by the application rates of Ca(H₂PO₄)_2, even up to 0.45 g/kg, but was affected by the application of nitrogen and potassium fertilizers. High contents of total Cd (6.19 mg/kg) and bioavailable Cd (2.72 mg/kg, 44%) in the studied soils resulted in elevated Cd content in pepper, and it decreased in the order of root (8.18 mg/kg) > stem (4.89 mg/kg) > fruit (3.88 mg/kg). This indicates that pepper planted in the studied soils may present potential health risks. Furthermore, phosphate amendment neither influences the bioavailable Cd in rhizosphere soil nor Cd uptake and transport in pepper plants. The findings of this study highlight that monocalcium phosphate is not a suitable choice for reducing the accumulation of Cd in pepper fruits in the studied soil and that other remediation strategies are needed. Full article