Context: Mepiquat chloride (N, N-dimethyl piperidinium chloride, MC) is a widely used plant growth regulator that inhibits excessive vegetative growth and promotes reproductive development in cotton. Variable-rate application (VRA) refers to delivering MC tailored to site-specific crop requirements. This approach reduces canopy variability while enhancing yield-related traits compared with uniform spraying. However, research in this field remains relatively limited. Objective: This study aims first to identify cotton phenotypes sensitive to MC, subsequently establish their estimation models to generate prescription maps of MC for VRA, and ultimately assess the performance of this technique across two environmental conditions. Methods: A field experiment with four MC application rates (0, 6, 12, and 18 g center dot ha-1) was carried out in Hejian City, Hebei Province, in 2023. An unmanned aerial vehicle (UAV) equipped with five monochrome sensors (blue, green, red, red edge, and near-infrared) was used to capture multispectral images for phenotypic estimation. Then, the VRA of MC based on the retrieved phenotypes was evaluated in Hejian City, Hebei Province, in 2024, as well as in Huanggang City, Hubei Province, in 2025. Results and conclusions: Statistical analyses identified the daily increment in plant height (PHI) and the length of the top five internodes (TOP5) as MC-responsive phenotypes. Direct extraction of PHI from differential digital surface model images performed slightly better (mean R2 = 0.79) than indirect calculation based on plant height (PH) measurements at two adjacent time points (mean R2 = 0.77). For TOP5 estimation, the accuracy achieved using features derived from multispectral images, particularly vegetation indices, was superior (R2 = 0.82) to that using point cloud-derived features (R2 = 0.73). Among the six machine learning models tested, the Gaussian process regression model demonstrated the best performance for TOP5 estimation, with an R2 of 0.87, an RMSE of 1.46 cm, and an NRMSE of 8.25%. In the field validation plots, VRA of MC based on prescription maps generated from TOP5 estimation not only effectively reduced the variability of PH, PHI, and TOP5 compared with uniform spraying, but also increased seed cotton yield (5.3% in 2024; 21.9% in 2025) and economic benefits (118.9 and 745.3 USD center dot ha-1 in 2024 and 2025, respectively).

Heat stress constrains wheat production in major cultivation areas worldwide and poses a particularly severe threat to winter wheat in China's Huang-Huai-Hai Plain, a challenge anticipated to intensify with shifting global climate patterns. Brazide, a novel plant growth regulator (PGR), enhances stress tolerance by modulating hormonal synthesis and signal transduction. The objective of this study was to evaluate the efficacy of brazide in enhancing heat tolerance, determine its optimal effective concentration, and elucidate its physiological mechanisms regarding leaf senescence and grain filling. In this two-year field study (2020-2022), JM22 was selected as the experimental cultivar to investigate the influence of foliar-applied brassinosteroid analogs on the growth dynamics and developmental processes at 12 days after anthesis (DAA). This investigation was particularly focused on the conditions of artificially induced heat stress (HT), at 24 DAA coinciding with a critical phase of the crop's development. The experiments included two temperature treatments (NT: natural temperature; HT: heat stress), and five PGR treatments (CK: water; B1: 0.05 mu mol L-1 28-homobrassinolide; B2: 0.05 mu mol L-1 14-hydroxylated brassinosteroid; B3: 0.05 mu mol L-1 brazide; B4: 0.5 mu mol L-1 brazide; B5: 5 mu mol L-1 brazide). The results indicate that HT adversely affected the leaf greenness retention, leaf physiological changes, grain filling process, and yield components, while brassinosteroid analogs enhanced wheat's resistance to HT. Among the foliar treatments, B3 (0.05 mu mol L-1 brazide) demonstrated the most significant effects. Compared to the control (CK), B3 maintained higher SPAD values (increasing them by 29.43 %-33.24 %) and leaf area (17.70 %- 22.76 %). Furthermore, it promoted dry matter accumulation (11.42 %-11.87 %), enhanced the average grain-filling rate (0.02-0.04 mg grain-1 d-1), and extended the effective grain-filling duration (1.28-1.30 days). The impact of different concentrations of brazide on wheat's greening performance diminished with increasing concentration. Brazide did not significantly affect the number of spikes and grains per spike but significantly increased the 1000-grain weight (TGW) (by up to 2.46 g). Under HT conditions across the 2020-2022 seasons, treatments B1-B5 increased grain yields (5.18 %-8.47 % and 4.05 %-9.58 %, respectively) compared to CK. Our experimental findings indicate that brazide application under HT effectively delayed heat-induced flag leaf senescence and thereby mitigated yield loss by synergistically enhancing the antioxidant defense system (increasing CAT, SOD, and POD activities while reducing MDA content), optimizing the endogenous hormonal balance (upregulating GA3 and ZR levels), and supporting the grain-filling process, with an optimal concentration of 0.05 mu mol L-1 . This study highlights the impact of external brazide application on heat stress and leaf senescence, as well as its regulatory role in grain development.

Ethephon (ETH) is widely applied to shape plant type for enhancing plant lodging resistance in maize high-yield and efficient production, however, there is limited information on how ethephon regulates root traits to mediate root anchorage strength for enhancing the lodging resistance. To clarify this, a two-year field experiment (2022 and 2023 summer maize growing seasons) was conducted to evaluate the regulatory effect of ETH application on the root development, morphological traits and anchorage strength in three maize varieties. ETH application advanced nodal root initiation, accelerated the growth rate of nodal root development, shortened the developmental duration of root whorl, and induced the formation of an additional nodal root whorl without significantly affecting nodal root number per whorl. Meanwhile, ETH application significantly increased root length and lateral root number, but reduced root diameter and root volume. Furthermore, ETH application increased root angle, top root angle and bottom root angle, while decreasing maximum and median width of root system, which facilitated the development of a steeper and more compact root system architecture. In addition, ETH application strengthened root anchorage by improving vertical root pulling resistance (VRPR), failure angle, anchorage strength and safety factor by 20.6, 18, 20.7, and 68.8%, respectively. Meanwhile, an increased root-to-shoot ratio of 14.7%, along with reductions in the ratios of plant height to VRPR and shoot fresh weight to VRPR of 21.5 and 26.8%, respectively, collectively indicated more efficient root development and improved shoot-root interaction in ETH-treated plants. Moreover, ETH effectively reduced the lodging rates by 73.9%, while increased the number of harvest ears, improved the grain yield and harvest index. Overall, ETH could mediate root morphology traits to shape steep root architecture and improve shoot–root interaction for enhancing the lodging resistance in maize.

Jasmonic acid (JA), a key phytohormone in plant defense, plays essential roles in regulating plant stress responses and growth. However, how JA signaling and nitrate signaling regulate nitrate uptake in maize (Zea mays L.) remains elusive. Here, we report that low-nitrate stress promotes JA accumulation in maize roots, and JA treatment leads to a low-nitrate phenotype. JA triggers ZmbHLH99 expression, encoding a transcription factor that binds to ZmNLP3.2 promoter and inhibits ZmNLP3.2 expression, thereby regulating nitrate uptake. In addition, the JA ZIM-domain (JAZ) transcriptional repressor ZmZIM13 interacts with ZmbHLH99 to release its inhibitory effect on the ZmNLP3.2-ZmNRT cascade and promotes ZmNLP3.2 expression. Furthermore, loss of ZmbHLH99 or overexpression of ZmZIM13 promotes plant growth and nitrate uptake, leading to higher grain yield. These findings reveal the transcriptional regulatory landscape of how JA signaling regulates nitrate uptake via the ZmZIM13-ZmbHLH99-ZmNLP3.2 module and integrates with nitrate signaling to coordinate plant growth and stress responses.

Poor light interception constrains maize (Zea mays L.) yield potential under high planting densities. This study evaluated an "interval spraying" strategy using N,N-diethyl-2-hexanoyl-oxygen radical ethylamine (2-ethyl chloride) phosphonic acid salt (DHEAP) to construct a wave-like canopy. Unlike traditional regulators (e.g., ethephon) DHEAP features a neutral pH and optimized stability, allowing for "inhibition compensation" regulation of internode elongation and plant height. In a two-year field experiment with maize hybrid Xianyu 335 at four densities (7.5, 9.0, 10.5, 12.0 & times; 10(4) plants ha(- 1)), DHEAP was applied to alternating four-row strips at the V8 stage. Results showed DHEAP significantly reduced sprayed plant (Tr) height while unsprayed plants (T0) maintained height, establishing a stable wave-like architecture. This structure significantly (p<0.05) expanded effective canopy surface area by 11.7 %-27.5 % compared to flat controls. Physiologically, a mechanism of "spatial complementarity" emerged: wave peaks (T0) maintained significantly higher net photosynthetic rates (Pn), while wave troughs (Tr) exhibited delayed senescence with elevated chlorophyll content (SPAD) and leaf area index (LAI). Consequently, canopy transmittance (CT) and radiation use efficiency (RUE) significantly improved under high densities. Path analysis confirmed that these improvements increased kernel number (KN) in T0 plants, overcompensating for biomass reduction in Tr. Yield response was strictly density dependent. A Johnson-Neyman analysis identified a critical threshold of 6.40 & times; 10(4) plants ha(- 1). Above this threshold, the wave-like canopy achieved a significant yield advantage, increasing grain yield by 6.5 %-11.0 % (p<0.05) at high densities (10.5-12.0 & times; 10(4) plants ha(- 1)). These findings demonstrate that interval DHEAP spraying is an effective strategy to optimize canopy light distribution and enhance RUE and yield in intensive maize production.

Timely monitoring of cotton defoliation progress is crucial for optimizing the quality of mechanical harvesting. To accurately assess the defoliation status prior to mechanical picking, a field experiment was conducted in Hejian, Hebei Province, China, in 2022. Using a DJI P4M multispectral drone, canopy images of cotton were collected before and after defoliation at three flight altitudes: 25 m, 50 m, and 100 m. The study employed machine learning algorithms including linear regression, Support Vector Machine (SVM), Generalized Additive Model (GAM), and Random Forest (RF) to invert the Leaf Area Index (LAI). Additionally, SVM-based supervised classification was introduced to eliminate background interference from soil and open cotton bolls, while the XGBoost model and SHAP method were used to analyze the main factors influencing LAI inversion. Key findings include the following: The univariate linear relationship between EVI and LAI proved to be the most robust, with the model constructed from 100 m flight altitude data performing best (validation set: R2 = 0.921, RMSE = 0.284). The rate of LAI change showed a strong positive correlation with field-measured defoliation rate (r = 0.83–0.88), confirming its reliability as a proxy indicator for defoliation progress. Soil and open cotton bolls were identified as major negative factors affecting LAI inversion accuracy. The optimal machine learning prediction model varied with days after spraying, demonstrating significant temporal variability. This study demonstrates that high-throughput LAI inversion based on drone-derived multispectral EVI enables precise and dynamic monitoring of cotton defoliation. The approach provides farmers and field managers with an efficient, non-destructive monitoring tool. By delivering real-time insight into defoliation progress, it plays a pivotal role in enabling precision defoliation management, reducing excessive chemical use, optimizing the scheduling of mechanical operations, and ultimately enhancing both the sustainability and profitability of cotton production.

Context: Harvest aids are widely used in mechanical cotton harvesting to improve defoliation and yield. However, the effects of environmental factors, cotton canopy structure, and management practices on these outcomes have not been systematically quantified. Methodology: We conducted a meta-analysis of 51 studies, using data from over 1130 observations of defoliation and 405 yield measurements and a two-year sink-source field experiment to assess the effects on cotton defoliation and yield. Additionally, XGBoost and SHAP analysis were applied to identify key factors influencing cotton defoliation and yield. Results: Compared to the control (only water), harvest aids increased defoliation and cotton yield by 88.6 % and 3.7 %, respectively, suggesting that the critical threshold for determining the optimal mechanical harvesting window is at a defoliation rate of 88.6 %. Thidiazuron-ethephon showed the highest performance, particularly at application rates of 2500-3000 mL/ha. Collectively, a pre-spray sink-source ratio of 0.30-0.55, boll opening rate > 55 %, post-spray rainfall <= 10 mm, and average humidity > 50 % significantly improved cotton defoliation and yield. Partial least square path modeling indicated that the cotton canopy structure before spraying (sink-source ratio and boll opening rate) was significantly positively correlated with defoliation (0.39) and yield (0.16), whereas rainfall was significantly negatively correlated with defoliation (-0.24) and yield (-0.36). Meta-regression and SHAP analysis revealed that the weather and cotton canopy structure before spraying jointly affect cotton defoliation and yield after defoliant application. XGBoost had good predictive ability for defoliation (R-2 > 0.8, RMSE < 15 %) and yield (R-2 > 0.6, RMSE < 10 %). Conclusion: Appropriate harvest aid selection under reasonable cotton strain configurations and post-application environmental conditions is a win-win for defoliation and yield and provides insights for reasonably adjusting harvest aid application for sustainable agriculture.

Ethylene plays an indispensable role in regulating plant growth and stress responses. However, the mechanisms underlying the regulation of Na+/H+ homoeostasis by ethylene and subsequent mediation of maize growth under salt stress remain unclear. ZmACO2, which encodes ethylene biosynthesis enzyme 1-aminocyclopropane-1-carboxylate oxidase2, is induced by salt stress. Thus, ZmACO2-overexpressing (ACO2-OE) and mutant (aco2-cr) plants were used to investigate how ethylene regulates Na+/H+ homoeostasis in maize under salt stress. The aco2-cr mutants exhibited significantly lower Na⁺ accumulation and Na⁺/K⁺ ratios than the wild-type and ACO2-OE plants. This phenotype was attributed to their higher expression of ZmSOS1 and ZmHKT1, which increased root net Na⁺ efflux by 20.65% and decreased Na⁺ transport from roots to shoots by 42.49% (p < 0.001), respectively. Compared to the other plants, aco2-cr mutants showed higher ZmMHA2 expression and plasma membrane H+-ATPase activities, which promoted net root H+ efflux to provide a greater H+ proton gradient for salt-overly-sensitive 1 (SOS1). Inhibition efficiencies of Na+ efflux and H+ influx by sodium orthovanadate were lower in aco2-cr mutants than in ACO2-OE and wild-type plants under salt stress; however, ACO2-OE plants showed a salt-sensitive phenotype. Overall, these findings showed that salt-induced ethylene inhibited plasma membrane H+-ATPase and SOS1 from disrupting Na+/H+ homoeostasis, thereby decreasing Na+ efflux in maize roots and also provided a strategy to improve salt tolerance by optimising ethylene levels in maize.

Land salinization threatens agricultural sustainability worldwide. Foliar delivery of nanotherapeutics is emerging as a tool for improving crop stress tolerance in diverse soils. Herein, we report that poly(acrylic) acid coated Mn3O4 nanoparticles (PMO) applied to leaves enhance cotton growth (up to 31.6%) and yield (up to 47.3%) in three saline lands with different soil types. We elucidated the molecular mechanisms by which PMO improve cotton salinity stress tolerance by reducing DNA methylation (up to 24.6%). The S-adenosylmethionine synthase 2 (SAMS2) enzyme involved in DNA methylation is a major component of the PMO protein corona in vivo. The interaction between PMO and SAMS2 results in the change of protein alpha helix (12.3% decrease) and betasheets (13.7% increase), with a consequent reduction in enzymatic Vmax (10.7%). Overall, PMO can be a biocompatible nanotherapeutic tool to improve crop salt tolerance by a targeted interaction with DNA methylation enzymes for sustainable agriculture.

Chemical defoliation is essential for mechanized cotton harvesting, but excessive thidiazuron (TDZ), frequently induces a "leaf sticking" phenotype characterized by wilting without abscission, which severely compromises harvest efficiency. We integrated field and greenhouse experiments with anatomical, physiological, and transcriptomic analyses to investigate this abnormal response. TDZ (0.45 and 2.27 mM) was rapidly absorbed by leaf blades within 3-6 h, and accumulation increased with concentration. Early cellular damage (3-24 h) featured membrane integrity loss, and cell death, occurring prior to substantial ROS accumulation or senescence/PCD-related gene activation, suggesting direct membrane perturbation rather than ROS- or transcription-mediated injury. At later stages (48-96 h), excessive ROS and upregulated senescence/PCD transcripts further aggravated cellular damage. The optimal concentration (0.45 mM) promoted abscission zone (AZ) cell separation and complete abscission by 96 h, an excessive concentration (2.27 mM) initiated AZ separation as early as 24 h but halted its progression, causing persistent adhesion and leaf sticking. Localized application revealed that TDZ application to the blade alone was sufficient to induce petiole wilting, confirming that leaves retain the ability to generate signals even under severe injury. Direct AZ application neither induced abscission nor visibly damaged AZ cells. These findings indicate that abscission failure under excessive TDZ is not due to impaired blade-to-AZ signaling or direct killing of AZ cells, but rather to disrupted coordination of blade-derived abscission cues. Collectively, excessive TDZ uncouples leaf damage from AZ differentiation by impairing signal coordination, providing a mechanistic framework for understanding defoliation failure and optimizing TDZ application strategies in cotton production.

The sink-source relationship significantly influences chemical defoliation in cotton. However, studies on the effects of sink-source manipulations at different phenological stages remain limited. To address this, we designed four treatments with varying sink-source ratios at the initial flowering stage (IFS), flowering and boll stage (FABS), and full boll stage (FBS): conventional plant type (CK), 50% leaves of the fruit branches removal (1/2 L), 50% boll removal (1/2B) and 100% boll removal (0B). The results demonstrated that the sink-source ratio affects defoliation outcomes, with distinct effects depending on the treatment stage. At IFS and FABS, defoliation rates increased with higher sink-source ratios following defoliant application, with the 1/2 L treatment exhibiting the highest defoliation rate and the 0B treatment the lowest. Conversely, at FBS, the CK treatment showed the highest defoliation rate, while the 1/2 L treatment had the lowest. This discrepancy may be attributed to compensatory mechanisms at FBS, where leaf removal enhanced the physiological activity of leaves (e.g., higher IAA content, lower ABA content, and increased net photosynthetic rate (Pn)), reducing sensitivity to defoliants. In contrast, at IFS and FABS, the compensatory effects of leaf removal likely subsided by the time of defoliation, and the high boll load accelerated leaf senescence (e.g., lower IAA content, higher ABA content, and reduced Pn), enhancing defoliant sensitivity. Consequently, the 1/2 L treatment not only raised the defoliation rate by 0.5-6.2% and 0.9-1.5% at IFS and FABS, but more importantly, it substantially reduced residual leaves by 33.3-65.9% and 28.2-39.0%, respectively. Additionally, there was no significant difference in yield between the CK and the 1/2 L treatment during these two periods. Thus, moderately increasing the sink-source ratio during early and middle FABS optimizes defoliation efficiency. This study provides theoretical insights and practical guidance for optimizing sink-source dynamics to improve chemical defoliation in cotton.

High crop yields depend on sufficient nutrient availability; however, potassium (K+) uptake mechanisms remain less well characterized than those for nitrogen and phosphorus. Although the KT/HAK/KUP transporter family mediates high-affinity K+ uptake in plants, its transcriptional regulation in crops remains largely unexplored. Herein, we identified GhKUP3aD as a pivotal high-affinity K+ transporter in cotton and demonstrated its essential role in maintaining K+ homeostasis under low-K+ stress. Mechanistically, we found that the C2H2-type zinc-finger transcription factor GhZAT10 directly binds to the GhKUP3aD promoter and functions as its transcriptional activator. Furthermore, GhMYC2s and GhEIN3dD, downstream components of jasmonate (JA) and ethylene signaling pathways, respectively, enhance GhZAT10 expression by directly binding to its promoter. Crucially, we discovered that GhMYC2s physically interact with GhEIN3dD, forming a composite transcriptional complex that synergistically amplifies GhZAT10 activation beyond their individual effects. Under K+-sufficient conditions, JA signaling repressors GhJAZ2/10 sequester GhMYC2s and GhZAT10, thereby preventing unnecessary metabolic expenditure. Notably, field experiments further confirmed that exogenous application of methyl jasmonate and 1-aminocyclopropane-1-carboxylic acid (an ethylene precursor) exerted substantial additive effects on photosynthetic performance and leaf K+ concentration, resulting in a combined 11.6% increase in seed cotton yield under moderate-to-severe soil K+ deficiency with available K+ levels below 60 mg kg-1. Taken together, our findings reveal that JA and ethylene signaling converge through a GhMYC2s-GhEIN3dD transcriptional complex to synergistically regulate the GhZAT10-GhKUP3aD module. These findings provide a mechanistic basis for hormonal crosstalk in cotton K+ uptake and suggest a potential mechanistic framework for enhancing K+ use efficiency in agricultural systems.

Seed priming with engineered nanoparticles can promote seed germination. Herein, we investigated how priming seeds with antioxidant poly(acrylic acid)-coated cerium oxide nanoparticles (PNC, 0.05 mM) impacts seed germination in cotton (Gossypium hirsutum L.). Seed priming with PNC significantly increased cotton hypocotyl elongation by 13 %-37 %, promoting seed germination in pot experiment. Meanwhile, the emergence rate increased by 15 %-16 % with 0.05 mM PNC-seed priming in the field. Transcriptome analysis identified PNC-induced differentially expressed genes (DEGs) related to the phytohormone, auxin (IAA), and brassinosteroid (BR) biosynthesis (e.g. GhTAA1, GhYUCCA, GhALDH, GhGH3, GhCYPs) and signal transduction (e.g. GhSAUR, GhBZR1). Consistently, PNC priming increased the accumulation of IAA (10 %-25 %) and BR (86 %-100 %) in cotton hypocotyls. In addition, PNC enhanced the expression of the xyloglucan endotransglucosylase/hydrolase (XTHs) genes, regulated by SAUR and BZR1 through IAA and BR signaling pathway and critical for cell elongation. Also, the cell lengths of the epidermis, endodermis, xylem, and pith in cotton hypocotyl increased by 21 %, 17 %, 31 %, and 21 %, respectively upon seed priming with 0.05 mM PNC. The results provide insights into the molecular mechanisms of nanoparticles-seed priming enhancement of plant seed gemination.

(1) Background: Nitric oxide (NO) serves as a crucial signaling molecule in plant abiotic stress responses. Although its role in enhancing drought resistance in cotton has been recognized, the specific mechanisms underlying this physiological and molecular regulation remain largely unexplored. This study aims to elucidate the multi-layered mechanisms by which NO modulates drought resistance in cotton; (2) Methods: Cotton seedlings were subjected to drought stress with the application of the NO donor sodium nitroprusside (SNP). A combination of confocal laser scanning microscopy, transcriptional expression analysis, biochemical assay of enzyme activity, virus-induced gene silencing (VIGS), and in vitro protein modification assays was applied to characterize the effects of NO on the drought stress response in cotton; (3) Results: Exogenous NO significantly reinforced drought resistance in cotton seedlings by improving leaf water retention capacity and photosynthetic efficiency, eliminating excessive drought-induced reactive oxygen species (ROS), upregulating the transcription and enzymatic activity of antioxidant enzymes, and promoting stomatal closure. Mechanistically, NO triggered S-nitrosylation of the plasma membrane H+-ATPase isoform GhHA2, thereby enhancing its protein stability; (4) Conclusions: These findings reveal that exogenous NO orchestrates cotton drought tolerance via multiple interconnected physiological and molecular pathways, in which the activation of the antioxidant defense system and the modulation of stomatal closure serve as central regulatory mechanisms.

Maize (Zea mays L.) is a vital global crop, contributing ∼37% of annual grain production. Enhancing yield per unit area is crucial for food security, yet research has primarily focused on single-ear traits, overlooking the regulation of double ears-a key determinant of prolificacy. While secondary ears drive yield variability under prolificacy-favoring conditions, the mechanisms governing ear formation across shoot positions remain poorly understood. Here, we performed high-resolution transcriptomic analysis of 66 samples from three ear types (primary, secondary and third) in maize inbred B73. We uncovered distinct hormonal developmental dynamics: strigolactone (SL) signaling genes, particularly SBP transcription factors, dominated in primary (I) ears, whereas ethylene-related genes (e.g., ZmEREB131, ZmACCO35) were enriched in third (III) ears. Functional validation confirmed that knockout of ZmEREB131 and ZmACCO35 accelerated development and elongated ears compared to wild-type, implicating ethylene (ETH) signaling in ear maturation arrest. Notably, SL inhibitor application synchronized primary and secondary ear development, boosting total yield by >20% without compromising primary ear performance. Our study elucidates the transcriptional networks underlying differential ear development and provides actionable strategies for yield improvement through targeted hormonal modulation. These findings advance the understanding of maize inflorescence biology and offer molecular tools for breeding high-yielding varieties.

Context: Increasing planting density improves maize (Zea mays L.) productivity but intensifies canopy crowding and competition for solar radiation. While vertical canopy architecture has been widely studied, the contribution of horizontal leaf azimuthal organization to canopy light distribution remains less explicitly evaluated under field conditions. Objective: This study examined whether ear-layer between-row leaf orientation provides complementary information beyond conventional vertical canopy traits and whether it is associated with LAI-based canopy crowding status, vertical light distribution, and yield related performance. Methods: We combined an independent equal row spacing experiment with a two-year multifactorial field experiment. Leaf azimuthal orientation was classified into in-row, diagonal, and between-row directions, and the ear-layer between-row fraction (BR_E) was used as the focal horizontal configuration trait. Regression analysis, relative importance analysis, two-gate screening, robustness tests, and piecewise structural equation modeling were used to evaluate associations among BR_E, canopy structure, light distribution metrics, radiation use efficiency, and grain yield. Results: Leaf azimuthal distribution showed leaf position dependent variation in the independent equal row spacing experiment, indicating that between-row orientation was not solely attributable to wide-narrow row geometry. In the multifactorial field experiment, BR_E contributed more strongly to variation in ear-layer intercepted PAR and grain yield than above- or below-ear between-row fractions. BR_E shared limited variance with measured vertical structural traits and showed weak direct differentiation by individual agronomic inputs. Instead, LAI_VT and LAI_density were identified as the LAI-based canopy crowding indicators most consistently associated with BR_E. Higher BR_E was associated with a steeper vertical gradient of intercepted PAR and an interception-oriented performance profile, characterized by higher grain yield but lower radiation use efficiency. Conclusion: Ear-layer between-row orientation is a complementary horizontal canopy configuration trait associated with LAI-based canopy crowding status and vertical light distribution patterns in high-density maize. These results support including horizontal azimuthal organization in canopy architecture analysis, while causal mechanisms and functional consequences of horizontal azimuthal configuration require further testing using time-resolved structural and physiological measurements.

High light stress is common during plant production. However, we still lack of powerful tools to deal with high light stress. In this study, poly(acrylic acid) coated Mn3O4 nanoparticles (PMO) were used to increase high light tolerance of cotton. Our results showed that the fluorescence intensity of hydrogen peroxide (H2O2), hydroxyl radical, and superoxide anion (O2•-) was significantly lower in PMO treated cotton plants than control plants under high light, accompanied with increased activities of peroxidase and catalase in PMO treated cotton plants. Further, under high-light stress, PMO treatment significantly downregulated actin depolymerization factor GhADF7 expression by 64.0% (first true leaf) and 41.0% (second true leaf) compared with the control, accompanied by a marked increase in actin filament (AF) fluorescence intensity and integrated density. Under normal growth conditions, foliar application of actin polymerization inhibitor and excessive H2O2 demonstrated that AF depolymerization led to increased ROS accumulation, whereas PMO effectively alleviated high-light-induced ROS accumulation. This result indicated that the ROS content and the stability of AF skeleton were mutually affected. Moreover, cotton plants with silencing of GhADF7 showed increased actin filament fluorescence intensity and integrated density while reducing H2O2 and O2•- levels in seedlings under high-light stress. Collectively, these results demonstrate that PMO enhances high-light tolerance in cotton by suppressing AF depolymerization through downregulation of GhADF7 expression and modulation of ROS homeostasis, thereby maintaining cytoskeletal stability. It highlights the potential of nanotechnology approach as a powerful tool to resist plant high light stress.

Chemical harvest aids facilitate mechanical cotton harvesting, but their potential carryover effects on succeeding wheat remain uncertain. Two independent site-year field experiments were conducted in Beijing during 2021–2022 and in Hejian, Hebei Province, during 2022–2023. Experiment 1 compared a freshwater control with preceding Xinsaili applications at 1500 and 3000 g ha−1, whereas Experiment 2 evaluated five biochar treatments under preceding freshwater or Xinsaili application at 1575 g ha−1. In Experiment 1, Xinsaili reduced early aboveground biomass and soil bacterial, fungal, and actinomycete abundance. At 3000 g ha−1, grain number per spike and grain yield decreased by 12.2% and 24.0%, respectively, relative to the water control. In Experiment 2, Xinsaili reduced mean and maximum grain-filling rates by 3.2% and 4.3%, respectively. For the biochar main effect, maize-straw biochar at 750 and 1500 kg ha−1 and rice-husk biochar at 1500 kg ha−1 increased the initial grain-filling potential from 0.25 mg grain−1 without biochar to 0.38–0.42 mg grain−1, with high-rate maize-straw biochar producing the greatest increase. Although Xinsaili × biochar interactions were significant for both grain-filling rates, no biochar treatment significantly improved either rate under Xinsaili application. The grain-filling responses were not consistent between the two independent experiments, potentially reflecting differences in site, year, wheat cultivar, Xinsaili application rate, and experimental design. Thidiazuron and ethephon residues were not quantified in soil or plant tissues; therefore, the observed responses represent indirect field evidence and do not demonstrate either residue-mediated effects or biochar-mediated remediation. Overall, preceding Xinsaili application was associated with treatment- and site-year-dependent wheat responses, while the capacity of biochar to improve final grain yield was not confirmed.

Introduction:Nitrogen (N)-efficient wheat cultivars achieve higher grain yields with equivalent N fertilizer inputs, and the grain filling character largely determines grain weight (GW) in cereal crops. However, the relationship of grain filling traits and N responsiveness (Nr) in wheat has not been fully evaluated. Methods:A two-year field experiment evaluated five wheat cultivars across varying N levels (0, 75, 150, and 225 kg N ha-1) to assess how grain filling traits and N-related characteristics influence Nr. Results:The results showed that N-responsiveness wheat cultivars exhibited higher grain yields and critical N supply, alongside lower chlorophyll degradation rates (CDR). The direct path coefficient of GW on yield was 0.478, which explained 85.2% of the yield variation and was negatively correlated with other yield components. Across the combinations of cultivar and N supply, the variation in GW was primarily driven by the duration of fast-increase period (Tfast), rather than by the duration of slow-increase period (T slow) and slight-increase period (Tslight). Furthermore, the sensitivity of T fast to N supply explained the Nr of grain yield in wheat. Structural equation modeling showed that adequate pre-anthesis N accumulation was the dominant factor driving the extension of T fast in high N-responsiveness wheat cultivates, secondary to lower CDR, which ultimately resulted in the highest GW. In addition, prolonging T fast induced enhanced post-anthesis N translocation in wheat, which contributed to higher N use efficiency (NUE). Discussion:Prolonging the T fast enhances N responsiveness in wheat grain yield, providing a novel framework for evaluating NUE. This finding also highlights the critical role of elevated N accumulation at anthesis under N fertilization.

Ethylene modulates plant fitness, but its role in rhizosphere soil multifunctionality remains unclear. This study demonstrates that endogenous ethylene suppresses C- and N-cycling functions while promoting organic P mineralization in the maize rhizosphere, ultimately diminishing the overall soil multifunctionality and attenuating its phenologically driven peak at the tasseling stage. Ethylene reshaped microbial community assembly by enriching opportunistic taxa (e.g., Actinobacteria) while reducing the diversity and relative abundance of sensitive taxa. Community composition (e.g., Bacillus) and α diversity of ethylene-sensitive taxa were negatively correlated with soil multifunctionality. Inoculation with ACC deaminase-producing Bacillus pumilus and Streptomyces gardneri (opportunistic strains) significantly elevated C- and N-cycling enzyme activities and boosted maize growth. However, a direct causal link between ACC deaminase production and these effects requires further experimental validation. Collectively, these findings elucidate that ethylene drives rhizosphere biogeochemical trade-offs through the selective filtering of microbial functional guilds, providing a theoretical foundation for rhizosphere microbiome management in crop production.