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Search Results (377)

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14 pages, 2065 KB  
Article
Nitrogen Form Regulates Aluminum Partitioning and Physiological Responses in Young Highbush Blueberry Plants Grown in Acidic Volcanic Soil
by Pamela Artacho, Paulina Fernández, María Ignacia Arias and Claudia Bonomelli
Agronomy 2026, 16(8), 842; https://doi.org/10.3390/agronomy16080842 - 21 Apr 2026
Viewed by 246
Abstract
Aluminum (Al) toxicity constrains plant performance in acidic volcanic soils, yet nitrogen (N) fertilization may influence Al availability and plant responses. This study evaluated the effects of N source and rate under contrasting soil liming conditions on vegetative growth, mineral nutrition, and physiological [...] Read more.
Aluminum (Al) toxicity constrains plant performance in acidic volcanic soils, yet nitrogen (N) fertilization may influence Al availability and plant responses. This study evaluated the effects of N source and rate under contrasting soil liming conditions on vegetative growth, mineral nutrition, and physiological performance of non-bearing northern highbush blueberry (Vaccinium corymbosum L. cv. Blue Ribbon®) plants. A split–split-plot experiment was conducted in southern Chile using urea or potassium nitrate applied at 0, 20, or 40 kg N ha−1 to plants grown in unlimed soil or soil amended with calcium carbonate or magnesium oxide. Vegetative growth, tissue mineral composition, stomatal conductance, chlorophyll fluorescence, and leaf chlorophyll were monitored during the first season. Growth responded primarily to soil liming rather than N supply, indicating low N demand and substantial soil N mineralization under the experimental conditions. Foliar N increased from 1.36 to 1.70% with increasing N rates. Urea nutrition reduced foliar Al concentration by 12% compared with nitrate. Under unlimed conditions, representing maximal soil Al availability, urea fertilization was associated with 70% higher Al retention in roots relative to nitrate. Chlorophyll content was consistently higher under urea supply, while the maximum photochemical efficiency of photosystem II remained unaffected. These findings indicate that N form influences plant Al partitioning independently of growth responses. Although the underlying mechanisms were not directly assessed, the observed patterns suggest that urea fertilization may reduce Al translocation to shoots under conditions of high Al availability. Full article
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15 pages, 2385 KB  
Article
Systemic Effects of Nitrate, Asparagine, and Glutamine on Nodulation and Biological Nitrogen Fixation in Soybean
by Jixuan Sun, Duo Zhao, Xiaomei Li, Liang Yang, Wei Zhao, Sha Li and Shoukun Dong
Plants 2026, 15(8), 1187; https://doi.org/10.3390/plants15081187 - 13 Apr 2026
Viewed by 443
Abstract
Although it is well established that nitrate exerts an inhibitory effect on nodulation and biological nitrogen fixation in soybean, the underlying mechanism remains unclear. In soybean plants, nitrate is assimilated into asparagine (Asn) and glutamine (Gln); their systemic circulation within the plant may [...] Read more.
Although it is well established that nitrate exerts an inhibitory effect on nodulation and biological nitrogen fixation in soybean, the underlying mechanism remains unclear. In soybean plants, nitrate is assimilated into asparagine (Asn) and glutamine (Gln); their systemic circulation within the plant may contribute to the reduced N-fixation capacity of nodules. To investigate the effects of nitrate, Asn, and Gln on soybean nodulation and biological N fixation, a unilateral nodulated double-root soybean system was used. The non-nodulated side roots were supplied with nitrate (14 mM), Asn (20 mM), or Gln (20 mM), while the nodulated side roots were not supplied with N. Changes in nodule number, nodule dry weight, nitrogenase activity, and N compound content were analyzed after 4 and 10 days of treatment. The results showed that all three exogenous N sources significantly reduced nodule number, nodule dry weight, and nodule nitrogenase activity after both 4 and 10 days of treatment, while promoting the accumulation of ureides, Asn, and Gln in leaves. Nitrate and Asn treatments increased the accumulation of ureides and Asn in nodules, whereas Gln had no significant effect on nitrogenous compounds in nodules. These results suggest that nitrate inhibits nodulation and biological N fixation primarily through its conversion to Asn in soybean plants. The accumulation of Asn in shoots and nodules may suppress nodulation and biological N fixation by promoting ureide accumulation. Full article
(This article belongs to the Section Crop Physiology and Crop Production)
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15 pages, 1016 KB  
Article
Stem Electrical Conductivity of Broccoli (Brassica oleracea L. var. italica Plenk) Under Nitrogen and Phosphorus Fertilizer Deficiency
by Jeong Yeon Kim, Su Kyeong Shin, Ye Eun Lee and Jin Hee Park
Agronomy 2026, 16(8), 778; https://doi.org/10.3390/agronomy16080778 - 9 Apr 2026
Viewed by 358
Abstract
Nitrogen (N) and phosphorus (P) are essential nutrients that play critical roles in plant physiological processes and the accumulation of N and P in broccoli head was significantly correlated with yield. Therefore, there is a need for a rapid, non-destructive diagnosis of crop [...] Read more.
Nitrogen (N) and phosphorus (P) are essential nutrients that play critical roles in plant physiological processes and the accumulation of N and P in broccoli head was significantly correlated with yield. Therefore, there is a need for a rapid, non-destructive diagnosis of crop status by detecting deficiencies in essential nutrients. This study evaluated the effects of N and P deficiency on field grown broccoli (Brassica oleracea L. var. italica Plenk) using a plant-induced electrical signal (PIES) sensor, in which needle electrodes are inserted into the stem to measure electrical conductivity reflecting plant water and ion status. Four treatments were established, including the control (N100P100) with sufficient N and P supply, N deficiency (N0P100), P deficiency (N100P0), and combined N–P deficiency (N0P0). For sufficient supply, urea and fused phosphate (FP) were applied at rates of 122 kg N ha−1 and 71 kg P ha−1, respectively. Soil, stem, and leaf nutrient contents, growth parameters, and stress related indicators were analyzed and their relationship with PIES values were evaluated. PIES was highest in control (N100P100) and lowest under N–P deficiency (N0P0). Higher PIES values were observed during the vegetative stage, whereas values declined during the reproductive stage, reflecting changes in physiological activity. Growth parameters such as shoot and root weight and stem diameter were generally superior in the control (N100P100) treatment, while leaf calcium (Ca), magnesium (Mg), and potassium (K) concentrations showed no significant differences among treatments. Total N content in leaves was higher in N fertilized treatments (control and P deficiency). Photosynthesis-related parameters, including soil plant analysis development (SPAD), Fv/Fm, and chlorophyll content, were lowest under N–P deficiency, which was reflected in the PIES. Principal component analysis (PCA) showed that the PIES was closely associated with growth and photosynthetic parameters and clearly distinguished N sufficient treatments (control and P deficiency) from N deficient treatments (N0P100, N0P0). Overall, these findings suggest that PIES monitoring can serve as a sensitive physiological indicator of nutrient stress and may be applied as an early diagnostic tool before visible growth inhibition occurs in broccoli cultivation. Full article
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22 pages, 2456 KB  
Article
Impacts of Non-Modified and Acid-Modified Biochars Generated from Date Palm Residues on Soil Fertility Improvement and Maize Growth
by Xu Zhang, Naxin Cui, Fuxing Liu, Yong Xue, Huaqiang Chu, Xuefei Zhou, Yalei Zhang, Mohamed H. H. Abbas, Mohammed E. Younis and Ahmed A. Abdelhafez
Sustainability 2026, 18(7), 3499; https://doi.org/10.3390/su18073499 - 2 Apr 2026
Viewed by 421
Abstract
This research evaluated the efficacy of using two types of biochar (non-modified and acidified) from date palm residues (fronds, leaves, pits) as soil amendments for enhancing soil fertility and maize growth. These biochars were produced through slow pyrolysis under oxygen-limited conditions at 500 [...] Read more.
This research evaluated the efficacy of using two types of biochar (non-modified and acidified) from date palm residues (fronds, leaves, pits) as soil amendments for enhancing soil fertility and maize growth. These biochars were produced through slow pyrolysis under oxygen-limited conditions at 500 °C. Our innovative approach was to minimize gas emissions by converting smoke into liquid fertilizer (LS), which was expected to improve seed germination and early plant growth stages. To assess this aim, a completely randomized experiment was conducted under lab conditions, in which 10 maize seeds were placed on double filter papers in Petri dishes and then exposed to seven concentrations of LS (0.0, 0.01, 0.10, 1.0, 10 and 100%, using distilled water for dilution v/v). The LS contains nutrients and bioactive compounds that may enhance seed germination and early plant growth at low concentrations, whereas higher concentrations may cause phytotoxic effects. Results showed that liquefied smoke at 0.1% increased the absolute percentage of maize germination from 75% (control) to 100% and achieved the highest root length of 9.80 cm. Acidified biochars at 5% reduced soil pH from 8.87 to 8.12 and enhanced potassium availability to 87.93 mg kg−1. Conversely, the non-modified biochars contributed to further increases in soil organic matter (up to 1.02%), nitrogen, and phosphorus. In addition, the application of acidified leaf biochar (5%) enhanced maize shoot growth by 133%, chlorophyll content by 39%, and potassium uptake by 110%. This research establishes a scalable approach for converting agricultural waste into climate-resilient resources, effectively addressing soil degradation in arid environments, boosting crop resilience, and furthering the objectives of a circular bioeconomy. Full article
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26 pages, 3645 KB  
Article
Abiotic Stress Tolerance of a Multipurpose Use Species Artemisia maritima from a Coastal Wetland: Mineral Nutrients, Salinity, and Heavy Metals
by Una Andersone-Ozola, Agnese Romule, Astra Jēkabsone, Anita Osvalde, Andis Karlsons, Līva Purmale-Trasūne and Gederts Ievinsh
Stresses 2026, 6(1), 12; https://doi.org/10.3390/stresses6010012 - 12 Mar 2026
Viewed by 1159
Abstract
Artemisia maritima holds potential applications in the rehabilitation of degraded environments, particularly in salt-affected areas, for biosaline agriculture aimed at biomass production for further valorization and green biotechnology. The aim of the present study was to investigate the response of A. maritima to [...] Read more.
Artemisia maritima holds potential applications in the rehabilitation of degraded environments, particularly in salt-affected areas, for biosaline agriculture aimed at biomass production for further valorization and green biotechnology. The aim of the present study was to investigate the response of A. maritima to alterations in soil chemical composition, including differences in mineral supply, the addition of various sodium salts, and contamination with several heavy metals (cadmium, lead, copper, manganese, zinc), in order to establish a scientific basis for further applied research. Under standard fertilization conditions, the growth of A. maritima plants was restrained by nitrogen deficiency. Surplus nitrogen enhanced mineral uptake and growth, especially for shoots, and stimulated clonal development. Low to moderate (50 and 100 mmol L−1) NaNO3 treatment significantly stimulated shoot growth, while Na2HPO4 and NaHCO3 treatments exhibited the most adverse effects at 200 and 400 mmol L−1, resulting in reduced growth and biomass, and even the deterioration of the aboveground parts. Chlorophyll fluorescence parameters served as reliable early indicators of the detrimental effects of salinity associated with individual anions. Shoot macronutrient levels remained unchanged for phosphorus and calcium, while nitrogen increased in nitrate treatments. Root mineral nutrient content was more susceptible to salinity, with significant changes observed for all macro- and micronutrients, varying depending on the specific element and anion type. The alterations in mineral nutrition observed for each anion treatment exhibited distinct characteristics. A. maritima plants demonstrated high tolerance to all heavy metals, with roots being more susceptible compared to shoots. At the shoot level, statistically significant growth inhibition was evident only for 1000 mg L−1 lead and 1000 mg L−1 zinc treatments. A. maritima plants can be characterized as high accumulators of cadmium, lead, manganese, and zinc, and as extreme accumulators of copper in shoots. Nitrophily, clonal expansion with a help of bud-bearing roots, and the ability to accumulate relatively high concentrations of mineral elements in shoots are among the important physiological characteristics of A. maritima plants, enabling them to exhibit high resilience in environmentally heterogeneous habitats. Full article
(This article belongs to the Topic Effect of Heavy Metals on Plants, 2nd Volume)
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18 pages, 6101 KB  
Article
Genotype-Dependent Effects of Silicon on Cell Wall Composition and Antioxidant Responses in Oats Under Nitrogen Deficiency
by Isis Vega, Sofia Pontigo, Patricia Poblete-Grant, Adriano Nunes-Nesi, Paula Cartes and Antonieta Ruiz
Plants 2026, 15(5), 777; https://doi.org/10.3390/plants15050777 - 3 Mar 2026
Viewed by 484
Abstract
Nitrogen (N) availability strongly regulates plant growth and metabolism, and its deficiency constrains plant development and yield. Silicon (Si) has been reported to enhance plant tolerance to multiple stresses; however, its influence on N metabolism in oats remains poorly understood. This study aimed [...] Read more.
Nitrogen (N) availability strongly regulates plant growth and metabolism, and its deficiency constrains plant development and yield. Silicon (Si) has been reported to enhance plant tolerance to multiple stresses; however, its influence on N metabolism in oats remains poorly understood. This study aimed to investigate the effects of Si on cell wall composition and antioxidant responses in oat genotypes grown under N limitation. Two oat genotypes with contrasting N tolerance were hydroponically cultivated under N-deficient (0.5 mM) or N-sufficient (5 mM) conditions in combination with 0 or 2 mM Si. Growth parameters, N and Si uptake, cell wall structural components, phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) activities, antioxidant responses, and oxidative damage were evaluated. In both genotypes grown under N deficiency, Si supply reduced shoot N content while enhancing Si accumulation. Moreover, Si application decreased lipid peroxidation in both genotypes under N-deficient conditions. In the N-sensitive genotype, Si increased cellulose deposition and antioxidant activity, whereas in the N-tolerant genotype, Si reduced lignin content and TAL activity. We conclude that Si supplementation improves the metabolic performance of oat genotypes under N-deficient conditions by modulating nutrient uptake, antioxidant responses, and cell wall composition. Full article
(This article belongs to the Special Issue Silicon and Its Physiological Role in Plant Growth and Development)
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21 pages, 3320 KB  
Article
Superior Growth Strategies and Stable Rhizosphere Microbial Communities Enhance the Competitive Advantage of the Invasive Plant Solanum rostratum over Its Native Congener S. nigrum
by Yuanzhen Tang, Ping Guan, Meini Shao, Shuai Wang, Gue Liu, Ming Guan, Houyi Liu, Yuan Yang, Xiaolei Li, Jin Bai, Chenyang Xue and Bo Qu
Plants 2026, 15(5), 687; https://doi.org/10.3390/plants15050687 - 25 Feb 2026
Viewed by 425
Abstract
Exploring how nitrogen deposition alters the competitive interactions between invasive plants and native plants is critical for predicting the invasion trends of invasive plants and for formulating their control strategies. In this study, the invasive plant Solanum rostratum and its native congener S. [...] Read more.
Exploring how nitrogen deposition alters the competitive interactions between invasive plants and native plants is critical for predicting the invasion trends of invasive plants and for formulating their control strategies. In this study, the invasive plant Solanum rostratum and its native congener S. nigrum were selected as research subjects, and three different nitrogen (N) concentration treatments (N1: 50 mg·kg−1, N2: 100 mg·kg−1, N3: 150 mg·kg−1) were set up to compare the two species in terms of growth and development, leaf nutrient utilization strategies, stress tolerance, and rhizosphere microbial community differences under competitive conditions. The results showed that the biomass of S. rostratum was 1.4 to 2.3 times that of S. nigrum; the former had a lower root–shoot ratio and a larger crown width, enabling it to seize more living space and light resources. Across all nitrogen treatments, the net photosynthetic rate of S. rostratum leaves was significantly higher than that of S. nigrum, reflecting a stronger carbon sequestration capacity. With the increase in soil nitrogen concentration, the malondialdehyde content in S. rostratum leaves showed a decreasing trend; meanwhile, its leaf soluble sugar and catalase contents were 3.5 to 4.3 times and 1.5 to 2.5 times those of S. nigrum, respectively, indicating a lower oxidative stress level and higher stress tolerance in S. rostratum. The leaf C/P and C/N ratios of S. rostratum increased with the rise in soil N, demonstrating a higher nutrient use efficiency, while the decrease in leaf phosphorus (P) content might be attributed to the element dilution effect caused by the rapid plant growth. In addition, the diversity and stability of the rhizosphere microbial community of S. rostratum gradually increased with increasing soil N and were significantly higher than those of S. nigrum. The rhizosphere-recruited microbes of the genera Comamonas and Chryseobacterium may help promote its root nutrient absorption and thus enhance its competitive ability. Collectively, our findings reveal that under exogenous N application, S. rostratum gains a significant growth advantage over S. nigrum, which is attributed to its stronger capacities for carbon assimilation and spatial resource acquisition, a nutrient strategy characterized by low acquisition and high utilization, as well as a stable and diverse rhizosphere microbial community. Full article
(This article belongs to the Topic Plant Invasion: 2nd Edition)
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14 pages, 1141 KB  
Article
PaenibacillusPseudomonas Consortium Improves Barley Performance with Minimal Impact on Native Rhizobacterial Community
by Jakub Dobrzyński, Aleksandra Naziębło, Iryna Kulkova, Magdalena Szpytma, Adrianna Antosik, Monika Sitarek-Andrzejczyk and Barbara Wróbel
Microorganisms 2026, 14(2), 488; https://doi.org/10.3390/microorganisms14020488 - 18 Feb 2026
Viewed by 751
Abstract
The intensive use of mineral nitrogen fertilizers in cereal production contributes to environmental degradation, highlighting the need for more sustainable crop management strategies. Plant growth-promoting bacteria (PGPB) offer a promising alternative; however, their effects on native rhizosphere communities remain underexplored, particularly in barley. [...] Read more.
The intensive use of mineral nitrogen fertilizers in cereal production contributes to environmental degradation, highlighting the need for more sustainable crop management strategies. Plant growth-promoting bacteria (PGPB) offer a promising alternative; however, their effects on native rhizosphere communities remain underexplored, particularly in barley. This study evaluates the impact of a bacterial consortium composed of Paenibacillus sp. Z15 and Pseudomonas sp. KR227 on barley growth, yield, and rhizosphere bacteria under field conditions in temperate climate (2025). Plant biometric traits, photosynthetic pigment content, and soil properties were measured, and rhizobacterial communities were analyzed using 16S rRNA gene (V3–V4) sequencing. The PGPB consortium significantly increased early root biomass (120%), shoot height (7.8%), and grain yield (15.5%), while no significant effects were observed on soil chemistry or photosynthetic pigments. Sequencing revealed no major changes in alpha or beta diversity; however, transient shifts in the relative abundance of specific taxa were detected relatively shortly after inoculation and mostly disappeared by harvest. These findings indicate that the Paenibacillus–Pseudomonas consortium can enhance barley performance without disrupting native rhizobacterial communities. Overall, the results support the potential of PGPB as a sustainable agronomic tool and provide new insights into PGPB–microbiome interactions in barley under field conditions. Full article
(This article belongs to the Special Issue Advances in Agro-Microbiology)
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22 pages, 3073 KB  
Article
Iodine-Enriched Urea Enhances Maize Tolerance to Water Deficit via Modulation of Pigments and Sugars
by Jucelino de Sousa Lima, Everton Geraldo de Morais, Leônidas Canuto dos Santos, Pedro Antônio Namorato Benevenute, Otávio Vitor Souza Andrade, Eduarda Santos de Andrade, Anyela Pierina Vega Quispe, João Victor da Costa Cezar, Paulo Eduardo Ribeiro Marchiori, Vitor de Laia Nascimento and Luiz Roberto Guimarães Guilherme
Plants 2026, 15(4), 606; https://doi.org/10.3390/plants15040606 - 14 Feb 2026
Viewed by 451
Abstract
Water deficit (WD) impairs maize growth, but the application of beneficial elements such as iodine (I) has shown potential to mitigate WD. Nevertheless, strategies for incorporating I into the soil are still needed. In this context, the present study incorporated I into urea [...] Read more.
Water deficit (WD) impairs maize growth, but the application of beneficial elements such as iodine (I) has shown potential to mitigate WD. Nevertheless, strategies for incorporating I into the soil are still needed. In this context, the present study incorporated I into urea (I-enriched urea) at different I rates (0, 750, 1500, and 3000 g I hectare−1) and evaluated its potential to alleviate WD in maize plants. For this purpose, maize plants were grown in Oxisol samples under simulated WD conditions and compared with plants grown without water limitation. Several parameters were evaluated during and after the stress period, including physiological parameters, pigment content, antioxidant activity, levels of compatible osmolytes, shoot dry matter, and shoot nitrogen (N) accumulation. Under WD conditions, the application of 1500 and 3000 g I hectare−1 via I-enriched urea, compared with no I application, increased the leaf electron transport rate and relative water content (RWC) while reducing membrane damage. These responses were directly associated with increased chlorophyll a, b, and total contents, and with lower levels of catalase and phenolic compounds. This effect also resulted in reduced superoxide dismutase (SOD) levels after the stress period. Moreover, in the first evaluation of irrigated plants, I-enriched urea promoted greater N uptake, increasing N accumulation in the shoot. Thus, the use of I-enriched urea at I application rates of 1500 and 3000 g I hectare−1 proved to be a promising strategy for mitigating WD. The results shown here have future implications that need validation under field conditions. Still, they suggest that I-enriched urea may be a viable agronomic approach to increase maize tolerance to WD and has high potential for integration into nutritional management strategies in environments subject to drought or irregular rainfall during maize growth. Full article
(This article belongs to the Special Issue Multifunctional Mediators in Plant Development and Stress Response)
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19 pages, 558 KB  
Article
Quantification of B-Values and Symbiotic Efficiency of Bradyrhizobium-Inoculated Soybean Varieties Using the δ15N Natural Abundance Method
by Haimanot Beruk, Tarekegn Yoseph, Georg Cadisch and Tewodros Ayalew
Nitrogen 2026, 7(1), 23; https://doi.org/10.3390/nitrogen7010023 - 14 Feb 2026
Viewed by 538
Abstract
Biological nitrogen fixation (BNF) is crucial for enhancing soybean productivity while reducing reliance on mineral nitrogen fertilizers. The accurate estimation of BNF via the δ15N natural abundance method depends on reliable B-values, which represent plants that derive all their nitrogen from [...] Read more.
Biological nitrogen fixation (BNF) is crucial for enhancing soybean productivity while reducing reliance on mineral nitrogen fertilizers. The accurate estimation of BNF via the δ15N natural abundance method depends on reliable B-values, which represent plants that derive all their nitrogen from fixation. This study aimed to assess the B-values and symbiotic efficiency of Bradyrhizobium-inoculated soybean varieties using δ15N natural abundance techniques. Eight strains and five soybean varieties were evaluated in sterilized sand culture using a factorial completely randomized design under lath-house conditions. Plants were analyzed for δ15N, shoot N concentration, shoot N content, and symbiotic efficiency (SE). The applied treatments showed highly significant effects with strong interactions, reflecting substantial genotypic variation in symbiotic performance. Strain SD-53 produced the lowest δ15N values (−0.24 to 0.14‰) and the highest SE, with several strain–variety combinations surpassing N-fertilized controls. Shoot N concentration and content ranged from 0.96–3.16% and 9.90–52.73 mg plant−1, respectively, and SE varied from 29.07 to 136.29%. δ15N showed strong negative correlations with SE and plant N traits. The study identified SD-53 as a promising inoculant candidate and generated the first regional soybean B-values (−0.24 to 0.14‰ for each tested variety and a mean of −0.08 ± 0.14‰) for Ethiopia. These values provide an important baseline for %Ndfa calculations and support future field validation and inoculant formulation. Full article
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15 pages, 2521 KB  
Article
Effects of Root-Cutting Treatment on Biomass, Photosynthetic Characteristics, and Soil Nutrients in Jerusalem Artichoke
by Hanyu Xu, Xin Li, Tiexia Zhu, Entian Zhang, Siyu Liu, Rongyu Dai, Jingkun Qin and Kai Gao
Agriculture 2026, 16(4), 411; https://doi.org/10.3390/agriculture16040411 - 11 Feb 2026
Viewed by 374
Abstract
Helianthus tuberosus L. tubers are the primary part utilized by humans for bioenergy and bioproduct production. Therefore, achieving high tuber yield is a core issue in Jerusalem artichoke cultivation and management. In this study, red-skinned Jerusalem artichoke was used as an experimental material. [...] Read more.
Helianthus tuberosus L. tubers are the primary part utilized by humans for bioenergy and bioproduct production. Therefore, achieving high tuber yield is a core issue in Jerusalem artichoke cultivation and management. In this study, red-skinned Jerusalem artichoke was used as an experimental material. Under field conditions from 2022 to 2023, different root-cutting treatments were established to investigate their effects on Jerusalem artichoke biomass, photosynthetic characteristics, and rhizosphere (non-rhizosphere) soil nutrient content, aiming to provide a theoretical basis for high-yield cultivation of Jerusalem artichoke. During the vegetative growth stage (70–75 days after planting), a “vertical cutting method” was applied; centered on the plant, vertical cuts were made through the horizontal root system at radii of 20 cm, 30 cm, 40 cm, and 50 cm to implement root-cutting treatments. The total biomass, underground biomass, tuber yield and root/shoot ratio of Jerusalem artichoke increased by 11.59–25.97%, 15.77–46.33%, 7.69–49.09% and 11.72–62.69%, respectively. The tuber yield was greatest under D1 (20 cm) (0.94 kg·plant−1 and 0.98 kg·plant−1). On the 7th and 15th days after root breakage, the photosynthetic characteristics and transpiration rate of the Jerusalem artichoke gradually increased with increasing root-cutting radius and were lower than those of the control. On the 21st day after the root-cutting treatment, the photosynthetic characteristics and transpiration rate of the Jerusalem artichoke plants gradually decreased with increasing root-cutting radius and were greater than those of the control plants. The water use efficiency of Jerusalem artichoke increased with increasing root-cutting radius. The contents of C, N, P, available phosphorus, alkali-hydrolyzed nitrogen, nitrate nitrogen showed that proper root-cutting can increase tuber yield of Jerusalem artichoke and improve rhizosphere soil nutrients. Full article
(This article belongs to the Section Agricultural Soils)
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18 pages, 1675 KB  
Article
γ-PGA Enhances Zea mays L. Seedling Growth by Fertile Rhizosphere Establishment and Osmotic Modulation in Saline Soil
by Xin Li, Weiming Shi, Herbert J. Kronzucker, Xiaodong Ding and Yilin Li
Agronomy 2026, 16(3), 317; https://doi.org/10.3390/agronomy16030317 - 27 Jan 2026
Viewed by 697
Abstract
Soil salinization is a major threat to agricultural sustainability. Poly-gamma-glutamic acid (γ-PGA), a biopolymer produced by microbial fermentation, has received attention as a biostimulant due to its positive effects on crop performance. However, the function of γ-PGA in crop salt stress tolerance and [...] Read more.
Soil salinization is a major threat to agricultural sustainability. Poly-gamma-glutamic acid (γ-PGA), a biopolymer produced by microbial fermentation, has received attention as a biostimulant due to its positive effects on crop performance. However, the function of γ-PGA in crop salt stress tolerance and its effect on the rhizosphere are unclear. This study explores the effects of γ-PGA application on rhizosphere soil nutrients and the soil–physical environment and examines the salt tolerance response of maize seedlings grown in saline–alkali soil under such an application regime. The results show a significant promotion of maize seedling growth and of nutrient accumulation with γ-PGA application under salt stress; plant dry weight, stem diameter, and plant height increased 121%, 39.5%, 18.4%, respectively, and shoot accumulation of nitrogen, phosphorus, potassium, and carbon increased by 1.38, 2.11, 1.50, and 1.36 times, respectively, under an optimal-concentration γ-PGA treatment (5.34 mg kg−1 (12 kg ha−1)) compared with the control. γ-PGA treatment significantly decreased rhizospheric pH and soil electrical conductivity and significantly increased nutrient availability in the rhizosphere, especially available nitrogen (AN) and available potassium (AK). Compared with the control, AN, available phosphorus (AP), and AK increased by 13.9%, 7.70%, and 17.7%, respectively, under an optimal concentration treatment with γ-PGA. γ-PGA application also significantly increased the activities of urease, acid phosphatase, alkaline phosphatase, dehydrogenase, and cellulose in rhizosphere soil by 35.5–39.3%, 35.4–39.3%, 5.59–8.85%, 18.9–19.8%, and 19.2–47.0%, respectively. γ-PGA application significantly decreased Na+ concentration and increased K+ concentration in shoots, resulting in a lowering of the Na+/K+ ratio by 30.5% and an increase in soluble sugar and soluble protein contents. Therefore, rhizosphere application of water-soluble and biodegradable γ-PGA facilitates the creation of an optimized rhizospheric environment for maize seedling and overcomes osmotic and ionic stresses, offering possibilities for future use in drip-irrigation systems in the cultivation of crops on saline-alkali land. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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20 pages, 6100 KB  
Article
Application of Sustainable Crab-Waste-Derived Nanochitosan as a Soil Amendment for Tomato Cultivation in Loam Soil
by Divya Shanmugavel and Omar Solorza-Feria
Sustainability 2026, 18(3), 1213; https://doi.org/10.3390/su18031213 - 25 Jan 2026
Viewed by 621
Abstract
Converting marine biowaste into nano-bioproducts for their application as bio-sourced, circular biostimulants to enhance crop productivity is a promising approach. This study evaluated chitosan–TPP nanoparticles (nanochitosan, ~38 nm) derived from blue crab (Callinectes sapidus) shells as a soil-applied biostimulant and conditioner [...] Read more.
Converting marine biowaste into nano-bioproducts for their application as bio-sourced, circular biostimulants to enhance crop productivity is a promising approach. This study evaluated chitosan–TPP nanoparticles (nanochitosan, ~38 nm) derived from blue crab (Callinectes sapidus) shells as a soil-applied biostimulant and conditioner for tomato (Solanum lycopersicum) grown in loam soil without mineral fertilizer. Our results showed that nanochitosan application as a soil supplement by drench improved the soil moisture content (39% vs. 22%), water-holding capacity (84% vs. 70%), total nitrogen (3.8 vs. 1.4 gm N kg−1), and organic carbon content (48.4 vs. 34.1 gm C kg−1) in nanochitosan-amended soil compared with the non-amended soil. This was accompanied by higher biomass, better root/shoot development and synthesis of phytohormones leading to increased shoot length, early flowering, and increased total soluble solids of fruits in nanochitosan-amended soil compared with control, suggesting that nanochitosan can act both as a beneficial soil conditioner and as a plant biostimulant. The results further show that nanochitosan-based formulations may be used not only as fertilizer-saving bio-inputs but also as bio-based nanochitosan plant biostimulants, which can partly substitute mineral fertilizer application for sustainable production of tomato. Moreover, generic fabrication of such nanochitosan from marine biowaste would support the circular-bioeconomy model to further improve sustainability of agroecosystems. Full article
(This article belongs to the Section Sustainable Agriculture)
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25 pages, 11228 KB  
Article
Optimal Branch Bending Angle for Korla Fragrant Pear: A Multi-Trait Physiological Trade-Off Framework
by Ablah Niyaz, Mansur Nasir, Shikui Zhang, Shaopeng Wang, Cuihui Min, Guoquan Fan, Dilraba Muhtar, Xianbiao Ma, Mirigul Tunyaz, Lihong Yao, Ruizhe Wang, Tianming He, Juan Song and Mayira Eziz
Plants 2026, 15(2), 339; https://doi.org/10.3390/plants15020339 - 22 Jan 2026
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Abstract
The optimal branch bending angle for Pyrus sinkiangensis Yü (Korla fragrant pear) remains undefined. In this study, the optimal angle was determined by integrating the phenological, nutritional, hormonal, and fruit-quality responses across a 15-day bloom window. Four branch angles (40°, 60°, 80°, and [...] Read more.
The optimal branch bending angle for Pyrus sinkiangensis Yü (Korla fragrant pear) remains undefined. In this study, the optimal angle was determined by integrating the phenological, nutritional, hormonal, and fruit-quality responses across a 15-day bloom window. Four branch angles (40°, 60°, 80°, and 100°) were applied to 8-year-old trees in spring 2022, and flowering dynamics, bud carbon/nitrogen status, leaf morphology/mineral content, fruiting-shoot architecture, endogenous hormones, and fruit quality were comprehensively evaluated. The 80° angle maximized the fruit set (11.77%) and bud soluble sugar content (8.84 mg/g DW), significantly outperforming the other angles (p < 0.05). The flowering rate peaked at 100° (7.89%) but was statistically comparable to that at 60° and 80° (p > 0.05); calyx removal was greatest at 60° (73.33%), with no significant difference from that at 80° (71%, p > 0.05). These reproductive benefits aligned with enhanced leaf source capacity—80° pulling resulted in the greatest leaf area (59.51 cm2), the greatest amount of chlorophyll (3.11 mg/g DW), and elevated N/Mg/Cu concentrations. Branch architecture was optimized at 80°, with the percentage of medium fruiting spurs reaching 41.1% and the xylem:phloem dry-weight ratio peaking at 1.78, indicating the development of efficient assimilate transport pathways. Hormonally, 80° triggered a distinct cascade: a transient GA4/GA7 surge (50.6 and 1.34 ng/g DW) on 28 April, followed by sustained IAA elevation (2.05 ng/g DW) and zeatin stabilization (0.27–0.29 ng/g DW) during ovary development. Consequently, the fruit quality was comprehensively improved at 80°—the single-fruit weight (110.7 g), soluble sugar content (10.08 mg/g DW), and sugar/acid ratio (17.08) were greatest, whereas the stone-cell content was lowest (0.49 mg/g DW). Principal component analysis of 57 traits confirmed 80° as the system-wide optimum (D = 0.718). These results demonstrate that an 80° bending angle synchronizes carbohydrate supply, hormone signaling, and fruit quality in Korla fragrant pear, providing a low-cost, nonchemical benchmark for precision canopy management in high-density orchards. An 80° branch-bending angle optimizes carbon-hormone synergy via a transient GA4/GA7 surge and sustained IAA-zeatin signaling, maximizing fruit set and quality in high-density Korla fragrant pear orchards. Full article
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Article
Influence of Saline Irrigation and Genotype on Yield, Grain Quality and Physiological Ideotypic Indicators of Bread Wheat in Hot Arid Zones
by Ayesha Rukhsar, Osama Kanbar, Henda Mahmoudi, Salima Yousfi, Maria Dolors Serret and José Luis Araus
Agronomy 2026, 16(2), 270; https://doi.org/10.3390/agronomy16020270 - 22 Jan 2026
Viewed by 385
Abstract
Wheat (Triticum aestivum L.) is a strategic food crop for arid, hot regions such as the Arabian Peninsula, the Middle East, and North Africa. In these areas, production is limited by extreme environmental and agronomic conditions, leading to heavy dependence on imported [...] Read more.
Wheat (Triticum aestivum L.) is a strategic food crop for arid, hot regions such as the Arabian Peninsula, the Middle East, and North Africa. In these areas, production is limited by extreme environmental and agronomic conditions, leading to heavy dependence on imported wheat. Irrigation is often essential for successful cultivation, but available water sources are frequently saline. This study evaluated the comparative effects of irrigation salinity and genotype on agronomic performance, physiological responses, and grain quality. Nine Syrian wheat genotypes and one French bread-making cultivar, Florence Aurora, were grown in sandy soil under three irrigation salinity levels (2.6, 10, and 15 dS m−1) across two seasons at the International Center for Biosaline Agriculture (Dubai, UAE). Salinity strongly negatively impacted yield, which decreased by 61% from the control to 15 dS m−1, along with key yield components such as thousand grain weight and total biomass. Physiological traits, including carbon isotope composition (δ13C) and Na concentrations in roots, shoots and grains, increased significantly with salinity, while chlorophyll content showed a modest decline. Effects on grain quality were relatively minor: total nitrogen concentration and most mineral levels increased slightly, mainly due to a passive concentration effect associated with reduced TGW. Genotypes varied significantly in yield, biomass, TGW, physiological traits, and grain quality. The highest-yielding genotypes under control conditions (ACSAD 981 and ACSAD 1147) also performed best under saline conditions, and no trade-off was observed between yield and grain quality parameters (TGW, nitrogen, zinc, and iron concentrations). Separate analyses conducted for control and saline treatments identified different drivers of genotypic variability. Under control conditions, chlorophyll content, closely linked with δ13C, was the best predictor of genotypic differences and was positively correlated with yield across genotypes. Under salinity stress, grain magnesium (Mg) concentration was the strongest predictor, followed by grain δ13C, with both traits positively correlated with yield. These findings highlight key physiological traits linked to salinity tolerance and offer insights into the mechanisms underlying genotypic variability under both optimal and saline irrigation conditions. Full article
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