Plant Nutrient Accumulation Research Articles

Micronutrients concentration and content in corn as affected by nitrogen, phosphorus, and potassium fertilization

AbstractThe interaction between nitrogen (N), phosphorus (P), and potassium (K) fertilizers significantly impacts the uptake of micronutrients in corn, influencing their availability in soil and uptake by plants. Understanding the interaction of macro‐ and micronutrients is a prerequisite to targeting nutrient balance in crop production. Therefore, a 2‐year field experiment was conducted to determine the effect of NPK fertilization on micronutrient uptake of rain‐fed corn (Zea mays L.). A randomized complete block design was employed with 12 treatments replicated three times. Different combinations of N, P, and K fertilizer rates were investigated for micronutrient concentration and uptake in rain‐fed corn. Findings revealed the order of nutrient accumulation in corn plants: iron (Fe) > manganese (Mn) > zinc (Zn) > copper (Cu). Nitrogen application influenced nutrient concentrations and uptake. Increasing N rates increased micronutrient concentrations in corn grain, except for Cu. Interestingly, Cu content in grains exhibited no correlation with nutrient supply, biomass, or other concentrations. As the N application rate increased, micronutrient content increased at early growth stage and physiological maturity. Phosphorus application showed negligible impact on grain micronutrient concentration and uptake. However, K application notably increased Mn, Fe, and Cu uptake in grains. This study underscores the need to consider not only grain yield but also nutritional quality when determining optimal NPK rates in rain‐fed corn cultivation.

Vermicompost Supply Enhances Fragrant-Rice Yield by Improving Soil Fertility and Eukaryotic Microbial Community Composition under Environmental Stress Conditions.

Heavy-metal contamination in agricultural soil, particularly of cadmium (Cd), poses serious threats to soil biodiversity, rice production, and food safety. Soil microbes improve soil fertility by regulating soil organic matter production, plant nutrient accumulation, and pollutant transformation. Addressing the impact of Cd toxicity on soil fungal community composition, soil health, and rice yield is urgently required for sustainable rice production. Vermicompost (VC) is an organic fertilizer that alleviates the toxic effects of Cd on soil microbial biodiversity and functionality and improves crop productivity sustainably. In the present study, we examined the effects of different doses of VC (i.e., 0, 3, and 6 tons ha-1) and levels of Cd stress (i.e., 0 and 25 mg Cd kg-1) on soil biochemical attributes, soil fungal community composition, and fragrant-rice grain yield. The results showed that the Cd toxicity significantly reduced soil fertility, eukaryotic microbial community composition and rice grain yield. However, the VC addition alleviated the Cd toxicity and significantly improved the soil fungal community; additionally, it enhanced the relative abundance of Ascomycota, Chlorophyta, Ciliophora, Basidiomycota, and Glomeromycta in Cd-contaminated soils. Moreover, the VC addition enhanced the soil's chemical attributes, including soil pH, soil organic carbon (SOC), available nitrogen (AN), total nitrogen (TN), and microbial biomass C and N, compared to non-VC treated soil under Cd toxicity conditions. Similarly, the VC application significantly increased rice grain yield and decreased the Cd uptake in rice. One possible explanation for the reduced Cd uptake in plants is that VC amendments influence the soil's biological properties, which ultimately reduces soil Cd bioavailability and subsequently influences the Cd uptake and accumulation in rice plants. RDA analysis determined that the leading fungal species were highly related to soil environmental attributes and microbial biomass C and N production. However, the relative abundance levels of Ascomycota, Basidiomycota, and Glomeromycta were strongly associated with soil environmental variables. Thus, the outcomes of this study reveal that the use of VC in Cd-contaminated soils could be useful for sustainable rice production and safe utilization of Cd-polluted soil.

Effect of plant-soil system on the restoration of community stability after wildfire in the northeast margin of Qinghai-Tibet plateau

Wildfires, as an environmental filter, are pivotal ecological disturbances that reshape plant communities and soil dynamics, playing a crucial role in regulating biogeographic patterns and ecosystem services. In this study, we aim to explore the effects of wildfires on forest ecosystems, specifically focusing on the plant-soil feedback mechanisms within the northeastern margin of the Qinghai-Tibet Plateau (QTP). Utilizing Partial Least Squares Path Modeling (PLS-PM), we investigated the interrelationships among soil physicochemical properties, enzyme activities, species diversity, and community stability at varying post-fire recovery stages (5, 15, and 23 years). Results indicated that in the early recovery stages, rapid changes in soil properties such as decreased pH (p < 0.001) and increased nutrient availability facilitate the emergence of early successional species with high resource utilization traits. As the ecosystem evolved toward a climax community, the soil and vegetation exhibit increased stability. Furthermore, soil enzyme activities displayed dynamic patterns that corresponded with changes in soil nutrient content, directly influencing the regeneration and diversity of plant communities. Importantly, our study documented a transition in the influence of soil properties on community stability from direct positive effects in initial recovery phases to negative impacts in later stages, while indirect benefits accrue through increased species diversity and enzyme activity. Vegetation composition and structure changed dynamically with recovery time during community succession. Plant nutrient absorption and accumulation affected nutrient dynamics in the soil, influencing plant regeneration, distribution, and diversity. Our results underscore the complex interactions between soil and vegetation that drive the recovery dynamics post-wildfire, highlighting the resilience of forest ecosystems to fire disturbances. This study contributes to the understanding of post-fire recovery processes and offers valuable insights for the management and restoration of fire-affected forest ecosystems.

Effects of LED Light Quality on Broccoli Microgreens Plant Growth and Nutrient Accumulation

Effects of LED Light Quality on Broccoli Microgreens Plant Growth and Nutrient Accumulation

Proteomic Analysis of Arachis hypogaea Seeds from Different Maturity Classes.

Physiological maturity impacts seed quality through various mechanisms including vigor, desiccation tolerance, dormancy induction, synthesis of raw materials (including seed storage proteins), and the reorganization of metabolisms. Peanut seed development can be classified into seven classes with four incremental stages per class. Based on the mesocarp color, the final three stages are commonly referred to as "orange", "brown", and "black". In 2017, freshly harvested pods from one genotype of runner market-type peanuts grown under conventional practices were obtained from the University of Georgia research facility. The pods were removed from the plant material and 'pod blasted' to reveal the mesocarp. After separation, the remainder of the pod outer layer was removed, and the seeds were segregated for proteomic analysis. The raw peanuts were analyzed by bottom-up LC-MS/MS proteomics, which was conducted by the Proteomics Resource Center at the Rockefeller University, to identify the significant protein composition differences in each maturity class. The proteomic data revealed differentially expressed proteins as a function of maturity class with multiple functions including plant defense, metabolism, cell signaling, nutrient accumulation, and packaging. Understanding the processes needed for seed maturation will enable peanut scientists to evaluate the traits needed for robust germination, hardiness of the seed in response to disease, and nutrient quality.

Improved bacterial composition and co-occurrence patterns of rhizosphere increased nutrient uptake and grain yield through cultivars mixtures in maize

Crop diversification contributes to agricultural productivity and resources efficient utilization. However, whether cultivar mixtures in maize affects soil bacterial community, nutrient uptake, plant growth and yield remains unknown. A two-year lysimetric experiment was conducted using two maize cultivars (LY16 and JS501) with different root system architectures planted in monoculture or in mixture under normal fertilization (NF), reduced fertilization (RF) or no addition of fertilizer (CK) and was assessed at the silking stages. Cultivar mixtures and monoculture of LY16 had higher shoot biomass, nutrient uptake and total root length at silking stage, and grain yield than monoculture of JS501 under NF and RF conditions. Under NF and RF conditions, cultivar mixtures and monoculture of LY16 led to an increase in bacterial diversity, significant changes in community structure, and a high abundance of Bacteroidia and biomarkers of Chitinophagaceae and Saprospiraceae (Bacteroidia). Cultivar mixtures showed specific responses from modules of the rhizosphere bacterial community co-occurrence network, and the relative abundance of keystone taxa of cultivar mixtures was higher than that of monoculture of JS501. The keystone taxa had a broad and significant positive correlation with plant nutrient accumulation and grain yield. Cultivar mixtures showed similar assembly processes of Bacteroidia with monoculture of LY16, and the increased abundance of Chitinophagaceae may lead to a healthy rhizosphere bacterial community. Overall, our findings indicate that cultivar mixtures significantly affects the assembly and composition of the rhizosphere bacterial community, and thus benefits plant nutrient acquisition and plant growth. These findings could deepen our understanding of the facilitating effect of rhizosphere functional microbial community (e.g. plant nutrition uptake or immunity)of cultivar mixtures.

Combined Application of Chemical and Organic Fertilizers: Effects on Yield and Soil Nutrients in Spring Wheat under Drip Irrigation

In this study, we established a feasible fertilization programming method for wheat production by exploring the effects of the combined application of chemical and organic fertilizers on wheat yield, nutrient uptake, soil nutrient content, and fertilizer utilization. Six treatments, no fertilizer (CK), conventional fertilizer (CF), optimized fertilizer (with reduced fertilizer amount) (RF), chemical fertilizer with organic fertilizer extract (RPAE), partial replacement of chemical fertilizer with raw amino acid powder (RAF), and partial replacement of chemical fertilizer with raw humic acid powder (RHF), were set up for a field experiment. The fertilizer application rates for the RF treatment were calculated based on fertilization-monitoring techniques (30.3% nitrogen and 24.8% phosphorus reductions in 2022 and 23.0% nitrogen and 1.5% phosphorus reductions in 2023). The effects of different fertilizer treatments on yield, dry matter accumulation, plant nutrient accumulation, soil nutrients, and nutrient utilization in wheat were investigated. The results showed that, on the basis of 23% nitrogen and 1.5% phosphorus reductions, there was no significant difference in wheat yield between the RF and CF treatments and that the utilization rate of nitrogen fertilizer was improved. The application of organic fertilizer promoted dry matter accumulation in different organs of wheat; increased plant nutrient accumulation; improved soil nutrient content, nutrient utilization rate, nutrient partial productivity, and nutrient agronomic use efficiency; and ensured stable and increased crop yield. Specifically, compared with CF, the RPAE, RAF, and RHF organic fertilizer treatments increased wheat yield by 3.85%, 1.97%, and 0.67%, respectively, and the utilization of nitrogen and phosphorus fertilizers induced by these treatments significantly increased by 40.46%, 39.28%, and 37.46% (nitrogen) and by 9.83%, 8.91%, and 7.46% (phosphorus), respectively. As a result of our experiment, we concluded that RPAE exerted the best effects among the three organic fertilizer treatments (RPAE, RAF, and RHF) and that its use can result in a higher wheat yield and fertilizer utilization rate in drip-irrigated wheat fields. The results of this study provide a theoretical basis for the combined application of chemical and organic fertilizers, which is conducive to sustainable agriculture development.

Zero-valent iron (nZVI) nanoparticles mediate SlERF1 expression to enhance cadmium stress tolerance in tomato

Cadmium (Cd) pollution threatens plant physiological and biochemical activities and crop production. Significant progress has been made in characterizing how nanoparticles affect Cd stress tolerance; however, the molecular mechanism of nZVI nanoparticles in Cd stress remains largely uncharacterized. Plants treated with nZVI and exposed to Cd had increased antioxidant capacity and reduced Cd accumulation in plant tissues. The nZVI treatment differentially affected the expression of genes involved in plant environmental responses, including those associated with the ERF transcription factor. SlEFR1 was upregulated by Cd stress in nZVI-treated plants when compared with the control and the predicted protein-protein interactions suggested SlERF1 interacts with proteins associated with plant hormone signaling pathway and related to stress. Yeast overexpressing SlEFR1 grew faster after Cd exposure and significantly had higher Cd stress tolerance when compared with empty vector controls. These results suggest that nZVI induces Cd stress tolerance by activating SlERF1 expression to improve plant growth and nutrient accumulation. Our study reveals the molecular mechanism of Cd stress tolerance for improved plant growth and will support new research on overcoming Cd stress and improving vegetable crop production.

Homogeneous microenvironmental conditions under nurses promote facilitation

Abstract Biotic interactions are highly affected by species traits and micro‐environmental variability. Research on facilitation has primarily focused on how nurse species alleviate abiotic stress for beneficiary species, while the impact of the micro‐environmental variability generated by nurse plants in shaping facilitation outcomes is poorly understood. This study has two objectives: (i) To evaluate which traits define beneficiary species and (ii) to evaluate whether nurse and non‐nurse species differ in their ability to reduce abiotic stress and its variability under their canopy. We sampled recruits in two arid and stressful environments to assess (i) which species accumulate more juveniles beneath their canopy controlling for their coverage (nurse vs. non‐nurse species) and (ii) which species benefited from facilitation by determining whether they tend to recruit more beneath other species or on the bare ground (beneficiary/non‐beneficiary). First, we compared how nurse and non‐nurse species modify the physical and chemical microenvironments underneath their canopy, both in terms of magnitude and variation. Second, we compared root growth, water retention and nutrient accumulation in juvenile plants of beneficiary and non‐beneficiary species. We found that facilitation is enhanced by species that provide a more homogeneous microenvironment rather than an intense reduction of microenvironmental stress under their canopy. In addition, the juveniles of beneficiary species invest more in root development, accumulate Ca and S in their shoot tissues, and show a higher water content than non‐beneficiary species. Our findings indicate that the homogeneity of microenvironments plays a crucial role in facilitative interactions, and the juveniles of beneficiary species show a less conservative strategy, investing more in resource acquisition than juveniles of non‐beneficiary species. Read the free Plain Language Summary for this article on the Journal blog.

Genome-Wide Identification of Selenium-Responsive MicroRNAs in Tea Plant (Camellia sinensis L. O. Kuntze)

Anadequate selenium (Se) intake can enhance human immunity and prevent diseases development. About one billion people in the world have varying degrees of Se deficiency in the world. Organic Se from tea infusion is the most easily absorbed and utilized Se form by the human body. Therefore the production of tea plants rich in Se is an effective way to increase Se dietary intake, but there are few studies on the involvement and functions of miRNAs in the responses of tea plants after Se treatment. MicroRNAs (miRNAs) are endogenous (non-coding) single-stranded RNAs that play crucial roles in regulating plant nutrient element acquisition and accumulation. Physiological analysis discovered that the total Se content in tea plant roots markedly increased under 0.05 mmol·L−1 selenite treatment, with no toxicity symptoms in the leaves and roots. To screen the miRNAs responsive to Se treatment in tea plants, miRNA libraries were constructed from the tea cultivar “Echa 1”. Using high-throughput sequencing, 455 known miRNAs and 203 novel miRNAs were identified in this study. In total, 13 miRNAs were selected that were differentially expressed in tea plants’ roots under 0.05 mmol·L−1 selenite treatments. Gene Ontology enrichment analysis revealed that the target genes of the differentially expressed miRNAs mainly belonged to the metabolic process, membrane, and catalytic activity ontologies. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis suggested that beta-alanine, taurine, hypotaurine, and sulfur metabolism were the most enriched pathways among the differentially expressed miRNAs, implying their involvement in Se accumulation and tolerance in tea plants. Further characterization of the data revealed that the number of novel miRNAs was comparable to that of known miRNAs, indicating that novel miRNAs significantly contributed to the regulation of Se accumulation in tea plant roots. Thisstudy lays the foundation for further research on the regulatory mechanisms underlying Se accumulation and tolerance in tea plants, providing targets to molecular breeding strategies for improving tea nutritional properties.

Exogenous Easily Extractable Glomalin-Related Soil Protein Induces Differential Response in Plant Growth of Tea Plants via Regulating Water Channel Protein Expression

Glomalin, a glycoprotein secreted by arbuscular mycorrhizal fungi (AMFs), exhibits multiple beneficial functions in regard to plant growth. However, the roles and regulatory mechanisms of exogenous easily extractable glomalin-related soil protein (EE-GRSP) in water and their effects on the quality of tea plants (Camellia sinensis (L.) O. Ktze.) remain unclear. The present study aimed to investigate the effects of a quarter-strength exogenous EE-GRSP solution (1/4 EE-GRSP), half-strength exogenous EE-GRSP solution (1/2 EE-GRSP), three-quarter-strength exogenous EE-GRSP solution (3/4 EE-GRSP), and full-strength exogenous EE-GRSP solution (full EE-GRSP) on plant growth, the root system architecture, leaf water status, and the tea quality of tea seedlings, along with examining the changes in the relative expression of water channel proteins (AQPs) in tea plants. The results indicated that exogenous EE-GRSP of different strengths had different effects on both the growth performance (height, leaf numbers, and biomass) and root architecture parameters of tea seedlings, and the best positive effects on plant growth and the root architecture appeared under the three-quarter-strength exogenous EE-GRSP treatment. Similarly, the exogenous EE-GRSP application also differently affected tea quality indicators, in which only the quarter- and half-strength exogenous EE-GRSP solutions significantly increased most of the indicators, including carbohydrates, tea polyphenols, total amino acids, catechins, and flavonoids. Moreover, the half- and three-quarter-strength exogenous EE-GRSP treatments significantly increased the leaf relative water content (LRWC), but all of the exogenous EE-GRSP treatments significantly decreased the leaf water potential (LWP). Furthermore, the expression of AQP genes in the root system of tea plants was related to the strength of the exogenous EE-GRSP treatments, and different genes were significantly up-regulated or down-regulated under the treatment of exogenous EE-GRSP at different strengths. Moreover, the correlation analysis showed that most of the relative expression of AQPs was significantly and positively correlated with tea plant growth, the root architecture, and the leaf relative water content, but negatively correlated with tea quality indicators; however, the expression of CsNIPs and CsSIPs was markedly and negatively correlated with plant growth performance. Therefore, we speculated that the application of exogenous EE-GRSP could facilitate plant growth and improve the quality indirectly by regulating the expression of root AQPs, thus ameliorating the water uptake and nutrient accumulation in tea plants.

Effects of Magnesium Imbalance on Root Growth and Nutrient Absorption in Different Genotypes of Vegetable Crops.

Magnesium (Mg) plays a crucial role in crop growth, but how Mg supply level affects root growth and nutrient absorption in vegetable crops with different genotypes has not been sufficiently investigated. In this study, the responses of tomato (Solanum lycopersicum L.) and cucumber (Cucumis sativus L.) crops to different levels of Mg supply were explored. Four levels of Mg treatment (i.e., 0.2, 1.0, 2.0, 3.0 mmol/L) were applied under hydroponic conditions, denoted as Mg0.2, Mg1, Mg2, and Mg3, respectively. The results showed that with increasing Mg levels, the plant biomass, root growth, and nutrient accumulation in both vegetable crops all increased until reaching their maximum values under the Mg2 treatment and then decreased. The total biomass per tomato plant of Mg2 treatment was 30.9%, 14.0%, and 14.0% higher than that of Mg0.2, Mg1, and Mg3 treatments, respectively, and greater increases were observed in cucumber plant biomass (by 54.3%, 17.4%, and 19.9%, respectively). Compared with the Mg0.2 treatment, the potassium (K) and calcium (Ca) contents in various plant parts of both crops remarkably decreased under the Mg3 treatment. This change was accompanied by prominently increased Mg contents in various plant parts and para-hydroxybenzoic acid and oxalic acid contents in root exudates. Irrespective of Mg level, plant biomass, root growth, nutrient accumulation, and root exudation of organic acids were all higher in tomato plants than in cucumber plants. Our findings indicate that excessive Mg supply promotes the roots to exude phenolic acids and hinders the plants from absorbing K and Ca in different genotypes of vegetable crops despite no effect on Mg absorption. A nutritional deficiency of Mg stimulates root exudation of organic acids and increases the types of exuded organic acids, which could facilitate plant adaption to Mg stress. In terms of root growth and nutrient absorption, tomato plants outperform cucumber plants under low and medium Mg levels, but the latter crop is more tolerant to Mg excess.

Accumulation of Lead and Nutrients in Soybean and Sorghum Cultivated in Lead-Affected Tropical Soils

ABSTRACT Lead is a potentially toxic chemical element, being responsible for many deleterious effects in living organisms. Therefore, understanding its dynamics and influence on plant growth is relevant for food security. The influence of Pb doses on nutrient accumulation in sorghum and soybean in two tropical soils with different buffering capacities was tested in a greenhouse study with four independent experiments (one per species/soil combination). The hypothesis was that the presence of Pb in soil decreases the accumulation of nutrients in soybean and sorghum plants. Soybean cultivated in a Typic Hapludox (TH) and sorghum, cultivated in both a Rhodic Acrudox (RA) and a TH, received 0, 200, 400, 800, 1200, 1600, 2200, and 2800 mg/kg of Pb, while soybean cultivated in RA received 0, 200, 400, 800, and 1600 mg/kg of Pb. Seeds were sown 24 h after application of Pb. Plants were harvested 21 days after the emergence of at least 50% of plants from the control treatment (approximately 30 days in total). Lead, macro, and micronutrient contents were determined in the shoot dry matter (SDM), and bioavailable Pb in soil was assessed by Mehlich-1. In general, TH allowed greater Pb uptake by plants, due to its lower buffering capacity. Soybean was the most affected crop with decreasing concentrations of N, K, Mg, and Ca, the latter was especially affected, with deficiency symptoms being observed. Effects on a longer time-scale are unknown, since significant decreases in nutrient contents were observed.

Effect of iron nanoparticles and conventional sources of Fe on growth, physiology and nutrient accumulation in wheat plants grown on normal and salt-affected soils

Salt stress is becoming a serious problem for the global environment and agricultural sector. Different sources of iron (Fe) can provide an eco-friendly solution to remediate salt-affected soils. The Fe nanoparticles (FeNPs) and conventional sources of Fe (iron-ethylene diamine tetra acetic acid; Fe-EDTA; and iron sulfate; FeSO4) were used to evaluate their effects on wheat crop grown in normal and salt-affected soils. Application of FeNPs (25 mg/kg) on normal soil increased the dry weights of wheat roots, shoots, and grains by 46%, 59%, and 77%, respectively. In salt-affected soil, FeNPs increased the dry weights of wheat roots, shoots, and grains by 65%, 78%, and 61%, respectively. The application of FeSO4 and Fe-EDTA increased the growth parameters of wheat in both normal and salt-affected soils compared to the respective controls. The photosynthetic parameters, including chlorophyll a (50%), chlorophyll b (67%), carotenoids (62%), and total chlorophyll contents (50%), were increased with the application of FeNPs under salt stress. The FeNPs increased plant-essential nutrients like iron, zinc, calcium, magnesium, and potassium in both normal and salt-affected soils. The experiment revealed that the application of Fe plays a significant role in enhancing the growth of wheat on alkaline normal and salt-affected soils. Maximum growth response was recorded with FeNPs than other Fe sources. The future must be focused on long term field experiments to economize the application of FeNPs on a large scale for commercialization.

The Effective Combination of Humic Acid Phosphate Fertilizer Regulating the Form Transformation of Phosphorus and the Chemical and Microbial Mechanism of Its Phosphorus Availability

In the process of phosphate fertilizer production, adding humic acid to produce humic-acid-value-added phosphate fertilizer can improve fertilizer efficiency and promote crop growth. Although studies have primarily focused on investigating the impact of humic acid’s structure and function on phosphorus availability in humic-acid-added phosphate fertilizers, there is limited research on the regulatory effects of phosphorus fertilizer structure and the synergistic mechanisms involving microorganisms. Therefore, this study aimed to examine the chemical and biological mechanisms underlying the increased efficiency of humic-acid-added phosphate fertilizers by implementing various treatment processes. These processes included physically blending humic acid with phosphate fertilizer (HA+P), chemically synthesizing humic acid phosphate fertilizer (HAP), using commercially available humic acid phosphate fertilizer (SHAP), employing ordinary potassium phosphate fertilizer (P), and implementing a control treatment with no phosphate fertilizer (CK). Investigating the synergistic mechanism of humic-acid-added phosphate fertilizers holds significant importance. The results showed that during the preparation of HAP at high temperature, a new absorption peak appeared at 1101 cm−1, and a new chemical bond -O- was formed. The hydroxyl fracture in humic acid combined with phosphoric acid to form a phosphate ester (P-O-C=O) structure. HAP residues were concentrated on the surface and loaded with more soil minerals. The content of highly active oxygen-containing functional groups—such as aromatic C-O, carboxyl/amide carbon and carbonyl carbon—increased significantly, while the content of alkyl carbon, oxyalkyl carbon, and aromatic carbon decreased. Upon combining humic acid with potassium phosphate, the carboxyl group and calcium ions formed the HA-m-P complex, increasing the content of soluble phosphate (H2PO4−) in the soil by 1.71%. Compared to HA+P treatment, HAP treatment significantly increased the soil’s available P content by 13.8–47.7% (P &lt; 0.05). The plant height, stem diameter, and above-ground biomass of HAP treatment were increased by 21.3%, 15.31%, and 61.02%, respectively, and the total accumulations of N, P, and K nutrient elements were increased by 6.71%, 31.13%, and 41.40%, respectively, compared to the control treatment. The results of high-throughput sequencing showed that the rhizosphere soil of HA+P and HAP treatment was rich in bacterial groups, the soil microbial structure was changed, and the bacterial community diversity was increased under HAP treatment. The number of genes encoding phytase and alkaline phosphatase associated with organophosphorus dissolution increased by 3.23% and 2.90%, respectively, in HAP treatment. Humic acid phosphate fertilizer forms phosphate esters in the process of chemical preparation. After application, the soil’s microbial community structure is changed, and soil enzyme activity related to phosphorus transformation is improved to promote tomatoes’ absorption of soil nutrients, thus promoting tomato plant growth and nutrient accumulation.

H2S Crosstalk in Rhizobia Modulates Essential Nutrient Allocation and Transport in Soybean

Hydrogen sulfide (H2S), a novel gas signaling molecule, plays a crucial role in plant growth and stress response. However, little attention has been devoted to the regulation of H2S on nutrient transport and utilization in legume–rhizobia symbiosis systems. Although we have previously proven that H2S synergized with rhizobia to considerably enhance nitrogen (N) metabolism and remobilization in N-deficient soybeans, it remains uncertain if changes in nutrient absorption, metabolism, and accumulation occur concurrently. Therefore, employing a synergistic treatment of H2S and rhizobia, we examined the dry matter biomass and carbon (C), N, phosphorous (P), and potassium (K) nutrient content in various organs of soybean from blooming to maturity. Firstly, H2S and rhizobia application obviously improved leaf and plant phenotypes and biomass accumulation in different organs during N-deficient soybean development. Second, from flowering to maturity, the contents and stoichiometric ratios of C, N, P, and K in various organs of soybean were changed to variable degrees by H2S and rhizobia. Furthermore, H2S collaborated with rhizobia to significantly affect grain nutrient harvest across soybean growth as well as overall plant nutrient accumulation. Consequently, H2S synergizes with rhizobia to optimize grain harvest quality and nutrient accumulation across the plant by managing the rational allocation and dynamic balance of nutrients in diverse organs, hence boosting soybean development and production.

Effect of rhizobia inoculation and seaweed extract (Ecklonia maxima) application on the growth, symbiotic performance and nutritional content of cowpea (Vigna unguiculata (L.) Walp.)

Research efforts to develop alternatives to chemical-based fertilizers for sustainable crop production has led to renewed interest in beneficial soil microbes such as rhizobia and plant growth promoting biostimulants such as the seaweed (Ecklonia maxima). This study assessed the interactive effect of the co-application of seaweed extract with two Bradyrhizobium strains (Inoculant 1 and Inoculant 2) on the growth, symbiotic performance and nutritional composition of three cowpea (Vigna unguiculata (L.) Walp.) genotypes (IT97K-390-2, Songotra and TVU13998) grown under glasshouse conditions. The response of cowpea to the treatments was genotype dependent, such that the combined application of inoculant 2 plus seaweed extract increased nodule dry matter in genotype Songotra, and together with sole inoculant 2 increased the parameter in genotype IT97K-390-2, just as the inoculation plus seaweed extract treatments increased the parameter in genotype TVU13998 when compared to their respective counterparts receiving other treatments. Sole inoculation or inoculation plus seaweed extract treatments increased shoot dry matter in all varieties (2.0 to 7.2 g.plant-1) relative to the control plants receiving sole nitrate (0.5 to 1.2 g.plant-1), sole seaweed extract (0.3 g.plant-1), nitrate plus seaweed extract (1.2 to 1.6 g.plant-1) or the absolute control (0.2 g.plant-1). Due to N2 fixation in the inoculated plants, their leaf δ15N (-2.66‰ to -1.20‰) were markedly lower (p≤0.001) than values recorded by the control plants (+3.30‰ to +510‰) which had no nodules; consequently, leaf N accumulation was greater in the inoculation-based treatments (41.2 to 258.2 mg.plant-1) relative to the uninoculated controls (1.7 to 24.7 mg.plant-1). In most instances, the sole inoculation and inoculation plus seaweed extract treatments increased leaf photosynthetic rates (except for genotype TVU13998 treated with inoculant 1 + seaweed extract), water use efficiency (δ13C) (except in genotype TVU13998) and the concentrations of macro and micronutrients in leaves (except for K in Songotra treated with inoculant 1 or inoculant 1 + seaweed extract as well as Mn in TVU13998 treated with inoculant 1 among others) of the cowpeas relative to the controls. We highlight the potential benefits of the synergistic interactions between rhizobia and seaweed extract for enhancing plant growth and nutrient accumulation in cowpea leaves.

Combined effect of elevated CO2 and Fe deficiency on common bean metabolism and mineral profile

Abstract Aims Elevated atmospheric CO2 (eCO2) and restricted iron (Fe) supply are known to impact plant growth and nutritional quality of food crops. However, studies aimed at understanding how eCO2 will interact with Fe deficiency are scarce. Changes in the nutritional status of the common bean (Phaseolus vulgaris L.) may significantly impact the nutritional status of populations that rely heavily on this crop. Methods To understand the combined effects of eCO2 and Fe deficiency on mechanisms relevant to plant nutrient uptake and accumulation, common bean plants were grown under Fe sufficiency (Fe+, 20 mM Fe-EDDHA) and Fe deficiency (Fe-, 0 mM Fe-EDDHA) combined with eCO2 (800 ppm) or ambient CO2 (aCO2, 400 ppm) in hydroponics until maturity. Results Elevated CO2, besides stimulating photosynthesis and stomatal closure, highly affected plant Fe metabolism: stimulated root ferric chelate reductase (FCR) activity by 6-fold and downregulated the expression of root FRO1 and IRT1 expressions by about 4-fold. In leaves, citrate and oxalate increased, but ferritin expression decreased by 9-fold. Such changes may have determined the differences on mineral accumulation patterns particularly the lower levels of Fe in roots (62%), leaves (38%) and seeds (50%). The combination of Fe deficiency and eCO2 doubled the effect of a single factor on FCR up-regulation, balanced the internal pH of Fe deficient plants, and resulted in the lowest Fe accumulation in all plant parts. Conclusions These results suggest that eCO2 directly affects the Fe uptake mechanism of common bean plants, decreasing plant Fe content.

Effects of different tillage systems and mowing time on nutrient accumulation and forage nutritive value of Cyperus esculentus.

Revealing the complex relationships between management practices, crop growth, forage nutritive value and soil quality will facilitate the development of more sustainable agricultural and livestock production systems. Cyperus esculentus is known as the king of oil crops and high-quality forage. However, there is little information about the effects of different planting modes {continuous cropping (CC)/rotation cropping (RC)} and initial mowing time on the plant nutrient accumulation and forage nutritive value. Here, in a field experiment, we designed two planting patterns, C. esculentus CC and C. esculentus - wheat RC. The leaves, tubers, roots, and soil samples were collected at three mowing time (on the 78th, 101th, and 124th days after seed sowing). Results revealed that RC significantly increased the total nitrogen (TN) and potassium (TK) content of the tuber (p<0.05), while significantly decreased the TN, total phosphorus (TP), crude protein (CP), and acid detergent fiber (ADF) contents of the leaves. Under the CC pattern, the TN, TP, and TK content of roots increased significantly on the 78th days after seed sowing, and the TK content of tubers increased significantly. Under the RC pattern, the ether extract (EE) content of tubers increased significantly on the 124th days after seed sowing, while the CP and TN content of leaves decreased significantly. Correlation analysis showed that soil pH was negatively correlated with TN content in leaves, tubers, and roots. The structural equation model showed that the soil pH directly affected the plant nutrient accumulation and forage nutritive value (β=0.68) via regulating these properties by changing soil available nutrients, anions, cations, and total nutrients. Overall, we propose that RC for C. esculentus-wheat is should not be recommended to maximize tubers and forage yield.

Effects of Valine and Urea on Carbon and Nitrogen Accumulation and Lignin Content in Peach Trees.

Nitrogen availability and uptake levels can affect nutrient accumulation in plants. In this study, the effects of valine and urea supplementation on the growth of new shoots, lignin content, and carbon and the nitrogen metabolism of 'Ruiguang 39/peach' were investigated. Relative to fertilization with urea, the application of valine inhibited shoot longitudinal growth, reduced the number of secondary shoots in autumn, and increased the degree of shoot lignification. The application of valine also increased the protein level of sucrose synthase (SS) and sucrose phosphate synthase (SPS) in plant leaves, phloem, and xylem, thereby increasing the soluble sugar and starch content. It also resulted in an increase in nitrate reductase (NR), glutamine synthase (GS), and glutamate synthase (GOGAT) protein levels, with an increase in plant contents of ammonium nitrogen, nitrate nitrogen, and soluble proteins. Although urea application increased the protein level of carbon- and nitrogen-metabolizing enzymes, the increase in plant growth reduced the overall nutrient accumulation and lignin content per unit tree mass. In conclusion, the application of valine has a positive effect on increasing the accumulation of carbon and nitrogen nutrients in peach trees and increasing the lignin content.