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Search Results (1,873)

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24 pages, 1487 KiB  
Article
A Hybrid Model for Soybean Yield Prediction Integrating Convolutional Neural Networks, Recurrent Neural Networks, and Graph Convolutional Networks
by Vikram S. Ingole, U. A. Kshirsagar, Vikash Singh, Manish Varun Yadav, Bipin Krishna and Roshan Kumar
Computation 2025, 13(1), 4; https://doi.org/10.3390/computation13010004 (registering DOI) - 27 Dec 2024
Abstract
Soybean yield prediction is one of the most critical activities for increasing agricultural productivity and ensuring food security. Traditional models often underestimate yields because of limitations associated with single data sources and simplistic model architectures. These prevent complex, multifaceted factors influencing crop growth [...] Read more.
Soybean yield prediction is one of the most critical activities for increasing agricultural productivity and ensuring food security. Traditional models often underestimate yields because of limitations associated with single data sources and simplistic model architectures. These prevent complex, multifaceted factors influencing crop growth and yield from being captured. In this line, this work fuses multi-source data—satellite imagery, weather data, and soil properties—through the approach of multi-modal fusion using Convolutional Neural Networks and Recurrent Neural Networks. While satellite imagery provides information on spatial data regarding crop health, weather data provides temporal insights, and the soil properties provide important fertility information. Fusing these heterogeneous data sources embeds an overall understanding of yield-determining factors in the model, decreasing the RMSE by 15% and improving R2 by 20% over single-source models. We further push the frontier of feature engineering by using Temporal Convolutional Networks (TCNs) and Graph Convolutional Networks (GCNs) to capture time series trends, geographic and topological information, and pest/disease incidence. TCNs can capture long-range temporal dependencies well, while the GCN model has complex spatial relationships and enhanced the features for making yield predictions. This increases the prediction accuracy by 10% and boosts the F1 score for low-yield area identification by 5%. Additionally, we introduce other improved model architectures: a custom UNet with attention mechanisms, Heterogeneous Graph Neural Networks (HGNNs), and Variational Auto-encoders. The attention mechanism enables more effective spatial feature encoding by focusing on critical image regions, while the HGNN captures interaction patterns that are complex between diverse data types. Finally, VAEs can generate robust feature representation. Such state-of-the-art architectures could then achieve an MAE improvement of 12%, while R2 for yield prediction improves by 25%. In this paper, the state of the art in yield prediction has been advanced due to the employment of multi-source data fusion, sophisticated feature engineering, and advanced neural network architectures. This provides a more accurate and reliable soybean yield forecast. Thus, the fusion of Convolutional Neural Networks with Recurrent Neural Networks and Graph Networks enhances the efficiency of the detection process. Full article
19 pages, 1684 KiB  
Article
Improving Soybean Germination and Nodule Development with Nitric Oxide-Releasing Polymeric Nanoparticles
by Ana Cristina Preisler, Giovanna Camargo do Carmo, Rafael Caetano da Silva, Ana Luisa de Oliveira Simões, Juliana de Carvalho Izidoro, Joana Claudio Pieretti, Roberta Albino dos Reis, André Luiz Floriano Jacob, Amedea Barozzi Seabra and Halley Caixeta Oliveira
Plants 2025, 14(1), 17; https://doi.org/10.3390/plants14010017 - 25 Dec 2024
Viewed by 11
Abstract
Nitric oxide (NO) is a multifunctional signaling molecule in plants, playing key roles in germination, microbial symbiosis, and nodule formation. However, its instability requires innovative approaches, such as using nanoencapsulated NO donors, to prolong its effects. This study evaluated the impact of treating [...] Read more.
Nitric oxide (NO) is a multifunctional signaling molecule in plants, playing key roles in germination, microbial symbiosis, and nodule formation. However, its instability requires innovative approaches, such as using nanoencapsulated NO donors, to prolong its effects. This study evaluated the impact of treating soybean (Glycine max) seeds with the NO donor S-nitrosoglutathione (GSNO), encapsulated in polymeric nanoparticles, on the germination, nodulation, and plant growth. Seeds were treated with free GSNO, chitosan nanoparticles with/without NO (NP CS-GSNO/NP CS-GSH, where GSH is glutathione, the NO donor precursor), and alginate nanoparticles with/without NO (NP Al-GSNO/NP Al-GSH). Chitosan nanoparticles (positive zeta potential) were smaller and released NO faster compared with alginate nanoparticles (negative zeta potential). The seed treatment with NP CS-GSNO (1 mM, related to GSNO concentration) significantly improved germination percentage, root length, number of secondary roots, and dry root mass of soybean compared with the control. Conversely, NP CS-GSH resulted in decreased root and shoot length. NP Al-GSNO enhanced shoot dry mass and increased the number of secondary roots by approximately threefold at the highest concentrations. NP CS-GSNO, NP Al-GSNO, and NP Al-GSH increased S-nitrosothiol levels in the roots by approximately fourfold compared with the control. However, NP CS-GSNO was the only treatment that increased the nodule dry mass of soybean plants. Therefore, our results indicate the potential of chitosan nanoparticles to improve the application of NO donors in soybean seeds. Full article
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<p>Kinetic curves of NO release from chitosan and alginate nanoparticles loaded with S-nitrosoglutathione (NP CS-GSNO and NP Al-GSNO). Data are expressed as mean ± standard error (n = 3).</p>
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<p>Germination rate (%) of <span class="html-italic">Glycine max</span> (L.) Merr. seeds following treatment with chitosan nanoparticles with and without NO (NP CS-GSNO and NP CS-GSH), alginate nanoparticles without NO (NP Al-GSH), and free GSNO. (<b>A</b>–<b>C</b>) Regression curves were fitted for concentrations within each formulation (<span class="html-italic">p</span> &lt; 0.05), namely NP CS-GSNO, NP CS-GSH, and free GSNO, respectively. The values shown represent the mean of four replicates. (<b>D</b>) Different letters above the bars indicate different means based on ANOVA followed by the Scott–Knott test for the NP Al-GSH treatment (<span class="html-italic">p</span> ≤ 0.05). Data are expressed as mean ± standard error (n = 4).</p>
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<p>Root length (cm) of <span class="html-italic">Glycine max</span> (L.) Merr. seedlings following seed treatment with chitosan nanoparticles with and without NO (NP CS-GSNO and NP CS-GSH), alginate nanoparticles without NO (NP Al-GSH), and free GSNO. The control treatment (zero concentration) refers to seeds treated with distilled water only. The values shown represent the mean of four replicates. Regression curves were fitted for concentrations within each formulation (<span class="html-italic">p</span> ≤ 0.05).</p>
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<p>Shoot length (cm) of <span class="html-italic">Glycine max</span> (L.) Merr. seedlings following seed treatment with chitosan nanoparticles with and without NO (NP CS-GSNO and NP CS-GSH) and alginate nanoparticles without NO (NP Al-GSH). The control treatment (zero concentration) refers to seeds treated with distilled water only. The values shown represent the mean (n = 4). Regression curves were fitted for concentrations within each formulation (<span class="html-italic">p</span> ≤ 0.05).</p>
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<p>Number of secondary roots (<b>A</b>–<b>D</b>), root dry weight (<b>E</b>), and shoot dry weight (<b>F</b>) of <span class="html-italic">Glycine max</span> (L.) Merr seedlings following seed treatment with chitosan nanoparticles with and without NO (NP CS-GSNO and NP CS-GSH), alginate nanoparticles with NO (NP Al-GSNO), and free GSNO. The control treatment (zero) refers to seeds treated with distilled water only. The values shown represent the mean of four replicates. Regression curves were fitted for concentrations within each formulation, and the resulting models were statistically significant (<span class="html-italic">p</span> ≤ 0.05).</p>
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<p>Water content (%) in <span class="html-italic">Glycine max</span> (L.) Merr. seeds at increasing time intervals following treatment with chitosan nanoparticles with and without NO (NP CS-GSNO and NP CS-GSH), alginate nanoparticles with and without NO (NP Al-GSNO and NP Al-GSH), free GSNO, and water (control). A concentration of 1.0 mM of GSNO/GSH was used in this experiment. The values shown represent the mean of four replicates. A regression curve was fitted for each treatment group over time (<span class="html-italic">p</span> ≤ 0.05).</p>
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<p>Effect of seed treatment with chitosan nanoparticles with and without NO (NP CS-GSNO and NP CS-GSH), alginate nanoparticles with and without NO (NP Al-GSNO and NP Al-GSH), free GSNO, and distilled water (control) on the S-nitrosothiol (RSNO) content in roots (<b>A</b>) and leaves (<b>B</b>) of soybean seedlings collected after 8 days. A concentration of 1.0 mM of GSNO/GSH was used in this experiment. The values are the mean ± standard error (n = 4). The presence of different letters above the bars indicates that the means are significantly different, as determined by ANOVA followed by the Scott–Knott test (<span class="html-italic">p</span> ≤ 0.05).</p>
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<p>Effect of seed treatment with chitosan nanoparticles with and without NO (NP CS-GSNO and NP CS-GSH), alginate nanoparticles with and without NO (NP Al-GSNO and NP Al-GSH), free GSNO, and water (control) on (<b>A</b>) stomatal conductance (mol m<sup>−2</sup> s<sup>−1</sup>), (<b>B</b>) transpiration (mmol m<sup>−2</sup> s<sup>−1</sup>), (<b>C</b>) internal/ambient CO₂ concentration (<span class="html-italic">C</span><sub>i</sub>/<span class="html-italic">C</span><sub>a</sub>), (<b>D</b>) net photosynthesis (μmol m<sup>−2</sup> s<sup>−1</sup>), (<b>E</b>) root dry mass, and (<b>F</b>) nodule dry mass of soybean plants after 35 days of growth in a greenhouse. The values are the mean ± standard error (n = 6). Columns with different letters indicate statistically significant differences (<span class="html-italic">p</span> ≤ 0.05) based on ANOVA followed by the Scott–Knott test.</p>
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35 pages, 4420 KiB  
Review
Application of Foundry Wastes in Eco-Efficient Construction Materials: A Review
by Ingried Aguiar, Sandra Cunha and José Aguiar
Appl. Sci. 2025, 15(1), 10; https://doi.org/10.3390/app15010010 - 24 Dec 2024
Viewed by 72
Abstract
Foundries generate millions of tons of waste annually, posing a challenge to companies that generate it and to the environment due to landfill disposal. Meanwhile, the construction sector contributes heavily to global resource consumption. Adopting a circular economy approach by integrating foundry wastes [...] Read more.
Foundries generate millions of tons of waste annually, posing a challenge to companies that generate it and to the environment due to landfill disposal. Meanwhile, the construction sector contributes heavily to global resource consumption. Adopting a circular economy approach by integrating foundry wastes into construction materials offers two main benefits: reducing landfill accumulation and preserving natural reserves of raw materials while also supporting the UN’s Sustainable Development Goals. This paper presents a review of recent studies on the use of foundry wastes in construction materials and provides an overview of the foundry industry, including its background, waste management, and statistics. Furthermore, a bibliometric analysis highlights the evolution of research in this area, showing a 182% increase in publications over the last 10 years. Key findings include that waste foundry sand is the most widely utilized foundry waste in construction materials, while ceramic mold shells and paraffin waxes remain underexplored. Concrete is the primary material incorporating foundry waste. The incorporation of foundry waste into construction materials improves durability and mechanical strength when used in appropriate proportions. The replacement content can reach up to 100%. These results underscore the feasibility of foundry waste as a sustainable alternative in construction, building circularity, and reducing environmental impact. Full article
(This article belongs to the Special Issue Recent Progress and Future Directions in Building Materials)
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<p>Topics addressed in the review.</p>
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<p>Top 10 foundry producers in 2019 (data from World Foundry Organization [<a href="#B2-applsci-15-00010" class="html-bibr">2</a>]).</p>
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<p>Investment casting process.</p>
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<p>Sand casting process.</p>
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<p>Trend of publications on foundry wastes over time (1986–2023).</p>
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<p>Top 10 countries by number of publications on foundry waste.</p>
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<p>Research areas with the most publications on foundry waste.</p>
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<p>Alignment of foundry waste research with United Nations Sustainable Development Goals.</p>
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<p>Keywords co-occurrence network in foundry waste research.</p>
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<p>Content percentage of different residues in construction materials.</p>
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<p>Content percentage of WFS in concrete and bricks.</p>
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<p>Content percentage of slags in SCM and concrete.</p>
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<p>Content percentage of EAFD in SCM, concrete, and mortars.</p>
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<p>Content percentage of CMC in SCM, concrete, and mortars.</p>
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17 pages, 267 KiB  
Article
Race, Labour, Law, and Capitalism: The Case of US Naturalization and Immigration Law from 1790 to 1965
by Anita C. Butera
Genealogy 2024, 8(4), 150; https://doi.org/10.3390/genealogy8040150 - 23 Dec 2024
Viewed by 335
Abstract
The relationship between race and labour has been analyzed from different theoretical perspectives. Some have focused on the connection between race and the extraction of surplus from people of colour, Black people in particular Others have integrated race within the context of capitalism [...] Read more.
The relationship between race and labour has been analyzed from different theoretical perspectives. Some have focused on the connection between race and the extraction of surplus from people of colour, Black people in particular Others have integrated race within the context of capitalism as a world system or have focused on race as a category of exploitation that defines both feudalism and capitalism that is essential for the survival of capitalism. This paper argues that, to understand the relation between race and labour, race must be understood as legal status. Race is a set of legal rights given to or withheld from workers because of loosely defined and arbitrarily selected physical characteristics. By assigning different rights to workers based on race, their labour is racialized, and race becomes an important element to the functioning of capitalism because it defines the value of labour. As legal status, race is defined and enforced by the state. In addition, this paper analyses the development of US naturalization and immigration law from 1790 to 1964, selected as an example of the process of racialization of labour. Specifically, it discusses the process of racialization of labour by connecting it to the concept of Westphalian sovereignty and the differentiation between natural and political rights. It concludes that, between 1790 and 1965, race supported the development and stability of US capitalism through the development of three distinct highly racialized labour markets: the Northeast, mostly defined by the racialization of European workers along a scale of whiteness; the West, determined by the racialization of Asian and, later, Latino workers; and the South, characterized by the racialization of African Americans and selected southern European workers, Italians in particular, and, later, Latino workers. These three markets operated in symbiosis with each other and featured different forms of racialization of labour, as defined by different forms of enforcement of race as legal status, ranging from the Chinese Exclusion Act of 1882 on the West Coast to the Jim Crow System that emerged in the southern states after the Compromise of 1877 and the Immigration Act of 1924 that dramatically limited immigration from southern and Eastern Europe. Full article
15 pages, 4947 KiB  
Technical Note
Deep-Transfer-Learning Strategies for Crop Yield Prediction Using Climate Records and Satellite Image Time-Series Data
by Abhasha Joshi, Biswajeet Pradhan, Subrata Chakraborty, Renuganth Varatharajoo, Shilpa Gite and Abdullah Alamri
Remote Sens. 2024, 16(24), 4804; https://doi.org/10.3390/rs16244804 - 23 Dec 2024
Viewed by 180
Abstract
The timely and reliable prediction of crop yields on a larger scale is crucial for ensuring a stable food supply and food security. In the last few years, many studies have demonstrated that deep learning can offer reliable solutions for crop yield prediction. [...] Read more.
The timely and reliable prediction of crop yields on a larger scale is crucial for ensuring a stable food supply and food security. In the last few years, many studies have demonstrated that deep learning can offer reliable solutions for crop yield prediction. However, a key challenge in applying deep-learning models to crop yield prediction is their reliance on extensive training data, which are often lacking in many parts of the world. To address this challenge, this study introduces TrAdaBoost.R2, along with fine-tuning and domain-adversarial neural network deep-transfer-learning strategies, for predicting the winter wheat yield across diverse climatic zones in the USA. All methods used the bidirectional LSTM (BiLSTM) architecture to leverage its sequential feature extraction capabilities. The proposed transfer-learning approaches outperformed the baseline deep-learning model, with mean absolute error reductions ranging from 9% to 28%, demonstrating the effectiveness of these methods. Furthermore, the results demonstrate that the semi-supervised transfer-learning approach using the two-stage version of TrAdaBoost.R2 and fine-tuning achieved a superior performance compared to the domain-adversarial neural network and standard TrAdaBoost.R2. Additionally, the study offers insights for improving the accuracy and generalizability of crop yield prediction models in diverse agricultural landscapes across different regions. Full article
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<p>Study area showing local and transfer location. The colored areas on the map denote the study counties.</p>
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<p>Transfer learning for crop yield prediction. For unsupervised transfer learning, we assume there are no yield data in the target area, and, for semi-supervised scenarios, limited historical yield data are available in the target location.</p>
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<p>Architecture of the base BiLSTM model.</p>
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<p>Comparison of crop yields between transfer and local areas from 2008 to 2020.</p>
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<p>Distribution of data in local and transfer area. (<b>a</b>) T-SNE plot of input variables, and (<b>b</b>) histograms showing the winter wheat yield distribution of counties in the local area and transfer area from 2008 to 2020.</p>
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<p>The absolute error maps of (<b>a</b>) DANN, (<b>b</b>) TrAdaBoost.R2, (<b>c</b>) two-stage TrAdaBoost.R2, and (<b>d</b>) fine-tuning-based transfer models averaged over the years 2019 and 2020.</p>
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<p>Scatterplot presents the relationship between reported and predicted yields across four transfer learning techniques: (<b>a</b>) two-stage TrAdaBoost.R2, (<b>b</b>) TrAdaBoost.R2, (<b>c</b>) fine tuning, and (<b>d</b>) DANN over testing years (1) 2019 and (2) 2020.</p>
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20 pages, 5108 KiB  
Review
Physio-Biochemical Mechanisms of Arbuscular Mycorrhizal Fungi Enhancing Plant Resistance to Abiotic Stress
by Dandi Sun, Xiaoqian Shang, Hanwen Cao, Soon-Jae Lee, Li Wang, Yantai Gan and Shoujiang Feng
Agriculture 2024, 14(12), 2361; https://doi.org/10.3390/agriculture14122361 - 22 Dec 2024
Viewed by 584
Abstract
Agricultural innovations in the past decades have addressed the mounting challenges of food, feed, and biofuel security. However, the overreliance on synthetic fertilizers and pesticides in agriculture has exacerbated biodiversity loss, environmental degradation, and soil health deterioration. Leveraging beneficial soil microorganisms, particularly arbuscular [...] Read more.
Agricultural innovations in the past decades have addressed the mounting challenges of food, feed, and biofuel security. However, the overreliance on synthetic fertilizers and pesticides in agriculture has exacerbated biodiversity loss, environmental degradation, and soil health deterioration. Leveraging beneficial soil microorganisms, particularly arbuscular mycorrhizal (AM) fungi, offers an emerging solution to reduce dependence on synthetic agrochemicals in crop production. Understanding the mechanisms can help maximize AM fungi’s benefits in response to abiotic stresses. In this review, we explore the main mechanisms of AM fungi in promoting soil nutrient mobilization and uptake, increasing water absorption, stimulating antioxidative enzyme activities, altering morphophysiological structure, and performing hormonal crosstalk when mycorrhizal plants face an abiotic stressor. Also, we highlight the necessity of innovating practical ways to cope with variations in AM fungal species, diversity in host species, soil, and environmental conditions, as well as difficulties in mass multiplication for commercialization. Understanding the mechanisms and limitations may help explore the biofertilizer potential of AM fungal symbiosis, benefiting crop production while addressing the environment and soil health issues. Full article
(This article belongs to the Special Issue Mycorrhizal Symbiosis in Agricultural Production)
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<p>Arbuscular mycorrhizal fungi colonize root cortical cells through germinating spores, forming hyphal branches, and developing an extraradical mycelium that forms an extensive network in the soil. The initial colonization involves hyphal contact on root surfaces through the outer cortex, the formation of a dense hyphal sheath surrounding the colonized surface (ectomycorrhizas), or the penetration of fungal hyphae into host tissues (endomycorrhizas), establishing the mutual-benefit symbiosis.</p>
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<p>Arbuscular mycorrhizal fungi colonize roots to form a mutually beneficial symbiosis that induces upward nutrient flow and downward carbon flow in the plant–soil–rhizosphere continuum. AM fungi require C sources from host plants for spore propagation and extraradical hyphal development. In contrast, AM fungi produce a network of extraradical mycelium, spreading from host roots into the surrounding soil and establishing belowground interconnections to supply plant-required nutrients like P, N, Zn, Cu, and Mg. These functioning features occur in the hyphosphere with hyphal exudates and other enzymes involved in the nutrient flow process. While the plant–AM fungi symbiotic relationship is a nutrient trade-off, the mutually beneficial association can enhance plant ability to acquire essential minerals, which is crucial for enhancing soil health through the contribution of hyphosphere microbiomes to nutrient cycling, carbon sequestration, and soil aggregation.</p>
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<p>Physiological mechanisms of osmotic adjustment at the (a) cellular, (b) whole plant, and (c) system scale in a typical dryland agroecosystem. It is typical that a water–carbon linear correlation occurs in plant scale, whereas at the ecosystem scale water–carbon correlation becomes nonlinear. Abbreviations: intercellular CO<sub>2</sub> concentration (ci), ambient stomatal CO<sub>2</sub> concentration (ca), conductance (gs), seasonal air temperature (Ta), relative humidity (Rh), vapor pressure deficit (VPD), soil water content (SWC), leaf area index (LAI), water use efficiency (WUE), and seasonal total evapotranspiration (ET), transpiration (T), soil evaporation (E), net ecosystem exchange (NEE), and gross primary productivity (GPP).</p>
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<p>Arbuscular mycorrhizal fungi enhance plant resistance to abiotic stress, which is through increasing photosynthesis, improving root-to-stem ratio, increasing nutrient uptake, increasing root surface areas, promoting metabolisms, balancing hormones, stimulating enzyme activities, and interacting with other microbiomes in the hyphosphere.</p>
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13 pages, 853 KiB  
Article
Impact of COVID-19 on Consumer Behavior in Home Gardening
by Pulkit Marwah, Qiqi Chen, Yijie Hou, Yu Yvette Zhang, Hongmin Qin and Mengmeng Gu
Horticulturae 2024, 10(12), 1373; https://doi.org/10.3390/horticulturae10121373 - 20 Dec 2024
Viewed by 359
Abstract
The COVID-19 pandemic has reshaped various aspects of life, influencing consumer behaviors and economic activities worldwide. This paper delves into the shifts in consumer preferences and shopping patterns for gardening products and services during and after the pandemic era. Through nationwide online surveys [...] Read more.
The COVID-19 pandemic has reshaped various aspects of life, influencing consumer behaviors and economic activities worldwide. This paper delves into the shifts in consumer preferences and shopping patterns for gardening products and services during and after the pandemic era. Through nationwide online surveys conducted from 2020 to 2022, we analyze changes in time spent and expenses on gardening and identify key demographic and pandemic-related factors influencing these behaviors during the pandemic era. We employed both generalized and standard ordered logistic regression models to assess the impact of various variables on the ordinal dependent variable. The findings reveal a significant surge in both time spending on home gardening activities and money invested in gardening products and services, especially among individuals who considered gardening beneficial for well-being and as a family activity. Notably, the preference for online shopping and mail delivery for gardening supplies emerged as a prominent trend during the pandemic, accompanied by a significant increase in the purchase of fruit plants, vegetable plants, and seeds, indicating that primary motivation for gardening was self-food consumption. These insights provide valuable guidance for businesses in the green industry, informing production, marketing practices, and economic recovery efforts post-COVID-19. Full article
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<p>Changes in time spent on home gardening compared to the same period of last year.</p>
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<p>Changes in expenses spent on gardening compared to the same period of last year.</p>
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<p>Preference of purchasing outlets with and without pandemic.</p>
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<p>Changes in consumers’ expenses on gardening products from 2020 to 2022.</p>
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<p>Changes in consumers’ expenses on types of plants from 2020 to 2022.</p>
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18 pages, 7906 KiB  
Review
Invasive Characteristics of Robinia pseudoacacia and Its Impacts on Species Diversity
by Hisashi Kato-Noguchi and Midori Kato
Diversity 2024, 16(12), 773; https://doi.org/10.3390/d16120773 - 19 Dec 2024
Viewed by 402
Abstract
Robinia pseudoacacia is native to North America and has been introduced into many other countries in Europe, South and South East Asia, South America, Africa, and Oceania. The species has been planted intensively in a large area of these countries because of its [...] Read more.
Robinia pseudoacacia is native to North America and has been introduced into many other countries in Europe, South and South East Asia, South America, Africa, and Oceania. The species has been planted intensively in a large area of these countries because of its ornamental and economic values. However, R. pseudoacacia often infests unintended places, including protected areas, and causes significant ecological impacts. The species is now listed as one of the harmful invasive plant species. The characteristics of its life-history, such as the high growth and reproduction rate and adaptive ability to various environmental conditions, may contribute to the invasiveness of the species. The defense ability against natural enemies such as pathogenic fungi and herbivores and its allelopathic potential against the competitive plant species may also contribute to its invasiveness. The R. pseudoacacia infestation alters the ecological functions of the plant community, including the soil microbe community, and reduces the abundance and diversity of the native plant species, including vertebrates and invertebrates in the introduced ranges. R. pseudoacacia is a shade intolerant and early successional tree species and is replaced by larger and more shade tolerant tree species in the native ranges, while plant succession seems not to occur always in the introduced ranges across the different ages of R. pseudoacacia stands. Several other review articles have summarized the afforestation, utilization, biology, and management of the species, but this is the first review focusing on the invasive mechanism of R. pseudoacacia and its impacts on species diversity. Full article
(This article belongs to the Special Issue Plant Diversity Hotspots in the 2020s)
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Graphical abstract

Graphical abstract
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<p><span class="html-italic">Robinia pseudoacacia</span>. Leaves, infestation and mature tree.</p>
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<p><span class="html-italic">Robinia pseudoacacia</span>. Fruiting stage and mature pods.</p>
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<p>Toxic substance of <span class="html-italic">R. pseudoacacia</span>, robinin.</p>
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<p>Allelochemicals of <span class="html-italic">R. pseudoacacia.</span> 1: gentisic acid, 2: vanillic acid, 3: syringic acid, 4: gallic acid, 5: hydroxybenzoic acid, 6: caffeic acid, 7: coumaric acid, 8: ferulic acid, 9: robinetin, 10: myricetin, 11: quercetin, 12: catechin.</p>
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<p>Invasive characteristics and impacts of <span class="html-italic">Robinia pseudoacacia</span>.</p>
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23 pages, 749 KiB  
Review
Mechanisms of Heavy Metal Tolerance in Bacteria: A Review
by Nnabueze Darlington Nnaji, Chukwudi U Anyanwu, Taghi Miri and Helen Onyeaka
Sustainability 2024, 16(24), 11124; https://doi.org/10.3390/su162411124 - 18 Dec 2024
Viewed by 342
Abstract
Heavy metal pollution from industrial activities and poor waste disposal poses significant environmental and health threats to humans and animals. This calls for sustainable approaches to the cleanup of heavy metals. This review explores metal tolerance mechanisms of bacteria such as the formation [...] Read more.
Heavy metal pollution from industrial activities and poor waste disposal poses significant environmental and health threats to humans and animals. This calls for sustainable approaches to the cleanup of heavy metals. This review explores metal tolerance mechanisms of bacteria such as the formation of biofilms, efflux systems, and enzymatic detoxification. These mechanisms allow bacteria communities to adapt and survive in contaminated environments. These adaptations are enhanced by mutations in the bacteria genes and by horizontal gene transfers, enabling bacteria species to survive under environmental stress while simultaneously contributing to nutrient cycling and the decomposition of organic matter. This review further explores the symbiotic interactions between bacteria, plants, and animals. These relationships enhance the metal tolerance ability of the different living organisms involved and are also very important in the bioremediation and phytoremediation of heavy metals. Plant growth-promoting rhizobacteria, Rhizobium, and Bacillus species are very important contributors to phytoremediation; they improve heavy metal uptake, improve the growth of roots, and plants resilience to stress. Moreover, this review highlights the importance of genetically engineered bacteria in closed-loop systems for optimized metal recovery. This offers environmentally friendly and sustainable options to the traditional remediation methods. Engineered Cupriavidus metallidurans CH34 and Pseudomonas putida strain 15420352 overexpressing metallothioneins have shown enhanced metal-binding capabilities, which makes them very effective in the treatment of industrial wastewaters and in biosorption applications. The use of engineered bacteria for the cleanup of heavy metals in closed-loop systems promotes the idea of a circular economy by recycling metals, thus reducing environmental waste. Multidisciplinary research that integrates synthetic biology, microbial ecology, and environmental science is very important for the advancement of metal bioremediation technologies. This review’s analysis on bacterial metal tolerance, symbiosis, and bioengineering strategies offers a pathway to effective bioremediation options, for the reclamation of heavy metal-polluted environments while promoting sustainable environmental practices. Full article
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<p>Bacterial tolerance mechanisms to heavy metals. Adapted from Thai et al. [<a href="#B64-sustainability-16-11124" class="html-bibr">64</a>].</p>
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26 pages, 4387 KiB  
Article
Differences in Perspectives Between Experts and Residents on Living Heritage: A Study of Traditional Chinese Villages in the Luzhong Region
by Xiaofeng Shi, Beau B. Beza, Chunlu Liu, Binglu Wu and Ning Qiu
Buildings 2024, 14(12), 4022; https://doi.org/10.3390/buildings14124022 - 18 Dec 2024
Viewed by 270
Abstract
The differences in the heritage perspectives of key stakeholders form an indispensable basis for formulating appropriate conservation strategies for living heritage. However, in existing practices, the differences in heritage perspectives between experts and local residents, who are both key stakeholders, often arise from [...] Read more.
The differences in the heritage perspectives of key stakeholders form an indispensable basis for formulating appropriate conservation strategies for living heritage. However, in existing practices, the differences in heritage perspectives between experts and local residents, who are both key stakeholders, often arise from expert experiences rather than being accurately measured. This study regarded traditional Chinese villages in the Luzhong region as a living heritage case for investigation and quantified such differences. Initially, this study provided a comprehensive description of living heritage using four dimensions: heritage value, heritage attributes, heritage composition, and heritage characteristics. Subsequently, a questionnaire tailored to traditional Chinese villages was developed, and a survey was conducted in the sample villages, resulting in 394 valid responses. According to the Pearson chi-square tests, the findings suggest that expert and local resident respondents showed slight disagreement regarding heritage attributes (x2 = 5.619); however, they presented varying degrees of differences concerning heritage value (x2 = 36.066) and heritage composition (x2 = 36.525), accompanied by distinct preferences. Furthermore, significant discrepancies were evident regarding heritage characteristics. Regarding the four aspects of heritage characteristics, there was a slight difference in the symbiosis of heritage elements (x2 = 3.877) but significant differences in the local resident as a heritage element (x2 = 36.525); there was a minor difference in vitality and continuity (x2 = 3.709) but a rare contradiction for integrity (x2 = 47.649). This study can furnish case data support for surmounting the drawbacks of blindly relying on expert experiences, particularly by integrating local perspectives to safeguard living heritage globally. Full article
(This article belongs to the Section Architectural Design, Urban Science, and Real Estate)
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<p>The constructure of describing cultural heritage.</p>
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<p>The description of living heritage.</p>
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<p>The flowchart of this investigation.</p>
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<p>Location diagram of the sample villages.</p>
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20 pages, 1434 KiB  
Review
Antioxidant Responses and Redox Regulation Within Plant-Beneficial Microbe Interaction
by María-Cruz González, Thomas Roitsch and Chandana Pandey
Antioxidants 2024, 13(12), 1553; https://doi.org/10.3390/antiox13121553 - 18 Dec 2024
Viewed by 396
Abstract
The increase in extreme climate events associated with global warming is a great menace to crop productivity nowadays. In addition to abiotic stresses, warmer conditions favor the spread of infectious diseases affecting plant performance. Within this context, beneficial microbes constitute a sustainable alternative [...] Read more.
The increase in extreme climate events associated with global warming is a great menace to crop productivity nowadays. In addition to abiotic stresses, warmer conditions favor the spread of infectious diseases affecting plant performance. Within this context, beneficial microbes constitute a sustainable alternative for the mitigation of the effects of climate change on plant growth and productivity. Used as biostimulants to improve plant growth, they also increase plant resistance to abiotic and biotic stresses through the generation of a primed status in the plant, leading to a better and faster response to stress. In this review, we have focused on the importance of a balanced redox status for the adequate performance of the plant and revisited the different antioxidant mechanisms supporting the biocontrol effect of beneficial microbes through the adjustment of the levels of reactive oxygen species (ROS). In addition, the different tools for the analysis of antioxidant responses and redox regulation have been evaluated. The importance of redox regulation in the activation of the immune responses through different mechanisms, such as transcriptional regulation, retrograde signaling, and post-translational modification of proteins, emerges as an important research goal for understanding the biocontrol activity of the beneficial microbes. Full article
(This article belongs to the Section Antioxidant Enzyme Systems)
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<p>Reactive oxygen species (ROS) production, ROS enzymatic detoxification, and redox regulation within the chloroplast. In the chloroplast, ROS are produced due to energy transference at PSII (singlet oxygen, <sup>1</sup>O<sub>2</sub>) and electron transference to oxygen in PSI (superoxide anion, O<sub>2</sub><sup>−</sup>). Superoxide anion is dismutated to hydrogen peroxide, which is in turn reduced by APX and ASC/GSH, through the ASC-GSH cycle. APX uses ascorbate to reduce hydrogen peroxide, generating monodehydroascorbate (MDA), which can be in turn reduced by monodehydroascorbate reductase (MDAR) using reducing equivalents. Spontaneous dismutation of MDA generates dehydroascorbate (DHA). Regeneration of ASC is catalyzed by dehydroascorbate reductase (DHAR) using GSH as source of reducing equivalents. GSH reduction is driven by glutathione reductase (GR). Redox regulation (represented by green arrows) in the chloroplast is dependent on disulfide–dithiol exchange of target proteins by Trxs, which are in turn reduced by FTR using Fd as source of reducing power. NTRC uses NADPH generated by FNR for the reduction of 2-Cys PRX, leading to hydrogen peroxide reduction. Whereas Trxs can also reduce 2-Cys-PRX, although less efficiently than NTRC, direct involvement of NTRC on protein reduction remains to be determined. Dashed lines indicate not yet established direct interaction. Protein complexes were schematized for a better understanding. Leaves image: <a href="https://www.flaticon.com/free-icon/leaves_1635265?term=leaves&amp;page=1&amp;position=4&amp;origin=search&amp;related_id=1635265" target="_blank">https://www.flaticon.com/free-icon/leaves_1635265?term=leaves&amp;page=1&amp;position=4&amp;origin=search&amp;related_id=1635265</a> (accessed on 16 September 2024).</p>
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<p>Effect of Plant-Growth-Promoting Rhizobacteria (PGPRs), Nitrogen-fixing bacteria, and Mychorriza on plant growth and resistance to abiotic and biotic stresses. The inoculation of the plant with microbes, which can be attracted by root exudates, alters nutrient availability, thus promoting plant growth and development. In addition, the microbes generate a primed state in the plants leading to enhanced resistance towards biotic and abiotic stresses. This effect is dependent on the control of ROS levels, through activation of enzymatic and non-enzymatic antioxidant mechanisms, and also on redox regulation mediated by Trxs, NTRC, and 2-Cys PRX. At the genome level, post-transcriptional modification of Cys alters subcellular localization of some TFs and results in the regulation of gene expression. PTMs of Cys residues, mediated directly or indirectly by ROS, also underlie operational retrograde signaling, allowing the adjustment of protein levels. Epigenetic modifications, such as DNA methylation, are emerging as key components in plant response to biotic stress and transgenerational priming, underlying the biocontrol activity of some microbes. At the proteome level, regulation of protein structure and/or activity through PTMs constitutes an additional layer of regulation. Dithiol–disulfide exchange of Cys residues results in the activation of key enzymes in photosynthesis. Some other PTMs, such as S-nitrosylation and glutathionylation, have been associated with gene transcription regulation and plant immunity. Figure was created in BioRender (<a href="https://BioRender.com/z93q802" target="_blank">https://BioRender.com/z93q802</a>, accessed on 16 September 2024).</p>
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16 pages, 3067 KiB  
Article
Field Application of Mycorrhizal Inoculant Influences Growth, Nutrition, and Physiological Parameters of Corn Plants and Affects Soil Microbiological Attributes
by Paulo Ademar Avelar Ferreira, Carina Marchezan, Gustavo Scopel, Natalia Teixeira Schwab, Emanuela Pille da Silva, Cláudio Roberto Fonsêca Sousa Soares, Gustavo Brunetto and Sidney Luiz Stürmer
Agronomy 2024, 14(12), 3006; https://doi.org/10.3390/agronomy14123006 - 17 Dec 2024
Viewed by 462
Abstract
Mycorrhizal inoculants can contribute to the development of corn crops by improving crop productivity. In this sense, the objective of this study was to evaluate the effects of a mycorrhizal inoculant on the dynamics of root system growth, gas exchange, corn crop productivity, [...] Read more.
Mycorrhizal inoculants can contribute to the development of corn crops by improving crop productivity. In this sense, the objective of this study was to evaluate the effects of a mycorrhizal inoculant on the dynamics of root system growth, gas exchange, corn crop productivity, and microbial activity in the rhizospheric soil in a no-till area with different levels of available soil phosphorus. The experiment was conducted during the 2019/2020 and 2020/2021 growing seasons. At 75 days after plant emergence, root morphological parameters (total root length (cm), average root diameter (mm), root surface area (cm2), and root volume), shoot biomass production, P content in the plant shoots, gas exchange, and microbiological attributes of the rhizospheric soil of corn were evaluated. At the end of the cycle, corn grain yield was determined. A beneficial effect of AMF inoculation was observed on the root and shoot parameters regardless of soil P level. Under conditions of evenly distributed rainfall during the experiment (2019/2020 season), AMF inoculation contributed to a 90% increase in acid phosphatase activity and a 76% increase in microbial biomass carbon (C-BIO), independent of soil P level. In contrast, under water deficit conditions (2020/2021 season), AMF inoculation provided a 29% increase in grain yield. We concluded that introducing a commercial mycorrhizal inoculant in corn benefits root system morphological parameters and physiological traits, and favors the activity of enzymes related to increased P availability, contributing to increased crop productivity in a no-till system. Full article
(This article belongs to the Special Issue Microorganisms in Agriculture—Nutrition and Health of Plants)
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<p>Corn sowing dates, precipitation, minimum, average, and maximum air temperatures throughout the 2019/2020 and 2020/2021 growing seasons. Santa Maria, RS, Brazil.</p>
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<p>Total length (<b>a</b>), average diameter (<b>b</b>), surface area (<b>c</b>), and root volume (<b>d</b>) of corn in the 2019/20 and 2020/21 cropping seasons in a no-till area after successive applications of phosphorus fertilizer with and without AMF inoculation. Means followed by the same uppercase letters compare inoculation within the same soil P level, and lowercase letters compare soil P levels under the same inoculation condition (Tukey—<span class="html-italic">p</span> ≤ 0.05). In figures (<b>a</b>,<b>d</b>), the orange bars compare the effect of inoculation when the interaction between the factors was not significant. In figure (<b>b</b>) the orange bars compare the P levels in the soil when the interaction between the factors was not significant.</p>
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<p>Distribution of the average root diameter observed in the 0–60 cm soil layer in corn plants grown under low and high soil P conditions, inoculated and non-inoculated with AMF in the (<b>a</b>) 2019/20 and (<b>b</b>) 2020/21 cropping seasons. The diameters evaluated were &lt;0.25, 0.25-0.40, 0.40-0.55 and greater than 0.55 mm.</p>
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<p>Dry matter production (<b>a</b>), P content in the shoot (<b>b</b>), and grain yield (<b>c</b>) of corn in the 2019/20 and 2020/21 cropping seasons in a no-till area after successive applications of phosphorus fertilizer with and without AMF inoculation. Means followed by the same uppercase letters compare inoculation within the same soil P level, and lowercase letters compare soil P levels under the same inoculation condition (Tukey—<span class="html-italic">p</span> ≤ 0.05). The oranges compare the effect of soil P levels when the interaction between the factors was not significant.</p>
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<p>Net photosynthesis rate (<b>a</b>), Intercellular CO<sub>2</sub> concentration (<b>b</b>), Instantaneous carboxylation efficiency (A/Ci) (<b>c</b>), and water use efficiency (WUE) (<b>d</b>) of corn in the 2019/20 and 2020/21 cropping seasons in a no-till area after successive applications of phosphorus fertilizer with and without AMF inoculation. Means followed by the same uppercase letters compare inoculation within the same soil P level, and lowercase letters compare soil P levels under the same inoculation condition (Tukey—<span class="html-italic">p</span> ≤ 0.05). The oranges compare the effect of inoculation when the interaction between the factors was not significant.</p>
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<p>Activity of the enzymes acid phosphatase (<b>a</b>) and β-glucosidase (<b>b</b>) in the rhizospheric soil of corn in a no-till area after successive applications of phosphorus fertilizer with and without AMF inoculation. Means followed by the same uppercase letters compare inoculation within the same soil P level, and lowercase letters compare soil P levels under the same inoculation condition (Tukey—<span class="html-italic">p</span> ≤ 0.05).</p>
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16 pages, 1529 KiB  
Article
How to Engage with Non-Human Others in Ecosystems from a Phenomenological and Interreligious Perspective
by Youngjin Kiem
Religions 2024, 15(12), 1539; https://doi.org/10.3390/rel15121539 - 17 Dec 2024
Viewed by 406
Abstract
Humanity is currently in the midst of a number of serious ecological crises. Various scientific, philosophical, and religious ideas have been put forth in response to these global crises. Here, I suggest that the solutions to ecological problems can be best achieved when [...] Read more.
Humanity is currently in the midst of a number of serious ecological crises. Various scientific, philosophical, and religious ideas have been put forth in response to these global crises. Here, I suggest that the solutions to ecological problems can be best achieved when we undergo an essential change in our perspective on the existence and value of the natural world. In this regard, interreligious engagement and research, which address the multiple worldviews that emerge from individual religions and philosophies, have great potential to fundamentally transform our view of ecosystems. The problem is how to conduct such interreligious engagement and research, which has—unfortunately—to this point been overlooked. In this context, I propose the “four-step method of interreligious sympoiesis to address the ecological crisis”. This is a phenomenological–hermeneutic method that involves the following steps: (1) Suspension of Judgment (Epoché): the mind’s performing an epoché, which is taken as an ethical or religious vow; (2) Empathetic Reduction: the mind’s engaging in empathy with non-human beings; (3) Symbiotic Reduction: the mind’s envisioning of proper coexistence between humans and non-human beings in both minimal and maximal ways; (4) Interreligious Hermeneutical Synthesis: the arranging and synthesizing of the ideas obtained from the above reductions in a specific or comprehensive manner from an interreligious perspective. This paper aims to expound and defend these ideas. Full article
(This article belongs to the Special Issue The Global Urgency of Interreligious Studies)
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<p>Step One in the Method.</p>
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<p>Step Two in the Method.</p>
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<p>Step Three in the Method.</p>
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<p>Step Four in the Method.</p>
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16 pages, 4560 KiB  
Article
Arbuscular Mycorrhizal Fungi as a Salt Bioaccumulation Mechanism for the Establishment of a Neotropical Halophytic Fern in Saline Soils
by Mónica A. Lugo, María A. Negritto, Esteban M. Crespo, Hebe J. Iriarte, Samuel Núñez, Luisa F. Espinosa and Marcela C. Pagano
Microorganisms 2024, 12(12), 2587; https://doi.org/10.3390/microorganisms12122587 - 13 Dec 2024
Viewed by 475
Abstract
Acrostichum aureum is a halophytic pantropical invasive fern growing in mangroves and swamps. Its association with arbuscular mycorrhizal fungi (AMF) has been reported in Asia. AMF and their symbiosis (AM) commonly colonise the absorption organs of terrestrial plants worldwide. Furthermore, AMF/AM are well [...] Read more.
Acrostichum aureum is a halophytic pantropical invasive fern growing in mangroves and swamps. Its association with arbuscular mycorrhizal fungi (AMF) has been reported in Asia. AMF and their symbiosis (AM) commonly colonise the absorption organs of terrestrial plants worldwide. Furthermore, AMF/AM are well known for their capacity to bioaccumulate toxic elements and to alleviate biotic and abiotic stress (e.g., salinity stress) in their hosts. However, the mechanisms underlying AMF involvement in the halophytism of A. aureum and the structures where NaCl accumulates remain unknown. This study shows that A. aureum forms AM in margins of natural thermal ponds in Neotropical wetlands. All mature sporophytes were colonised by AMF, with high percentages for root length (ca. 57%), arbuscules (23), and hyphae (25) and low values for vesicles (2%). In A. aureum–AMF symbiosis, NaCl accumulated in AMF vesicles, and CaSO4 precipitated in colonised roots. Therefore, AM can contribute to the halophytic nature of this fern, allowing it to thrive in saline and thermal environments by capturing NaCl from fern tissues, compartmentalising it inside its vesicles, and precipitating CaSO4. Full article
(This article belongs to the Section Plant Microbe Interactions)
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<p>Sampling site in El Volcán thermal ponds, near the Córdoba River mouth in the Caribbean Sea, Magdalena Department, Colombia.</p>
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<p><span class="html-italic">Acrostichum aureum</span> in the El Volcán thermal ponds, Córdoba River, Colombia. (<b>a</b>) Fern sporophytes growing on the margin. (<b>b</b>) Frond of <span class="html-italic">A. aureum</span> exhibiting fertile and non-fertile pinnae. Photo credits: (<b>a</b>), María A. Negritto; (<b>b</b>), Samuel Núñez.</p>
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<p>Colonisation by AMF in fine roots of <span class="html-italic">Acrostichum aureum</span>. (<b>a</b>) General view of a fern root colonised by AMF; (<b>b</b>) AMF vesicles; (<b>c</b>) AMF hyphal coils and arbuscules; (<b>d</b>) AMF arbuscules. Arrowheads indicate illustrated structures. Photo credit: Mónica A. Lugo.</p>
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<p>AMF structures outside and inside fine roots of <span class="html-italic">Acrostichum aureum</span> with dense cytoplasmic content (arrowhead). (<b>a</b>) AMF hypha; (<b>b</b>) AMF spores outside roots; (<b>c</b>) AMF vesicles; (<b>d</b>) AMF arbuscules inside roots. Photo credit: Mónica A. Lugo.</p>
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<p>Salt crystals inside AMF vesicles. (<b>a</b>) Vesicles of AMF with NaCl crystals (indicated by the arrowhead) observed under optical microscope. (<b>b</b>) The EDX analysis of the crystals in the vesicles showed the elemental composition of NaCl. NaCl crystals and each salt element are indicated by arrowheads. Photo credit: Mónica A. Lugo.</p>
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<p>Salts accumulated inside roots of <span class="html-italic">Acrostichum aureum</span> analysed by SEM-EDX. (<b>a</b>) SEM image of amorphous crystals obtained with the backscattered electron detector (black arrowhead). (<b>b</b>) X-ray mapping indicating the distribution of S in an <span class="html-italic">A. aureum</span> root (red arrowhead). (<b>c</b>) X-ray mapping indicating the distribution of Ca in the root (yellow arrowhead). (<b>d</b>) EDX spectrum of amorphous crystals, showing their CaSO<sub>4</sub> composition (red and yellow arrowheads).</p>
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28 pages, 2618 KiB  
Review
The Importance of Mycorrhizal Fungi and Their Associated Bacteria in Promoting Crops’ Performance: An Applicative Perspective
by Miriana Bortolot, Beatrice Buffoni, Sonia Mazzarino, Gregory Hoff, Elena Martino, Valentina Fiorilli and Alessandra Salvioli Di Fossalunga
Horticulturae 2024, 10(12), 1326; https://doi.org/10.3390/horticulturae10121326 - 11 Dec 2024
Viewed by 518
Abstract
Agricultural systems are particularly impacted by global climate change (CC), responsible for the introduction of multiple environmental stressors negatively affecting plant growth. Soil microbial communities are crucial in agricultural practices, influencing crop performance and soil health. Human activities and CC threaten soil microbial [...] Read more.
Agricultural systems are particularly impacted by global climate change (CC), responsible for the introduction of multiple environmental stressors negatively affecting plant growth. Soil microbial communities are crucial in agricultural practices, influencing crop performance and soil health. Human activities and CC threaten soil microbial biodiversity, leading to soil quality degradation and decreasing plant health and productivity. Among plant-beneficial microorganisms, mycorrhizal fungi are widespread in terrestrial ecosystems, including agroecosystems, and they play a key role by enhancing plants’ fitness and resilience to both abiotic and biotic stresses. Therefore, exploring the role of mycorrhizal symbiosis in sustainable agriculture has become increasingly critical. Moreover, the application of mycorrhizal bioinoculants could reduce dependence on inorganic fertilizers, enhance crop yield, and support plants in overcoming environmental stresses. This review, after briefly introducing taxonomy, morphology and mechanisms supporting the symbiosis establishment, reports the roles of mycorrhizal fungi and their associated bacteria in improving plant nutrition and mitigating CC-induced abiotic stresses such as drought and salinity, also giving specific examples. The focus is on arbuscular mycorrhizal fungi (AMF), but ericoid mycorrhizal (ErM) fungi are also considered as promising microorganisms for a sustainable agricultural model. New emerging concepts are illustrated, such as the role of AMF hyphosphere in acting as a preferential niche to host plant growth-promoting bacteria and the potential of ErM fungi to improve plant performance on Ericaceae plants but also on non-host plants, behaving as endophytes. Finally, the potential and limitations of mycorrhizal-based bioinoculants are discussed as possible alternatives to chemical-based products. To this aim, possible ways to overcome problems and limitations to their use are discussed such as proper formulations, the systematic check of AMF propagule viability and the application of suitable agronomical practices in the field. Full article
(This article belongs to the Special Issue Microbial Interaction with Horticulture Plant Growth and Development)
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<p>Schematic presentation of the AM colonization process and the rhizosphere and hyphosphere microbiome. AM fungal spores (S) germinate after a molecular dialog between partners (i.e., SLs and COs). Fungal hyphae reach the root epidermis (EP) and develop a swollen structure called hyphopodia (HP). After this contact, the fungal hyphae penetrate the root and progress until the cortex cells, where AM fungi form arbuscules (ARB); in these structures, the nutrient exchange occurs bidirectionally. The arbuscule is surrounded by a plant-derived membrane (PAM, peri-arbuscular membrane in gray) and between the PAM and fungal cell wall there is an apoplastic space called the peri-arbuscular space (in yellow). Outside the root, bacteria live in association with the plant in a narrow space called rhizosphere (in non-mycorrhizal root plants, area in blue), mycorrhizosphere (in mycorrhizal root plants, area in green), and in association with the hyphae (hyphosphere area in orange). Bacteria that live inside the spore are called endobacteria [<a href="#B67-horticulturae-10-01326" class="html-bibr">67</a>]. ARB = arbuscule (Y, young, or M, mature), ERM = extraradical mycelium, HB = hyphal branching, IRM = intraradical mycelium, N = nucleus, EN = endodermis.</p>
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<p>Publications per year related to: (<b>a</b>) bacterial–fungal interaction in crop plants and soil (keywords used in PUBMED: interaction, crop, plant, soil, fungi, fungal, mycorrhizal, bacteria), and (<b>b</b>) mycorrhiza helper bacteria in crop plants and soil (keywords used in PUBMED: crop, plant, soil, mycorrhiza helper bacteria). In figure (<b>c</b>), we have a focus on mycorrhiza helper bacteria publications in the last 20 years.</p>
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<p>(<b>a</b>–<b>e</b>) ErM symbiosis morphology. (<b>a</b>) <span class="html-italic">In vitro V. myrtillus</span> non-inoculated seedlings. (<b>b</b>) <span class="html-italic">In vitro V. myrtillus</span> seedlings inoculated with <span class="html-italic">O. maius</span>. (<b>c</b>) Transverse section of a <span class="html-italic">V. oxycoccos</span> hair root characterized by very large epidermal cells (Ep) colonized by an ericoid fungus (arrow), a single layer of cortical cells (C), the endodermis (E), the vascular cylinder (VC). (<b>d</b>) Light microscope observation of a <span class="html-italic">V. myrtillus</span> hair root colonized by <span class="html-italic">O. maius</span>; the typical coils formed by the fungus inside the root epidermal cells can be seen (cotton blue staining). (<b>e</b>) Morphology of a densely intertwined intracellular fungal coil; the outer tangential wall of the epidermal cells is very thick. The intracellular hyphae are separated from the cytoplasm of the epidermal root cell by the plant cell membrane that surrounds the fungal coil (perisymbiotic membrane) and by an interface matrix (modified with permission from [<a href="#B138-horticulturae-10-01326" class="html-bibr">138</a>] (<b>a</b>,<b>b</b>,<b>d</b>); [<a href="#B174-horticulturae-10-01326" class="html-bibr">174</a>] (<b>c</b>); [<a href="#B175-horticulturae-10-01326" class="html-bibr">175</a>] (<b>e</b>)). (<b>f</b>) Microcuttings (the insertion on the upper left corner) derived from <span class="html-italic">in vitro</span> cultured <span class="html-italic">R. fortunei</span> grown on a sterilized peat-based substrate non-inoculated (CK) and inoculated with an <span class="html-italic">O. maius</span> strain. (<b>g</b>) Ex vitro rooting of <span class="html-italic">R. fortunei</span> microcuttings non-inoculated (CK) and inoculated with an <span class="html-italic">O. maius</span> strain three months after being transplanted to 10-centimeter diameter containers. (<b>h</b>) Plant hair roots after washing away the substrate ((<b>f</b>–<b>h</b>): modified with permission from [<a href="#B167-horticulturae-10-01326" class="html-bibr">167</a>]).</p>
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