Plants

22 pages, 1603 KiB

Open AccessArticle

Effects of Different Calcium Preparations on Fresh-Cut Quality and Storage Quality of Starkrimson Apple

by Maoxiang Sun, Fen Wang, Jianchao Ci, Yangyang Liu, Keyi Li, Dong Wang, Wen Yu, Yu Zhuang and Yuansong Xiao

Plants 2025, 14(9), 1293; https://doi.org/10.3390/plants14091293 - 24 Apr 2025

Abstract

Appropriate calcium treatments help maintain the appearance, nutritional quality, and postharvest quality of apples, reducing losses during storage. This study investigated the effects of different calcium preparations on the fresh-cut quality and ultrastructure of ‘Starkrimson’ apples. The treatments included control (CK), calcium chloride [...] Read more.

Appropriate calcium treatments help maintain the appearance, nutritional quality, and postharvest quality of apples, reducing losses during storage. This study investigated the effects of different calcium preparations on the fresh-cut quality and ultrastructure of ‘Starkrimson’ apples. The treatments included control (CK), calcium chloride (T1), sorbitol-chelated calcium (T2), and calcium nitrate (T3). The results demonstrated that sorbitol-chelated calcium significantly inhibited the decline in fresh-cut firmness and pectin content while reducing the increase in cellulose content and minimizing ultrastructural damage. Apples treated with sorbitol-chelated calcium maintained the best fresh-cut hardness and soluble pectin contents, which were 35.71% and 15.42% higher than that of CK on the 12th day, and the cellulose was 27.08% lower than that of CK. Under transmission electron microscopy, the pulp cell surface in the T2 group remained intact, with no bending or deformation, and the middle lamella was well preserved. Additionally, T2 treatment promoted the expression of aroma-related genes during fruit storage. Sorbitol-chelated calcium effectively preserved color and significantly reduced the browning and microbial spoilage of fresh-cut apples, particularly postharvest pathogen growth. The study demonstrates that sorbitol-chelated calcium preserves fresh-cut apple quality by reinforcing cell wall integrity through calcium-mediated crosslinking, suppressing pectin degradation and cellulose accumulation, and activating aroma-related genes (AAT1, AAT2, LOX) to enhance volatile synthesis, thereby reducing microbial spoilage and enzymatic browning during storage. Full article

(This article belongs to the Special Issue Preserving Fruit Quality: Innovations in Postharvest Storage for Horticultural Plants)

19 pages, 6335 KiB

Open AccessArticle

Response of Soil Microbial Diversity to Triple-Cropping System in Paddy Fields in Middle Reaches of Yangtze River

by Haiying Tang, Junlin Zhou, Ning Liu, Yao Huang, Qin Liu, Faizah Amer Altihani and Binjuan Yang

Plants 2025, 14(9), 1292; https://doi.org/10.3390/plants14091292 - 24 Apr 2025

Abstract

To explore the characteristics of soil microbial community structure diversity for different planting patterns in paddy fields, and to screen out the planting patterns suitable for the promotion of double-cropping rice areas in the middle reaches of the Yangtze River, five typical planting [...] Read more.

To explore the characteristics of soil microbial community structure diversity for different planting patterns in paddy fields, and to screen out the planting patterns suitable for the promotion of double-cropping rice areas in the middle reaches of the Yangtze River, five typical planting patterns were set up in this study. The five patterns are Chinese milk vetch–early rice–late rice (CRR, CK), Chinese milk vetch–early rice–sweet potato || late soybean (CRI), rapeseed–early rice–late rice (RRR), rapeseed–early rice–sweet potato || late soybean (RRI) and potato–early rice–late rice (PRR). The variation characteristics of soil microbial community structure diversity and the correlation between soil environmental factors and soil microbial community structure diversity under the triple-cropping system in the double-cropping rice area of the middle reaches of the Yangtze River were studied by 16S rRNA high-throughput sequencing and real-time fluorescence quantitative polymerase chain reaction (PCR). The results showed that after two years of experiment, the pH values of each treatment increased, and the rapeseed–early rice–late rice (RRR) model performed better. The soil organic matter and total nitrogen content of the milk vetch–early rice–sweet potato || late soybean (CRI) model was the highest, which increased by 7.89~35.02% and 6.59~26.80% compared with other treatments. The content of soil available phosphorus and available potassium in the potato–early rice–late rice (PRR) model was higher than that in other treatments, which was increased by 29.48% and 126.49% compared with the control. The Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–sweet potato || late soybean (RRI) models were beneficial to increasing soil nitrate nitrogen and ammonium nitrogen content. Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–late rice (RRR) patterns were beneficial for improving the microbial diversity index. Proteobacteria, Chloroflexi, and Actinobacteria are the top three dominant phyla in terms of the relative abundance of soil bacteria, and the top three dominant fungi are Ascomycota, Basidiomycota, and Mucor. The Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–sweet potato || late soybean (RRI) patterns increased the relative abundance of soil Actinobacteria and Ascomycota. The contents of ammonium nitrogen, total organic carbon, nitrate nitrogen, and available phosphorus were the main environmental factors affecting soil microbial community structure. The findings can provide references for screening out the planting patterns suitable for the promotion of double-cropping rice areas in the middle reaches of the Yangtze River. Full article

(This article belongs to the Section Plant–Soil Interactions)

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16 pages, 3080 KiB

Open AccessArticle

Selenium Alleviates Cadmium Toxicity in Pepper (Capsicum annuum L.) by Reducing Accumulation, Enhancing Stress Resistance, and Promoting Growth

by Chen Cheng, Jianxiu Liu, Jiahui Liu, Zhiqiang Gao, Yang Yang, Bo Zhu, Fengxian Yao and Qing Ye

Plants 2025, 14(9), 1291; https://doi.org/10.3390/plants14091291 - 24 Apr 2025

Abstract

The enrichment of cadmium (Cd) is an important factor threatening crop growth and food safety. However, it is unclear whether exogenous selenium (Se) can simultaneously achieve Cd reduction and promote the growth of peppers. This study used Yuefeng 750 and Hongtianhu 101 as [...] Read more.

The enrichment of cadmium (Cd) is an important factor threatening crop growth and food safety. However, it is unclear whether exogenous selenium (Se) can simultaneously achieve Cd reduction and promote the growth of peppers. This study used Yuefeng 750 and Hongtianhu 101 as materials and investigated the interaction effects of different Se-Cd concentrations (Cd = 2 and 5 μM; Se = 0, 0.5, and 2 μM) on the uptake and transport of Cd and Se, resistance physiology, and growth and development of pepper seedlings in a hydroponic experiment. The organ Cd content was significantly increased in pepper seedlings, inhibiting their growth and aggravating their physiological stress under Cd application. However, the growth and photosynthetic capacity of peppers were promoted after Se application under Cd stress. The superoxide anion (O₂⁻), hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and abscisic acid (ABA) contents and indole-3-acetic acid oxidase (IAAO) activity in the leaves showed a significantly progressive decline, while the proline (Pro), ascorbic acid (ASA), and trans zeatin riboside (ZR) contents showed a significant rising trend. Thus, the growth, development, and dry matter accumulation of peppers were enhanced by reducing Cd stress. Meanwhile, the application of exogenous Se significantly improved the accumulation of Se in seedlings. In addition, compared to Hongtianhu 101, the Yuefeng 750 cultivars had a greater Cd and Se enrichment capacity. The cultivation of Cd-excluding cultivars combined with exogenous Se addition can be used as a recommended solution to reduce Cd toxicity and achieve Cd reduction and Se enrichment in peppers under Cd pollution. Full article

(This article belongs to the Special Issue Abiotic and Biotic Stress of the Crops and Horticultural Plants, 2nd Edition)

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16 pages, 2643 KiB

Open AccessArticle

Strategies to Improve γ-Aminobutyric Acid Biosynthesis in Rice via Optimal Conditions

by Lixing Shen, Yulu Yang, Xiong Liu, Huibo Zhao, Yanfang Zhang, Lan Shen, Li Zhu, Jiang Hu, Deyong Ren, Qiang Zhang, Zhenyu Gao, Guojun Dong, Qing Li, Qian Qian, Dali Zeng and Guangheng Zhang

Plants 2025, 14(9), 1290; https://doi.org/10.3390/plants14091290 - 24 Apr 2025

Abstract

The γ-aminobutyric acid (GABA), a ubiquitous non-protein amino acid in plants and animals, exhibits diverse biological activities and holds promise in human disease prevention and treatment. Prior studies have shown that germination could substantially elevate GABA levels in rice, but these investigations typically [...] Read more.

The γ-aminobutyric acid (GABA), a ubiquitous non-protein amino acid in plants and animals, exhibits diverse biological activities and holds promise in human disease prevention and treatment. Prior studies have shown that germination could substantially elevate GABA levels in rice, but these investigations typically focused on limited germplasms, hindering the generalization of their findings. This study aims to identify optimal conditions for enriching GABA in a diverse set of 225 rice germplasms by examining the effects of various germination times, temperatures, and soaking solution pH levels, while elucidating the key factors influencing GABA enrichment in germinated brown rice. The optimal GABA enrichment in germinated brown rice was achieved under the following conditions: a germination temperature of 37 °C, a germination duration of 48 h, and a soaking solution pH of 5.5. Under these conditions, we found significant differences in GABA content among different germplasms. Subsequent correlation analyses demonstrated that GABA content showed significant positive correlations with embryo weight in brown rice, relative embryo weight, relative embryo weight in germinated brown rice, as well as glutamate (Glu) and proline (Pro) concentrations. Therefore, larger brown rice embryos, higher Glu and Pro content in germinated brown rice, and external Glu application contribute to increased GABA content. Our findings provide essential materials and theoretical insights for screening and developing GABA-rich functional rice germplasms, facilitating variety selection and breeding programs. Full article

(This article belongs to the Section Plant Physiology and Metabolism)

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20 pages, 3440 KiB

Open AccessArticle

Response of Watermelon to Drought Stress and Its Drought-Resistance Evaluation

by Kaili Ren, Taoxia Tang, Weiping Kong, Yongquan Su, Yuping Wang, Hong Cheng, Yonggang Yang and Xiaoqin Zhao

Plants 2025, 14(9), 1289; https://doi.org/10.3390/plants14091289 - 24 Apr 2025

Abstract

This study investigated the response of watermelon seedlings to drought stress by assessing the growth, physiological, and biochemical indices using a pot-based continuous drought method. Drought stress indices, phenotypic plasticity indices, and membership function values were calculated, followed by a correlation analysis, principal [...] Read more.

This study investigated the response of watermelon seedlings to drought stress by assessing the growth, physiological, and biochemical indices using a pot-based continuous drought method. Drought stress indices, phenotypic plasticity indices, and membership function values were calculated, followed by a correlation analysis, principal component analysis, and cluster analysis, to comprehensively evaluate the drought resistance of 13 watermelon genotypes. The results revealed that drought stress significantly reduced the fresh and dry weights, root length, root area, root volume, root tips, and forks of watermelon seedlings. Additionally, drought significantly reduced the relative water content of leaves and increased the levels of osmotic-adjustment substances (soluble sugars, soluble proteins, proline, and starch). Persistent drought also modulated the activities of antioxidant enzymes (SOD, POD, and CAT), leading to oxidative stress through the accumulation of H₂O₂. Membrane damage, indicated by a significant increase in the MDA content and relative conductivity, was observed, adversely affecting seedling growth. Phenotypic plasticity indices indicated that watermelon exhibits strong adaptability to drought. Cluster analysis categorized the 13 genotypes into four groups: highly drought-resistant (14X5), drought-resistant (LK13, JLR, HXF1, 14X4, 14X1, and 14X6), low drought-resistant (21F05, JH1, JR3, 14X7, and 16F02), and drought-sensitive (16C07). This study provides valuable genetic resources for breeding drought-resistant watermelon varieties. Full article

(This article belongs to the Section Plant Response to Abiotic Stress and Climate Change)

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20 pages, 6404 KiB

Open AccessArticle

Effects of Arbuscular Mycorrhizal Fungi on the Growth and Nutrient Uptake in Wheat Under Low Potassium Stress

by An-Qi Han, Shuai-Bo Chen, Dan-Dan Zhang, Jin Liu, Meng-Chuan Zhang, Bin Wang, Yue Xiao, Hai-Tao Liu, Tian-Cai Guo, Guo-Zhang Kang and Ge-Zi Li

Plants 2025, 14(9), 1288; https://doi.org/10.3390/plants14091288 - 24 Apr 2025

Abstract

Potassium (K) plays important roles in plant growth and development processes, while low K (LK) stress inhibits plant growth by altering reactive oxygen species accumulation. Arbuscular mycorrhizal fungi (AMF) promote nutrient absorption and transport in plants. However, the roles of AMF in affecting [...] Read more.

Potassium (K) plays important roles in plant growth and development processes, while low K (LK) stress inhibits plant growth by altering reactive oxygen species accumulation. Arbuscular mycorrhizal fungi (AMF) promote nutrient absorption and transport in plants. However, the roles of AMF in affecting K nutrition are less well studied than those of other nutrients, especially in wheat. In this study, the effects of AMF on four wheat varieties were evaluated; results showed that the inoculation with the AMF-Rhizophagus intraradices significantly increased mycorrhizal colonization, fresh and dry weights, ascorbic acid, and glutathione contents, while decreasing malondialdehyde contents under both normal and LK stress treatments. It is worth noting that the contents of K and several nutrient elements were more significantly increased in roots than in shoots, suggesting that AMF mainly affect the uptake of K and other nutrient elements in the roots. Moreover, the expression levels of K transporter genes were higher than those of nitrogen and phosphorus transporter genes, especially under AMF combined with LK stress treatments. These results indicate that AMF improves wheat growth and antioxidant activity by regulating K transporter gene expression and affecting K uptake and transport. Therefore, AMF could be used as a sustainable agricultural alternative in wheat under LK soils. Full article

(This article belongs to the Special Issue Cell Physiology and Stress Adaptation of Crops)

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Graphical abstract

14 pages, 2409 KiB

Open AccessArticle

Genome-Wide Analysis of GRETCHEN HAGEN3 Genes and Characterization of IAA-Amido Synthetase Gene CsGH3.1 in Rhizome Proliferation in Cymbidium sinense ‘Qijianbaimo’

by Sisi Jia, Cuiling Liu, Chushu Liao, Ruizhen Zeng, Li Xie, Qian Wei and Zhisheng Zhang

Plants 2025, 14(9), 1287; https://doi.org/10.3390/plants14091287 - 24 Apr 2025

Abstract

This study systematically identified and functionally analyzed the GRETCHEN HAGEN 3 (GH3) gene family in Cymbidium sinense ‘Qijianbaimo’ (CSQ). Seven GH3 genes (CsGH3.1–CsGH3.7) were identified using genomic and transcriptomic data. Phylogenetic analysis revealed that CsGH3s are divided into [...] Read more.

This study systematically identified and functionally analyzed the GRETCHEN HAGEN 3 (GH3) gene family in Cymbidium sinense ‘Qijianbaimo’ (CSQ). Seven GH3 genes (CsGH3.1–CsGH3.7) were identified using genomic and transcriptomic data. Phylogenetic analysis revealed that CsGH3s are divided into two subfamilies, with CsGH3.1–CsGH3.4 belonging to subfamily II and CsGH3.5–CsGH3.7 to subfamily I. Gene structure analysis showed that CsGH3s contain one to four exons, and their promoter regions feature auxin and jasmonic acid response elements. CsGH3.1 and CsGH3.2 were significantly upregulated in response to naphthaleneacetic acid (NAA) during rhizome proliferation, indicating their pivotal role in auxin homeostasis regulation. The overexpression of CsGH3.1 in Arabidopsis led to restricted growth and a significant reduction in callus proliferation rates, further confirming its role in regulating cell proliferation and auxin homeostasis. This study provides new insights into the function of the CsGH3.1 gene in the rhizome proliferation of Cymbidium sinense and lays a foundation for future research on the molecular mechanism of micropropagation in Cymbidium. Full article

(This article belongs to the Section Plant Genetics, Genomics and Biotechnology)

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19 pages, 2945 KiB

Open AccessReview

Advances in Small RNA Regulation of Female Gametophyte Development in Flowering Plants

by Yanfen Liu, Qing He, Han Su, Xinpeng Xi, Xiaoyuan Xu, Yuan Qin and Hanyang Cai

Plants 2025, 14(9), 1286; https://doi.org/10.3390/plants14091286 - 23 Apr 2025

Abstract

Female gametophyte development in flowering plants is a highly intricate process involving a series of tightly regulated biological events, including the establishment and differentiation of a macrospore mother cell (MMC), the formation of a functional macrospore (FM), and the subsequent development of the [...] Read more.

Female gametophyte development in flowering plants is a highly intricate process involving a series of tightly regulated biological events, including the establishment and differentiation of a macrospore mother cell (MMC), the formation of a functional macrospore (FM), and the subsequent development of the embryo sac. The seamless progression of these events is crucial for the completion of sexual reproduction and the alternation of generations in plants. Small RNAs are ubiquitously present in eukaryotic organisms. Based on their biogenesis, function, and involvement in biological pathways, plant small RNAs are primarily categorized into four classes: miRNAs (microRNAs), ta-siRNAs (trans-acting-siRNAs), hc-siRNAs (heterochromatic-siRNAs), and nat-siRNAs (natural antisense transcript-derived siRNAs). Current studies show that small RNAs play an important role in plant reproductive development, such as female gametophyte development and ovule development. In this review, we systematically elucidate the biogenesis and molecular mechanism of small RNAs and summarize the latest research advances on their roles in regulating megasporogenesis and megagametogenesis in plants. The aim of this review is to provide insights into the mechanisms underlying plant reproductive development through the lens of small RNAs, offering a theoretical foundation for improving crop quality, yield, genetic improvement, and breeding. Full article

(This article belongs to the Section Plant Development and Morphogenesis)

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28 pages, 10871 KiB

Open AccessArticle

Optimization of Water and Nitrogen Application Rates for Synergistic Improvement of Yield and Quality in Solar Greenhouse Cucumber Production on the North China Plain

by Chunting Wang, Xiaoman Qiang, Kai Wang, Huanhuan Li, Xianbo Zhang, Shengxing Liu and Xuewen Gong

Plants 2025, 14(9), 1285; https://doi.org/10.3390/plants14091285 - 23 Apr 2025

Abstract

To address the scientific challenges of low water–fertilizer use efficiency and the difficulty in achieving the synergistic improvement of the yield and quality in solar greenhouse cucumber production on the North China Plain, this study investigated the effects of varying water and nitrogen [...] Read more.

To address the scientific challenges of low water–fertilizer use efficiency and the difficulty in achieving the synergistic improvement of the yield and quality in solar greenhouse cucumber production on the North China Plain, this study investigated the effects of varying water and nitrogen supplies on cucumber growth, yields, water–nitrogen use efficiency, and quality. The aim was to establish optimized water and nitrogen management strategies for high-yield, high-quality, and resource-efficient cultivation. A two-factor completely randomized design was implemented, with three irrigation levels (W1:

1.0 E_{p - 20}

, W2:

0.75 E_{p - 20}

, and W3:

0.5 E_{p - 20}

) based on cumulative pan evaporation and four nitrogen application amounts (N1: 432 kg·ha⁻¹, N2: 360 kg·ha⁻¹, N3: 288 kg·ha⁻¹, N4: 216 kg·ha⁻¹). Cucumber growth indicators were observed during the growing season, and the water and nitrogen application rates were scientifically optimized. The results showed that a full water and nitrogen supply enhanced the leaf area index, dry weight accumulation, and yield. Moderate water and nitrogen savings had a minimal impact on plant growth and production while significantly improving the water and fertilizer use efficiency. Using principal component analysis to comprehensively evaluate the cucumber quality, it was found that the irrigation amount had a significant impact on quality, with the quality improving as the irrigation amount decreased. By employing a regression formula and spatial analysis methods, this study optimized the water and nitrogen application rates with the goals of maximizing the cucumber yield, water–nitrogen efficiency, and quality. For spring cucumbers, the recommended combination is an irrigation amount of 225~240 mm and a nitrogen application amount of 350~380 kg·ha⁻¹. For autumn cucumbers, the recommended combination is an irrigation amount of 105~120 mm and a nitrogen application amount of 375~400 kg·ha⁻¹. This research provides theoretical and technical support for high-yield, high-quality, and efficient irrigation and nitrogen management in solar greenhouses in the North China Plain. Full article

(This article belongs to the Section Plant Physiology and Metabolism)

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22 pages, 4650 KiB

Open AccessArticle

RGB Indices Can Be Used to Estimate NDVI, PRI, and Fv/Fm in Wheat and Pea Plants Under Soil Drought and Salinization

by Yuriy Zolin, Alyona Popova, Lyubov Yudina, Kseniya Grebneva, Karina Abasheva, Vladimir Sukhov and Ekaterina Sukhova

Plants 2025, 14(9), 1284; https://doi.org/10.3390/plants14091284 - 23 Apr 2025

Abstract

Soil drought and salinization are key abiotic stressors for agricultural plants; the development of methods of their early detection is an important applied task. Measurement of red-green-blue (RGB) indices, which are calculated on basis of color images, is a simple method of proximal [...] Read more.

Soil drought and salinization are key abiotic stressors for agricultural plants; the development of methods of their early detection is an important applied task. Measurement of red-green-blue (RGB) indices, which are calculated on basis of color images, is a simple method of proximal and remote sensing of plant health under the action of stressors. Potentially, RGB indices can be used to estimate narrow-band reflectance indices and/or photosynthetic parameters in plants. Analysis of this problem was the main task of the current work. We investigated relationships of six RGB indices (r, g, b, ExG, VEG, and VARI) to widely used narrow-band reflectance indices (the normalized difference vegetation index, NDVI, and photochemical reflectance index, PRI) and the potential quantum yield of photosystem II (Fv/Fm) in wheat and pea plants under soil drought and salinization. It was shown that investigated RGB indices, NDVI, PRI, and Fv/Fm were significantly changed under the action of both stressors; changes in some RGB indices (e.g., ExG) were initiated on the early stage of action of drought or salinization. Correlation analysis showed that RGB indices (especially, ExG, VARY, and g) were strongly related to the NDVI, PRI, and Fv/Fm; linear regressions between these values were calculated. It means that RGB indices measured by simple and low-cost color cameras can be used to estimate plant parameters (NDVI, PRI, and Fv/Fm) requiring sophisticated equipment to measure. Full article

(This article belongs to the Special Issue The Application of Spectral Techniques in Agriculture and Forestry—2nd Edition)

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22 pages, 4533 KiB

Open AccessArticle

Meta-Analysis of Mixed Sowing Effects on Forage Yield and Water Use Efficiency in China: Influencing Factors and Optimal Conditions

by Weiqiang Guo, Yuanbo Jiang, Minhua Yin, Yi Ling, Yanxia Kang, Guangping Qi, Yaya Duan, Yanlin Ma, Yushuo Liu, Gen Ling and Kaili Pan

Plants 2025, 14(9), 1283; https://doi.org/10.3390/plants14091283 - 23 Apr 2025

Abstract

Mixed sowing of forage grass can reduce soil erosion, improving forage nutritional composition, enhancing grassland productivity, and increasing community stability. It addresses issues faced by sown pasture, including a lack of diversity in planting patterns, low resource utilization efficiency, and poor sustainability. However, [...] Read more.

Mixed sowing of forage grass can reduce soil erosion, improving forage nutritional composition, enhancing grassland productivity, and increasing community stability. It addresses issues faced by sown pasture, including a lack of diversity in planting patterns, low resource utilization efficiency, and poor sustainability. However, the effects of mixed sowing on forage yield and water use efficiency (WUE) vary depending on regional environmental conditions, management practices, and temporal factors. Based on publicly available field experiment data, this study utilized meta-analysis to quantitatively examine the effects of mixed sowing on forage yield and WUE in China. Additionally, a random forest model was employed to analyze the main influencing factors. The results showed that, compared with monoculture, mixed sowing significantly improved forage yield and WUE, with average increases of 58.3% (confidence interval: 44.3–72.3%) and 32.0% (confidence interval: 19.2–44.8%), respectively. Regarding yield, the effect of mixed sowing was the most pronounced in Shaanxi. Optimal conditions included experiments conducted during 2006–2008, annual precipitation of 200–600 mm, soil pH of 4−5, average annual temperature of 10–15 °C, altitudes below 2000 m, alfalfa (Medicago sativa) and Bromus inermis as the forage combination, two species in the mixture, a legume-to-grass species ratio of 1:1, a total seeding rate of 40–50 kg·ha⁻¹, and mixed sowing in the same row. For WUE, significant effects were observed in Gansu under the following conditions: experiments conducted during 2018–2020, annual precipitation of 400–600 mm, an average annual temperature of 5–10 °C, a soil pH of 8–9, altitudes of 1000–2000 m, oats (Avena sativa) and peas (Pisum sativum) as the forage combination, two species in the mixture, a legume-to-grass species ratio of 1:1, a total seeding rate of <50 kg·ha⁻¹, and mixed sowing in alternate rows. The random forest model indicated that the effects of mixed sowing on forage yield were primarily influenced by annual precipitation, average annual temperature, and experimental region. In contrast, the effects on WUE were mainly determined by forage combination, species type, and the legume-to-grass species ratio. This study provides a reference for enhancing alfalfa productivity and achieving efficient water use. Full article

(This article belongs to the Special Issue Enhancing Soil Health and Crop Productivity Through Sustainable Agricultural Practices)

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29 pages, 5167 KiB

Open AccessArticle

Silicon-Mediated Modulation of Olive Leaf Phytochemistry: Genotype-Specific and Stress-Dependent Responses

by Marin Cukrov, Velemir Ninkovic, Luna Maslov Bandić, Šime Marcelić, Igor Palčić, Mario Franić, Paula Žurga, Valerija Majetić Germek, Igor Lukić, Darija Lemić and Igor Pasković

Plants 2025, 14(9), 1282; https://doi.org/10.3390/plants14091282 - 23 Apr 2025

Abstract

Secondary metabolites in olive (Olea europaea L.) leaves constitute a complex framework wherein phenylpropanoids, terpenoids, and secoiridoids in particular, serve as major contributors to olive plant resilience. Silicon (Si) stands as a mediator of defense mechanisms in plants, enhancing their protective responses [...] Read more.

Secondary metabolites in olive (Olea europaea L.) leaves constitute a complex framework wherein phenylpropanoids, terpenoids, and secoiridoids in particular, serve as major contributors to olive plant resilience. Silicon (Si) stands as a mediator of defense mechanisms in plants, enhancing their protective responses and adaptability. A field trial on one-year-old plantlets of two metabolically distinct olive genotypes was conducted to investigate the effects of foliar-applied Si on the phytochemical profiles of locally treated leaves. Silicon’s systemic effects in juvenile leaves were also appraised. We accounted for intervarietal differences in nutrient uptake and conducted in situ measurements of physiological indices. The peak of the summer season and the onset of autumn were chosen as the two sampling time points. Intense summer conditions prompted metabolic adjustments that resulted in phytochemical profiles unique to each cultivar. These profiles were further significantly altered by Si while remaining genotype-specific, with substantial increases in prominent compounds like oleuropein (105% and 252%) and verbascoside (62% and 126%), depending on the genotype. As the pressure from environmental factors eased, the differences in Si-mediated phytochemical responses emerged. Silicon had a limited effect on the phytochemical profile of the resilient cultivar which acquired a metabolic steady-state, while it significantly altered the profile of its metabolically more versatile counterpart, resulting with a progressive increase in its oleuropein (37%) and verbascoside (26%) levels. These effects extended to untreated, juvenile leaves as well. While effective in altering and improving the phytochemical composition of olive leaves, Si acted in a manner that adhered to each genotype’s metabolic foundation. The intensity of environmental constraints, along with each cultivar’s inherent sensitivity to them, seems to be tied to silicon’s capacity to mediate significant phytochemical alterations. The extent of silicon’s prophylactic function may therefore be dependent on a genotype’s metabolic foundation and overall sensitivity, and as such it seems inseparable from stress and its intensity. Full article

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14 pages, 4272 KiB

Open AccessArticle

Identification of a Highly Virulent Verticillium nonalfalfae Strain Vn011 and Expression Analysis of Its Orphan Genes During Potato Inoculation

by Mengyuan Wan, Xinlong Chen, Xiaoxi Yi, Yi Fu, Yuanliang Jin and Dianqiu Lyu

Plants 2025, 14(9), 1281; https://doi.org/10.3390/plants14091281 - 23 Apr 2025

Abstract

Potato (Solanum tuberosum L.) is an important food crop and in recent years, Verticillium wilt has become one of the major diseases limiting potato production. To study potato Verticillium wilt, a highly pathogenic strain was isolated from field samples in Heilongjiang. After [...] Read more.

Potato (Solanum tuberosum L.) is an important food crop and in recent years, Verticillium wilt has become one of the major diseases limiting potato production. To study potato Verticillium wilt, a highly pathogenic strain was isolated from field samples in Heilongjiang. After sequencing and morphological identification, the strain was confirmed as a host-specialized Verticillium nonalfalfae (V. nonalfalfae), Vn011. The genome analysis revealed 151 orphan genes in Vn011, and comparative transcriptomic analysis before and after potato inoculation showed differential expression of 21 genes, including several encoding low-complexity regions (LCRs) and transmembrane (TM) domains. These domains are known to be involved in pathogen signaling, protein folding, and phase separation processes. This study presents the whole-genome sequence of Vn011, having predicted and analyzed the expression changes of orphan genes during the infection process of V. nonalfalfae in potato, and provides new insights into the pathogenic mechanisms of the pathogen. Further research on these orphan genes will not only enhance the understanding of the evolutionary adaptation of V. nonalfalfae, but may also provide new molecular targets for the control of potato wilt disease. Full article

(This article belongs to the Section Plant Molecular Biology)

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13 pages, 2399 KiB

Open AccessArticle

Transcriptome Analysis of Pepper Leaves in Response to Tomato Brown Rugose Fruit Virus Infection

by Boshen Zhang, Donghai Wang, Mangle Chen, Jiali Yang, Junmin Li, Jianping Chen, Fei Yan and Shaofei Rao

Plants 2025, 14(9), 1280; https://doi.org/10.3390/plants14091280 - 23 Apr 2025

Abstract

Chili pepper (Capsicum annuum L.) is a very important vegetable crop, commonly used as a spice or seasoning in various dishes. With the growth of the global population, the demand for chili peppers has also increased exponentially. Tomato brown rugose fruit virus [...] Read more.

Chili pepper (Capsicum annuum L.) is a very important vegetable crop, commonly used as a spice or seasoning in various dishes. With the growth of the global population, the demand for chili peppers has also increased exponentially. Tomato brown rugose fruit virus (ToBRFV) is an emerging tobamovirus that has spread to dozens of countries worldwide. Its infection in chili peppers can severely impact yield and quality, posing a significant threat to the chili pepper industry. However, the transcriptional response of chili peppers to ToBRFV infection has not been studied yet. This research utilized RNA-Seq technology to analyze the transcriptional profiles of chili pepper leaves (‘Haonong 11’) 13 days post-infection with ToBRFV or mock treatment, identifying a total of 1468 differentially expressed genes (DEGs), of which 1366 were upregulated and 102 were downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that the DEGs were involved in biological processes such as defense response, response to reactive oxygen species, protein folding, and plant-pathogen interaction. Twelve DEGs were validated by RT-qPCR, with their expression trends consistent with the transcriptome data, indicating the reliability of the high-throughput data. Our systematic analysis provides a molecular basis for the response of chili pepper leaves to ToBRFV infection at the transcriptomic level and offers potential candidate genes for further research into the interaction mechanisms between ToBRFV and plant hosts. Full article

(This article belongs to the Section Plant Protection and Biotic Interactions)

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22 pages, 7129 KiB

Open AccessArticle

First Report of a Psyllid Vector of ‘Candidatus Phytoplasma pruni’ (Strain 16SrIII-J)

by Tomás Llantén, Sebastián Cabrera, Javiera Fuentes, Camila Gamboa, Constanza González, Alan Zamorano, Tomislav Curkovic, Daniel Burckhardt and Nicola Fiore

Plants 2025, 14(9), 1279; https://doi.org/10.3390/plants14091279 - 23 Apr 2025

Abstract

In Graneros, O’Higgins Region, Chile, the mallow psyllid (Russelliana solanicola Tuthill, 1959) from Malva nicaeensis L. was identified as a potential vector of ‘Candidatus Phytoplasma pruni’. Over an 8-month period, 2089 specimens of a species of Psylloidea, including immatures and adults, [...] Read more.

In Graneros, O’Higgins Region, Chile, the mallow psyllid (Russelliana solanicola Tuthill, 1959) from Malva nicaeensis L. was identified as a potential vector of ‘Candidatus Phytoplasma pruni’. Over an 8-month period, 2089 specimens of a species of Psylloidea, including immatures and adults, were captured. We only selected the adults used for transmission trials in Catharanthus roseus (L.) G. Don (periwinkle) plants. By nested PCR, using primer pairs for phytoplasma detection in 16S rRNA and IdpA genes, 7 out of 113 (6.2%) periwinkle plants used in transmission trials were found to be infected by phytoplasmas. Insects that fed on these plants also tested positive for the same phytoplasmas. Periwinkle plants never showed virescence and phyllody, as commonly occurs with phytoplasma 16SrIII-J infection due to the effector SAP54. In this case, using primer pairs for the SAP54 gene, an amplification product was never obtained. Virtual restriction fragment length polymorphism (RFLP) analysis of F2nR2 fragments indicated that the phytoplasma, found in both periwinkle plants and insects used in transmission trials, belongs to the 16SrIII-J ribosomal subgroup. The COI gene of the psyllids samples was amplified and sequenced, showing a similarity ranging from 84.84% to 85.02% with R. solanicola from Solanum tuberosum L. The mitochondrial genome of the psyllid was also sequenced, revealing a 14,835 bp circular DNA molecule with 37 genes. The mallow psyllid transmitted the phytoplasma 16SrIII-J to periwinkle plants. The molecular identification of the insect does not match the morphological one, indicating that the mallow psyllid may constitute a cryptic species within the polyphagous R. solanicola species. This is the first report of a psyllid as a vector of the phytoplasma 16SrIII-J. Full article

(This article belongs to the Collection Plant Disease Diagnostics and Surveillance in Plant Protection)

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20 pages, 5619 KiB

Open AccessArticle

Effects of Water–Nitrogen Coupling on Root Distribution and Yield of Summer Maize at Different Growth Stages

by Yanbin Li, Qian Wang, Shikai Gao, Xiaomeng Wang, Aofeng He and Pengcheng He

Plants 2025, 14(9), 1278; https://doi.org/10.3390/plants14091278 - 22 Apr 2025

Abstract

This research investigates the influence of water–nitrogen coupling on soil water content, nitrogen dynamics, and root distribution in farmland, along with the interactions among soil water, nitrogen transport, root distribution, and crop yield. A field experiment was conducted under moderate drought stress (50–60% [...] Read more.

This research investigates the influence of water–nitrogen coupling on soil water content, nitrogen dynamics, and root distribution in farmland, along with the interactions among soil water, nitrogen transport, root distribution, and crop yield. A field experiment was conducted under moderate drought stress (50–60% of field capacity) and three nitrogen application rates (100, 200, and 300 kg·ha⁻¹, split-applied at 50% during sowing and 50% at the jointing stage, labeled as N₁, N₂, and N₃) at the two critical growth stages (jointing stage P₁ and tasseling-silking stage P₂) of maize (Denghai 605). The results demonstrated that maize root morphological parameters exhibited the trend N₂ > N₁ > N₃ under different nitrogen treatments. Compared to N₂, low nitrogen (N₁) decreased root morphological parameters by 35.01–49.60% on average, whereas high nitrogen (N₃) led to a reduction of 49.93–61.37%. The N₂ treatment consistently maintained greater water uptake, with the highest yield of 13,336 kg·ha⁻¹ observed under the CKN₂ treatment, representing increases of 16.1% and 9.2% compared to the P₁N₂ and P₂N₂ treatments, respectively. Drought stress at the jointing stage (P₁) inhibited root development more severely than at the tasseling-silking stage (P₂), demonstrating a bidirectional adaptation strategy characterized by deeper vertical penetration under water stress and increased horizontal expansion under nitrogen imbalance. Correlation analysis revealed a positive correlation between soil nutrient content and maize yield indicators. At the same time, root characteristic values were significantly negatively correlated with yield (p < 0.05). Appropriate water–nitrogen management effectively stimulated root growth, mitigated nitrogen leaching risks, and improved yield. These findings offer a theoretical foundation for optimizing water and nitrogen management in maize production within the Yellow River Basin. Full article

(This article belongs to the Topic Irrigation and Fertilization Management for Sustainable Agricultural Production)

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21 pages, 5383 KiB

Open AccessArticle

Phytotoxicity Assessment of Solanum lycopersicum L. Seedlings Moderately Irrigated with Non-Thermal Plasma Treated Water Containing Sulfamethoxazole

by Marius Cicirma, Marius Dumitru, Sergiu Emil Georgescu and Aurora Neagoe

Plants 2025, 14(9), 1277; https://doi.org/10.3390/plants14091277 - 22 Apr 2025

Abstract

Contamination of agricultural ecosystems with antibiotics including sulfamethoxazole (SMX) can create favorable conditions to increase bacterial abundance in soil with antibiotic-resistant genes and can also affect plants. The aim of this research was to assess the phytotoxicity of tomato after irrigation with SMX [...] Read more.

Contamination of agricultural ecosystems with antibiotics including sulfamethoxazole (SMX) can create favorable conditions to increase bacterial abundance in soil with antibiotic-resistant genes and can also affect plants. The aim of this research was to assess the phytotoxicity of tomato after irrigation with SMX degraded in 20 min using the non-thermal plasma-ozonation technique (T20). To achieve this, two experiments were performed at the scales of Petri dishes and pots using Solanum lycopersicum L. species, cultivar Zaraza, subjected to irrigation treatments that were compared to a distilled water control. In plates, T20 solution improved root length and also seedling vigor indexes, but the germination index, germination speed, and biomass were slightly decreased. In soil, although T20 reduced the seedling root length, their growth was not inhibited (15.3%), while in plates they exhibited a growth promotion effect with 90% more than the control. The physical–chemical and geochemical variables measured in the soil were suitable for crop characteristics and plant growth and showed statistically significant variations after harvesting. In T20-treated shoots, compared to SMX, better results were obtained for their length, assimilatory pigments, and biomass, thus selectively reducing the tomato seedling phytotoxicity depending on the endpoints, type of control, and growth methods tested. Full article

(This article belongs to the Special Issue Agricultural Water Pollution Treatment and Water Use Safety)

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19 pages, 4999 KiB

Open AccessArticle

ABA Enhances Drought Resistance During Rapeseed (Brassica napus L.) Seed Germination Through the Gene Regulatory Network Mediated by ABA Insensitive 5

by Dan Luo, Qian Huang, Manyi Chen, Haibo Li, Guangyuan Lu, Huimin Feng and Yan Lv

Plants 2025, 14(9), 1276; https://doi.org/10.3390/plants14091276 - 22 Apr 2025

Abstract

ABA Insensitive 5 (ABI5) is a basic leucine zipper (bZIP) transcription factor (TF) that plays a critical role in seed dormancy and germination, particularly under stress conditions. This study identified ABI5 as an important candidate gene regulating seed germination under drought stress during [...] Read more.

ABA Insensitive 5 (ABI5) is a basic leucine zipper (bZIP) transcription factor (TF) that plays a critical role in seed dormancy and germination, particularly under stress conditions. This study identified ABI5 as an important candidate gene regulating seed germination under drought stress during early germination in rapeseed (Brassica napus L.) seeds through Genome-Wide Association Study (GWAS). Using Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9 (CRISPR/CAS9) technology, ABI5 mutant plants were generated, showing higher germination rates and more developed root systems at 72 h. Transcriptomic analysis of wild-type (WT) and mutant seeds under water, 2μM of abscisic acid (ABA), and 10% PEG treatments after 0, 24, 48, and 72 h revealed complex changes in gene regulatory networks due to ABI5 mutation. Differential expression analysis showed that the number of downregulated differentially expressed genes (DEGs) in the mutant was significantly higher than upregulated DEGs at multiple time points and treatments, indicating a negative regulatory role for ABI5 in gene expression. Weighted Gene Co-Expression Network Analysis (WGCNA) revealed that genes related to ABA content, such as those in the glutathione metabolism pathway, were similarly downregulated in the ABI5 mutants. Key genes, including BnA03g0120550.1 (GST), BnA09g0366300.1 (GST), BnA10g0413960.1 (gshA), and BnC02g0518750.1 (GST), were identified as potential candidates in ABI5-regulated drought responses. Additionally, TFs involved in regulating the glutathione metabolism pathway were identified, providing insights into the collaboration of ABI5 with other TF. This comprehensive transcriptomic analysis of ABI5 mutant plants highlights how ABI5 affects gene expression in multiple pathways, impacting seed germination and drought resistance, offering a foundation for improving drought tolerance in rapeseed. Full article

(This article belongs to the Special Issue Cell Physiology and Stress Adaptation of Crops)

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22 pages, 2623 KiB

Open AccessReview

Leaves and Tree Rings as Biomonitoring Archives of Atmospheric Mercury Deposition: An Ecophysiological Perspective

by Fabrizio Monaci and Davide Baroni

Plants 2025, 14(9), 1275; https://doi.org/10.3390/plants14091275 - 22 Apr 2025

Abstract

Trees mediate critical biogeochemical cycles involving nutrients, pollutants, water, and energy at the interface between terrestrial biosphere and atmosphere. Forest ecosystems significantly influence the global cycling of mercury (Hg), serving as important sinks and potential sources of re-emission through various biotic and abiotic [...] Read more.

Trees mediate critical biogeochemical cycles involving nutrients, pollutants, water, and energy at the interface between terrestrial biosphere and atmosphere. Forest ecosystems significantly influence the global cycling of mercury (Hg), serving as important sinks and potential sources of re-emission through various biotic and abiotic processes. Anthropogenic Hg emissions, predominantly from industrial activities, mining, and fossil fuel combustion, have substantially altered the natural Hg cycle, intensifying ecotoxicological concerns and establishing forests as primary routes for atmospheric Hg deposition into terrestrial reservoirs. This perturbation profoundly affects global atmospheric Hg concentrations, residence times, and spatial distribution patterns. While early investigations focused on forest stands near heavily polluted areas, contemporary research has expanded to diverse ecosystems, revealing that trees provide tissues that function as temporal archives for atmospheric-terrestrial Hg exchange. Leaves capture high-resolution records of contemporary Hg dynamics at sub-annual timescales, whereas annual growth rings preserve multi-decadal chronologies of historical atmospheric exposure. Incorporating this dual temporal perspective is crucial for analysing Hg deposition trends and assessing the efficacy of environmental policies designed to control and mitigate Hg pollution. This review critically evaluates recent developments concerning the ecophysiological determinants of Hg accumulation in trees, highlighting how combined foliar and dendrochemical analytical methods strengthen our mechanistic understanding of vegetation-atmosphere Hg exchange. To enhance biomonitoring approaches, we emphasised the need for methodological standardisation, deeper integration of ecophysiological variables, and consideration of climate change implications as priority research areas. Furthermore, integrating Hg measurements with functional markers (δ¹³C and δ¹⁸O) and Hg isotope analyses strengthens the capacity to differentiate between physiological and environmental influences on Hg accumulation, thereby refining the mechanistic framework underlying effective tree-based Hg biomonitoring. Full article

(This article belongs to the Special Issue Biological Responses of Plants to Environmental Pollution)

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