International Journal of Plant Biology

20 pages, 800 KiB

Open AccessArticle

The Influence of Plant Growth Regulators (PGRs) on Physical and Chemical Characteristics of Hops (Humulus lupulus L.)

by Mengzi Zhang, Nicholas A. Wendrick, Sean M. Campbell, Jacob E. Gazaleh, Heqiang Huo, Katherine A. Thompson-Witrick and Brian J. Pearson

Int. J. Plant Biol. 2025, 16(3), 79; https://doi.org/10.3390/ijpb16030079 - 8 Jul 2025

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Abstract

Hops (Humulus lupulus L.) are a critical component in beer brewing. The growing demand for craft beer has increased interest in hop cultivation in non-traditional regions where unfavorable climatic conditions hinder optimal yield and quality. To address these challenges, this study investigates [...] Read more.

Hops (Humulus lupulus L.) are a critical component in beer brewing. The growing demand for craft beer has increased interest in hop cultivation in non-traditional regions where unfavorable climatic conditions hinder optimal yield and quality. To address these challenges, this study investigates the effects of plant growth regulators (PGRs) on hop cone yield and chemical compositions. In two separate studies, year-1 Cascade hops were subjected to various PGR treatments in the field. PGR treatments generally had minimal effect on the dry cone yield in study I. In study II, a combination of Ethephon at 45 mg/L and ProGibb at 3 mg/L significantly increased the cone yield by 125% compared to the control. While all treatments had a “good quality” hop storage index, a combination of Ethephon and ProGibb produced alpha acid percentages within the commercial standard range. Ethephon at 30 mg/L combined with ProGibb at 2 mg/L enhanced bitterness and aroma, delivering the highest concentration of volatile organic compounds at 569.7 mg/L, thereby enhancing aroma compounds associated with fruity esters, monoterpenes, and sesquiterpenes. This study demonstrates that specific PGR treatments can improve the chemical composition of hops grown in non-traditional regions, with implications for optimizing aroma and bitterness in beer. Full article

(This article belongs to the Section Plant Physiology)

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19 pages, 2268 KiB

Open AccessArticle

Methyl Jasmonate and Ammonium Bicarbonate: Distinct and Synergistic Impacts on Indoor Cannabis Production Dynamics

by Jose F. Da Cunha Leme Filho, Spencer Schuchman, Avery Shikanai, Shiksha Sharma, Thais Alberti, Andre A. Diatta, Alan Walters and Karla L. Gage

Int. J. Plant Biol. 2025, 16(3), 78; https://doi.org/10.3390/ijpb16030078 - 8 Jul 2025

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Abstract

As high-CBD cannabis (Cannabis sativa L.) gains legal and commercial relevance in the United States, studies evaluating how external inputs impact critical traits remain limited. This study investigates the effects of methyl jasmonate (MeJA), ammonium bicarbonate (AB), and the genetic source (mother [...] Read more.

As high-CBD cannabis (Cannabis sativa L.) gains legal and commercial relevance in the United States, studies evaluating how external inputs impact critical traits remain limited. This study investigates the effects of methyl jasmonate (MeJA), ammonium bicarbonate (AB), and the genetic source (mother plant identity) on the growth and secondary metabolite traits of indoor cannabis. Plants were treated with 1 mM MeJA and/or AB under controlled conditions, and key traits, such as plant height, chlorophyll content, biomass, trichome density, and cannabinoid concentration, were measured. The MeJA treatment led to a significant 32% increase in trichome density. However, it did not significantly alter CBD or THC concentrations. The AB treatment enhanced vegetative growth, increasing chlorophyll content and plant height while reducing CBD concentrations, but the biomass gains could compensate for the lower cannabinoid in the total production. An interaction between MeJA and AB altered the CBD content, suggesting that MeJA may mitigate AB’s negative effect on cannabinoid synthesis. The genetic source significantly influenced most of the measured traits, highlighting the role of the genotype in trait expression and the importance of clonal consistency. These findings highlight the complex dynamics of external inputs and genetic factors in cannabis production, emphasizing the need for further research to optimize cultivation strategies. Future studies should refine input combinations and doses to improve both yield and cannabinoid profiles. Full article

(This article belongs to the Special Issue Challenges in Cannabis sativa: Breeding and Secondary Metabolite Synthesis)

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21 pages, 4024 KiB

Open AccessArticle

Floristic Diversity, Indicator and Suitable Species for Andean Livestock in the Sillapata Micro-Watershed, Acopalca

by Raúl M. Yaranga, Fernan C. Chanamé, Edith M. Maldonado and Javier A. Orellana

Int. J. Plant Biol. 2025, 16(3), 77; https://doi.org/10.3390/ijpb16030077 - 7 Jul 2025

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Abstract

Andean grassland ecosystems in Peru are characterized by diverse plant species adapted to environmental factors including weather, soil type, elevation, slope orientation, and soil moisture. This study evaluated the floristic composition, alpha diversity, indicator species, and suitable species for Andean livestock in the [...] Read more.

Andean grassland ecosystems in Peru are characterized by diverse plant species adapted to environmental factors including weather, soil type, elevation, slope orientation, and soil moisture. This study evaluated the floristic composition, alpha diversity, indicator species, and suitable species for Andean livestock in the Sillapata micro-watershed, Junín region, Peru, across rainy and dry seasons. Data collection involved 100 m linear transects, and analyses included floristic composition and dissimilarity, Shannon-Wiener (H′) and Simpson (D) diversity indices, and the identification of indicator and suitable species using QGIS vs 3.28.14 and R software vs 4.3.2. Results revealed a total of 130 species classified into 74 genera and 23 families, with Asteraceae and Poaceae as the dominant families, exhibiting variations in richness and dissimilarity between control points and seasonal periods. Alpha diversity (H′) ranged from 2.07 to 3.1867, while Simpson’s index (D) ranged from 0.7644 to 0.9234. Six indicator species were identified, along with 11 families containing suitable species, predominantly Poaceae (38–60%), Cyperaceae (11–15%), and Asteraceae (3–9%). The findings indicate that the studied ecosystem exhibits a heterogeneous floristic composition with medium to low and variable diversity, influenced by seasonal climatic changes and the current grassland management regime, which involves rotational grazing with cattle adapted to high-altitude conditions. Full article

(This article belongs to the Section Plant Ecology and Biodiversity)

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14 pages, 996 KiB

Open AccessArticle

Interactive Effect of Copper and Herbivory on the Whole-Plant Growth of Leucaena leucocephala

by Shirley Margarita Amaya-Martín, Horacio Salomón Ballina-Gómez, Esaú Ruíz-Sánchez, Gabriel Jesús Azcorra-Perera, Roberto Rafael Ruiz-Santiago and Jacques Fils Pierre

Int. J. Plant Biol. 2025, 16(3), 76; https://doi.org/10.3390/ijpb16030076 - 6 Jul 2025

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Abstract

This study investigated how Leucaena leucocephala, a dry forest plant, copes with soil copper and herbivory caused by Schistocerca piceifrons, crucial for understanding species adaptation in stressed environments. A 33-day factorial experiment with three copper and two herbivory treatments assessed seedling [...] Read more.

This study investigated how Leucaena leucocephala, a dry forest plant, copes with soil copper and herbivory caused by Schistocerca piceifrons, crucial for understanding species adaptation in stressed environments. A 33-day factorial experiment with three copper and two herbivory treatments assessed seedling growth rates (relative growth rate of biomass—RGR_B, and leaf area—RGR_LA), morphology, net assimilation rate (NAR), biomass allocation, and survival. Seedlings demonstrated compensatory growth in terms of RGR_B and RGR_LA under high copper and herbivory. Although copper decreased overall survival, surviving individuals effectively compensated for herbivory damage. These tolerance responses, primarily driven by an increased NAR (accounting for 98% of compensation), aligned with the limiting resource model. While most morphological components remained stable, herbivory specifically increased the root–shoot ratio. These findings indicate L. leucocephala possesses significant resilience through physiological adjustments, like enhancing NAR, and biomass reallocation strategies, allowing it to persist despite multiple stressors common in dry forests. Full article

(This article belongs to the Special Issue Plant Resistance to Insects)

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14 pages, 2148 KiB

Open AccessArticle

Exploring the Potential of Biocontrol Agent Against Root and Stem Rot Disease in Durian (Durio zibethinus)

by Ponchanok Datmanee, Nattarika Jitfour, Dusit Athinuwat and Wilawan Chuaboon

Int. J. Plant Biol. 2025, 16(3), 75; https://doi.org/10.3390/ijpb16030075 - 6 Jul 2025

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Abstract

The study of antagonistic bacterial strains isolated from the soil around durian tree roots demonstrated their ability to inhibit the growth of Phytophthora palmivora. The pathogens were screened from 30 samples collected around durian trees (leaves, soil around the roots, and debris [...] Read more.

The study of antagonistic bacterial strains isolated from the soil around durian tree roots demonstrated their ability to inhibit the growth of Phytophthora palmivora. The pathogens were screened from 30 samples collected around durian trees (leaves, soil around the roots, and debris under the tree) showing symptoms of root and stem rot disease. A total of 17 pathogen strains were isolated and grouped into 3 groups, TNP05, MNP13, and KNP21, originating from Chanthaburi province, Thailand. When P. palmivora isolates were tested for pathogenicity on leaves and durian trees, it was found that the strain MNP13 had the highest capacity to cause root and stem rot disease. A total of 196 beneficial bacteria isolates were collected from several samples around durian trees. The samples included leaves, soil surrounding the roots, and organic debris beneath the trees. Based on their colony characteristics on nutrient glucose agar (NGA), these isolates were divided into 8 groups. The efficacy of the beneficial bacteria against root and stem rot disease was tested using the Dual culture method and arranged in a Completely Randomized Design (CRD) with 5 replications. The experiment showed that bacterial isolates NJTU05, NJTU10, and NJTU13 effectively inhibited the growth of P. palmivora isolate MNP13, with inhibition rates of 76.66, 67.59, and 69.07%, respectively, compared to chemical control using metalaxyl 80% WP. Among the tested strains, NJTU05 was identified as the most effective bacterial strain for controlling major durian diseases. Biochemical identification and 16S rRNA sequencing revealed that bacterial strain NJTU05 was closely related to Brevibacillus formosus with a 99.70% identity. Full article

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

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14 pages, 1899 KiB

Open AccessArticle

Ascorbate Regulates Root Development Through Auxin Response in Arabidopsis thaliana

by Taras Pasternak

Int. J. Plant Biol. 2025, 16(3), 74; https://doi.org/10.3390/ijpb16030074 - 3 Jul 2025

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Abstract

Ascorbic acid (ASC) is a furan-based lactone derived from 2-ketogluconic acid that functions as a major antioxidant and redox buffer in mature plant tissues, although its content is lower in meristematic cells. ASC is commonly considered a reactive oxygen species (ROS) scavenger; however, [...] Read more.

Ascorbic acid (ASC) is a furan-based lactone derived from 2-ketogluconic acid that functions as a major antioxidant and redox buffer in mature plant tissues, although its content is lower in meristematic cells. ASC is commonly considered a reactive oxygen species (ROS) scavenger; however, its role in the regulation of plant development remains unclear. Additionally, the chemical behavior of ascorbate warrants special attention during ASC supplementation in in vitro plant culture. In this study, I investigated in detail the behavior of ascorbate in plant tissue culture medium and its uptake by plants. As a secondary objective, the role of ascorbate in root growth regulation was evaluated. The effects of low ASC levels on root architecture and its interaction with auxin signaling were studied using the vtc1 and vtc2 mutants of Arabidopsis thaliana, as well as through external ascorbate supplementation. Several marker lines for auxin response/distribution were used, along with direct ascorbate measurement via HPLC. Reducing ascorbate content through mutations had no significant effect on root development or auxin signaling, whereas high-concentration ASC supplementation inhibited both auxin signaling and root development, as demonstrated using auxin response and transport markers. At the organ level, ASC supplementation significantly downregulated auxin response-mediated cell cycle activation during lateral root induction. Based on the data presented, exogenous ascorbate may regulate root development through its interaction with auxin signaling pathways. Full article

(This article belongs to the Section Plant Physiology)

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24 pages, 3225 KiB

Open AccessArticle

Assessment of Paulownia tomentosa Steud. Regeneration Capacity Through Root Cutting Diameters, Growth Hormone doses and Soil Types

by Afef H. Nasraoui, Yasmin M. Heikal, Mohammed Ali, Chedly Abidi and Youssef Ammari

Int. J. Plant Biol. 2025, 16(3), 73; https://doi.org/10.3390/ijpb16030073 - 1 Jul 2025

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Abstract

This investigation proposes an effective protocol (cutting) for Paulownia tomentosa production in Tunisia during the 2022–2024 period. The effects of the three interactive parameters: root cutting diameter (L1, 0.5; L2, 0.8; L3, 1.25; and L4, 2 cm), indole-3-butyric acid (IBA) hormone concentrations (C, [...] Read more.

This investigation proposes an effective protocol (cutting) for Paulownia tomentosa production in Tunisia during the 2022–2024 period. The effects of the three interactive parameters: root cutting diameter (L1, 0.5; L2, 0.8; L3, 1.25; and L4, 2 cm), indole-3-butyric acid (IBA) hormone concentrations (C, 0; T1, 0.1%; and T2, 0.3%), and soil type (S1: 50% silt + 50% potting soil, and S2: 43% potting soil + 43% silt + 14% sand), were investigated. The data showed that cutting roots with 0.5 cm dimensions, a cutting treatment with hormone (0.3%), and the S2 soil type corresponded to a growth enhancement in height. These results revealed the broad changes in flowering of P. tomentosa. Also, data revealed that the root cutting diameter had the greatest influence on the biochemical contents of 4-month-old P. tomentosa sprouts. The studied pathway revealed that the auxin precursor IBA contributes toward active auxin [indole-3-acetic acid (IAA)] biosynthesis. Overall, this study found substantial changes in the morphological, biochemical, and floral features of new P. tomentosa sprouts under the interactive factors. To summarize, vegetative propagation of Paulownia, particularly through root cutting, allows for proliferation and plantation development. These findings can be applied to future breeding efforts with Paulownia to improve and protect it as a woody species, forage, and medicinal plant. Full article

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11 pages, 6980 KiB

Open AccessCommunication

Pollination and Essential Oil Production of Lavandula angustifolia Mill. (Lamiaceae)

by Riley B. Jackson, Tyler M. Wilson, Joseph S. Wilson, Zabrina Ruggles, Lindsey Topham Wilson, Chris Packer, Jacob G. Young, Christopher R. Bowerbank and Richard E. Carlson

Int. J. Plant Biol. 2025, 16(3), 72; https://doi.org/10.3390/ijpb16030072 - 1 Jul 2025

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Abstract

Lavandula angustifolia Mill., lavender, is an aromatic plant in the Lamiaceae family. Lavender, which is native to the Mediterranean region but cultivated throughout the world, is an important economic plant. Several studies have investigated two aspects of this aromatic plant: (1) which pollinators, [...] Read more.

Lavandula angustifolia Mill., lavender, is an aromatic plant in the Lamiaceae family. Lavender, which is native to the Mediterranean region but cultivated throughout the world, is an important economic plant. Several studies have investigated two aspects of this aromatic plant: (1) which pollinators, particularly bees, pollinate lavender, and (2) the composition of lavender essential oil. However, little research has been conducted to investigate how pollination affects either the yield or phytochemistry of lavender. The current study, which was conducted in North America, investigates which bee species visit lavender and how pollination affects plant chemistry, specifically the essential oil produced by lavender. Over the course of the 5-week observational period, a total of 12 species (across 10 genera) of bees were identified visiting lavender. Compared to previous studies on cultivated lavender at the same site (Mt. Nebo Botanical Farm, Mona, UT), four bee species not previously observed on lavender were identified. These included Hoplitis producta, Nomada sp., Osmia trevoris, and Megachile snowi. Pollinated lavender, compared to lavender excluded from pollinators, produced more essential oil (yield (w/w) = 1.49% vs. 1.07%), lower relative amounts of linalool (35.4% vs. 39.9%), and higher relative amounts of linalyl acetate (21.3% vs. 16.8%). The findings of this study demonstrate the ecological interactions between pollinators and lavender, and how those interactions impact phytochemistry. Full article

(This article belongs to the Special Issue Plant Resistance to Insects)

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11 pages, 25050 KiB

Open AccessArticle

Screening of Ty1-copia Retrotransposons in Water Onion (Crinum thaianum), an Endangered Species in Thailand

by Piriya Putanyawiwat, Chatuporn Kuleung, Mayura Veerana and Vipa Hongtrakul

Int. J. Plant Biol. 2025, 16(3), 71; https://doi.org/10.3390/ijpb16030071 - 26 Jun 2025

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Abstract

Crinum thaianum, commonly known as water onion, is an endangered species which is primarily threatened by flood-control-related habitat destruction and illegal harvesting for export, resulting in a sharp population decline; its genetic data still remains poorly studied. Retrotransposon-based markers have received significant [...] Read more.

Crinum thaianum, commonly known as water onion, is an endangered species which is primarily threatened by flood-control-related habitat destruction and illegal harvesting for export, resulting in a sharp population decline; its genetic data still remains poorly studied. Retrotransposon-based markers have received significant attention due to their higher potential informativeness compared to conventional marker methods in genetic diversity studies. This study focused on the screening of Ty1-copia retrotransposons, which have been widely studied and are commonly used as molecular markers in various plant species. Ty1-copia reverse transcriptase (rt) fragments were amplified using degenerate primers targeting conserved regions, followed by cloning and sequencing. Sequences were screened for rt gene homology and translated into amino acid sequences. Lineages were assigned by alignment, and phylogenetic analysis was performed for each isolated sequence with a set of well-classified rt genes. The p-distance values were calculated between the isolated sequences and their closest homologous sequences. A total of 123 isolated sequences were analyzed, representing conserved domains in the rt gene of Ty1-copia elements from C. thaianum and four other Crinum species. The results revealed sequence homology to the Ale, TAR, or Angela lineages, which showed the closest resemblance to 9, 4, and 110 isolated rt sequences, respectively. The conserved rt domain SIYGLKQA was mostly found in Angela (87.27%), while SLY/HGLKQS/L and SLYG/ELKQF/S were mostly found in Ale (66.67%) and TAR (75.00%), respectively. The p-distance values obtained from comparisons with Ty1-copia elements in other plants suggest that the Angela and TAR lineages are more evolutionarily conserved than the Ale lineage. Whilst our study sheds light on the variety of Ty1-copia retrotransposons in C. thaianum and other Crinum species, further research on additional Crinum species and other plants is required to enhance our understanding and facilitate future retrotransposon-based marker development. Full article

(This article belongs to the Section Plant Biochemistry and Genetics)

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Int. J. Plant Biol., Volume 16, Issue 3 (September 2025) – 9 articles

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