Search Results (85)

With the aim of developing an efficient propagation method for the exploitation of Thymelaea hirsuta and T. artonraira ssp. tartonraira in the xeriscaping and pharmaceutical industry, the effects of the following were examined on the in vitro germination of their seeds: (i) pretreatment (mechanical and chemical scarification or immersion in hot water; (ii) incubation temperature (5–30 °C); (iii) incubation light conditions (16 h photoperiod or continuous darkness); (iv) storage period at room temperature and darkness (up to 24 months). Seeds collected for two years from the same wild plants in Greece were surface-sterilized with a 15% commercial bleach solution for 15 min after the abovementioned treatments and placed for germination in Petri dishes containing a half-strength MS medium in growth chambers. The rate and final percentage of germination were recorded. For both species, scarification after immersion in concentrated H₂SO₄, preferably for 20 min, was necessary for seed germination, which indicates coat dormancy. Higher germination percentages were observed at temperatures of 10–20 °C, under continuous darkness for T. hirsuta (79–100%) and regardless of photoperiod for T. tartonraira (73–90%). Long storage reduced germination of only T. tartonraira (54–68% at optimum temperatures, 23 months after harvest), while T. hirsuta seeds stored for 5 months germinated at significantly lower percentages (40% maximum) compared to seeds stored for 9–24 months, revealing a dry after-ripening process. Seeds of both species harvested at different years showed stable behavior in terms of germination. For both species, an effective seed propagation protocol suitable for their exploitation as ornamental and landscape plants was developed. Full article

High concentrations of sodium chloride (NaCl) in soil and water are increasingly common conditions in tomato (Solanum lycopersicum L.) production that impair the development and yield of this crop, generating the need for tolerant varieties. This research aimed to identify tomato lines tolerant to salinity during germination and early seedling development. A standard germination test was carried out in which 93 lines were evaluated under conditions of 0 and 80 mM NaCl for 12 days in a germination chamber with a temperature of 28 ± 1 °C and relative humidity of 80 ± 5%. At the seedling stage, 88 lines were evaluated under conditions of 0 and 150 mM NaCl in a floating raft system. During germination, saline conditions decreased germination percentage (37%), plumule (43%) and radicle (47%) length, dry matter (44%) and germination rate index (70%). At the seedling stage, NaCl decreased (p ≤ 0.05) plant height (44%) and leaf area (50%), without modifying root, aerial and total dry matter or root length. Twenty-eight tolerant lines were identified at germination and twenty-three at the seedling stage, seven of which were tolerant at both stages. This implies that salinity tolerance mechanisms differ in the developmental stages studied and makes it possible to combine these mechanisms to prolong tolerance during plant development. Full article

Crops are continually subjected to frequent and extreme changes in climate, such as high temperatures and soil water deficits. Many studies have shown the individual effects of these factors on plants, but their combined effects on reproductive growth and subsequent seed germinability have received little attention. In this study, we used canola (Brassica napus) plants and grew them through their lifecycle under two temperature regimes (20/10 °C and 24/14 °C, 16 h light/8 h dark) in controlled-environment growth chambers. Half of the plants were watered to field capacity (well-watered) and the other half at wilting point (water-stressed). During the reproductive stage, the flower, silique, and seed traits were measured. Higher temperatures decreased the petal width by 1.17 times but increased petal anthocyanins by 1.03 times. The water deficit decreased the silique length and total seed number by 1.21 and 1.32 times, respectively, but increased nectar sugar concentration by 1.28 times. The total volume of nectar was affected by the interaction of temperature and water. The nectar volume was lowest in the water-stressed plants under higher temperatures (2.66 ± 0.29 µL per flower) but highest in the well-watered plants under the same temperature regime (5.73 ± 0.37 µL per flower). In conclusion, the combined effects of temperature and water were less pronounced than the individual effects of these factors on canola reproductive yield. Full article

The present study aimed to investigate the effects of exogenous carnitine treatments on maize seed germination by stimulating lipid metabolism and regulating the mitochondrial respiratory pathway. Maize seeds were grown as control, 5, 7.5, and 10 μM carnitine treatment groups in a germination chamber at 25 °C under dark conditions for 5 d. It was determined that carnitine treatments increased the germination rate (GR), germination index (GI), germination potential (GP), vigor index (VI), root and hypocotyl length, fresh weight (FW), and content of total soluble protein but decreased the total carbohydrate content. It was also found that it increased the activities of α-amylase, isocitrate lyase (ICL), and malate synthase (MS) enzymes, which are critical in the germination process, and upregulated the expression of ICL and MS genes. To clarify the potential of carnitine treatments to promote the participation of lipids in respiration in roots and hypocotyls, lipase, carnitine acyltransferases (CATI and CATII), and citrate synthase (CS) enzyme activities were examined, and significant increases in these activities were detected. It was also found that gene levels of respiratory enzymes cytochrome oxidase (COX), pyruvate dehydrogenase (PDH), and Atp synthase, lipase, and CS proteins were upregulated by carnitine treatment. In support of the enzyme and gene change findings, significant changes were determined in fatty acid contents, free carnitine, and long-chain acylcarnitine levels in seeds, roots, and hypocotyls depending on carnitine application. In roots and hypocotyls, carnitine treatments significantly increased glutamine synthase (GS) and glutamate dehydrogenase (NADH-GDH) activities and gene expression levels, which are closely related to the tricarboxylic acid cycle (TCA). It was also noted that all proteins analyzed at the gene expression level were upregulated by carnitine applications in seeds. In addition, significant increases were recorded in antioxidant enzyme ascorbate peroxidase (APX) and superoxide dismutase (SOD) activities and total ascorbate (AsA) and glutathione (GSH) contents in roots and hypocotyls, while decreases were determined in guaiacol peroxidase (GPX) and catalase activities. Significant changes were recorded in all parameters examined, especially with 7.5 µM carnitine application. The findings suggest that carnitine may promote the transport of fatty acids to mitochondrial respiration by accelerating lipid catabolism in five-day-old maize and contribute to seed germination and growth and development processes by activating other metabolic pathways associated with respiration in this process. Full article

Pluchea ovalis (Pers.) DC. is an invasive alien plant species. It has spread widely on the island of Tenerife since it was first introduced, becoming a major threat to the island’s flora. The aims of this study are to analyze its germination capacity under different environmental conditions (e.g., light and temperature) and determine its effects on soil properties and native plant communities. Germination assays were carried out both in a germination chamber and in a greenhouse. Twelve plots were also established in the field to determine its effect on soil properties and plant species composition. Our results reveal that the germination capacity of Pluchea ovalis decreases under high temperature ranges and increases on flooded substrates. In addition, Pluchea ovalis can modify soil physicochemical properties by increasing soil magnesium content. As its invasive potential has been demonstrated, this study contributes with evidence of its effects on environmental conditions and species composition. Moreover, we recommend its inclusion in the Spanish Alien Invasive Species Catalogue and the development of further studies about its potential distribution and effects in the Canary Islands. Full article

Irrigation water quality is of critical importance for optimum crop yield of economically important field crops in the Kahramanmaraş plains. A preliminary ecotoxicological assessment is necessary before large-scale irrigation. Therefore, this study aims to evaluate the quality of irrigation water supplied from different water sources (Karasu, Erkenez, and Oklu streams on the Aksu River and Sır Dam) and the effects on the seed germination and early seedling growth of different field crops (wheat, alfalfa, ryegrass, and maize) irrigated with this water. For this, in order to evaluate the effects on seed germination and early growth parameters of forage crop seedlings, a Petri dish germination test was carried out with four replications using a completely randomized design (CRD). Before the germination assay, heavy metal concentrations including copper (Cu), iron (Fe), lead (Pb), chromium (Cr), arsenic (As), nickel (Ni), and cadmium (Cd) were analyzed in water samples obtained from different water sources. In all water samples used for the experiment, Cu concentrations exceeded the acceptable limit of 0.2 mg L⁻¹. The Cu levels found were 0.98 mg L⁻¹ in Karasu (KC), 1.627 mg L⁻¹ in Oklu (OC), 0.945 mg L⁻¹ in Erkenez (EC), and 1.218 mg L⁻¹ in Sır Dam (SD) waters. Additionally, Fe exceeded the limit only in KC, while Cd surpassed the permissible levels in EC and SD water samples. Seeds exposed to different water treatments were germinated in a climate chamber at 20 ± 1 °C. Over two weeks, daily germination and seedling growth parameters were measured. The results indicated that higher heavy metal concentrations in irrigation water led to a decline in seed germination rates and adversely impacted early seedling growth. Notably, water from Karasu Creek exhibited the most significant negative impact on all germination and growth parameters in the tested crops, especially due to Cu and Fe metal toxicity. Additionally, ryegrass seeds were most affected by these irrigation waters. This study highlights the importance of using uncontaminated quality irrigation water for optimal crop production by quantifying its impact, such as the percentage of decrease in germination or seedling growth. Full article

Kentucky bluegrass (KBG) has poor seed establishment in the fall when used as a perennial groundcover in corn production. This study was conducted to investigate the effect of various seed treatments and soil amendments on the establishment of KBG under drought and non-drought conditions, simulated in a growth chamber. The effect of seed treatments, soil amendments, and irrigation frequency on KBG germination and shoot dry weight were measured over 21 days in a controlled environment at 21 °C, 50% RH, and exposure to a constant red light. The treatments were the Hydroloc seed treatment, a lime soil amendment, the Pivot Bio seed treatment, an ammonium nitrate soil amendment, a gibberellic acid seed treatment, osmotic seed priming, and an untreated control. The layout was a randomized complete block design, with two irrigation frequencies (restricted and full irrigation) and four replications (blocks). The irrigation treatments were applied to whole plots and the seed treatments were applied to subplots. The entire experiment was repeated four times. Irrigation affected the germination of all the seed treatments, but the size of the effect depended on the seed treatment applied. The control and Hydroloc treatments did not have significantly different dry shoot weights, while all the other treatments had significantly different dry shoot weights when comparing the irrigation regimes. The Hydroloc treatment significantly outperformed all the other treatments in regard to the restricted and full irrigation regime. These results indicate that the Hydroloc seed treatment improves KBG germination and shoot dry weight in drought and non-drought conditions, promoting KBG establishment in a wide range of soil moisture conditions. Full article

The present study aimed to chemically profile the hydroalcoholic extracts from the microalgae (MEs) Nannochloropsis oculata, Phaeodactylum tricornutum, Tetradesmus obliquus, and Tetraselmis tetrathele and evaluate their effects on the development of Colletotrichum lindemuthianum and anthracnose symptoms, as well as on the initial growth of bean plants. For this, MEs were analyzed using UPLC coupled with a mass spectrometer, allowing the identification of peaks and annotation of potential metabolites. Fungal mycelial growth was assessed seven days after inoculation, and conidial germination was measured 72 h after incubation, using ME concentrations of 0, 0.1, 0.5, and 1.0 mg·mL⁻¹. Bean seeds of the IPR Uirapuru cultivar were sown and treated with 3 mL of extracts at four time points: at sowing and 72 h after each previous treatment. After 11 days of cultivation in a growth chamber, the plants were divided into two groups: one for anthracnose control assessment and the other for evaluating growth promotion by MEs. Plant length as well as fresh and dry weights of shoots and roots were determined, leaf pigments were quantified, and anthracnose severity was assessed using a diagrammatic scale. The UPLC analysis identified 32 compounds in the extracts of the four microalgae, belonging to different chemical and functional groups, with lipids being the most significant fraction. The extracts exhibited variability and diversity in chemical composition depending on the microalgal species. MEs did not affect mycelial growth yet increased the germination of C. lindemuthianum conidia, regardless of the dose or species used. Anthracnose severity was not affected by the microalgae extracts. Regarding growth promotion, the extracts showed varying effects but generally increased shoot and root length, fresh biomass, and leaf pigment content. Full article

Background: The germination and early development of Origanum vulgare L. subsp. hirtum (Link) Ietswaart (Greek oregano) were studied to assess the plant’s response to different temperatures. Methods: After germination, seedlings were cultivated in control (25 °C) and cold (15 °C) chambers with standard growth parameters. Comparative analyses of plant morphology and leaf anatomy were conducted to identify structural modifications induced by different temperatures. Physiological evaluations, including photosynthetic pigment measurements, phenolic content, and antioxidant activity, were performed to assess differences between the plants grown under the two temperature conditions. Methanolic extracts from the leaves were tested for cytotoxicity on MCF-7 breast adenocarcinoma cells and SH-SY5Y neuroblastoma cells, as well as on nine microbial strains. Additionally, biomarkers from the leaves affected by temperature changes were determined using LC-HRMS/MS analysis. Results: Comparative analyses revealed distinct structural and physiological modifications under cold conditions. The methanolic extracts from plants grown at 15 °C exhibited notably higher cytotoxic activity in both cell lines but demonstrated no activity against microbial strains. The results highlight the influence of low temperature on enhancing the bioactive properties of Greek oregano. Conclusions: The findings provide valuable insights into the environmental adaptability of oregano, demonstrating the impact of low temperature on its bioactive properties. The therapeutic potential of methanolic extracts cultured at 15 °C is imprinted in cytotoxicity in SH-SY5Y and MCF-7 cells and the absence of any activity against microbial strains. Full article

The ability of entomopathogenic fungi, such as Beauveria bassiana, to infect insects by penetrating their cuticle is well documented. However, some insects have evolved mechanisms to combat fungal infections. The red flour beetle (Tribolium castaneum), a major pest causing significant economic losses in stored product environments globally, embeds antifungal compounds within its cuticle as a protective barrier. Previous reports have addressed the contributions of non-cuticular infection routes, noting an increase in mortality in beetles fed with conidia. In this study, we further explore the progression and dynamics of oral exposure in the gut of T. castaneum after feeding with an encapsulated B. bassiana conidia formulation. First, we characterized the formulation surface using atomic force microscopy, observing no significant topological differences between capsules containing and not containing conidia. Confocal microscopy confirmed uniform conidia distribution within the hydrogel matrix. Then, larvae and adult insects fed with the conidia-encapsulated formulation exhibited B. bassiana distributed throughout the alimentary canal, with a higher presence of conidia before the pyloric chamber. More conidia were found in the larval midgut and hindgut compared to adults, but no germinated conidia were observed in the epithelium. These results suggest that the presence of conidia obstructs the gut, impairing the insect’s ability to ingest, process, and absorb nutrients. This disruption may weaken the host, increasing its susceptibility to infections and, ultimately, leading to death. By providing the first direct observation of fungal conidia within the alimentary canal of T. castaneum, this study highlights a novel aspect of fungal–host interaction and opens new avenues for advancing fungal-based pest control strategies by exploiting stage-specific vulnerabilities. Full article

Plastic pollution is a global concern due to its adverse environmental effects. Plastic production and consumption have continued to rise and are expected to double by 2050. Plastic disposal and degradation produce small particles of plastic—less than 5 mm—that can accumulate, infiltrate, or travel through soil, air, water, plants, and the environment. Healthy soil is a system in sync with good physical, chemical, and biological properties capable of supporting life. There is enough research to show the effects of microplastics (MPs) in aquatic environments; however, much is unclear about the effects of MPs on soil and food systems. To address this knowledge gap, two replicated germination experiments were conducted under a controlled environment in a germination chamber at the Water School Lab, Florida Gulf Coast University. The objective of this study was to determine the germination percentage (GP), mean germination time (MGT) and germination index (GI) of alfalfa seeds (Medicago sativa-VNS (variety not stated)) when germinated under two types of MP-treated soils: (1) fiber-fill plastic (FF) at 0.2% and 1% concentration and (2) plastic packaging (PP) at 0.2% and 1% concentration. The experiments were conducted in the germination chamber for 30 days at optimum germination temperatures of 25/18 °C day/night, with a 12-h photoperiod. The physical (texture, structure), chemical (pH, EC, moisture content (MC), and biological (microorganisms count) properties of the soil were analyzed in the laboratory to understand the impact of MPs on soil properties. In conclusion, our research shows MPs have minimal impacts on germination. Soil pH and MC (moisture content) decreased while EC increased across all treatments, and soil texture was negligibly altered. Microbial communities grew significantly across all treatments, showing that MPs can stimulate bacterial growth. Full article

(1) Background: According to the IUCN, Boswellia pirottae is classified as a vulnerable species. However, knowledge of its seed characteristics and germination behaviour is lacking. (2) Methods: The aim of this research was to characterise the seeds and evaluate the effects of seed colour and controlled temperatures on seed germination. The seeds were segregated into the following colour categories: light brown (LB), brown (B), and dark brown (DB). The seeds were evaluated under controlled constant temperatures (23 °C) and at room (fluctuating) temperature independently. One-way ANOVA, t-test, and germination indexes were used for analyses. (3) Results: The results showed significant differences in the mean seed masses of LB, B, and DB seeds. Similarly, the differently coloured seeds varied in their water imbibition rates. The result showed significant differences in the mean germination of the seeds in both the controlled temperature (23 °C) and room-temperature chambers among the LB, B, and DB seeds. However, the t-test revealed no significant differences in the mean germination of the seeds of similar colours between controlled temperature and room temperature conditions. (4) Conclusions: The seed’s colour significantly influenced the seed mass, water imbibition capacity, and germination rate relative to the temperature treatment. Dark brown seeds are recommended for seed collection aimed at seedling propagation. Full article

The aim of this work was to analyze the influence of thermal conditions and the presence of biomass in the chamber on the composting process. The work analyzed the process of the aerobic decomposition of grass, the inoculating fraction and the structure-forming fraction. The analysis covered the batch composting process using veterinary biomass in the treatment chamber. Observations of the process included the following: determining the rate of mineralization, process temperatures, pH, process gas concentrations, chemical composition, physical properties of the compost, and the maturity of the compost. In all analyzed samples, the composting process works correctly in terms of thermal parameters; the obtained fresh compost, after the thermophilic phase has ended, requires action be taken with reference to the values of the seed generation index and the respiration activity (AT4) parameter. After the thermophilic phase, after 60 days of composting, it was noted that for P1 (Probe 1) and P2 (Probe 2) mixtures, the seed germination level decreased below 10%. The AT4 parameter for the P1 and P2 compost samples was between 29.8 and 26.2 mg O₂∙g⁻¹. The improvement of the germination level to values in the 30% to 40% range for the maturing compost samples was caused by the thermal conversion of biomass with the regulation of air and water conditions. The phytotoxicity of the compost was overcome, while an improvement in the value of the AT4 index was achieved. Full article

In strawberry (Fragaria × ananassa Duch.) breeding programs, seed dormancy adversely affects germination, resulting in delayed seedling emergence and low germination rates. This study investigated the best solution to enhance strawberry seed germination both in terms of efficiency and timing by evaluating the effect of three key factors: genotype, pre-sowing treatment, and germination medium. Chemical scarification treatment with the sulfuric acid of seeds from three different genotypes was optimized; treated seeds were placed to germinate on three germination media (Murashige and Skoog medium, peat, and filter paper) in a growth chamber. Seedlings obtained were acclimatized for evaluating post-acclimatization survival rate and possible phenotypic differences regarding seedling development. Chemical scarification treatment produced the best results, with germination rates of around 100% and the highest speed of germination compared to the not-treated controls. Indeed, more than 90% of the seeds germinated 14 days after sowing, regardless of the genotype or germination medium tested. Seedlings germinated on filter paper gave the poorest performances in terms of post-acclimatization survival rate and showed lower average plant height. In conclusion, it was demonstrated that excellent germination rates can be achieved through proper seed scarification, which is not genotype dependent; furthermore, when this method is combined with the correct germination medium, excellent seedling quality can be achieved. Full article

Chemical products, such as seed dressings, are often used to regulate crop growth and development and improve yields. In this study, we investigated a seed dressing containing 0.136% gibberellic acid (GA), indole-3-acetic acid (IAA)-, and brassinolide (BL) as a wettable powder (WP), hereafter referred to as GA-IAA-BL WP. This product is a new plant growth regulator of plant origin that can improve crop stress resistance and yield. However, its effect on maize seed germination and seedling growth under low-temperature stress is unclear. In this study, GA-IAA-BL WP was applied to maize ‘Liukexing 99’ seeds at 50, 100, 150, or 200 mg mL⁻¹, and seeds were germinated in an artificial climatic chamber at 10, 15, or 25 °C for 14 d. Application at 100 mg mL⁻¹ significantly increased the germination rate as well as seedling shoot and root length and dry and fresh weight at all three temperatures. This application rate also increased the contents of proline, malondialdehyde, soluble sugars, and soluble proteins; the activities of catalase, superoxide dismutase, and peroxidase; and root vigor. Our results demonstrate that GA-IAA-BL WP can reduce the negative impacts of low-temperature stress on seed germination and seedling growth. Full article