Germination Experiments Research Articles

Response of the germinable soil seed bank of temperate Leymus chinensis meadows to mowing regimes

Mowing is a primary practice in temperate L. chinensis meadows, which are severely degraded due to frequent mowing, overgrazing, and other factors, necessitating restoration and sustainable management. The natural recovery of these grasslands hinges on their germinable soil seed banks, which form the basis for future productivity. Thus, germinable soil seed banks are critical for restoring overexploited meadows. In this study, we conducted germination experiments on 135 soil samples from various depths to comprehensively analyze the germinable seed bank under different mowing regimes. The main results were as follows: (1) the germinable soil seed bank density decreased significantly with a mowing event per year (C1), and the number of perennial grass seeds and upper grass seeds also decreased under the mowing event per year; (2) the size of the germinable soil seed bank increased under the other mowing regimes (control area without mowing or grazing, CK; mowing event every 2 years, C2; mowing event every 3 years, C3; and mowing event every six years, C6) relative to that under once-a-year mowing. With increasing soil depth, the number of germinable soil seeds decreased significantly. Most of the seeds in the germinable soil seed banks were distributed in the 0–2 cm soil layer, accounting for approximately 80% of the total, and at depths of 5–10 cm, the number of seeds of upper grasses was greater than that of perennial grasses. (3). During the mowing event each year, the seed bank of germinable soil seeds significantly decreased. Mowing every 2 years provides a one-year interval for natural vegetation growth, allowing for greater retention of seeds in the germinable soil seed bank. Mowing every 6 years significantly reduces the disturbance frequency, providing ample time for plant reproduction and resulting in the accumulation of germinable seeds in the soil.

Impact of Fungal Symbionts of Co-occurring Orchids on the Seed Germination of Serapias orientalis and Spiranthes spiralis.

Interactions with mycorrhizal fungi are increasingly recognized as crucial ecological factors influencing orchids' distribution and local abundance. While some orchid species interact with multiple fungal partners, others show selectivity in their mycorrhizal associations. Additionally, orchids that share the same habitat often form relationships with different fungal partners, possibly to reduce competition and ensure stable coexistence. However, the direct impact of variations in mycorrhizal partners on seed germination remains largely unknown.We examined how fungal associates' specific identity and originaffect seed germination in Spiranthes spiralis and Serapias orientalis through in situ symbiotic germination experiments. A total of four fungal isolates, Tulasnellaceae and Ceratobasidiaceae were successfully isolated and cultured from S. spiralis and S. orientalis and two additional orchid species found in the same habitat: Neotinea tridentata and Orchis provincialis. While all fungal strains facilitated the swelling of seed embryos, only the fungal associate, a member of the Ceratobasidiaceae family isolated from N. tridentata, (NT2)was capable of inducing protocorm formation and subsequent seedling growth of S. spiralis seeds. Another fungal associate belonging to the Tulasnellaceae family and isolated from O. provincialis (OP3)supported seed germination up to the seedling stage of S. orientalis seeds. However, the remaining two fungal strains did not support seed germination. We conclude that fungal associates of co-occurring orchids can promote seed germination and seedling growth in S. spiralis and S. orientalis.

Fabrication of 2D/2D Bi2MoO6/Sx@g-C3N(4-y) type-II heterojunction photocatalyst for enhanced visible-light-mediated degradation of tetracycline in wastewater.

Aquatic biota and human health are seriously threatened by the dramatic rise in antibiotics in environmental matrices. In this regard, the present study aims to improve knowledge of the combined effects of heterojunction design and defect engineering on the photocatalytic degradation of pharmaceuticals in aqueous matrices. Advantageously, the positioning of the valence band (VB) and conduction band (CB) levels of Sx@g-C3N(4-y), being higher than those of Bi2MoO6, demonstrates the feasibility of forming a type-II heterojunction between these materials. Initially, S and N defects were inserted in S-doped g-C3N4 through an alkali-assisted calcination method (referred to as Sx@g-C3N(4-y)), as affirmed by the reduced concentrations of S and N in the end product. Thereafter, the Bi2MoO6/Sx@g-C3N(4-y) photocatalysts (referred to as BSxNy) were synthesized via a solvothermal method followed by calcination. Among the prepared samples, the integration of 10% Sx@g-C3N(4-y) with Bi2MoO6 (referred to as BSxNy (II)) demonstrated superior photocatalytic performance. Under optimal conditions, BSxNy (II) achieved a remarkable 92.4% degradation efficiency of tetracycline (TCL) in an aqueous solution after 60 min. The degradation rate of BSxNy (II) transcended that of pristine Sx@g-C3N(4-y) and Bi2MoO6 by 4.86 and 3.41 times, respectively. The higher number of active sites and the greater electron-hole pair separation are responsible for this improvement in the rate of TCL degradation. The photocatalyst also exhibited remarkable thermal/chemical stability and possessed reusability, as noted by 84% TCL degradation TCL up to 5 cycles. The radical scavenging experiment indicated O2˙- as the primary contributor towards TCL degradation, with h+ and ˙OH playing a secondary role. Additionally, a seed germination experiment used to measure phytotoxicity determined that the treated effluent was non-phytotoxic, making it suitable for irrigation.

Seed germination and seedling emergence responding to different osmotic potentials and burial depths of 242 Leptochloa chinensis populations

AbstractLeptochloa chinensis is a troublesome rice weed in many countries, and knowledge of its seed germination ecology varied in different reports. To reveal the range and general characteristics of L. chinensis seed germination under different drought stresses, and seedling emergence under different burial depths, we conducted a serial of germination experiments with 242 L. chinensis populations collected along ranges spanning 4° latitudes and 4° longitudes from rice fields in eastern China. We found that 1000‐seed weight ranged from 0.056 to 0.129 g, with an average of 0.088 g; the OR50 (the osmotic potentials at which the germination percentage reaches 50%) was −0.47 to −0.07 MPa, with an average of −0.28 MPa; and BR50 (the burial depth at which the emergence percentage reaches 50%) ranged from 0.07 to 0.26 cm, with an average of 0.18 cm. At −0.5 MPa, the mean germination percentage of 242 populations was 4.1%. Seed germination percentages under 0.5 and 1.5 cm quartz sand layer were both >75%, while no seedling emerged up to the surface of quartz sand. Populations collected from rice fields in northern regions leaned to be higher in 1000‐seed weights, and OR50 values. Moreover, populations collected from transplanting rice fields slightly and significantly leaned to be more adapted to drought stresses and soil burial depths. The ability to quickly germinate, together with seed germination sensitive to drought stress and seedling emergence sensitive to soil burial, facilitate L. chinensis to avoid suicide seed germination, occupy niches under suitable environments and escape chemical control practices on rice fields.

Hydrothermal treatment of septic sludge: Revealing temperature-sensitive dissolved organic matter and potential toxicity relationships in the hydrothermal liquid

Hydrothermal treatment of septic sludge can result in the transfer of significant amounts of dissolved organic matter (DOM) into the hydrothermal liquid (HL). However, there is a lack of research exploring the relationship between temperature-sensitive fractions of DOM in HL and ecological risks. In this study, spectroscopic techniques combining two-dimensional correlation spectroscopy (2D-COS), self-organizing maps (SOM) and structural equation modeling (SEM), respectively, were employed to investigate temperature-sensitive DOM and its potential correlation with phytotoxicity at five process temperatures (180–340 °C). The findings revealed that DOM content peaked at 260 °C, measuring 7625 mg·CL−1. At peak levels, the concentrations of chemical oxygen demand, ammonium nitrogen, total nitrogen, and total phosphorus in the HL reached 16900 mg L−1, 34.8 mg L−1, 1920 mg L−1 and 756 mg L−1, respectively. Results from EEM-PARAFAC-SOM indicated that temperature significantly influences the variations in fluorescent components within DOM. Additionally, 2D-COS analysis identified conjugated structures and critical turning points at 220 °C and 300 °C. Notably, the -CO-NH- functional group, which is closely associated with aromatic protein II, exhibited the highest sensitivity to temperature changes. Wheat seed germination experiments revealed that the DOM sample at 180 °C exhibited the most pronounced inhibition of wheat root length, while demonstrating the least effect on germination. In contrast, seed growth was most severely impaired at 340 °C. SEM analysis revealed the influence of temperature—both direct and indirect—on the properties of DOM, identifying aromatic protein I as the primary determinant limiting seed germination. This research provides valuable insights for the management and utilization of HL.

Seaweed liquid extract AS novel sustainable solutions for phycobioremediation plant germination, and feed additive for marine invertebrate copepod

Several studies have shown the importance of using seaweed liquid extract (True-Algae-Max, TAM) as a fish feed additive, and fish-water conditioner. In addition, TAM has demonstrated significant growth improvement when used as a plant growth biostimulant. This study investigates whether seaweed liquid extract (TAM) can achieve good results in new experimental fields such as chromium remediation, plant germination, and live feed supplementation for marine invertebrate Copepod (Oithona nana). In this study, several doses of TAM were tested, for the first time, for their impact on the remediation of chromium (Cr6+) ions from aqueous solutions and as an aqua feed additive for marine copepods (Oithona nana). In addition, it has been tested as promising for the seed germination of Fenugreek (Trigonella foenum-graecum) and Faba bean (Vicia faba L.). The most important factors influencing the removal (%) of Cr6+, identified using a two-level Plackett–Burman factorial design, were selected for additional optimization utilizing a rotatable central composite design. The maximum adsorption of Cr6+ was 93.65% under ideal operating circumstances, which included an initial Cr6+ concentration of 60 mg L−1, a temperature of 25 °C, a pH of 3, a TAM biomass of 0.05 g, and a contact time of 60 min at agitation conditions. Plackett–Burman design data shows the significance of each factor and how well the model fits the Cr6+ removal. The results of the germination experiment revealed that the highest significant increase in seed germination was achieved using a TAM level of 0.30 mg mL−1 with V. faba (88%) and 0.03 mg mL−1 with T. foenum-graecum (96.6%). Additionally, compared to the control group, TAM at a level of 0.037 mg mL−1 showed high root length enhancement on V. faba (184%) and T. foenum-graecum (188%). The results of the copepod O. nana feeding additive experiment found that the group fed on starch supplemented with TAM at a level of 0.3 mL L−1, compared to the control group that fed starch only, showed the highest increment in population growth (134.74%), fecundity (270.16%), and population composition of males (133.45%), adults (120.37%), and nauplius (203.18%). Moreover, compared to the control group, the copepod that fed starch supplemented with TAM levels achieved the highest Omega-9 content. In conclusion, it is shown that TAM is a feasible, efficient, and sustainable solution for biodegradable adsorbent for the Cr6+ from aqueous solution, enhances plant seed germination and root length, and is a novel feed additive for marine copepod O. nana, especially in marine invertebrate hatcheries.

Electro-activated peroxymonosulfate based on hollow cubic skeleton nanoflower cathode catalyst MoSe2/cubic nanocage (CNC) for enhanced degradation of norfloxacin: Performance, mechanism, degradation pathways and toxicity

Recently, antibiotic wastewater pollution has become increasingly serious. In this study, a novel hollow cubic framework self-supported nanoflower-like cathode catalyst (MoSe2/CNC) based on Co Fe prussian blue analogues (CoFePBA)-derived cubic nanocage (CNC) loaded with MoSe2 was successfully prepared and utilized in an electro-activated peroxymonosulfate (PMS) system for norfloxacin (NOR) degradation. Benefit from the combined structures of MoSe2, MoC, and Co/FeNC, the electrocatalytic activity and specific surface area were greatly improved. The effects of catalyst dosage and ratio, current, PMS concentration, electrolyte type, pH, as well as initial concentration were comprehensively investigated. Under the optimal conditions, NOR and TOC removal reached 92.70% and 82.17%, respectively, which was superior to the previous studies. Additionally, ·O2− was proved to be the primary reactive species for NOR degradation.·Based on density functional theory (DFT) and intermediates analysis, NOR underwent substitution and ring-opening reactions in the piperazine ring, substitution of fluoride ions, and cleavage of the carboxyl group and tetrahydropyridine ring, ultimately converting into water, carbon dioxide, and inorganic ions. Moreover, toxicity assessment and seed germination experiments demonstrated that the toxicity of NOR and intermediates were strongly decreased by electro-activated PMS system based on MoSe2/CNC cathode. Overall, this study not only contributes to the evolution of efficient and sustainable wastewater purification technology, but also provides valuable insights into the degradation of antibiotic wastewater.

Determining the effects of reduced water availability on seed germination of five bottomland hardwood tree species

Globally, floodplain forests are experiencing shifts in species composition associated with drier conditions and disruptions of flood pulse hydrology. The specific processes behind these shifts in composition are not fully understood, but differential effects of drought on regeneration processes such as seed germination may be partially responsible. To determine how reduced water availability impacts seed germination of different floodplain tree species, a lab-controlled germination experiment was conducted. Seeds from tree species common to floodplain forests of the southeastern and southcentral United States whose abundance have been altered by drier hydrogeomorphic conditions were examined. These seeds included desiccation resistant, or orthodox, seeds of sugarberry (Celtis laevigata) and green ash (Fraxinus pennsylvanica), and desiccation sensitive, or recalcitrant, acorns of overcup oak (Quercus lyrata), water oak (Quercus nigra), and willow oak (Quercus phellos). Seeds of each species were incubated with one of eight osmotically adjusted water solutions ranging in water potential from 0.0 MPa to −1.4 MPa. This reduction in water potential decreases the water available to the seeds for germination. After four weeks, seed germination of all species decreased with reduced water potential; however, desiccation tolerance did not correspond with the ability to germinate under lower water potential. Orthodox seeds only germinated in higher water potential treatments. Sugarberry reached 30 % germination in only the control 0.0 MPa treatment while green ash reached 30 % germination in treatments as low as −0.4 MPa. In contrast, recalcitrant acorns continued to germinate under lower water potentials. Water oak maintained 30 % or greater germination under all treatments and willow oak reached 30 % down to −0.8 MPa. Overcup oak was the only species to not respond to water potential treatment. With respect to maximum germination, sugarberry and green ash reached maximum germination an average of 9 days sooner than the oak species. The results of this study agree with others that demonstrate that seed germination success is sensitive to environmental water conditions and that species specific differences in germination traits are linked to broader life history strategies that are adaptive to common environmental conditions in their range.

Comparative study of adsorption and slow-release performance and mechanism of phosphoric acid and ammonia-modified biochars on 2,4-dichlorophenoxyacetic acid

Developing slow-release pesticides and reducing the migration of pesticides are the keys to improving the utilization efficiency of pesticides. Here, phosphorus-modified (P-WBC) and subsequent ammonia-modified biochar (NP-WBC) were prepared using pine tree sawdust at different pyrolysis temperatures (300 °C, 500 °C, and 700 °C), while the adsorption and desorption capacities of P-WBC and NP-WBC on 2,4-dichlorophenoxyacetic acid (2,4-D) were compared, as well as their intrinsic mechanism disparity. It was found that pyrolysis temperature, phosphorus- and ammonia-modification all improved the adsorption and slow-release of 2,4-D from biochar significantly through enriching the surface morphology, pore structure and optimizing the composition of functional groups of biochar. The adsorption mechanisms involved pore filling, hydrogen bonding, π-π interactions and phosphorus/nitrogen (P/N)-containing groups bonding, while the release behavior was predominantly governed by Fickian diffusion. The main active reaction sites of P-WBC and NP-WBC were the edge-located phosphate-like functional groups (C-O-P1) and pyridinic N, respectively, and C-O-P1 had the highest affinity for 2,4-D, as corroborated by density functional theory (DFT) calculation. Compared to NP-WBC, P-WBC exhibited greater 2,4-D adsorption and slow-release capacities, which was attributed to the stronger hydrogen bonding and P-containing functional groups bonding of C-O-P1 with 2,4-D. In particular, 500 °C P-WBC demonstrated exceptional thermal stability, great 2,4-D adsorption capacity (75.27 mg/g), and the most effective slow-release performance (9.34%). In addition, further germination experiments showed that 500 °C P-WBC loaded with 2,4-D (500 °C P-WBC@2,4-D) exhibited equivalent herbicidal efficacy to commercially available 2,4-D while also reducing the toxicity of the pesticide to maize to a certain extent. This work offers an avenue for the synthesis to prepare biochar as a carrier for slow-release pesticides under suitable pyrolysis temperature and modification method, improve pesticide efficiency, and reduce environmental pollution.

Effects of bear endozoochory on germination and dispersal of huckleberry in the Canadian Rocky Mountains.

Berries are a staple of bear diets during late summer and fall in the southern Rocky Mountains, enabling bears to build up fat reserves and prepare to enter torpor during winter. In turn, bears can benefit fruiting shrubs through dispersal of their seeds. Bears are highly mobile species and seed passage through their guts (endozoochory) can influence seed germination in three ways: deinhibition (removal of germination inhibiting compounds), scarification (mechanical or chemical alteration) and fertilization (enhancement of germination from increased nutrients). We conducted a germination experiment to assess the ways each mechanism of bear endozoochory affects germination success of huckleberry (Vaccinium membranaceum.) in the southern Canadian Rocky Mountains. The potential for bears to act as long-distance seed dispersers was also investigated, using a combination of available literature on bear gut retention times and movement data of 74 GPS radio-collared grizzly bears. Deinhibition had a positive significant impact (28.5% germination for the Seeds from Berry treatment compared to 0.2% for Whole Berry at 60 days), while scarification and fertilization did not have detectable positive effects on huckleberry germination success. These results suggest that the removing germination-inhibiting compounds in berry pulp is the primary mechanism through which endozoochory can increase germination in huckleberry seed. We estimated that 50% of the seeds defecated by bears in the region are dispersed 1.1 km away from feeding places (and up to 7 km). The surfaces covered by the seed shadow was up to 149.6 km2, demonstrating that bears can act as effective vectors of seeds over long distances. Endozoochory bolsters the germination success of seeds from fruiting shrubs, and enables seeds to spread to new locations using bears as dispersal agents. Development, resource extraction, and climate change may disrupt the beneficial relationship between bears and huckleberries, where huckleberries help bears gain fat, and bears help spread huckleberry seeds-a process that may become increasingly important as climate change alters habitats.

A visible seedling-stage screening system for the Brassica napus hybrid breeding by a novel hypocotyl length-regulated gene BnHL.

Rapeseed (Brassica napus) is a globally significant oilseed crop with strong heterosis performance. Recessive genic male sterility (RGMS) is one of the key approaches for utilizing heterosis in B. napus. However, this method faces the inherent challenge of being time-consuming and labour-intensive for removing fertile plants during seed production. Here, we report a hypocotyl length-regulated gene, BnHL, which is closely linked to a known fertility gene, BnMs2, serving as a seedling morphology marker. This marker could be used to identify fertile plants in the breeding of RGMS lines based on hypocotyl traits. By targeting the BnHL gene, both homozygous and heterozygous edited mutants exhibited significantly longer hypocotyls than the wild type (WT). Furthermore, germination experiments revealed that 7 days after seed germination, the difference in hypocotyl length between the mutant and the WT seedlings reached its maximum, effectively distinguishing fertile plants under both white (W) and red/far-red (R/FR) light. Mutations in BnHL did not result in significant changes in main agronomic traits. Thus, this study provides a comprehensive strategy for screening and identifying a new morphological marker gene for early screening in RGMS hybrid breeding with completely non-transgene during the whole production.

Effects of manakin gut passage on germination of a neotropical melastome shrub (Melastomataceae)

AbstractGut passage is an important but understudied component of animal‐mediated seed dispersal that can impact germination and survival. Melastomataceae plants are abundant and ecologically important throughout the tropics, but studies have obtained contrasting results regarding effects of avian gut passage on melastome germination. We conducted a paired germination experiment to test how gut passage by four species of manakins—key avian dispersers of melastomes—affects germination of the pioneer melastome shrub Miconia rubescens. Manakin gut passage accelerated M. rubescens germination, with gut‐passed seeds germinating an average of 5.1 days earlier than controls, and percent germination of gut‐passed seeds was significantly higher at 20 and 40 days post‐planting. Interestingly, manakin species varied in their gut passage effects, with L. velutina having stronger overall germination effects than M. manacus. Within species, greater body mass was correlated with higher percent germination and shorter times to first germination. Within M. manacus, seeds passed by females had significantly shorter times to first germination than seeds passed by males. Because control seeds were manually depulped in the experiment, the observed gut passage effects are likely attributable to minor scarification of the seed coat during gut transit. Our results suggest manakin gut passage can have biologically meaningful impacts on melastome germination, and the magnitude of these effects can vary based on manakin species, mass, and sex. This study refines our understanding of the “quality” component of seed disperser effectiveness in an iconic dispersal mutualism, with implications for plant community composition and recovery of deforested neotropical ecosystems.Abstract in Spanish is available with online material.

The reproductive strategy of a typical distylous Ophiorrhiza alatiflora (Rubiaceae), in fragmented habitat.

Heterostyly is a genetically controlled style polymorphism, that plays an important role in promoting outcrossing and improving reproductive fitness. Although distyly is often studied in plants of the Rubiaceae family, little attention has been paid to the reproductive strategies of distylous species in fragmented habitats. Here, We report for the first time the growth of Ophiorrhiza alatiflora, a type distylous species, in karst areas and evaluate its reciprocity between long styled morph and short one. We analyze the two distyly morph differences in the ancillary polymorphic of flowers and explore their reproductive strategy in fragmented habitats. In this study, we measured the floral characteristics of different morphs and performed differential secondary metabolite analysis on different morphs and tissue organs; Different pollination treatments were carried out to observe the fruit set, pollen germination, and pollen tube elongation of O. alatiflora. Our research indicates that O. alatiflora is a typical distylous plant for the distyly has high reciprocity. Both morphs exhibit the highest fruit set of intermorph outcrossing; The pollen germination and pollen tube elongation experiments have also demonstrated that the affinity of pollen from intermorph outcrossing is highest, regardless of whether it is the long or short morph as the maternal parent; Meanwhile, O. alatiflora is an incompletely self-incompatible plant that exhibits a certain degree of self-pollination and intramorph outcrossing, which may be one of the important means to ensure sustainable reproduction in severely disturbed habitats. In the ancillary polymorphic of flowers, L-morphs flowers produce more pollen, and S-morph flowers produce more ovules to improve their male-female fitness and compensate for the asymmetry of pollen flow; Compared with S-morphs, L-morphs contain significantly higher levels of several kinds of terpenoids. S-morphs produce more flavonoids than L-morphs. The differences in secondary metabolites between L-morphs and S-morphs are mainly reflected in the different nutritional organs (including stems and leaves). Overall, our work has revealed the unique reproductive strategy of O. alatiflora in fragmented habitats based on the characteristics of distyly, verifying the hypothesis that the distyly of O. alatiflora promotes outcrossing and avoids male-female interference, improving male-female fitness and this is the first time in the Ophiorrhiza genus.

Effect of Genotype and Altitude on the Germination of Freshly Collected Seeds from Wild-Growing Populations of Campanula pelviformis Lam. and Petromarula pinnata (L.) A. DC. (Campanulaceae)

The genetic wealth of range-restricted species is threatened by human activities such as habitat fragmentation or alteration. This research focused on the genotype effect in sexual propagation with freshly collected seeds of vulnerable local endemic plants in Crete, namely, Campanula pelviformis and Petromarula pinnata (Campanulaceae), which can be sustainably utilized for agro-alimentary, medicinal, and ornamental purposes. The morphological characteristics of seed length, width, and weight of freshly collected seeds from five wild-growing populations of C. pelviformis and seven wild-growing populations of P. pinnata from lowlands (<500 m) and semi-mountainous (>500 m) altitudes were measured and subjected to germination experiments at four incubation temperature treatments (10, 15, 20, and 25 °C). The effects of temperature, genotype, and their interactions were statistically significant for seed germination, with the results similar to those of previous studies on stored seeds of the same populations. Freshly collected seeds of both species germinated best at incubation temperatures of 10 °C and 15 °C (>68.13% for all population of C. pelviformis and >80.63% for six out of seven populations of P. pinnata), while significant differences were detected among genotypes for both species at each incubation temperature and among genotypes, even from similar altitudes. A statistically significant effect of altitude on germination percentages was observed at an incubation temperature of 20 °C between lowland and semi-mountainous genotypes for both species. The data produced in this study may enhance conservation efforts and lead to species-specific information that can be exploited in the future for their introduction as novel multi-purpose crops.

Tetracycline but not sulfamethazine inhibits early root growth of wild grassland species, while seed germination is hardly affected by either antibiotic

Seed germination and early growth of grassland species might be influenced by veterinary antibiotics that are extensively released into agricultural habitats. Therefore, we tested impacts of the commonly used antibiotics tetracycline and sulfamethazine, single and in mixture, on seed germination and seedling root growth of six typical species of temperate European grasslands (Carum carvi, Centaurea jacea, Galium mollugo, Plantago lanceolata, Silene latifolia, Dactylis glomerata). In standardised germination experiments, we assessed three germination variables (germination percentage, mean germination time, synchrony of germination) and one post-germination variable (seedling root length) under different environmentally realistic antibiotic concentrations (0.1, 1, 10 mg l−1 and a water control). While the germination variables were only irregularly and weakly affected by both antibiotics, seedling root length was strongly reduced by tetracycline, but not by sulfamethazine. Among the test species, D. glomerata was most sensitive to tetracycline with the average root length reduced up to 81 % in the 10 mg l−1 treatment. Its germination behaviour, however, was almost insensitive to the two antibiotics. Mixture effects were only shown in relation to the germination of single species, where the binary mixture produced effects but not the two single antibiotics or, conversely, effects of single antibiotics were lost in the mixture. These findings highlight the potential threat of plant regeneration from seed by veterinary antibiotics, particularly affecting early root growth and potentially influencing plant population growth in natural habitats.

Parental environment as a factor shaping salinity tolerance in halophyte Tripolium pannonicum L.

Parental environment can significantly influence a range of plant traits across different growth phases and developmental stages. The impact of parental salinity variability on offspring germination and environmental factor response still requires thorough investigation. Therefore, we investigated seeds of Tripolium pannonicum L. from low-saline (Cie) and high-saline (Ino) habitats to elucidate the germination potential and adaptation potential of progeny to varying salinity levels. Germination and growth experiments were conducted to analyze germination parameters, plant areas, water-related traits, the concentration of organic solutes, malondialdehyde, and the activity of crucial oxidative defence enzymes. In the germination experiment, Cie seeds demonstrated higher germination potential with longer germination time under 200–400 mM NaCl compare with Ino seeds. The Cie population achieved the highest shoot and roots area at 100 mM and 300 mM NaCl, respectively. The Ino population exhibited its highest shoot and roots area at 200 mM NaCl. The Ino population indicated an increase in stem cortex cell area at 400 mM NaCl. The Ino population enhanced the synthesis of osmolytes as part of the salinity tolerance mechanism. Antioxidant enzyme analysis indicated higher peroxidase activity in Ino and higher superoxide dismutase activity in Cie under salinity, suggesting distinct enzymatic roles in salinity adaptation between populations. Our findings highlight the critical role of parental environmental conditions in shaping progeny traits, enhancing germination potential, and enabling adaptation of progeny plants to diverse environmental niches. The study underscores population-specific responses to environmental factor, emphasizing the complexity of halophyte adaptation mechanisms to salinity.

The seed germination and seedling phytotoxicity of decabromodiphenyl ethane to tall fescue under citric acid amendment.

The novel brominated flame retardant decabromodiphenyl ethane (DBDPE) has biological toxicity, persistence, long-range migration and bioaccumulation ability. However, there is currently little research on the phytotoxicity of DBDPE in plants. The perennial herbaceous plant tall fescue (Festuca elata Keng ex E. B. Alexeev) was selected as the model organism for use in seed germination experiments, and the phytotoxicity of DBDPE in the soil of tall fescue was studied. The results indicated that DBDPE had a significant effect on the germination and growth of tall fescue seedlings. Citric acid reduced the stress caused by DBDPE in plants, effectively alleviating the phytotoxicity of DBDPE in tall fescue. The root vitality and protein content significantly increased after the application of citric acid, increasing by 74.93-183.90%, 146.44-147.67%, respectively. The contents of proline and soluble sugars significantly decreased after the application of citric acid, decreasing by 45.18-59.69% and 23.03%, respectively (P < 0.05). There was no significant difference in superoxide dismutase (SOD) or peroxidase (POD) activity in tall fescue seedlings, and the catalase (CAT) activity and malondialdehyde (MDA) content were significantly lower after the application of citric acid, decreasing by 64.62-67.91% and 29.10-49.80%, respectively (P < 0.05). Tall fescue seedlings bioaccumulated DBDPE, with biological concentration factors (BCFs) ranging from 4.28 to 18.38 and transfer factors (TFs) ranging from 0.43 to 0.54. This study provides theoretical support for the study of the toxicity of DBDPE to plants and offers a research foundation for exploring the phytoremediation of DBDPE-contaminated soil by tall fescue.

YOLOv8-licorice: a lightweight salt-resistance detection method for licorice based on seed germination state.

Seeds will display different germination states during the germination process, and their good or bad state directly influences the subsequent growth and yield of the crop. This study aimed to address the difficulties of obtaining the images of seed germination process in all time series and studying the dynamic evolution law of seed germination state under stress conditions. A licorice sprouting experiment was performed using a seed sprouting phenotype acquisition system to obtain images of the sprouting process of licorice in full-time sequence. A labeled dataset of licorice full-time sequence sprouting process images was constructed based on the four states of unsprouted, sprouted, cracked, and shelled in the sprouting process. An optimized model, YOLOv8-Licorice, was developed based on the YOLOv8-n model and its effectiveness was demonstrated by comparative and ablation tests. Different salt stress environments were simulated via NaCl aqueous solution concentration, and germination experiments of licorice seeds were performed under different salt stresses. The germination state of licorice under different salt stress environments was detected using the YOLOv8-Licorice detection model. Percentage curve of licorice seeds in an unsprouted state displayed a continuous decreasing trend. For the percentage curve of licorice seeds in the sprouted state, an increasing and then decreasing trend was observed under the condition of 0-200 mmol/L NaCl solution, and a continuous increasing trend was observed under the condition of 240-300 mmol/L NaCl solution. Licorice seeds in the cracked state demonstrated percentage curves with an increasing and then decreasing trend under the condition of 0-140 mmol/L NaCl solution and a continuous increasing trend under the condition of 160-300 mmol/L NaCl solution. The percentage curve of licorice seeds in shelled state displayed a continuous increasing trend in 0-200 mmol/L NaCl solution condition and remained horizontal in 220-300 mmol/L NaCl solution condition. Overall, this study provides a valuable method involving the seed sprouting phenotype acquisition system and the proposed method for detecting the germination state of licorice seeds. This method serves as a valuable reference to comprehensively understand the seed sprouting process under triggering treatment.

Facilitators or predators? The role of seed-feeding beetles in the germination of an ornamental and invasive plant in an urban environment

Leucaena leucocephala is a forage legume that provides cellulose, firewood, and shade in cities, although it presents a dangerous allelopathic and invasive potential. Its main natural enemy is the endophytic beetle Acanthoscelides macrophthalmus (Chrysomelidae: Bruchinae), whose larvae penetrate seeds and can consume the entire endosperm and embryos. However, there is much to explore on how the abundance of larvae inside the seed affects the plant germination, resulting in an antagonistic (predation) or mutualistic (facilitation) interaction. Our goal was to test how these beetles affect the germination of L. leucocephala seeds from an urban environment in Uberlândia, MG. We hypothesized that a single larva inside the seed facilitates germination since the exit holes left break the physical dormancy and enable water imbibition. On the other hand, two or more larvae inside the same seed result in predation, as the amount of endosperm is not enough for beetle satiation before they attack the seed embryo. We collected 100 pods, dissected them, and quantified and qualified the seeds. In the germination experiment, we used healthy seeds (control), scarified healthy seeds (physical treatment), and attacked seeds (one, two, or more larvae). We found that beetles infested 74% of the sampled seeds. Independently of the abundance of larvae inside the seed, attacked seeds did not germinate. The scarified seeds germinate faster and in greater quantity. Therefore, our hypothesis was rejected for the studied plant population. Acanthoscelides macrophthalmus acts only as a predator in an antagonistic interaction that decreases the germination rate of L. leucocephala.

Assessing the Role of AtGRP7 Arginine 141, a Target of Dimethylation by PRMT5, in Flowering Time Control and Stress Response.

PROTEIN ARGININE METHYLTRANSFERASES (PRMTs) catalyze arginine (R) methylation that is critical for transcriptional and post-transcriptional gene regulation. In Arabidopsis, PRMT5 that catalyzes symmetric R dimethylation is best characterized. PRMT5 mutants are late-flowering and show altered responses to environmental stress. Among PRMT5 targets are Arabidopsis thaliana GLYCINE RICH RNA BINDING PROTEIN 7 (AtGRP7) and AtGRP8 that promote the transition to flowering. AtGRP7 R141 has been shown to be modified by PRMT5. Here, we tested whether this symmetric dimethylation of R141 is important for AtGRP7's physiological role in flowering time control. We constructed AtGRP7 mutant variants with non-methylable R141 (R141A, R141K). Genomic clones containing these variants complemented the late-flowering phenotype of the grp7-1 mutant to the same extent as wild-type AtGRP7. Furthermore, overexpression of AtGRP7 R141A or R141K promoted flowering similar to overexpression of the wild-type protein. Thus, flowering time does not depend on R141 and its modification. However, germination experiments showed that R141 contributes to the activity of AtGRP7 in response to abiotic stress reactions mediated by abscisic acid during early development. Immunoprecipitation of AtGRP7-GFP in the prmt5 background revealed that antibodies against dimethylated arginine still recognized AtGRP7, suggesting that additional methyltransferases may be responsible for modification of AtGRP7.