Higher Germination Research Articles

Physiological quality of Passiflora edulis Sims seeds evaluated by different processing methods, storage times and packages

ABSTRACT Maintaining seed vigour during the storage process is essential for the success of germplasm banks of sexually propagated species such as Passiflora edulis. However, the literature is still scarce regarding efficient preservation methods, especially for long periods. The objective of this study was to evaluate the effect of different seed processing methods, types of packaging and storage conditions of Passiflora edulis seeds for a period of five years. Different seed processing methods (natural fermentation and use of a mixer), packaging (Falcon tubes, plastic bags and paper bags), storage temperatures (room temperature, cold chamber and refrigerator) and evaluation times (one, three and five years) were analysed. Seeds stored in a refrigerator and cold chamber maintained high germination (>90%) for up to five years. However, seeds stored at room temperature reduced their viability after one year of storage. No significant variations were observed between the seed processing and packaging methods evaluated. Absence of respiratory activity was confirmed by the tetrazolium test performed on seeds stored for five years at room temperature. To maintain the vigour of P. edulis seeds, it is recommended to store them in a cold room or refrigerator in different packaging and using different methods for seed extraction.

Primary screening of growth-stimulating properties of rhizosphere microorganisms in relation to tomato seeds

The ability of bacterial isolates isolated from the rhizosphere of cultivated and wild plants of arid ecosystems of the Astrakhan region, which have the ability to tryptophan-induced synthesis of indolyl-3-acetic acid, to stimulate the germination of tomato seeds of the varieties “Sanka”, “Volgogradsky”, “Cosmonaut Volkov”, was studied. “Newbie” Experimental studies were carried out through laboratory experiments by incubating seeds in humid chambers; laboratory germination and morphometric parameters of seedlings were assessed. It was revealed that most of the studied suspensions of isolates have a stimulating effect on tomato seeds. High germination (90% or more) of seeds of the “Sanka” variety was observed when 12 isolates were treated with suspensions; variety “Volgogradsky” – suspensions of 9 isolates; variety “Cosmonaut Volkov” – suspensions of 2 isolates; variety “Novichok” – suspensions of 3 isolates. Suspensions of isolates 16/19 and 31/20 contributed to high germination of seeds of all varieties: up to 86.6–100% and 90–100%, respectively, and isolate 9/19 significantly reduced the germination of seeds of the varieties “Volgogradsky”, “Cosmonaut Volkov” and “Novichok” by 66.6–56.7%. When assessing the morphometric parameters of seedlings in the experiment, it was noted that the suspension of isolate 16/19 helps to increase the biomass of the varieties “Sanka”, “Volgogradsky” and “Cosmonaut Volkov” up to 273–449%. Suspension of isolate 31/20 has a stimulating effect on the morphometric parameters of seedlings of all varieties: it stimulates root development by 73.3–183.3%, stem development by 46.8–100.5%. The isolate 9/19 suspension not only inhibits seed germination, but also causes a reduced accumulation of seedling biomass, inhibits the development of roots and stems of seedlings of the varieties “Volgogradsky”, “Cosmonaut Volkov” and “Novichok”. Thus, during experimental studies, isolates (16/19 and 31/20) of rhizosphere bacteria were identified that have a stimulating effect on both the germination of tomato seeds and the morphometric parameters of seedlings.

English

Coffee breeding programs aim at developing superior genotypes, which entail exploring the genetic variability existing in conilon/robusta coffee. This study aimed at examining the variability and estimate genetic param of physical and physiological nature in Coffea canephora seeds in order to provide bases for the selection of genotypes for superior seeds quality. Forty-three C. canephora genotypes were evaluated for 11 physical and physiological seed traits. Estimates of genetic param, environmental variance, phenotypic variance, genotypic variance, broad-sense heritability, variation index and Pearson's correlation were obtained. The Dissimilarity between genotypes was obtained by generalized Mahalanobis distance. The dendrogram was constructed using unweighted pair group method with arithmetic mean (UPGMA). C. canephora genotypes presented high germination potential and exhibited genetic diversity for all seed traits, with estimates of genetic variance greater than environmental variance. Heritability reached values above 96.0% and all genetic variation indices found were higher than unity. The UPGMA hierarchical method grouped the genotypes in three groups. The physical traits (circumference, area and roundness) were those that contributed the most to explaining the dissimilarity between genotypes. Genotypes Alecrim, AP, Bamburral, Z39 and Tardio C were the most divergent. The results revealed the presence of genetic variability between C. canephora genotypes and greater genetic than environmental influence on the characters of seeds, indicating that selection for the studied traits showed favorable conditions in terms of immediate gain.

Preliminary Studies on Seed Dormancy of Premna latifolia Roxb.

Background: Premna latifolia Roxb. (Lamiaceae) is a deciduous tree distributed in Africa to China, throughout Indochina and Malaysia, to Australia and the Pacific. The various parts of the plant (leaves, stem bark and root) is reported to have numerous medicinal properties. The lack of understanding and consideration of dormancy and germination traits of a species could result in unsuccessful restoration programme. The aim of the present study was to investigate the nature of seed dormancy of P. latifolia that have low germination in natural conditions. Materials and Methods: To determine the type of seed dormancy, water imbibition and germination test were performed. Seeds were treated by mechanical scarification, Gibberellic acid (GA) and combined treatment of scarification and GA before allowing them to imbibe in moist paper. Results: All the treated (mechanically scarified, GA treated, mechanically scarified + GA treated) and untreated (control) seeds imbibed water for 4 days, however the maximum imbibition occurred in scarified seed + GA3 500ppm for 24 h (40.3%) followed by mechanically scarified seeds (38.7%). Higher germination was observed in scarified seeds + GA3 500ppm for 24 h (44%) followed by GA3 500ppm for 24 h (29.3%). Whereas, lowest germination was observed in untreated seeds (6.6%). Conclusion: Seeds possess non -deep physiological dormancy which requires scarification and treatment of GA to enhance germination.

Study of the efficacy of five growing media for nursery production of an endangered species, Afzelia africana Smith ex Pers in Côte d'Ivoire

Afzelia africana Smith ex Pers is an endangered plant species listed on the International Union for Conservation of Nature (IUCN) Red List. The low level of natural regeneration of this species requires it to be reproduced in a controlled environment in order to reconstitute its population by providing good quality seedlings. As the growing medium is an important factor in the quality of the seedlings, the influence of the substrates soil + wood chip compost, soil + poultry droppings, soil + rice straw compost, soil + cocoa pod husk compost and soil on the germination and growth of Afzelia africana in the nursery was evaluated through a completely randomised design. The soil + wood chips compost performed best, with a high germination rate (76.7%). It enabled the production of taller seedlings (15.6 cm; p = 0.004), with larger collar diameters (4.4 mm; p = 0.001), higher total dry matter (2.25 g.plant-1; p = 0.005) and higher root dry matter (2.25 g.plant-1; p = 0.005). The mixture of three parts soil + one part poultry droppings was toxic for the seedlings, resulting in 60.6% mortality. The use of growing media containing a mixture of soil and wood chips compost is effective for the production of vigorous seedlings. This compost can be recommended for nursery production of Afzelia africana.

Seed ecology of the arid zone invasive thistle; Centaurea melitensis L.: A study of the effects of seasonal temperature, pH, salinity and moisture stress

AbstractCentaurea melitensis L., known commonly as Malta thistle, is an aggressive and invasive weed species native to the Mediterranean region. This species now occupies a diverse range of ecosystems and climate types across the globe, including the semi‐arid zone of New South Wales, Australia. This semi‐arid climate differs dramatically from its native Mediterranean climate, therefore, we aimed to identify if local adaptations in the seed ecology for C. melitensis have developed. Seeds were collected from mature C. melitensis at Nanya Station, located within the Scotia region of NSW, and then transported to Federation University Australia, Mt. Helen, Victoria. Under laboratory conditions, mature seeds were tested for their germination responses to temperature (17/7, 25/15, 30/20, 35/25°C), photoperiod (12 h light and 12 h dark [L/D], 24 h dark [D]), salinity (0, 25, 50, 100, 150, 200, and 250 mM), osmotic potential (0, −0.1, −0.2, −0.4, −0.6, and −0.8 MPa), and pH (5, 6, 6.2, 7, 8, 9, and 10). The seeds achieved 100% germination in the 17/7°C treatment, with light not being a limiting factor. The seeds exposed to the 25/15°C (D) and 30/20°C (D) treatments also maintained high germination percentage, whilst germination was significantly reduced in the 35/25°C (D) treatment. The L/D photoperiod maintained a 77.5% germination rate at 35/25°C. Whilst increased salinity reduced seed germination from 97.5% in the control to 6% at 250 mM, this species nevertheless demonstrated resistance to osmotic stress with 23% germination observed at 0.8 MPa. Germination exceeded 90% at all of the soil pH treatments, although mean germination time was significantly reduced when seeds were treated with a solution of pH 10. Our results demonstrate that the C. melitensis seeds collected in Australia's semi‐arid zone demonstrated high germination plasticity and are capable of competitive germination in warmer and drier conditions compared to its native Mediterranean climate. Therefore, management efforts that prioritise restricting the spread of C. melitensis seeds into new environments, for example through practising correct sanitation protocols, coupled with the early detection and control of emerging populations will be critical for C. melitensis management in Australia.

Strategies for effective high pressure germination or inactivation of Bacillus spores involving nisin.

Extremely resistant spore-forming bacteria are widely distributed in nature. They infiltrate the food chain and processing environments, posing risks of spoilage and food safety. Traditional heat-intensive inactivation methods often negatively affect the product quality. HP germination-inactivation offers a potential solution for better preserving sensitive ingredients while inactivating spores. However, the presence of ungerminated (superdormant) spores hampers the strategy's success and safety. Knowledge of strategies to overcome resistance to HP germination is vital to progress mild spore control technologies. Our study contributes to the evaluation and development of mild preservation processes by evaluating strategies to enhance the HP germination-inactivation efficacy. Mild preservation processes can fulfill the consumers' demand for safe and minimally processed food.

Relationship between seed coat colour and seed vigour in cowpea (Vigna unguiculata Walp (L.)

In the present study, the 25 genotypes were grouped into two seed color groups including pigmented (n = 19; black, brown, dark brown, grey, dark grey seed color) and unpigmented (n = 6; cream and white seed color) for studying the association of seed coat color with seed vigor. Despite high germination (>84%) of all genotypes in the laboratory, unpigmented genotypes recorded low (34-54%) field emergence than pigmented genotypes (52-78%). Rapid initial (30 min) rate of water uptake (-0.75**), water uptake at one hour of imbibition (-0.70**), low proportion of seed coat (0.67**), and greater electrical conductivity of seed leachate (-0.72**) was associated with low field emergence in unpigmented cowpea genotypes. No significant correlation or association was observed between field emergence and laboratory germination in the present investigation suggesting that laboratory germination can not be used for predicting field emergence in cowpea. Instead, the electrical conductivity of seed leachate could be used to predict the field emergence of cowpea.

Streptomyces fradiae Mitigates the Impact of Potato Virus Y by Inducing Systemic Resistance in Two Egyptian Potato (Solanum tuberosum L.) Cultivars

In this study, the impact of culture media filtrate of QD3 actinobacterial isolate on two potato cultivars, Spunta and Diamond, infected with potato virus Y (PVY) was investigated. Various parameters, including infection percentage, PVY virus infectivity, disease severity scoring, PVY optical density, photosynthetic and defense-related biochemical markers, enzymatic profiling, phenolic compounds, proline content, salicylic acid levels, and growth and yield parameters, were assessed to elucidate the potential of the QD3 actinobacterial isolate culture filtrate in mitigating PVY-induced damage. The physiological and biochemical characteristics of the QD3 actinobacterial isolate, including its salinity tolerance, pH preferences, and metabolic traits, were investigated. Molecular identification via 16S rRNA gene sequencing confirmed its classification as Streptomyces fradiae QD3, and it was deposited in GenBank with the gene accession number MN160630. Distinct responses between Spunta and Diamond cultivars, with Spunta displaying greater resistance to PVY infection. Notably, pre-infection foliar application of the QD3 filtrate significantly reduced disease symptoms and virus infection in both cultivars. For post-PVY infection, the QD3 filtrate effectively mitigated disease severity and the PVY optical density. Furthermore, the QD3 filtrate positively influenced photosynthetic pigments, enzymatic antioxidant activities, and key biochemical components associated with plant defense mechanisms. Gas chromatography‒mass spectrometry (GC‒MS) analysis revealed palmitic acid (hexadecanoic acid, methyl ester) and oleic acid (9-octadecanoic acid, methyl ester) as the most prominent compounds, with retention times of 23.23 min and 26.41 min, representing 53.27% and 23.25%, respectively, of the total peak area as primary unsaturated fatty acids and demonstrating antiviral effects against plant viruses. Cytotoxicity assays on normal human skin fibroblasts (HSFs) revealed the safety of QD3 metabolites, with low discernible toxicity at high concentrations, reinforcing their potential as safe and effective interventions. The phytotoxicity results indicate that all the seeds presented high germination rates of approximately 95–98%, suggesting that the treatment conditions had no phytotoxic effect on the Brassica oleracea (broccoli) seeds, Lactuca sativa (lettuce) seeds, and Eruca sativa (arugula or rocket) seeds. Overall, the results of this study suggest that the S. fradiae filtrate has promising anti-PVY properties, influencing various physiological, biochemical, and molecular aspects in potato cultivars. These findings provide valuable insights into potential strategies for managing PVY infections in potato crops, emphasizing the importance of Streptomyces-derived interventions in enhancing plant health and crop protection.

Temperature Effects on Seed Germination and Seedling Biochemical Profile of Cannabis Landraces

This study investigated the effect of temperature on the germination and seedling biochemical profiles of eight cannabis landraces, namely Ladysmith Ugwayi wesiZulu (L1) and Iswazi (L2), Durban Poison (H1), Bergville Ugwayi wesiZulu (B1), Natal (B2), and Iswazi (B3), and Msinga Ugwayi wesiZulu (M1) and Iswazi (M2). Seed viability, germination rate, and germination percentage were evaluated along with seedling amino acids, carbohydrates, and fatty acids methyl esters (FAMEs) under day/night temperature regimes of 20/15 °C, 30/25 °C, and 40/35 °C. Results showed a significant effect (p < 0.001) of temperature on germination percentage, rate, and biochemical profiles of cannabis landraces. Landraces L1, B1, H1, B2, and M1 had higher germination at 20/15 °C, while B3, M2, and L2 performed better at 30/25 °C. Biochemical profiles varied with temperature and landraces. Amino acid content increased with temperature but did not correlate with germination indexes. Carbohydrates and FAMEs decreased with rising temperature, peaking at 30/25 °C. FAMEs strongly correlated with germination indexes, linking lipid composition to seed performance. Sorbitol positively correlated with germination, while glucose and fructose showed indirect correlations. This study underscores the impact of temperature on germination and the biochemical profiles of cannabis landraces, highlighting the importance of considering genotype-specific responses in varietal selection.

A Novel Enterococcus-Based Nanofertilizer Promotes Seedling Growth and Vigor in Wheat (Triticum aestivum L.).

Excessive use of chemical fertilizers poses significant environmental and health concerns. Microbial-based biofertilizers are increasingly being promoted as safe alternatives. However, they have limitations such as gaining farmers' trust, the need for technical expertise, and the variable performance of microbes in the field. The development of nanobiofertilizers as agro-stimulants and agro-protective agents for climate-smart and sustainable agriculture could overcome these limitations. In the present study, auxin-producing Enterococcus sp. SR9, based on its plant growth-promoting traits, was selected for the microbe-assisted synthesis of silver nanoparticles (AgNPs). These microbial-nanoparticles SR9AgNPs were characterized using UV/Vis spectrophotometry, scanning electron microscopy, and a size analyzer. To test the efficacy of SR9AgNPs compared to treatment with the SR9 isolate alone, the germination rates of cucumber (Cucumis sativus), tomato (Solanum lycopersicum), and wheat (Triticum aestivum L.) seeds were analyzed. The data revealed that seeds simultaneously treated with SR9AgNPs and SR9 showed better germination rates than untreated control plants. In the case of vigor, wheat showed the most positive response to the nanoparticle treatment, with a higher vigor index than the other crops analyzed. The toxicity assessment of SR9AgNPs demonstrated no apparent toxicity at a concentration of 100 ppm, resulting in the highest germination and biomass gain in wheat seedlings. This work represents the first step in the characterization of microbial-assisted SR9AgNPs and encourages future studies to extend these conclusions to other relevant crops under field conditions.

Germination of soybean seeds after low-temperature storage and its dependence on weather and climate conditions in the places of reproduction of accessions

Background. Soybean (Glycine max (L.) Merr.) is a microbiotic whose seeds quickly lose germination in uncontrolled conditions at room temperatures. This determines the need to preserve accessions in special conditions. Low temperature storage (LTS) allows to maintain high seed germination ability, but not for all accessions. Therefore, it is relevant to assess the results of LTS at the VIR Genebank and to make an attempt to determine the best geographical conditions for growing plants and harvesting seeds that will be subjected to LTS. Materials and methods. The work was carried out on 312 soybean accessions from the VIR collection, originating from almost the entire area of soybean cultivation. The accessions used in the research were reproduced at three VIR experiment stations (ES), namely Adler ES, Kuban ES (Krasnodar Territory) and the Far East ES (Primorsky Territory). The seeds were harvested in 1999 to 2017 and stored in sealed foil laminated bags at –10°C from 2002 to 2021. The accessions were removed from LTS and germination assessed in 2022. Results. At the beginning of LTS, seed germination (Gi) ranged from 12 to 100% (averaging 79.1%), while that after LTS (Gr) ranged from 1 to 97% (57.8% on average). The retention of germination ability was expressed as the germination index (GI = Gr / Gi), which ranged from 0.02 to 1.73 (an average of 0.72). All the indicators of germination in the range of up to 20 years of LTS were not associated with the duration of LTS and with the number of years before LTS (0.5-4 years in our research). The climatic conditions characteristic of the place of reproduction had a significant impact on Gi and Gr, but not on GI. The average Gi of seeds obtained at the Adler ES and Kuban ES did not differ significantly (77.4% and 75.7%), while that of seeds harvested at the Far East ES was significantly higher (84.0%). Gr of the accessions from the Far East ES (64.3%) was also greater than that of accessions from the Kuban ES (52.2%) and Adler ES (57.2%). The excessively high sum of temperatures above 10°C (recorded in some years at all stations) reduced Gi, Gr but had little effect on GI. The highest values of Gi, Gr, and GI were demonstrated by the accessions maturing in 101-120 days. Additionally drying of the most late-ripening accessions (later than 140 days) in sheaves under an awning yielded seeds with high germination ability and good LTS tolerance. Conclusion. The seeds from different places of reproduction of accessions differed in germination before and after LTS, and, on an average, the highest values were demonstrated by the seeds harvested at the Far East ES, where the temperature regime is closer to the optimal one for soybeans. The seed germination index showed relative independence from the conditions of reproduction of accessions, including the climate and weather conditions, as well as the initial germination ability and LTS duration.

Halophilic Phosphate-Solubilizing Microbes (Priestia megaterium and Bacillus velezensis) Isolated from Arabian Sea Seamount Sediments for Plant Growth Promotion.

Arabian Sea is a highly productive Ocean owing to deep upwelling with reports on phosphorus cycling in ocean sediments. In this study, microbes from sea mounts of the Arabian Sea at varying depths (400m, 900m) were screened to isolate and characterize phosphate-solubilizing bacteria (PSB) with plant growth-promoting properties. Out of the seven morphologically different PSBs, two bacterial strains with maximum phosphate solubilization index were identified as Priestia megaterium (H1) and Bacillus velezensis (H2) based on biochemical and molecular characteristics. Different factors influencing phosphatase production were optimized, which showed maximum solubilization at temperature of 30°C (97.5μg/mL), glucose as best carbon source (70µg/mL), 1-M NaCl (114.1µg/mL), and pH 8 (134.3µg/mL) indicating their halophilic and alkaliphilic characteristics. Alkaline phosphatase enzyme was extracted and partially purified from both PSBs wherein H2 strains showed greater specific activity (24.83 U/mg). Metabolomics studies through HPLC revealed maximum production of gluconic acid (483.75mg/L) in addition to lactic, oxalic, acetic, and succinic acid during solubilization. Biopriming effect of PSBs on tomato seed germination showed high germination index (80%) in consortia of both isolates which was also validated through root colonization by SEM analysis. Further studies using pot assay experiments also showed comparable results in marine PSB consortia with positive control (Phosphobacteria) for plant growth attributes including root height and weight. These findings suggest that the halophilic PSB strains from marine sediments could be used as potential bio-inoculants to enhance plant growth and combat saline stress for sustainable Agriculture.

Microclimatic effects of tree shelters on the early establishment and resilience of seeded acorns vs. outplanted seedlings

Little is known about the effects of tree shelters on the early response of oak seedlings produced by acorn seeding. In this paper, we explore the effects on holm oak (Quercus ilex L. subsp. ballota (Desf.) Samp.) seedlings of the microenvironment created by the tree shelters and the restoration method (seeding vs. outplanting) in terms of emergence, survival, growth, and resilience after harvesting. For this purpose, seedling height [H], root collar diameter [RCD], number of leaves, and aerial biomass were monitored. We made two sowings of acorns in February 2017 and February 2018, together with a seedling outplanting in February 2018 in a common garden site in semiarid SE Spain. In total, 600 acorns were randomly sowed and 300 nursery-grown seedlings were outplanted and studied until 2022. Mother tree and initial acorn mass were also monitored as additional variables in the analyses. Tree shelters consisted of closed plastic Tubes, Mixed tubes, Cork shelters, Tiles, and a Control with no shelter. Emergence rate was positively influenced by the Tube shelter (86%) as compared to the Control (64%), and especially by the initial acorn mass. By contrast, mother tree or year of sowing seemed to have no effect. The survival rate for the emerged acorns (88%) was statistically similar to that of outplanted seedlings (91%), and was unaffected by mother tree, tree shelter, or acorn mass. In terms of growth, the slenderness ratio (H:RCD) was considerably higher in seedlings from directly seeded acorns than for those that were outplanted. With the exception of Tile, all the shelters showed a higher slenderness ratio than the Control, especially the Tube shelter, which also showed a lower number of leaves and a lower aboveground dry biomass than the Control, Cork, and Tile shelters. Virtually no interactions were observed between the mother tree and the tree shelter. At harvesting, all the growth-related parameters were still strongly dependent on the acorn mass and the initial seedling features recorded after the first growing season. Resprouting rate and growth were also highly dependent on the acorn mass and the plant features at the beginning of the experiment and at harvesting. In summary, we did not find evidence to support tree shelters to improve the microclimate of holm oak seedlings both seeded or outplanted. Direct acorn seeding can be as successful as outplanting of nursery-grown seedlings. Selection of heavy acorns from mothers with a high germination and emergence rate is highly advisable.

Nuclear DNA Markers to Distinguish between Salix caprea, Salix gracilistyla, and Their Interspecific Hybrids

The Salix genus of the Salicaceae family has advantages such as rapid initial growth, a high germination rate, and asexual reproduction; therefore, it is used as a short-rotation energy crop for biomass production. The National Institute of Forest Science created new interspecific hybrid cultivars with superior biomass production by artificially interbreeding Salix caprea L. and Salix gracilistyla Miq. Identifying these hybrids during the seedling stage is challenging because their separate reproductive and vegetative growth stages necessitate prolonged observation of their morphological characteristics. Consequently, a reliable identification method is required to overcome these limitations. This study aimed to develop nuclear DNA markers to distinguish between S. caprea, S. gracilistyla, and their interspecific hybrids. An evaluation of 35 nuclear simple-sequence repeat (nSSR) markers in the Salix genus revealed two markers that distinguish these parent species and their hybrids. A sequence analysis confirmed the presence of insertion-deletion (InDel) regions within the nSSR markers that differed between S. caprea and S. gracilistyla. To effectively identify hybrids, a primer set comprising the InDel region, which exhibited only interspecies differences and no intraspecies differences, was developed. The results of this study will facilitate the genetic resource management of interspecific hybrids between S. caprea and S. gracilistyla, thus allowing for early identification and improved management of hybrids.

Pre-Germinative Treatments and In Vitro Germination of Dianthus caryophyllus and Alstroemeria spp. Seeds

Alstroemeria spp. and carnation (Dianthus caryophyllus L.) have considerable and increasing economic importance in the floriculture market, therefore breeders carry out intense breeding programs to select new superior varieties. However, poor germination of hybrid seeds remains a bottleneck. Based on this assumption, seed pre-treatments and in vitro germination protocols, using different germination substrates, were applied in Alstroemeria spp. and carnation to improve germinability. Seed viability was tested using the 2,3,5-triphenyl tetrazolium chloride (TTC) test, and resulted in 91.10% ± 2.33 and 86.66% ± 3.85 in Alstroemeria and carnation, respectively. In Alstroemeria, pre-treatment with potassium nitrate (KNO3) in combination with modified ½ Murashige and Skoog (MS) medium ensured high germination uniformity combined with high germination percentage, showing significantly higher values than the control. In carnation, a suitable seed sterilization procedure was set up (up to 95.8% sterility); treatments with gibberellic acid (GA3) and KNO3 did not influence germination percentage compared to the control. A high multiplication rate of seedling lines was obtained on hormone-free MS medium.

Glycolipopeptide biosurfactant produced by Klebsiella pneumoniae ssp. ozaenae BK34: Virtue in germination and growth of chickpea (Cicer arietinum L.) HC-1 crop

Modern agriculture consumes many persistent and non-biodegradable agrochemicals enhancing production and economy for farmers. Besides, chemical surfactants are used as adjuvant to augment the action of agrochemicals. A toxicity concern of these agrochemicals and adjuvants on life forms and environment cannot be ignored. Microbiologically produced, eco-friendly, biodegradable surfactants could be suggested as an alternative, however, compatibility with plants and beneficial microflora needs to be ascertained before applying them into agriculture. The current study included evaluation of biosurfactant BS34 produced by Klebsiella pneumoniae BK34 towards germination and growth of chickpea [Cicer arietinum (L.)] seeds. The biosurfactant BS34 was characterized as surfactin like glycolipopeptide based on Fourier transform infrared spectroscopy and Liquid chromatography-Mass spectrometry characterization. The biosurfactant was found non-phytotoxic during in-vitro germination of chickpea seeds as evident from very high germination index of 187.74 as opposed to the almost negligible germination index of 0.04 shown by highly phytotoxic chemical surfactant. In comparison to control, the biosurfactant seed treatment [1%(w/v)] in an in-vivo study on chickpea increased the plant height by 18%, nodule number by 11.13%, nodule fresh weight by 12.66% shoot weight by 11.20% and root weight by 34.61%. Contrarily, seed treatment by 1% (w/v) sodium dodecyl sulfate (SDS) inhibited the germination and growth of chickpea seeds again documenting superiority of biosurfactants over their chemical counterparts. Improved seed germination, growth and yield attributes of chickpea crop in presence of non-phytotoxic glycolipopeptide biosurfactant produced by Klebsiella pneumoniae ssp. ozaenae BK34 suggests its potential as an alternative to chemical surfactants used in agriculture.

Sulfuric acid as a germination stimulator in forage soybean seeds (Neonotonia wightii)

Forage soybean (Neonotonia wightii) is a legume frequently used as a cover crop in field crops. However, as a species of the Phaseoloideae subfamily, it is characterized by the physical latency of the seed, which makes it difficult to obtain a high, homogeneous, and rapid germination. The aim of the present study was to determine which method of scarification stimulates the germination process to a greater extent. The following immersion times were evaluated: 5 to 20 minutes in 98% sulfuric acid, 24 hours in 5.4% sodium hypochlorite, water, and gibberellic acid [100 ppm], 15 minutes of treatment with sandpaper and the combination of these last two. They were distributed in a completely randomized experimental design, where eight treatments and a control were evaluated, with three replicates each and 200 seeds as experimental units, subjected to controlled conditions (germination chambers at constant temperatures and a relative humidity of 27 °C and 70%, respectively) during the spring of 2022. The results were favorable, a high germination percentage was obtained from seeds subjected to a 20-minute immersion time in sulfuric acid (90% germination and an average of six germinated seeds per day) and this was significantly higher than the rest, making it an effective method to break the physical latency of the seeds, as it removes the impermeable cover allowing inhibition and consequently the activation of the seed’s metabolism.

Influence of seed pre-treatment and storage on germination and physiological characteristics of seeds of common mullein (Verbascum thapsus L.)

We report the seed germination and associated metabolic responses of differentially stored seeds of Verbascum thapsus L. (Scrophulariaceae), an economically and medicinally important herb from the cold desert region of Lahaul (Himachal Pradesh, India) in trans Himalaya, to certain physico-chemical and GA₃ treatments. The freshly harvested seeds of V. thapsus exhibited high (96 %) viability but low germination (55 %). During the storage of seeds under ambient conditions, viability did not change until 1-year but declined progressively thereafter showing a 33 % decline in 4-year stored seeds. The seed germination was promoted to varying extents by acid scarification (AS), SNP (sodium nitroprusside), SHC (sodium hypochlorite) and GA₃ pre-treatments. Storage-dependent changes in seed germination performance and responsiveness to different effectors were evident. Germination performance improved significantly due to 1-year storage followed by a sharp decline subsequently. The responsiveness of seeds to various treatments tended to be higher in seeds stored for ≥2 years. The changes in germination were paralleled by those in α-amylase activity in seeds. Lipid peroxidation generally increased during storage that was paralleled by a gradual decline in superoxide dismutase (SOD) activity and phenolic contents. Catalase (CAT) activity increased transiently in 1-year stored seeds and declined thereafter. Data are expected to have implications for multiplication and cultivation of V. thapsus.

Preparation, Characterization, and Testing of Compost Tea Derived from Seaweed and Fish Residues

Non-aerated compost tea (CT) was prepared from compost derived from rockweed (Ascophyllum nodosum) and fish (cod, common ling, haddock, saithe) residues that fermented in water. Electrical conductivity, pH, concentrations of dry matter, ash, C, macronutrients (N, P, K, Ca, and Mg), and micronutrients (Cu, Fe, Mn, Mo, and Zn) of CT prepared under different fermentation conditions were measured. The effects of process factors, i.e., water/compost mass ratio (4.2–9.8 g/g) and fermentation time (4.2–9.8 days = 100–236 h), on the physicochemical properties of CT were quantified using quadratic polynomial models. CT obtained at optimal levels of process factors (4.2 g/g and 5.6 days = 134 h) was tested for lettuce seed germination and seedling growth. Diluted CT (25% CT + 75% ultrapure water) improved seedling growth while achieving a high germination percentage (97%).