Initial Stages Of Germination Research Articles

Study on the metabolic changes and regulatory mechanism of Aspergillus flavus conidia germination.

Aspergillus flavus conidia are widespread in air; they attach to food and feed crops and secrete aflatoxins, which results in serious contamination. Germination of A. flavus conidia is the most critical step in contamination of food by A. flavus. This study aims to gain an insight into A. flavus conidia through dormancy to germination to provide a theoretical basis for inhibition of A. flavus conidia germination. The morphological changes and regulation mechanism of A. flavus conidia germination at 0, 4, 8, and 12 hours were observed. Transcriptomic and metabolomic analyses showed that conidia became active from dormancy (0 hour) to the initial stage of germination (4 hours), cellular respiration and energy metabolism increased, and amino acids and lipids were synthesized rapidly. The number of differentially expressed genes and differential metabolites was highest at this stage. Besides, we found that conidia germination had selectivity for different carbon and nitrogen sources. Compared with monosaccharides, disaccharides, as the only carbon source, significantly promoted the germination of conidia. Moreover, MepA, one of genes in the ammonium transporter family was studied. The gene deletion mutant ΔMepA had a significant growth defect, and the expression of MeaA was significantly upregulated in ΔMepA compared with the wild-type, indicating that both MepA and MeaA played an important role in transporting ammonium ions.IMPORTANCEThis is the first study to use combined transcriptomic and metabolomics analyses to explore the biological changes during germination of Aspergillus flavus conidia. The biological process with the highest changes occurred in 0-4 hours at the initial stage of germination. Compared with polysaccharides, monosaccharides significantly increased the size of conidia, while significantly decreasing the germination rate of conidia. Both MeaA and MepA were involved in ammonia transport and metabolism during conidia germination.

Differential responses of six Casuarina species to NaCl seed priming and salt stress during germination and early seedling growth

The degradation of salinized soils is imposing a steady decline in productivity, leading to significant socio-economic and environmental repercussions. As a promising solution for revitalizing depleted soil potential, the cultivation of salt-tolerant plants such as Casuarina emerges as a viable approach. This study delves into this prospect by evaluating six Casuarina species to discern their levels of tolerance to varying concentrations of NaCl, particularly in the initial stages of germination and seedling growth. The imposition of salt stress instigated a reduction in both germination capacity and speed. High variability in salt tolerance was observed between the tested species. Notably, the final germination percentages at 100 mM NaCl unveiled considerable disparities: C. torulosa, C. tenuissima, and C. stricta exhibited percentages of 33%, 19%, and 10%, respectively, while C. cunninghamiana, C. equisetifolia, and C. glauca showcased higher germination rates at 63%, 62%, and 55%, respectively. Furthermore, the increase of the recovery rate with high NaCl concentration confirmed that the salinity caused only an osmotic effect and not a toxic one on the studied species. Additionally, the adoption of seed priming showcased marked enhancements in germination rates across all NaCl concentrations, effectively expediting the germination process. In response to salinity stress, reductions were noted in root length (RL), and shoot length (SL). All germination parameters and the computation of the salt tolerance index (STI) facilitated the classification of the six Casuarina species in a descending order of salinity tolerance: C. cunninghamiana Miq. > C. equisetifolia L. > C. glauca Sieb. > C. torulosa Ait. > C. tenuissima Sieb. > C. stricta Ait.

Coordinated Lipid Mobilization during Seed Development and Germination in Peanut (Arachis hypogaea L.).

Peanut (Arachis hypogaea L.) is one of the most important oil crops in the world due to its lipid-rich seeds. Lipid accumulation and degradation play crucial roles in peanut seed maturation and seedling establishment, respectively. Here, we utilized lipidomics and transcriptomics to comprehensively identify lipids and the associated functional genes that are important in the development and germination processes of a large-seed peanut variety. A total of 332 lipids were identified; triacylglycerols (TAGs) and diacylglycerols were the most abundant during seed maturation, constituting 70.43 and 16.11%, respectively, of the total lipids. Significant alterations in lipid profiles were observed throughout seed maturation and germination. Notably, TAG (18:1/18:1/18:2) and (18:1/18:2/18:2) peaked at 23386.63 and 23392.43 nmol/g, respectively, at the final stage of seed development. Levels of hydroxylated TAGs (HO-TAGs) increased significantly during the initial stage of germination. Accumulation patterns revealed an inverse relationship between free fatty acids and TAGs. Lipid degradation was determined to be regulated by diacylglycerol acyltransferase, triacylglycerol lipase, and associated transcription factors, predominantly yielding oleic acid, linoleic acid, and linolenic acid. Collectively, the results of this study provide valuable insights into lipid dynamics during the development and germination of large-seed peanuts, gene resources, and guiding future research into lipid accumulation in an economically important crop.

Formation of staling aldehydes in different grain bed layers in an industrial scale maltings

Understanding the contribution of raw materials to the quality of the final product is crucial for the food industry. In the brewing process, malt delivers various compounds that compromise the flavour stability of beer, including staling aldehydes and their precursors. The primary aim of this study was to investigate the evolution of staling aldehydes and their cysteinylated counterparts throughout industrial scale pale malt production. The second objective was to study the extent to which process related gradients (e.g., temperature, moisture) may contribute to the differential formation of free and bound state aldehydes. Samples were collected from two industrial scale, pale lager malt production processes as a function of process time (germination, kilning, and cooling) and the position of the kernals in the grain bed (bottom, middle and top layers) during kilning. The levels of free and cysteinylated aldehydes were determined. The results show that the initial stage of germination is accompanied by enzymatic fatty acid oxidation as reflected by the formation of hexanal and trans-2-nonenal. Drying at elevated temperature (at a critical moisture content of 6-9%) results in the intensified formation of cysteinylated Strecker aldehydes and furfural. Moreover, a rapid increase in the formation of (cysteinylated) Strecker aldehydes furfural and trans-2-nonenal continued through kilning. A clear effect of temperature and moisture gradients was observed on the formation of aldehydes and it is concluded that exposure to heat load plays a critical role in the development of cysteinylated aldehydes during malt production. This publication is dedicated to the memory of Professor Luc De Cooman.

R3-MYB proteins OsTCL1 and OsTCL2 modulate seed germination via dual pathways in rice

Salt and drought stress are common abiotic factors that exert a detrimental influence on seed germination, potentially leading to significantly impaired growth and production in rice. Gaining a comprehensive understanding of the molecular response of seeds to abiotic stress during the germination is of paramount importance. In the present study, we identified two R3-MYB genes in rice, namely OsTCL1 and OsTCL2, and characterized their roles in regulating seed germination under salt and drought stress. Plants with tcl1 and tcl2 mutant alleles exhibited delayed seed germination, particularly under stress conditions. The tcl1 tcl2 double mutant showed an even more pronounced reduction in germination during initial stages of germination, thereby indicating a redundant regulatory function of OsTCL1 and OsTCL2 in seed germination under abiotic stresses. Furthermore, we demonstrated that the transcript levels of several phospholipase D (PLD) genes were downregulated in the tcl1 tcl2 mutant, resulting in a decreased level of the phosphatidic acid (PA) product. Application of 1-butanol, a competitive substrate inhibitor of PLD-dependent production of PA, attenuated the stress response of the tcl1 tcl2 mutant. This suggests that OsTCL1 and OsTCL2 partially modulate seed germination through the PLD-PA signaling pathway. Moreover, there were alterations in the expression of genes involved in abscisic acid (ABA) biosynthesis, metabolism and signaling transduction in the double mutant. These changes affected the endogenous ABA level and ABA response, thereby influencing seed germination. Application of both 1-butanol and ABA synthesis inhibitor sodium tungstate (Na2WO4) nearly eliminated the differences in stress response between wild type and the tcl1 tcl2 mutant. This indicates that OsTCL1 and OsTCL2 synergistically coordinate seed germination under abiotic stresses through both the PLD-PA signaling and ABA-mediated pathways.

Characterization and Germination Performance of Lettuce Sativa by Iron Oxide Nanoparticles Seed Priming

Increasing food availability and ensuring food security have become critical issues for nations with varying levels of economic growth. The agricultural sector plays an essential role in these developments. To cater to this, seed priming is a typical method for controlling the hydration of seeds, ensuring that the plant can consume water and proceed to the initial stage of germination. The main objective of this research is to characterise the synthesis of chemical iron oxide nanoparticles (FeNPs) and investigate the germination performance of Lactuca sativa (lettuce). Iron oxide (Fe) is important for various processes in plants, such as photosynthesis. The chemical method was chosen to synthesise the nanoparticles as it can reduce the overall cost, has a high yield, and is safe for the environment. In this experiment, two salt solutions were chosen as the reducing agents for the chemical method. The effect of seed priming with different concentrations of FeNPs (1, 2, 4, 6, 8, and 10 ppm) on seedling growth parameters such as germination rate and average shoot and root length varieties was studied on the fifth and eighth days of seedling development. Seed priming with FeNPs increased the germination rate more than control at all studied concentrations. As a result, among the 5 different concentrations, 1 ppm shows an increase in germination rate, average length of root of Lactuca sativa (lettuce) seeds, and shoot better than the others. The germination rate of 1 ppm is 80%, compared to the control at 70%. Seed priming with FeNPs was nontoxic in comparison to the control, but it decreased the amount of chlorophyll and can be used to increase the nonenzymatic antioxidant capacity during the early phases of Lactuca sativa (lettuce) seedling development. Overall, this study suggests that using FeNPs to prime the seeds of Lactuca sativa (lettuce) can potentially increase crop yield and help keep the demand for food production stable.

Tracking Spatial Distribution Alterations of Multiple Endogenous Molecules during Lentil Germination by MALDI Mass Spectrometry Imaging

Exploring the spatial distribution alterations of metabolites during lentil germination is essential to reveal the nutritional value, physiological function, and metabolic pathway in lentils. Hence, an effective matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) method was established for the first time to visualize the spatial localization changes of 53 metabolites in lentils during germination for 12-72 h. The results of MALDI-MSI analysis showed that phosphatidylinositols, phosphatidylethanolamines, phosphatidylglycerols, and phosphatidic acids were mainly located in the cotyledons of lentils throughout the germination process, while triacylglycerols, phosphatidylcholines, diacylglycerols, amino acids, choline, and spermine spread throughout the lentil tissue at the initial stage of germination and gradually presented obvious distribution characteristics in the radicle with increasing germination time. Heat map analysis was used to visualize the correlations between lipid content changes and germination time, which supported the use of germinated lentils as nutraceutical or functional food.

Multi-Parameter Characterization of Disease-Suppressive Bio-composts from Aromatic Plant Residues Evaluated for Garden Cress (Lepidium sativum L.) Cultivation

Garden cress is a vegetable crop in the Brassicaceae family that is appreciated for its nutraceutical and taste-giving components in minimally processed food chains. Due to its very short cycle, which depends on the range of production from microgreens to baby-leaf vegetables, this crop is threatened by soil-borne pathologies developing within the initial stages of germination and emergence. This study aims to evaluate the suppressive bio-compost as an innovative means to counteract the main telluric diseases of garden cress and reduce the risks of yield loss by adopting sustainable remedies and decreasing the dependence on synthetic fungicides. Therefore, eleven green composts obtained using both previously distilled and raw aromatic plant residues were analyzed for suppressive properties against Rhizoctonia solani and Sclerotinia sclerotiorum on sown garden cress. The biological active component of the composts, detected by CO2-release, FDA-hydrolysis and microbial counts, proved to be indispensable for pathogen control in vitro and in vivo, as demonstrated by the loss of suppressiveness after sterilization. Cross-polarization magic angle spinning 13C-nuclear magnetic resonance (CP-MAS-13C-NMR) was used to analyze the molecular distribution of organic C in composts. The results indicated the suitability of the feedstock used to make quality compost. The suppression levels shown by composts P1 (40% wood chips, 30% escarole and 30% a mixture of sage, basil, mint and parsley) and P2 (40% wood chips, 30% escarole and 30% a mixture of essential oil-free sage, basil and rosemary) are promising for the sustainable, non-chemical production of garden cress vegetables.

Comparison of Presowing Wheat Treatments by Low-Temperature Plasma, Electric Field, Cold Hardening, and Action of Tebuconazole-Based Disinfectant

This work compares the presowing treatment of winter wheat seeds with a low-temperature plasma, a constant high-voltage electric field, a plant protection disinfectant, and cold hardening on the resistance of seedlings to freezing and their morphophysiological characteristics at the initial stage of germination. Various treatment combinations were considered, including the effect of the disinfectant jointly with low-temperature plasma treatment. The greatest stimulating effect from the point of view of seedlings’ morphophysiological characteristics was achieved when seeds were cold-hardened. The action of low-temperature plasma is noticeable up to the third day of germination. The treatment with the low-temperature plasma of seeds pretreated and not-pretreated with the disinfectant had a similar effect on the morphophysiological characteristics of seedlings. The plasma treatment and the electric field were combined with each other, i.e., the plasma treatment effects were added to the electric field effects. Resistance to low temperatures was increased with the hardening of seeds treated with the electric field and the disinfectant. Resistance to low temperatures was reduced when treated with the electric field and/or low-temperature plasma after being treated with the disinfectant.

Seed and seedling morphology of Bauhinia scandens L.

Bauhinia scandens has potential importance as an ornamental and medicinal plant. Researchers have isolated and identified 1-O-alkylglycerol in the leaves of the B. scandens plant, and established antitumor properties using the Brine Shrimp toxicity test, an internationally accepted bioassay. Although this species has high potential, little is known about the viability of seedling production and the morphology of these plants, particularly in terms of seed characteristics and initial stages of germination. The objective of this study was to characterize the seed morphology, germination, and seedlings of B. scandens. Seed water content, weight, and coloration were evaluated. This study also included a description of seed biometrics, external and internal structures, germination, and seedling morphology. Internal seed morphology was evaluated by the anatomical sectioning and X-ray methods. The morphology data obtained were subjected to descriptive statistical analysis and germination data were determined using Cramér’s V. B. scandens seeds have a coloration ranging from very dark grayish-red to dark reddish-brown, flat oblong shapes, and rounded bases and apexes with full or slightly undulating margins. Healthy seedlings are produced mainly by seeds with well-formed internal structures. The reddish petiole of the seedling leaves is a taxonomic character for B. scandens identification. The non-domestication and genetic variability of this species reflect on the seed and seedling color and size variation.

Transcriptome analysis of Cinnamomum migao seed germination in medicinal plants of Southwest China

BackgroundCinnamomum migao is an endangered evergreen woody plant species endemic to China. Its fruit is used as a traditional medicine by the Miao nationality of China and has a high commercial value. However, its seed germination rate is extremely low under natural and artificial conditions. As the foundation of plant propagation, seed germination involves a series of physiological, cellular, and molecular changes; however, the molecular events and systematic changes occurring during C. migao seed germination remain unclear.ResultsIn this study, combined with the changes in physiological indexes and transcription levels, we revealed the regulation characteristics of cell structures, storage substances, and antioxidant capacity during seed germination. Electron microscopy analysis revealed that abundant smooth and full oil bodies were present in the cotyledons of the seeds. With seed germination, oil bodies and other substances gradually degraded to supply energy; this was consistent with the content of storage substances. In parallel to electron microscopy and physiological analyses, transcriptome analysis showed that 80–90 % of differentially expressed genes (DEGs) appeared after seed imbibition, reflecting important development and physiological changes. The unigenes involved in material metabolism (glycerolipid metabolism, fatty acid degradation, and starch and sucrose metabolism) and energy supply pathways (pentose phosphate pathway, glycolysis pathway, pyruvate metabolism, tricarboxylic acid cycle, and oxidative phosphorylation) were differentially expressed in the four germination stages. Among these DEGs, a small number of genes in the energy supply pathway at the initial stage of germination maintained high level of expression to maintain seed vigor and germination ability. Genes involved in lipid metabolism were firstly activated at a large scale in the LK (seed coat fissure) stage, and then genes involved in carbohydrates (CHO) metabolism were activated, which had their own species specificity.ConclusionsOur study revealed the transcriptional levels of genes and the sequence of their corresponding metabolic pathways during seed germination. The changes in cell structure and physiological indexes also confirmed these events. Our findings provide a foundation for determining the molecular mechanisms underlying seed germination.

Рентгеновская компьютерная томография структуры корней и динамика почвенной биоты на ранних стадиях роста ячменя (Hordeum vulgare L.)

The architecture of the seed bed, a certain alternation of compacted and loose sections of the arable horizon, largely determines the development of the root system of plants. The morphology and growth of the root system of the germinating seed in the created seed bed is also determined by the composition of the surrounding soil biota. Dynamic studies of the development of the root system and composition of the surrounding soil biota is an essential methodological and practical problem in soil cultivation, agrophysics, and soil biology. This task is especially important in the first few days when the root system is laid and the plant rhizosphere is formed. Modern tomography makes it possible to carry out such studies that do not violate the soil-root biological system, in particular, in model mesoscale experimental physical models. The aim of this research was to use x-ray computed tomography to study the structure of the roots of barley seedlings in the early stages of development, while simultaneously studying changes in the number and dominant groups of microorganisms in the basal biota. Barley seeds (variety Mikhailovsky) in a model physical experiment with a twolayer soil bed density (soil density range from 0.7 to 1.2 g / cm3) Albic Glossic Retisols (Lomic, Cutanic), WRB, 2014 were laid for germination at the layer boundary in a special cylindrical box with a volume of about 3 cm3 at optimal humidity. The position of the seed in the soil of the seedbed model is shown in the tomographic image (See Fig. 1). During the period from planting to 7 days, the dynamics of the root system was studied using a Bruker X-ray microtomography “SkyScan 1172G” (Bruker, Belgium) while studying the composition of soil biota, which was reconstructed by microbial markers (fatty acids and their derivatives). Markers were determined by molecular gas chromatography - mass spectrometry. Computer tomography allowed to record the volume distribution of roots at different periods of germination in the aggregated and compacted layers of agro-sod-podzolic soil. In this case, the roots successfully mastered the entire soil space, regardless of the plowing architecture of soil density created at the initial stage of germination. The total number of bacteria also increased by the 5th day with the constant dominance of 3 phyla: Actinobacteria, Proteobacteria and Firmicutes in the biota; the other two, Bacteroidetes and Cyanobacteria, were represented in relatively small numbers. In the phylum Actinobacteria, aerobic hydrolytics of complex carbohydrates Rhodococcus equi were presented in the largest amount on the 5th day, in the Firmicutes phylum it is anaerobic hydrolytic Ruminococcus sp. and the anaerobic nitrogen fixator Clostridium pasteurianum, in the phylum Proteobacteria-the aerobic nitrifier Nitrobacter sp. with a subsequent decrease in the number on the 7th day. The increase in these species indicates the initial destruction of the cellulose shell of the grain and the processes of fixation and conversion of nitrogen in the microbiota of the germinating seed, necessary for the formation of the C/N ratio. During the germination of the seed, pores are formed that are filled with water, gas, or organic matter. The structure of the microbial community changes in response to the ongoing processes, while the accumulation of metabolic products of aerobic and anaerobic species of microorganisms occurs. The quantitative study of the complex of microorganisms by the molecular method allows us to display the reaction of the microbiome to structural changes in the soil, since certain conditions stimulate an increase in the share of species with appropriate ecological functions in the community. The combination with the computer visualization obtained as a result of the application of the X-ray tomography method makes it possible to more clearly characterize the processes occurring in the rhizosphere.

Osmolyte accumulation and antioxidant metabolism during germination of vigorous maize seeds subjected to water deficit

The objective of this work was to evaluate the alterations of antioxidant enzyme reserves and antioxidant enzymes during germination under water deficit in maize hybrids and to associate with seed vigor, determining the mechanisms related to tolerance for this stress. Two three-way maize hybrids were characterized by their vigor at different levels of water deficit induced by polyethylene glycol 6000. Next, the seeds were hydrated at different osmotic potentials (0.0, -0.3, and -0.9 MPa) and removed at different times to assess the levels of the total soluble protein, total soluble sugars, proline, starch, and antioxidant enzymes, such as superoxide dismutase, catalase and ascorbate peroxidase. The analysis of variance, Tukey test at 5% and principal component analysis (PCA) were used. The vigorous hybrid (HT1) was more efficient than the low vigor hybrid seeds (HT2) in mobilizing the total soluble protein during the initial stages of germination and the total soluble sugars before and after root protrusion under water deficit in addition to increasing the catalase activity at the different osmotic potentials that were assessed.

Time-lapse single-cell transcriptomics reveals modulation of histone H3 for dormancy breaking in fission yeast

How quiescent cells break dormancy is a key issue in eukaryotic cells including cancer. Fungal spores, for example, remain quiescent for long periods until nourished, although the mechanisms by which dormancy is broken remain enigmatic. Transcriptome analysis could provide a clue, but methods to synchronously germinate large numbers of spores are lacking, and thus it remains a challenge to analyse gene expression upon germination. Hence, we develop methods to assemble transcriptomes from individual, asynchronous spore cells of fission yeast undergoing germination to assess transcriptomic changes over time. The virtual time-lapse analyses highlights one of three copies of histone H3 genes whose transcription fluctuates during the initial stage of germination. Disruption of this temporal fluctuation causes defects in spore germination despite no visible defects in other stages of the life cycle. We conclude that modulation of histone H3 expression is a crucial ‘wake-up’ trigger at dormancy breaking.

Hydropriming and Biopriming Improve Medicago truncatula Seed Germination and Upregulate DNA Repair and Antioxidant Genes.

Seed germination is a critical parameter for the successful development of sustainable agricultural practices. While seed germination is impaired by environmental constraints emerging from the climate change scenario, several types of simple procedures, known as priming, can be used to enhance it. Seed priming is defined as the process of regulating seed germination by managing a series of parameters during the initial stages of germination. Hydropriming is a highly accessible and economic technique that involves soaking of seeds in water followed by drying. Biopriming refers to the inoculation of seeds with beneficial microorganism. The present study aims to investigate whether hydropriming and biopriming could enhance seed germination. Thereby, the germination of Medicago truncatula seeds exposed to hydropriming and/or Bacillus spp. isolates was monitored for two-weeks. The seeds were sown in trays containing two types of in situ agricultural soils collected from Northern India (Karsara, Varanasi). This region is believed to be contaminated by solid waste from a nearby power plant. Phenotypic parameters had been monitored and compared to find the most appropriate combination of treatments. Additionally, qRT-PCR was used to evaluate the expression levels of specific genes used as molecular indicators of seed quality. The results show that, while hydropriming significantly enhanced seed germination percentage, biopriming resulted in improved seedling development, represented by increased biomass rather than seedling length. At a molecular level, this is reflected by the upregulation of genes involved in DNA damage repair and antioxidant defence. In conclusion, hydropriming and biopriming are efficient to improve seed germination and seedling establishment in soils collected from damaged sites of Northern India; this is reflected by morphological parameters and molecular hallmarks of seed quality.

Assessing the Need of Pre-germination Anaerobic Stress-Tolerant Varieties in Indian Soybean (Glycine max (L.) Merrill)

In the wake of unprecedented extreme precipitation scenario, this paper attempts to evaluate the need of breeding efforts to develop soybean ideotypes for moisture extremes in case of excessive rainfall in highly productive soybean areas of India. During the monsoon months, the decadal rainfall analysis in selected high soybean-producing districts of Madhya Pradesh (highest rainfall 350.27 mm in July), Maharashtra (highest rainfall 223.73 mm in July) and Rajasthan (highest rainfall 290.06 mm in August) indicated that the crop has every chance to get exposed to waterlogging stress in its initial stages of germination (pre-germination) and initial seedling establishment, thereby adversely affecting the vegetative phase of the crop. Hence, genetic enhancement of soybean through tolerant varieties/cultivars to pre-germination anaerobic stress should be a viable strategy to overcome waterlogging in any case, providing good yield to soybean producers.

Investigation of fractality and variation of fractal dimension in germinating seed

The fractal analysis has now been recognized as a potential mathematical tool in analyzing complex structures. The present work reports not only the fractal nature of Vigna radiata seed analyzed with the help of Field Emission Scanning Electron Microscopic images but also the variation of fractal dimension (FD) in a germinating seed. The variation of FD during germination in different media—water, salt, and diesel soot with carbon nanoparticles (CNPs)—is studied using the box-counting technique. The study is the first report of the fractality of seed. Irrespective of the media, the FD attains a maximum value on the day of germination and decreases after that. The time (T) for achieving maximum FD varies with the nature of stress. In the study, when the CNPs of diesel soot lower the T value, the salt raises the T value with respect to the control set. The Fourier Transform Infrared analysis of the seeds germinating in different media shows an increased rate of protein formation during the initial stage of germination and a steady state after that. In conjunction with the literature, the variation in the amino nitrogen, soluble nucleotide—RNA, and protein content of the seed during the initial days of germination gets reflected in its FD.

Spatio-Temporal Metabolite and Elemental Profiling of Salt Stressed Barley Seeds During Initial Stages of Germination by MALDI-MSI and µ-XRF Spectrometry.

Seed germination is the essential first step in crop establishment, and can be severely affected by salinity stress which can inhibit essential metabolic processes during the germination process. Salt stress during seed germination can trigger lipid-dependent signalling cascades that activate plant adaptation processes, lead to changes in membrane fluidity to help resist the stress, and cause secondary metabolite responses due to increased oxidative stress. In germinating barley (Hordeum vulgare), knowledge of the changes in spatial distribution of lipids and other small molecules at a cellular level in response to salt stress is limited. In this study, mass spectrometry imaging (MSI), liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS), inductively coupled plasma mass spectrometry (ICP-MS), and X-ray fluorescence (XRF) were used to determine the spatial distribution of metabolites, lipids and a range of elements, such as K+ and Na+, in seeds of two barley genotypes with contrasting germination phenology (Australian barley varieties Mundah and Keel). We detected and tentatively identified more than 200 lipid species belonging to seven major lipid classes (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, prenol lipids, sterol lipids, and polyketides) that differed in their spatial distribution based on genotype (Mundah or Keel), time post-imbibition (0 to 72 h), or treatment (control or salt). We found a tentative flavonoid was discriminant in post-imbibed Mundah embryos under saline conditions, and a delayed flavonoid response in Keel relative to Mundah. We further employed MSI-MS/MS and LC-QToF-MS/MS to explore the identity of the discriminant flavonoid and study the temporal pattern in five additional barley genotypes. ICP-MS was used to quantify the elemental composition of both Mundah and Keel seeds, showing a significant increase in Na+ in salt treated samples. Spatial mapping of elements using µ-XRF localized the elements within the seeds. This study integrates data obtained from three mass spectrometry platforms together with µ-XRF to yield information on the localization of lipids, metabolites and elements improving our understanding of the germination process under salt stress at a molecular level.

The effect of sodium chloride salinity on coated and uncoated alfalfa seeds germination

In this study, a pod experiment was conducted to evaluate the effect of sodium chloride salinity on germination of coated and uncoated seeds of alfalfa seeds under controlled greenhouse conditions at Konya in May 2013. The experimental design was a split-split plot with salinity treatments as main plots, coated and uncoated seeds subplots. Pots were irrigated with tap water (0.3 dS m-1) or (3.0, 6.0 or 9.0 dS m-1). As result of study, seed germination was significantly affected by irrigation water salinity at the initial stage of germination. For coated and uncoated seed, the final seed germination exceeded 79.00% except at the salt concentrations higher than 3.0 dSm-1 where germination percentage statically decreased down. The highest germination rate index (GRI, 14.29%), germination index (GI, 998.75), and coefficient of velocity of germination (CVG, 16.97) values were obtained from the coated seeds irrigated with the tap water while the lowest GRI (1.79%), GI (138.75), and CVG (12.57) values were obtained from the uncoated seeds irrigated with salt concentration of electrical conductivity (EC) of 12.0 dS m-1. Earlier germinations were recorded for coated seeds as indicated by lower value of mean germination time (MGT) and time of 50% germination (T50).

Limits of seed germination of phytomeliorants under conditions of heavy metals toxic concentrations

The aim of the study is to conduct biological testing at the initial stages of plant objects viability in the model conditions of heavy metal pollution. The paper presents the results of laboratory experiments to assess the impact of different concentrations of heavy metal salts on the viability of yellow melilot and great trefoil seeds. In the course of the conducted experimental studies the author has been established a direct dependence of the decrease in the indices of germination energy and laboratory germination of seeds with an increase in the concentration of phytotoxicant salts, determined the critical (threshold) concentration of the studied elements and the metal content, in which the processes of growth and development of seeds remain. The concentration of 0,01% cadmium, zinc, lead and copper was optimal for germination of melilot seeds, where germination was equal to 80%, 74%, 69% and 64%, respectively. For great trefoil seeds, high germination rates were noted in case of 0,01% contamination with lead, zinc, cadmium and copper - 82%, 80%, 77% and 76%, respectively, and in 0,1% salt solution of lead, copper and zinc there were recorded 75%, 74% and 72% of seedlings. Zinc in the concentration of 0,01% at the initial stages of germination of phytomeliorant seeds stimulated germination energy. The tendency of resistance to pollution by lead, zinc and copper was observed at sprouts of a great trefoil, and to pollution by cadmium the greatest resistance was shown by a melilot yellow. Defining the limits of the leguminous plant seeds germination in the presence of a toxic agent will allow research and development in respect of biological restoration of contaminated soils and can be used in technologically disturbed lands.