Normal Seedlings Research Articles

Seed biopriming with Parachlorella, Bacillus subtilis, and Trichoderma harzianum alleviates the effects of salinity in soybean

BackgroundSeed conditioning with bioinputs (biopriming) offers a promising and sustainable alternative to mitigate the adverse effects of salt stress on soybeans. This study aims to evaluate the potential of isolated or combined biopriming using microalgae and different microorganisms in alleviating salinity-induced stress in soybeans in early-stage.MethodsSeeds were subjected to five biopriming treatments: Parachlorella sp. microalgae culture, Bacillus subtilis, Trichoderma harzianum, Parachlorella sp. + B. subtilis, and Parachlorella sp. + T. harzianum, along with a control group without biopriming. Subsequently, the seeds were exposed to two conditions: (i) control (0.0 MPa), and (ii) salinity induced by NaCl (-0.8 MPa). Germination, photochemical indicators, and seedling performance were assessed.ResultsSalinity impaired root protrusion and seed physiology, resulting in a high percentage of abnormal seedlings, thus creating a stressful condition. However, biopriming alleviated the negative effects of salinity, particularly with T. harzianum, Parachlorella sp. + B. subtilis, and Parachlorella sp. + T. harzianum, which led to high germination rates and normal seedlings. All biopriming treatments, especially the combined ones, reduced the suppression of non-photochemical quenching, thereby enhancing the maximum yield of photosystem II. Seedlings under salt stress without biopriming exhibited short lengths and low fresh and dry mass, whereas those bioprimed with Parachlorella sp. + B. subtilis and Parachlorella sp. + T. harzianum showed significantly higher values.ConclusionSeed biopriming, especially with Parachlorella sp. microalgae culture combined with B. subtilis or T. harzianum, effectively alleviates the stressful effects of salinity on germination and early-stage growth seedling of soybeans.

Integrative transcriptomic analysis reveals the molecular responses of tobacco to magnesium deficiency

IntroductionMagnesium (Mg) is a crucial macronutrient for plants. Understanding the molecular responses of plants to different levels of Mg supply is important for improving cultivation practices and breeding new varieties with efficient Mg utilization.MethodsIn this study, we conducted a comprehensive transcriptome analysis on tobacco (Nicotiana tabacum L.) seedling leaves to investigate changes in gene expression in response to different levels of Mg supply, including Mg-deficient, 1/4-normal Mg, normal Mg, and 4×-normal Mg, with a particular focus on Mg deficiency at 5, 15 and 25 days after treatment (DAT), respectively.ResultsA total of 11,267 differentially expressed genes (DEGs) were identified in the Mg-deficient, 1/4-normal Mg, and/or 4×-normal Mg seedlings compared to the normal Mg seedlings. The global gene expression profiles revealed potential mechanisms involved in the response to Mg deficiency in tobacco leaves, including down-regulation of genes–two DEGs encoding mitochondria-localized NtMGT7 and NtMGT9 homologs, and one DEG encoding a tonoplast-localized NtMHX1 homolog–associated with Mg trafficking from the cytosol to mitochondria and vacuoles, decreased expression of genes linked to photosynthesis and carbon fixation at later stages, and up-regulation of genes related to antioxidant defenses, such as NtPODs, NtPrxs, and NtGSTs.DiscussionOur findings provide new insights into the molecular mechanisms underlying how tobacco responds to Mg deficiency.

The Optimal Moisture Content for Cryopreservation of Longjing Tea Seeds

BACKGROUND: Most plant species produce seeds that can be dried to c. 3-7% moisture content, i. e., orthodox, and successfully stored in liquid nitrogen. However, tea seeds are often described as 'recalcitrant', i. e., they die when to lower moisture levels safe for cry opreservation. OBJECTIVE: In this study, we investigated the tolerance to desiccation and freezing of Longjing tea (Camellia sinensis) seeds and analyzed the reason behind seed mortality during desiccation and cryopreservation. MATERIALS AND METHODS: We analyzed the desiccation capacity of tea seeds from Hangzhou, China and subjected the desiccated seeds to programmed cooling and thermal analysis using differential scanning calorimeter (DSC). Subsequently, we used the exotherms to determine the frozen and unfrozen water. We analyzed seed germination and seedling establishment at different water content after storing seeds in liquid nitrogen and correlated the survival with the bound and unbound water. RESULTS: Results showed that the seeds could tolerate drying to 7.9% moisture content without significant viability loss. Moreover, the germination percentage declined sharply after cryopreservation, and the lowest moisture content at which a normal seedling could develop was 11.3±1%, although seeds dried to lower MC did germinate but did not grow into the seedling phase. CONCLUSION: Longjing tea seeds used in this study were neither orthodox nor recalcitrant. We show that the interaction between lipids and freezable water in seeds may lead to the cryoinjury.

The Quality of Tree Seedlings in The Nursery Owned by PT Bukit Asam, Tarahan Port Unit, Bandar Lampung City, Lampung Province, Indonesia

Rehabilitation of post-coal mining land and other land that has been used as a site for a series of mining activities requires seedlings of adequate quantity and quality. Therefore, research on the quality of tree seedlings in the nursery owned by PT Bukit Asam was carried out to determine the physical-physiological condition and classification of the quality of the seedlings. Observations were made on 10 sample seedlings which taken randomly from each tree species. The data collected consists of tree species, seedling height, stem diameter, straightness of the stem, length of the woody stem, number of leaves and/or live crown ratio, compactness of the growing medium, and health condition of the seedling. The seedling quality analysis was carried out based on the criteria that listed in the Indonesian National Standards (INS). The results of the research show that tree species which its seedling meet the standard criteria for normal seedlings are 11 species or 68.75% of all trees species. There are no species of tree seedlings in the first quality category (F). There are 6 species of tree seedlings in the second quality category (S) or 37.50% of the total number of trees species. There are 5 species of non-quality tree seedlings or 31.25% of the total number of trees species. Meanwhile, there are 5 species of tree seedlings which quality criteria are not listed in INS.

The effect of seed packaging materials, storage period and conditions on the physiological sorghum seedlings

Seed quality is fundamental to agricultural productivity and sustainability. Sorghum, as a versatile crop with a wide range of applications, requires high-quality seeds for optimal production. Understanding the seed storage condition, storage period and packaging materials on seed physiological quality is a basis of field crop establishment. This study aimed to evaluate the impact of packaging materials, storage conditions, and storage periods on the physiological quality of sorghum seedlings. One hundred grams of sorghum seed from 5.4 kg of cleaned sorghum seeds were packed in polyethylene bags, polypropylene bags, and aluminium foil. The seeds in packaging materials were stored at 3 different temperatures for 2, 4, and 6 months and the sample of ten grams was taken every 2 months of storage time for germination test. The data on normal seedlings, abnormal seedlings lengths, and seedling dry weight were recorded. The results showed that polyethylene bags at 10°C and 2 months of storage preserved seedling physiological quality more than aluminium foil and polypropylene bags. This may be attributed to the impervious properties of polyethylene hence preventing oxidative reactions and seed deterioration. To guarantee the successful field establishment and strong plant stand of sorghum crops, findings advise seed producers and farmers regarding appropriate seed storage procedures.

Comparative Studies on The Efficacy of Some Fungicides Activities on Fungal Seed Borne Pathogens of Commercial Maize Seeds

This study investigated the efficacy of some fungicides activities on fungal seed borne pathogens of two commercial maize seeds (Sammaz 15 and Sammaz 52). A total of 2500 seeds were randomly picked for each variety to represent a working sample from the seed reference collections. Out of the 2500 seeds, 400 seeds were surface–sterilized with 10% sodium hypochlorite solution, cultured and examined microscopically for the presence of fungal pathogens. Molecular analysis confirmed that all isolated pathogens matched with the reference accession from NCBI molecular database. Seeds were treated with different dosages of fungicides viz Thiram and Metalaxy + Tebuconazole and incubated for 5 days. The effect of the various fungicides on the incidence of seed- borne fungi, effect on seed germination and interaction of the fungicide were evaluated and analyzed. Percentage occurrence of the fungal pathogens revealed that Sammaz 15 have F. solani (29.0%), A. flavus (20.3%), A. niger (19.0%) and Rhizpus stolanifera (15.0%). In Sammaz 52, A.niger (40.0%), A. flavus (19.7%) and F. solani (27.0%). It was observed that F. solani was predominant in sammaz 15 while A. niger was predominant in Sammaz 52. Thiram (45.88 mm) at all doses showed greater inhibitory effects on mycelia growth than Metalaxyl + Tebucanozole (24.25 mm). The correlation analysis performed on the data set reveals that there is a negative significant correlation between zone of inhibition and percent disease incidence (r = -0.99***), but the relationship was positive with number of non-infected seeds (r = 0.99***). This shows that increasing the zone of inhibition will increase the number of non-infected seeds and the normal seedling (germination percentage). Thiram fungicides observed to be more effective in reducing the disease incidence than Metalaxyl fungicides.

Time of Application of Desiccant Herbicides Affects Photosynthetic Pigments, Physiological Indicators, and the Quality of Cowpea Seeds.

Chemical desiccation is widely used in agriculture to anticipate harvest and mitigate the effects of adverse environmental conditions. It is applied to both grains and seeds. Although this practice is widely used, there are still significant gaps in understanding the effects of different herbicide application times on seed quality and plant physiological responses. The objective of this study was to evaluate the effects of different herbicide application times on cowpea, focusing on seed quality, physiological responses, and biochemical composition, including chlorophylls, carotenoids, sugars, and proline, under nocturnal desiccation. In the first experiment, eight herbicides and two mixtures were applied at night: diquat, flumioxazin, diquat + flumioxazin, glufosinate ammonium, saflufenacil, carfentrazone, diquat + carfentrazone, atrazine, and glyphosate. All of the tested herbicides caused a reduction in normal seedling formation, with the diquat + carfentrazone combination resulting in 100% abnormal seedlings. A significant decrease in chlorophyll levels (chlorophyll a: 63.5%, chlorophyll b: 50.2%) was observed using diquat, which indicates damage to photosynthetic processes, while the carotenoid content increased. Total soluble sugars and proline were also negatively impacted, reflecting physiological stress and metabolic changes in seedlings. In the second experiment, three application times were tested with diquat, diquat + flumioxazin, and diquat + carfentrazone. Nocturnal application showed the most significant reduction in chlorophyll levels and increased carotenoid levels. Application at noon and late afternoon also significantly changed the soluble sugar and proline levels. These results indicate that the herbicide application time directly influences the seeds' physiological quality.

Physiological quality of green corn seeds under water stress conditions

This study aimed to evaluate the physiological quality of green corn seeds subjected to water stress. The experimental design used was completely randomized, in a 2 x 5 factorial arrangement, consisting of two corn hybrids (AG1051 and BRS3046) and five osmotic potentials (0; -0.4; -0.8; -1.2 and – 1.6 MPa) simulated with aqueous solutions of polyethylene glycol 6000 (PEG 6000), with four replications of 50 seeds per treatment, totaling 40 experimental units. The analyzed variables were: water content, germination, root protrusion, final root protrusion, germination speed index, root length and coleoptile length. There was a significant effect of the interaction between hybrid factors and osmotic potentials for all analyzed variables, except for final root protrusion, which showed an isolated effect for the two factors studied. The results obtained indicated a higher percentage of germination and initial development of green corn seedlings for green corn seeds, hybrids AG1051 and BRS3046 at the osmotic potential of 0.0 MPa. The germination and vigor of green corn seeds decrease under water stress conditions from the osmotic potential of -0.4 MPa induced by PEG 6000, inhibiting the development of normal seedlings, affecting seed viability. Hybrid AG1051 presents superior germination and vigor compared to BRS3046.

The impact of chitosan nanoparticles on seedling and germination attributes and enzymatic activity of guar (Cyamopsis tetragonoloba L.) under osmotic stress

This research was conducted to examine the effects of nano chitosan particles on seed germination and seedling growth of guar (Cyamopsis tetragonoloba L.) under osmotic stress conditions. This experiment was conducted in a factorial layout based on a completely randomized design with two factors and four replications. The experimental factors included: osmotic stress at five levels (0, −3, −6, −9 and −12 bar) and seed priming with nano chitosan particles at five concentrations (0, 50, 100, 200, and 300 ppm). The evaluated parameters in this study were alometric traits and enzymatic activities including proline, catalase, ascorbate peroxidase, superoxide dismutase, and total soluble sugar, as well as the content of chlorophyll a, b, and carotenoids. The results indicated the significant effect of most of the studied quantitative and qualitative traits. The highest values of seedling, plumule and radicle length (48.20, 17.79 and 30.15 mm, respectively), and the fresh weight of seedlings and plumule (0.9743 and 0.9192 g, respectively) were observed at a concentration of 200 ppm of chitosan nanoparticles. The highest amount of all studied parameters observed under non-stress conditions (control), and the lowest values of them obtained in −12 bar of osmotic stress. Furthermore, by increasing of osmotic stress levels, germination percentage and rate and seed vigor showed a decreasing trend about 56, 83 and 95% compared to the control. Besed on the interaction effects, the maximum values of seedling and plumule length were achieved with the application of 200 ppm chitosan nanoparticles in combination with no osmotic stress. Under non-osmotic conditions, concentrations of 300, 100, and 200 ppm chitosan led to the highest values of germination percentage and rate and seed vigor, respectively. Additionally, the highest percentage of normal seedlings (94%) and the lowest percentage of abnormal seedlings (zero) were obtained under the application of 200 ppm of nano chitosan and no osmotic stress. In relation to qualitative traits, the lowest values of soluble sugar and proline were obtained at the osmotic level of −12 bar. Moreover, the application of 200 ppm of nano chitosan and −6 bar of osmotic stress resulted in the highest levels of catalase, superoxide dismutase, ascorbate peroxidase, chlorophyll a, b, and carotenoids. As a whole, the results of the study demonstrated that seed priming with chitosan nanoparticles can reduce the negative effects of drought stress on guar seedlings. In addition, application of 200 ppm of this substance was the most suitable treatments that improve most quantitative and qualitative indices of guar. Keywords: Enzymatic activity, Nano particles, Priming, Seed structure.

Evaluating The Physical Quality of Trembesi Seedlings (Samanea saman) in The Permanent Nursery of BPDAS Indragiri Rokan, Pekanbaru City, Riau Province

The availability of high-quality seedlings is crucial for reforestation and forest rehabilitation initiatives aimed at mitigating deforestation. This study assesses the physical quality of rain tree (Samanea saman) seedlings produced by the Permanent Nursery of BPDAS Indragiri Rokan, located in Pekanbaru, Riau Province. A systematic sampling method with a random start was employed, involving 15,155 raintree seedlings that were six months old, from which a sample size of 200 seedlings was selected following SNI 8420 of 2018. The parameters observed included seedling height, stem diameter, leaf count (LCR), compactness of the planting medium, and root crown ratio. Data analysis was conducted based on the general and specific quality requirements outlined in SNI and Perdirjen RLPS No. P.05/V-Set/2009. The findings revealed that 66.5% of the seedlings satisfied the general requirements, while 72.38% met the specific requirements. The rain tree seedlings were classified within quality class D, with a percentage of normal seedlings falling below 95% and several samples exhibiting damage from pests and diseases. These results underscore the necessity for enhancements in nursery management, particularly concerning pest and disease control, to elevate the quality of raintree seedlings in future production.

Inbreeding in Chinese fir: Insights into the adaptive growth traits of selfed progeny from mRNA, miRNA, and copy number variation.

The impact of inbreeding on biological processes is well documented in individuals with severe inbreeding depression. However, the biological processes influencing the adaptive growth of normal selfed individuals are unknown. Here, we aimed to investigate how inbreeding affects gene expression for adaptive growth of normal selfed seedlings from a self-fertilizing parent in Chinese fir (Cunninghamia lanceolata). Using RNA-seq data from above- and underground tissues of abnormal and normal selfed seedlings, we analyzed GO biological processes network. We also sequenced small RNAs in the aboveground tissues and measured the copy number variations (CNV) of the hub genes. Phenotypic fitness analysis revealed that the normal seedlings were better adapted than their abnormal counterparts. Upregulated differentially expressed genes (DEGs) were associated with development processes, and downregulated DEGs were mainly enriched in fundamental metabolism and stress response. Results of mRNA-miRNA parallel sequencing revealed that upregulated target genes were predominantly associated with development, highlighting their crucial role in phosphorylation in signal transduction networks. We also discovered a moderate correlation (0.1328 < R2 < 0.6257) between CNV and gene expression levels for three hub genes (TMKL1, GT2, and RHY1A). We uncovered the key biological processes underpinning the growth of normal selfed seedlings and established the relationship between CNV and the expression levels of hub genes in selfed seedlings. Understanding the candidate genes involved in the growth of selfed seedlings will help us comprehend the genetic mechanisms behind inbreeding depression in the evolutionary biology of plants.

Pollen morphology and reproductive biology of Calophyllum brasiliense Cambess. (Calophyllaceae)

Pollen morphology and the reproductive biology of Calophyllum brasiliense were investigated in Parque Estadual das Fontes do Ipiranga, São Paulo, Brazil. The study encompassed pollen analyses using light, scanning, and transmission electron microscopy. Additionally, we collected data on reproductive biology, main visitors/pollinators, fruit set, and seed germination. The species exhibits individuals with perfect flowers (hermaphrodites) as well as male individuals with staminate and perfect flowers. Flowering occurs in October and November, and flowers have diurnal anthesis and pollen as a floral resource. Pollen grains are monads of medium size, isopolar, oblate-spheroidal to prolate-spheroidal, 3-(4)-zonocolporate, with exine fossulate-perforate with supratectal microechini. Hermaphrodite individuals have the highest proportion of malformed pollen due to their reduced grain size. The pollen grains from the hermaphrodite individuals displayed a low viability (0.06%), while those from male individuals had higher viability (66.38% and 55.78% for perfect and staminate flowers, respectively). The stigma was receptive throughout the anthesis period. Cross-pollination between perfect flowers of male and hermaphrodite individuals resulted in 8.80% success in fruit set, but led to the development of one abnormal seedling. Cross-pollination between staminate flowers and perfect flowers of hermaphrodite individuals showed a 7.70% success rate and the control group showed an 8.00% success rate, both groups leading to the development of normal seedlings. This tree species shows relatively low reproductive success and relies on pollinators (mainly Apis mellifera, Paratrigona subnuda, Tetragonisca angustula, and Halictidae sp. 1) for the setting of fruits and seeds.

Polyembryony in Santalum album – a double-edged sword for plant regeneration

ABSTRACT Santalum album is a hemiparasitic evergreen tree known for its heartwood oil, widely used in the cosmetics and aromatherapy industry. Overexploitation in the past few decades has led to the classification of this species as Vulnerable on the IUCN Red List of Threatened Species. Drupes of S. album are single-seeded and usually monoembryonic in nature, producing normal seedlings. However, in a previous study, we also observed some polyembryonic seeds. In this news article we share our polyembryony findings from Marayoor population as well as the growth and survival of seedlings which emerged from polyembryonic seeds. We found that less than 1% of the seeds in Marayoor population exhibited polyembryony (duplets). The general trend was that one radicle emerged 2-3 days earlier than the other and grew faster and healthier compared to the radicle from monoembryonic seeds. The second (smaller) seedling from polyembryonic seeds began to degenerate if not separated, but it survived well (albeit with low growth potential) once transplanted into a separate polybag. In S. album, polyembryony does not seems to be an essential ecological competitive strategy, unlike in several invasive species. For mass-scale seedling production of this vulnerable species, we recommend separating twin seedlings soon after their emergence for a better survival rate.

Exploring physiological variables and lipid fraction characteristics in chia nutlets: Correlations with biophysical techniques across varieties with varying germinative power and vigor

Understanding aging in seeds is vital for conservation and long-term preservation. This study examined the physiological and lipid characteristics of three chia varieties (WN, MNI, MNII) using conventional and biophysical methods to establish correlations and explore aging mechanisms. Variables assessed included thousand seed weight, moisture content (MC), and germination parameters, such as normal germination power (NGP), hypocotyl and radicle length, vigor, viability, as well as lipid characteristics, and thermal parameters. Physiological differences were prominent, especially in the MNII, with longer mean germination times (MGT = 2.11 d) and reduced NGP (63.24%). The WN variety exhibited superior germination (NGP = 95.9%), while MNI had an NGP of 93.2% and the highest vigor. Lipid analysis revealed significant differences, particularly in free fatty acid content (FFA). The oxidative status and tocopherol content were evaluated, with high germination in WN being associated with the combination of tocopherol isomers. The thermal analysis highlighted the predictive potential of ΔH for seed health and viability. Spectral analysis distinguished nutlets and oils, showcasing unique vibrational patterns. The correlation analysis revealed significant relationships crucial for conservation. MGT showed positive correlations with moisture content, electrical conductivity, and FFA, but negative correlations with germinated nutlets (GN) and normal seedlings (NS). MC positively correlated with FFA, abnormal seedlings (AS), and deteriorated nutlets, yet negatively correlated with GN and NS. Electrical conductivity emerged as a germination indicator, positively correlating with FFA and deteriorated nutlets, and negatively with GN and NS. δ-tocopherol content positively correlated with successful germination and NS, but negatively with AS. Thus, this research provides relevant knowledge on the conservation of chia nutlets by offering information on seed deterioration markers that can be obtained by FT-IR and DSC. This is particularly valuable for studying germplasm with a limited sample size, common in gene banks.

Production and Quality of Radish Seeds with Sulfur in Top Dressing and Organic Compost at Planting Fertilization

Aims: This study evaluates the effects of top dressing sulfur (S) fertilization, with and without organic compost before planting, on radish seed production and quality. Study Design: Eight treatments were studied in a factorial scheme (4 x 2): four S doses in top dressing fertilization (0, 60, 120, 180 kg ha-1 of S), with or without organic compost (50 t ha-1) in fertilization before seeding. Place and Duration of the Study: The experiment was carried out in the São Manuel Experimental Farm (22°46’ South, 48°34’ West, 740 m above sea level) in the School of Agriculture (FCA) of the Sao Paulo State University (UNESP) located in São Manuel, SP, Brazil. Radish sown happened in April, and harvest and seed analysis occurred in October 2017. Methodology: Radish seeds were manually harvested (188 days after being sown), cleaned, and dried. Evaluations of seed production per plant, weight of 1000 seeds, and seed quality (germination (%), germination first count, germination speed index, and dry weight of normal seedlings) were performed. Results: Applying organic compost increased radish seed production and the weight of 1000 seeds. Where no organic compost was applied, the higher the S dose, the greater the seed production per plant. With organic compost fertilization, the highest seed production and the weight of 1000 seeds were obtained with top dressing fertilization with 68 kg ha-1 of S. Germination and germination speed index were not affected by either factor, organic compost fertilization or S dose. Where no organic compost was applied, the higher the S dose, the lower the leachate level in the electrical conductivity test. Conclusion: The radish base fertilization with organic compost plus top dressing S fertilization (68 kg ha-1) is indicated for radish seed production.

One-Time Contact Application of Controlled-Release Urea and Optimized Method Improved Rice Yield and Nitrogen Use Efficiency with 50% Nitrogen Input

Excessive nitrogen application is a common phenomenon in rice production in China, which will lead to a low nitrogen utilization rate and increase farmers’ production costs. In Jingzhou, Hubei Province, for two consecutive years (2021, 2022), rice was planted with nursery-box total fertilization (NBTF) technology to provide technical support for rice seedling box contact fertilization technology. The results showed that, compared with the conventional treatment, the seedling emergence rate decreased by 7.70–11.87%, but the seedling quality significantly improved and the plant height significantly increased by 4.38–6.06% in the full-heading stage after the aforementioned treatments. The leaf area index significantly increased by 16.75–34.55%, 10.04–19.30%, and 12.13–18.60% in the tiller, booting, and full-heading stages, respectively, whereas the photosynthetic rate significantly increased by 3.80–5.25% in the booting stage. The rice yield under the 50% CRU and 50% CRU + S treatments was the same as that under the FFP treatment. The rice yield under 50% CRU + BT and 50% CRU + BT + S treatments was 7.50–10.61% higher than that under the FFP treatment; nitrogen partial factor productivity increased by 96.15–123.63%. NBTF combined with Boxingtanzhuang (in Chinese) seedling trays showed an increase in yield, whereas normal seedling trays showed a stable yield. It is suggested that the seedling tray and fertilizer should be specialized in the rice seedling box, and the height of the seedling tray should be increased by 3–5 cm. At the same time, special controlled-release urea should be selected to ensure less N release before emergence and improve the seedling emergence rate so as to popularize NBTF technology in a large area.

Effect of dormancy on the emergence of Tabernaemontana heterophylla seedlings in different substrates

The composition and dynamics of plant communities are determined by the survival, dispersal and persistence of seeds in the soil, some of the fundamental aspects for understanding plant biology, among which seed dormancy is of particular importance. The aim of this work was to find out whether seed dormancy is affected by certain substrates in order to improve the production of Tabernaemontana heterophylla seedlings. Treatments were carried out with different substrates (T1. Sand, T2. Vegetable clay, T3. Vegetable clay + sand (1:1 ratio), T4. Vermiculite, T5. Cattle manure, T6. Sawdust and T7. Organic compost) in 7 x 4 factorial schemes, the results of which were subjected to an analysis of variance and a comparison of means with the Tukey test at a probability of 5%. The seeds with visible germination structure (hypocotyl) showed an apical meristem in a dormant stage. The number of normal seedlings did not exceed 25% of the germinated seeds in all treatments, with a high proportion of non-viable seeds observed. In the absence of technical information on overcome dormancy, it is important to use strategies that stimulate germination and subsequent seedling growth. The slow germination combined with the presence of dormancy in the hypocotyledon were factors that negatively affected the propagation of the species studied.

Low nitrogen priming improves nitrogen uptake and assimilation adaptation to nitrogen deficit stress in wheat seedling.

Early-stage low nitrogen priming promotes root growth and delays leaf senescence through gene expression, enhancing nitrogen absorption and assimilation in wheat seedlings, thereby alleviating growth inhibition under nitrogen deficit stress and supporting normal seedling development. Verifying the strategies to reduce the amount of nitrogen (N) fertilizer while maintaining high crop yields is important for improving crop N use efficiency (NUE) and protecting the environment. To determine whether low N (LN) priming (LNP) can alleviate the impact of N-deficit stress on the growth of wheat seedlings and improve their tolerance to N-deficit stress, we conducted hydroponic experiments using two wheat cultivars, Yangmai 158 (YM158, LN tolerant) and Zaoyangmai (ZYM, LN sensitive) to study the effects of LNP on wheat seedlings under N-deficit stress. N-deficit stress decreased the plant dry weight, leaf area, and leaf N content (LNC), while LNP could significantly reduce this reduction. Distinct sensitivities to N-deficit stress were observed between the wheat cultivars, with ZYM showing an early decrease in leaf N content compared to YM158, which exhibited a late-stage reduction. LNP promoted root growth, expanded N uptake area, and upregulated the expression of TaNRT1.1, TaNRT2.1, and TaNRT2.2 in wheat seedlings, suggesting that LNP can enhance root N uptake capacity to increase N accumulation in plants. In addition, LNP improved the activity of glutamine synthase (GS) to enhance the capacity of N assimilation of plants. The relative expression of TaGS1 in the lower leaves of priming and stress (PS) was lower than that of no priming and stress (NS) after LNP, indicating that the rate of N transfer from the lower leaves to the upper leaves became slower after LNP, which alleviated the senescence of the lower leaves. The relative expression of TaGS2 was significantly increased, which might be related to the enhanced photorespiratory ammonia assimilation capacity after LNP, which reduced the N loss and maintained higher LNC. Therefore, LNP in the early stage can improve the N absorption and assimilation ability and maintain the normal N supply to alleviate the inhibition of N-deficit stress in wheat seedlings.

Boron nutrition improves peanuts yield and seed quality in a low B sandy soil

ABSTRACT Peanuts are mainly grown in sandy soils with low boron content, which may limit the crop yield, especially runner-type cultivars that have high-yields. Boron deficiency causes hollow heart in peanut seeds, reducing yield and seed quality, but the best strategy to supply boron to peanut is still not known. This study aimed to evaluate peanuts nutrition, yield, and seed quality as a function of boron rate, source, and application form. The study was conducted for two years in sandy soils with low boron in southeastern Brazil. Treatments included application of boron via soil: control (boron unfertilized), boric acid at 1.5 kg ha -1 of B, Ulexite (1.5 and 3.0 kg ha -1 of B), and sodium tetraborate (1.5 and 3.0 kg ha -1 of B) combined with foliar fertilization (sub-plots): 0, 400, 800 and 1200 g ha -1 of B (boric acid) with four replicates. Boron fertilization via soil and foliar increased peanuts yield by 20 % (1100 kg ha -1 ) and 14 % (700 kg ha -1 ) - the average of the two crops, respectively. Combined use of soil and foliar fertilizer was justified only in years with water deficit and when the rate applied via soil was low (&lt;3.0 kg ha -1 ). Boron application via soil or application of 400 g ha -1 of B via foliar fertilization increased seed germination rate by 10 to 13 %. Boron fertilization increased the percentage of normal seedlings, seedling weight, and length and reduced the germination time. Foliar and soil boron applications efficiently improved peanut seed nutrition, yield, and quality. However, soil application performed better, showing a higher percentage of yield increase.

Corn processing by pulsed electric fields with respect to microbial inactivation and improvement of seed vigour

Pulsed electric field (PEF) treatment of corn grains to improve seed vigour and inactivation of endogenous microflora by energies ranging from 1.20 to 28.8 J were applied to determine effectiveness of applied energies on germination rate (GR), normal seedling rate (NSR), electrical conductivity (EC), ability to germinate under salt (100- and 200 mM salt) and cold (at 10 °C for 7 days and at 25 °C for 5 days) stresses. Moreover, the effect of PEF treatments was further investigated for the inactivation of total aerobic mesophilic bacteria (TAMB), total mold and yeast (TMY), and inactivation rate (%) of Aspergillus parasiticus. Increased energy provided 11.10 % increase in GR, 21.22 % increase in NSR, 95.50 % increase in germination at 10 °C for 7 days. Germination under stress conditions revealed 32.53 %, 68.35 %, and 76 % increase in germination at 25 °C for 5 days, under 100 mM- and 200 mM NaCI salt stresses. Inactivation on the mean initial TAMB and TMY were approximately 9.25 and 7.93 log, respectively, with 63.33 ± 0.22 % reduction in A. parasiticus culture. PEF treated corn seedlings had stronger and taller body formation with stronger roots. The most optimal processing parameters were detected as 300 Hz, 28.80 J, and 19.78 sec. PEF treatment carries a high potential to improve corn vigour with inactivation of surface microflora.