Early Stages Of Plant Development Research Articles

The most relevant drought-tolerant indices for selecting barley drought-tolerant genotypes

During its development cycle, lack of water is one of the factors reducing plant growth and yields, in the world's arid regions. The identification of indices that characterize the most tolerant genotypes to drought is very useful since it allows us to evaluate the tolerance of large varieties collections within a short and early stage. This study aimed to identify the most efficient drought tolerance indicators and evaluate, from the early stage of plant development, the germination parameters that would be correlated with drought tolerance in the field. If such correlations were identified, it would be possible to screen dozens of genotypes in the laboratory and identify the most tolerant ones before moving into the field. To attain this objective, two tests were carried out: The first one was realized in the laboratory to assess some germination parameters (germination rate, root length, root number, etc.) of sixteen North African barley genotypes (Algerians, Tunisians, and Egyptians) at the germination stage, under polyethylene glycol (PEG-6000) induced stress. The second test was carried out in the field to measure the grain yield of the same genotypes, under favorable and limited water conditions. The laboratory test revealed significant differences between root lengths (RL) of different genotypes within each water regime and between different treatments (control and PEG-6000 solution). The obtained result showed the superiority of most Egyptian genotypes, especially under stress conditions induced by PEG-6000. The field trial also showed significant differences in grain yields under both water regimes (stressful and non-stressful regimes) and pointed to the high performance of the majority of Egyptian genotypes. The calculated indices [(STI), (SSI), (YSI), and (TOL)] showed variable correlations depending on the index used and concluded that STI and YSI are the best indicators of drought tolerance compared to the others. Among the germination parameters, only the root length (RL) under PEG stress is positively correlated with grain yield, obtained under drought conditions in the field. Therefore, it would be possible to use this parameter to select, at an early stage, the most drought-tolerant genotypes.

Effect of Cultivar and Temperature on Disease Development of Macrophomina Root Rot in Strawberry

Root rot, or charcoal rot, caused by the soilborne fungus Macrophomina phaseolina, is a significant disease affecting strawberry production worldwide. Field trials were conducted for five seasons (2016–2017 to 2020–2021) to evaluate strawberry host plant resistance to Macrophomina root rot (MRR) in California. A wide range of plant resistance to MRR was observed. Because low disease severity occurred in the fifth season, a summary of the first to fourth seasons showed that ‘Osceola’ was highly resistant, whereas ‘Festival’, ‘Sweet Ann’, and ‘Ruby June’ were highly susceptible. Disease severity varied over the seasons for specific cultivars, as did the average final mortality for all cultivars. Models were built to investigate the relationship between environmental variables and final disease mortality among the seasons. Strong positive associations were found between the soil temperature during the first month after planting ( R2 = 0.79, P < 0.0001) or air temperature mid-season ( R2 = 0.79, P < 0.0001) and the final disease mortality of eight cultivars. We concluded that the soil temperature during the early stage of plant development and the mid-season air temperature are important factors in disease development for MRR. Screening new strawberry cultivars and elite breeding lines against MRR should be ongoing as part of a standard process for determining the susceptibility of currently grown and potentially new cultivars.

The significance of the two cytosolic glutamine synthetase enzymes, GLN1;3 and GLN1;5, in the context of seed development and germination in Arabidopsis thaliana

Glutamine synthetase (GS), an initial enzyme in nitrogen (N) plant metabolism, exists as a group of isoenzymes found in both cytosolic (GS1) and plastids (GS2) and has gathered significant attention for enhancing N use efficiency and crop yield.This work focuses on the A. thaliana GLN1;3 and GLN1;5 genes, the two predicted most expressed genes in seeds, among the five isogenes encoding GS1 in this species. The expression patterns were studied using transgenic marker line plants and qPCR during seed development and germination. The observed patterns highlight distinct functions for the two genes and confirm GLN1;5 as the most highly expressed GS1 gene in seeds. The GLN1;5, expression, oriented towards hypocotyl and cotyledons, suggests a role in protein turnover during germination, while the radicle-oriented expression of GLN1;3 supports a function in early external N uptake.While the single mutants exhibited a normal phenotype, except for a decrease in seed parameters, the double gln1;3/gln1;5 mutant displayed a germination delay, substantial impairment in growth, nitrogen metabolism, and number and quality of the seeds, as well as a diminishing in flowering. Although seed and pollen-specific, GLN1;5 expression is upregulated in the meristems of the gln1;3 mutants, filling the lack of GLN1;3 and ensuring the normal functioning of the gln1;3 mutants.These findings validate earlier in silico data on the expression patterns of GLN1;3 and GL1;5 genes in seeds, explore their different functions, and underscore their essential role in plant growth, seed production, germination, and early stages of plant development.

Genome-wide identification of WRKY transcription factor family members in Miscanthus sinensis (Miscanthus sinensis Anderss)

Miscanthus is an emerging sustainable bioenergy crop whose growing environment is subject to many abiotic and biological stresses. WRKY transcription factors play an important role in stress response and growth of biotic and abiotic. To clarify the distribution and expression of the WRKY genes in Miscanthus, it is necessary to classify and phylogenetically analyze the WRKY genes in Miscanthus. The v7.1 genome assembly of Miscanthus was analyzed by constructing an evolutionary tree. In Miscanthus, there are 179 WRKY genes were identified. The 179 MsWRKYs were classified into three groups with conserved gene structure and motif composition. The tissue expression profile of the WRKY genes showed that MsWRKY genes played an essential role in all growth stages of plants. At the early stage of plant development, the MsWRKY gene is mainly expressed in the rhizome of plants. In the middle stage, it is mainly expressed in the leaf. At the end stage, mainly in the stem. According to the results, it showed significant differences in the expression of the MsWRKY in different stages of Miscanthus sinensis. The results of the study contribute to a better understanding of the role of the MsWRKY gene in the growth and development of Miscanthus.

EXPLORING THE RESPONSE MECHANISMS OF RICE TO SALINITY STRESS

The world's agricultural productivity has been on the decline due to salinity, which is a significant abiotic element. To find a solution to this problem, researchers have been concentrating their efforts on the enzymes and biochemical pathways involved in salt tolerance. The ultimate objective is to develop crops that are resistant to salt. Developments in molecular biology have facilitated the production of salt-tolerant cultivars by conventional breeding techniques. A significant amount of salt can inhibit the growth of rice (Oryza sativa L.), a major food crop in many nations. This is especially true during the early stages of plant development. Rice's physiological, molecular, and biochemical reactions to excessive salinity have been the subject of significant exploration and investigation. The possible applications and implications of salinity tolerance are also discussed in this article, as well as the approaches that can be used to locate plants that are tolerant of salt.

Effect of calcium chloride concentration on seed germination and young seedling parameters in rice (Oryza Sativa L.)

The study was conducted with five rice varieties (Osmanchik 97, Gala, Luna, CL 34, Cameo) in order to determine and compare the effect of increased concentrations of CaCl2 on seed germination during the early stages of plant development. Variations include: control (deionized distilled water), 50 mM, 100 mM, 150 mM, 200 mM, 250 mM, and 300 mM CaCl2 concentrations. Germinating energy, germination rate, germination rate coefficient, germination index degree, germination index, mean germination time, sprout and root length, sprouts and roots fresh and dry weight, seed vitality index and salinity tolerance were determined. The data were analyzed with SPSS program. The results show that the application of increasing concentrations of CaCl2 salinity in the order of 50-200 mM leads to a prolongation of the mean germination time of the seeds and has an inhibitory effect on the growth of sprouts and roots, this effect being more pronounced on the roots . The cultivars Osmanchik 97 and Gala are relatively more tolerant to salinization with low and medium concentrations of CaCl2 in terms of seed germination. At salinity levels from 250 mM to 300 mM CaCl2 solution, all tested cultivars were sensitive.

Regenerative strategies of Euterpe edulis (Arecaceae) at its altitudinal limits in the Atlantic Forest

AbstractPopulations occurring at the limit of a species' altitudinal distribution undergo strong environmental filtering. Rapid climate change intensifies this process, impacting ecological responses of populations. Understanding the effects of climate change, especially in the early stages of plant development, has become essential to predict vulnerability to extinction. However, few studies have explored initial establishment strategies of plant populations at the limit of their distribution in the face of global warming. We tested the effects of increasing temperatures on germination performance and on initial seedling establishment on two populations of Euterpe edulis, a palm tree widely distributed in the Atlantic Forest between 0 and 1400 m altitude. The tests were conducted in a laboratory, where the seeds were exposed to three conditions for 90 days: control at 25°C, and two treatments at higher temperatures (35 and 40°C). Germination percentage was not affected by population, seed size class or treatments. Average time for germination only increased in the Montane Forest population in the most extreme treatment, while in the sea level Restinga population, time for germination was affected by a small temperature increase. Mortality percentage in the Restinga population was similar in the post‐germination phase and in the temperature treatments. We concluded that E. edulis populations located at their lower altitudinal limit are closer to the species thermal limit, thus being more vulnerable to temperature increase than populations at the upper limit of the species' altitudinal distribution.

Selecting plant species to rehabilitate Phytophthora cinnamomi infested forest

For most Western Australian plant species, no information is available on the effect of Phytophthora cinnamomi on seedling emergence, early survival, and early plant growth. Such information is required when selecting species for rehabilitating Eucalyptus marginata (jarrah) forest areas affected by Phytophthora dieback. This study evaluates the response of several native species to P. cinnamomi to identify those resistant to the pathogen at the early stages of plant development. Firstly, the effect of P. cinnamomi on seedling emergence and early survival was evaluated for 50 native species. Then, 24 species were selected and tested for their resistance to P. cinnamomi when more mature. They were infested at 5–7 months old and disease impact assessed after two months. Of 38 species that emerged in sufficient numbers for statistical analysis, P. cinnamomi did not affect either emergence or survival of 9 species, emergence or survival was decreased in 14 species, and both emergence and survival were significantly decreased in 15 species. Of the species tested at 5–7 months old, two were resistant, six were moderately resistant, ten were susceptible, three were highly susceptible, and three were tolerant hosts of P. cinnamomi. These results indicate that field resistance recorded from mature plants may be due to asymptomatic infection or resistance may not be present in seedlings. Therefore, data from mature plants may not be appropriate when selecting species for seed-based restoration.

A Novel, Precise and High-Throughput Technology for Viroid Detection in Cannabis (MFDetectTM)

Hop latent viroid (HLVd) is a severe disease of cannabis, causing substantial economic losses in plant yield and crop value for growers worldwide. The best way to control the disease is early detection to limit the spread of the viroid in grow facilities. This study describes MFDetectTM as a rapid, highly sensitive, and high-throughput tool for detecting HLVd in the early stages of plant development. Furthermore, in the largest research study conducted so far for HLVd detection in cannabis, we compared MFDetectTM with quantitative RT-PCR in a time course experiment using different plant tissues, leaves, petioles, and roots at different plant developmental stages to demonstrate both technologies are comparable. Our study found leaf tissue is a suitable plant material for HLVd detection, with the viroid titer increasing in the infected leaf tissue with the age of plants. The study showed that other tissue types, including petiole and roots, were equally sensitive to detection via MFDetectTM. The assay developed in this research allows the screening of thousands of plants in a week. The assay can be scaled easily to provide growers with a quick turnaround and a cost-effective diagnostic tool for screening many plants and tissue types at different stages of development.

Indices of antioxidant and osmoprotective systems in seedlings of winter wheat cultivars with different frost resistance

The functioning of the stress-protective systems of wheat under the action of cold at the early stages of plant development remains poorly studied. The aim of this work was a comparative study of antioxidant activity and the content of sugars and proline as indicators of osmoprotective activity during cold adaptation of seedlings of seven winter bread wheat (Triticum aestivum L.) cultivars that differ significantly in frost resistance. The 3-day-old etiolated seedlings were hardened at 2°C for 6 days and then frozen for 5 h at -6 or -9°C. Two days after freezing, the survival of seedlings was assessed by their ability to grow. A decrease in ROS content, an increase in the activity of antioxidant enzymes catalase and guaiacol peroxidase and accumulation of sugars in the shoots of high-frost-resistant cultivars during hardening were detected. The absolute values of catalase and guaiacol peroxidase activity correlated positively with the frost resistance of seedlings. The negative correlation between the frost tolerance of the cultivars and the accumulation of proline in the seedlings during hardening was recorded. The possibility of using the studied biochemical indices for frost resistance screening of winter wheat varieties at the seedling stage was stated. Keywords: antioxidant system, cold hardening, frost resistance, osmolytes, oxidative stress, Triticum aestivum

Genetic diversity of wild barley (<i>Hordeum spontaneum</i> K. Koch) in the context of resistance to toxic aluminum ions

Background. The problem of resistance to aluminum toxicity of soils is very relevant for the cultivated type of barley. The area of acidic soils in Russia is about forty percent of the total area of arable land, so the toxicity of aluminum is one of the main factors that reduce the yield of barley. The study of wild relatives of the main crops, including barley, is of considerable interest for the development of stress-resistant cultivars. Wild barley Hordeum spontaneum K. Koch has biological characteristics similar to the cultivated H. vulgare L., grows in various ecogeographic zones, and is well adapted to local soil and climate conditions. All this makes it possible to use it as a new donor of source material for breeding high-yielding cultivars adapted to certain environmental conditions. The objective of this work was to search for H. spontaneum genotypes highly resistant to ionic (Al3+) toxicity.Materials and methods. One hundred accessions of H. spontaneum from the collection of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) were examined. The resistance of barley accessions to toxic aluminum ions was studied at the early stages of plant development by the root test method (185 mcМ Al3+, pH 4.0) with the calculation of root and sprout length indices.Results and conclusions. The studied fragment of the wild barley collection demonstrated broad genetic diversity in terms of resistance to phytotoxic aluminum ions. Laboratory assessment allowed us to identify barley genotypes differing in the reaction of their roots and sprouts at the early phases of ontogenesis. The identified genotypes with a high level of resistance to ion stress can be used as a valuable source of genetic material to improve existing cultivars and develop new ones by introgression of foreign resistance genes.

Concerning the issue of early diagnostics of low tannin content in faba bean seeds (<i>Vicia faba</i> L.)

Background. The use of faba bean (Vicia faba L.) as a feed and food plant is hindered by the presence of antinutritional substances and in particular phenolic compounds – tannins – in the seed coat. The existence of low-tannin or zero-tannin forms in the faba bean gene pool allows breeders to promote this trait. The aim of this work was to carry out biochemical validation of a known morphological marker of low tannin content and identify relationships of some phenotypic traits characterized by accumulation of phenolic compounds (tannins and anthocyanins) with their concentration for use as additional morphological markers of the low content of these antinutrients in bean seeds.Materials and methods. Associations of the presence/absence of anthocyanin in seedlings, pigmentation on petals, and dark extrafloral nectaries on stipules with the content of tannins and anthocyanins were analyzed in 10 faba bean accessions with different seed coat colors from the VIR collection. The plants were grown and evaluated in Leningrad Province in 2020–2021. Tannins in seeds were assessed using Leventhal’s method. Anthocyanins were analyzed in the green biomass of plants using a spectrophotometric method.Results and conclusion. Different combinations of the studied morphological features associated with the coloration of the studied organs were found. A high positive correlation between the levels of anthocyanins and tannins (r = 0.79) was identified as well as a direct connection of the high value of these traits with the presence of a dark extrafloral nectary on stipules and anthocyanin in seedlings. The absence of anthocyanin staining on seedlings and the absence of dark-colored extrafloral nectaries on stipules can serve as markers of low-tannin genotypes in the early stages of plant development. The light seed coat color that does not darken for a long time may also be the evidence of low tannin content.

Gemellar Competition as a Key Component in Seed–Seedling Transition of Handroanthus chrysotrichus (Mart. ex A. DC.) Mattos (Bignoniaceae)

The occurrence of more than one embryo per seed (polyembryony) is common among angiosperms; however, there are gaps in the knowledge of its effects on the early stages of plant development. In this context, we study the effects of polyembryony and intraspecific variability in gemellar competition during the seed–seedling transition in Neotropical Handroanthus chrysotricus (Bignoniaceae). We used seeds from five cultivated trees in an urban environment inserted in a biodiversity hotspot (Cerrado). Embryo mass, seed germination, seedling emergence and seedling morphometry were evaluated. We did not find intraspecific variability in seed germination, seedling emergence or the mean number of embryos and seedlings per seed. On the other hand, intraspecific variability was observed during the transition from embryo to seedling. When only one seedling emerged from a seed, the seed–seedling transition was more asynchronous than when more seedlings emerged from one seed (with higher uncertainty and a longer time to emergence of the last seedling). The mass of embryos and seedlings decreased with the increase in the number of embryos in a seed, reinforcing the occurrence of gemellar competition. However, the total mass of embryos per seed was similar. The increase in seedlings per seed also decreased the morphometric measurements of each one. A positive morphometric aspect of the emergence of two seedlings per seed was that they had the highest total seedling mass, evidencing the positive Allee effect. Polyembryony had both positive and negative effects on seed germination and seedling morphology in the species, which helps to understand how this phenomenon acts on seed biology and plant establishment.

Seed Priming with Single-Walled Carbon Nanotubes Grafted with Pluronic P85 Preserves the Functional and Structural Characteristics of Pea Plants.

The engineering of carbon nanotubes in the last decades resulted in a variety of applications in electronics, electrochemistry, and biomedicine. A number of reports also evidenced their valuable application in agriculture as plant growth regulators and nanocarriers. In this work, we explored the effect of seed priming with single-walled carbon nanotubes grafted with Pluronic P85 polymer (denoted P85-SWCNT) on Pisum sativum (var. RAN-1) seed germination, early stages of plant development, leaf anatomy, and photosynthetic efficiency. We evaluated the observed effects in relation to hydro- (control) and P85-primed seeds. Our data clearly revealed that seed priming with P85-SWCNT is safe for the plant since it does not impair the seed germination, plant development, leaf anatomy, biomass, and photosynthetic activity, and even increases the amount of photochemically active photosystem II centers in a concentration-dependent manner. Only 300 mg/L concentration exerts an adverse effect on those parameters. The P85 polymer, however, was found to exhibit a number of negative effects on plant growth (i.e., root length, leaf anatomy, biomass accumulation and photoprotection capability), most probably related to the unfavorable interaction of P85 unimers with plant membranes. Our findings substantiate the future exploration and exploitation of P85-SWCNT as nanocarriers of specific substances promoting not only plant growth at optimal conditions but also better plant performance under a variety of environmental stresses.

Metabolic Study of Cucumber Seeds and Seedlings in the Light of the New, Controversial Trend of Preventive Use of Systemic Fungicides.

Cucumber is one of the most commonly produced vegetable crops. The greatest economic losses in the yields of these crops have resulted from fungal infections-powdery mildew and downy mildew. The action of fungicides not only affects the fungi, but can also lead to metabolic disorders in plants. However, some fungicides have been reported to have positive physiological effects. Our research focused on the action of two commercially available fungicides, Scorpion 325 SC and Magnicur Finito 687,5 SC, on plant metabolism. Two approaches were used to check the effect of the fungicides at the early stage of plant development when metabolic changes occur most dynamically: spraying on the leaves of cucumber seedlings and presowing seed treatment. The application of the fungicide formulation as a presowing seed treatment caused perturbations in the phytase activity, leading to disorders in the energetic status of the germinating seeds. In addition, the tested preparations changed the morphology of the germinating seeds, limiting the growth of the stem. Furthermore, the application of the tested fungicides on seedlings also showed a disruption in the energetic status and in the antioxidative system. Therefore, the use of pesticides as agents causes a "green effect" and requires a much deeper understanding of plant metabolism.

Cytokinin localization and dynamics in rye plants under chilling and kernel priming with zeatin

In the early stages of plant development, a sharp chilling can pose a significant threat to cold-resistant crops, such as winter cereals, in particular, rye. Phytohormones from the cytokinin family play a crucial role in regulating plant response to low-temperature stress. Pre-sowing seed priming with cytokinin solutions is a promising approach to improving the stress tolerance of cereals. The aim of this study was to investigate the impact of chilling on the dynamics and localization of cytokinins in plants of rye cv. Boguslavka in the early stages of development, to determine the possibility of mitigating the adverse effects of cold stress through kernel priming with a zeatin solution, and to assess the effect of this substance on the balance of endogenous cytokinins. Kernels were soaked in either water or a zeatin solution (10—6 М), and plants were grown under controlled conditions of the vegetation chamber. Chilling was induced by exposing 7-day-old plants to the refrigerator for 2 h or twice for 6 h over two days. Endogenous cytokinins were analyzed using the HPLC-MS method. We found significant changes in the cytokinin pool in plants exposed to 2 °C for 2 h while no morphological alterations were observed. The content of trans-zeatin and trans-zeatin riboside increased considerable in the shoots of the plants grown from the kernels soaked in water, whereas in the roots, the level of these cytokinins dropped sharply. Prolonged chilling led to retarded shoot growth and elongated roots. Simultaneously, the level of trans-zeatin, isopentenyladenosine and isopentenyladenine in the shoots decreased to minimum values, while the amount of trans-zeatin riboside increased almost twofold. Transformations of the cytokinin pool in the roots followed a similar pattern. Overall, under the cold stress at the alarm stage, cytokinin balance changes were aimed at maintaining growth processes, while during the acclimation stage, they contributed to growth inhibition. Pre-sowing priming of rye kernels with a zeatin solution allowed plants to maintain normal growth and morphology under of prolonged chilling. This treatment significantly affected the homeostasis of endogenous cytokinins, resulting in a more moderate rearrangement of the cytokinin pool in stressed plants than in the control. We assume that changes in the balance of cytokinins due to seed priming allow plants to improve cold tolerance. Seed treatment with cytokinins could be a promising approach to increasing the adaptive properties of plants.

Dynamic changes of blue/red light supply affect yield, biometrical and biochemical characteristics of tomato cultivars

The utilization of Light Emitting Diodes (LED) is considered one of the most impacting innovations in modern tomato production systems. The characteristics of artificial light supplied to tomato in greenhouse conditions influence the fruit yield response over the year-round crop cycle. The present work aimed to evaluate the effects of dynamic artificial light application on the growth of two tomato hybrids. The experimental protocol was based on the factorial combination between two artificial light spectra supplied to plants (a spectrum composed of blue 450 nm, red 660 nm with deep pink 400-800 nm as a background, and a white 4000 K light as a control) and two early ripening tomato hybrids (‘Signum F1’ and ‘Meteor F1’). The use of blue/red light-emitting diodes (LEDs) in a growth chamber, accompanied by a gradual increase in the red component during the vegetation phase, significantly enhanced the yield of the two tomato cultivars, with an increase of 1.61 to 1.75 times compared to control plants exposed to white light. Notably, the predominant application of blue LEDs during the early stages of plant development resulted in a reduction in plant height by 1.2-1.5 times. The selected technology involving dynamic adjustments in blue/red light proportions led to a notable increase in chlorophyll and carotene levels in tomato leaves, with enhancements of 1.41-1.46 times and 1.29-1.37 times, respectively. Moreover, the variations in blue/red light demonstrated a significant positive impact on carotenoid accumulation in the fruit, resulting in an increase of 1.29 -1.37 times compared to control plants. The increase in fruit monosaccharide organic acid content in response to blue/red light application resulted in the production of tomato fruit with high taste index and nutritional value, suggesting interesting prospects of this new technology utilization

Boron toxicity tolerance in barley may be related to intrinsically higher levels of reactive oxygen species in the shoots

There is considerable intra-and interspecific variation in boron (B) toxicity tolerance in crop plants. In this study, we aimed to investigate the mechanisms involved in tolerance to excess B in barley (Hordeum vulgare) in the early stages of plant development. To do this, B-sensitive (B?lb?l-89) and B-tolerant (Tarm-92) barley cultivars were grown hydroponically under control and B stress conditions (10 mM H3BO3) for 4 or 7 days. The hydrogen peroxide (H2O2), malondialdehyde (MDA), total phenolic, total flavonoid, anthocyanin, proline, and total sugar contents, as well as DPPH radical scavenging capacity, were then determined for both cultivars. Our results showed that B treatment led to significant increases in the B concentration of the barley cultivars for both exposure times. However, there were no drastic differences in the B concentration of the roots and shoots between the sensitive and tolerant cultivars. While the dry root weight of B?lb?l-89 was reduced after 7 days of B stress (p < 0.05), such a decrease was not observed in Tarm-92. The H2O2, MDA, proline, total sugar, and anthocyanin contents of both cultivars increased considerably in response to excess B during at least one treatment period (p < 0.05). The H2O2 content of Tarm-92 under control and B stress conditions was significantly greater than that of B?lb?l-89, but there was no difference in the MDA content and radical scavenging capacity between the two cultivars. Finally, a 35% increase was found in the total flavonoid content of the Tarm-92 seedlings exposed to B stress for 4 days. In conclusion, the findings of this study suggest that tolerance to B toxicity in barley seedlings may be related to their capacity to tolerate higher levels of reactive oxygen species.

Physiological assessment of drought resistance and heat resistance of spring barley varieties by laboratory methods

One of the main conditions for the stable growth of grain production of spring barley is the expansion of sown areas, using varieties with high adaptive properties and capable of providing high yields in a changing climate. The purpose of the work is to determine the drought resistance and heat resistance of varieties and lines of spring barley using laboratory methods. The article presents studies of physiological indicators of resistance at an early stage of plant development to extreme environmental factors (drought and relatively high air temperatures). The physiological method of early diagnostics of seeds and seedlings provides information on the general initial level of physiological and biochemical processes in germinating seeds under stressful conditions and allows one to get an idea of the resistance of adult plants. Such a primary assessment gives grounds for the selection of promising samples for a deeper study of their stability. When determining the resistance of varieties and lines of spring barley to abiotic stressors, samples were identified that, in terms of a set of indicators (drought resistance, heat resistance, degree of depression, index of complex resistance and growth of germinal roots), values significantly exceeding the standard variety Ratnik (36.6; 91, 1; 2.13%; 184.3 rel. units and 2.78 cm, respectively): Zernogradsky 1717 (45.6; 84.0; 5.19%; 194.8 rel. units and 4.76 cm), Zernogradsky 1716 (4.3; 83.4; 5.43%; 188.0 relative units and 3.67 cm), Zernogradsky 1701 (36.2; 87.0; 3.17%; , 4 relative units and 2.56 cm).

Sole and combined effect of micronutrients on germination and seedling growth attributes of sweet corn (Zea mays L. saccharata)

Micronutrient deficiency is a major constraint to crop productivity in most regions. Agronomic interventions such as micronutrient seed soaking could significantly improve seedling establishment in micronutrient deficient soils also. Iron (Fe), Manganese (Mn), and Zinc (Zn) are essential to plant metabolism and are needed in relatively small but critical amounts by plants. Little attention has been paid to studying the impact of different micronutrients application on the early seedling stage. Laboratory studies were carried out to determine the effect of different micronutrient treatments on germination, and early growth as well as biochemical analysis of seedlings. After sterilization, seeds were soaked in different micronutrient solutions for 24 hrs. The cigar roll method was used for seed germination under well-defined conditions. After seven days of germination, various seedling traits and biochemical parameters were recorded. Effects of seed soaking with different combinations of Iron, Zinc, and Manganese on growth and biochemical attributes of maize (sweet corn) were studied. The single or combined effects of the experimental treatments significantly affected the growth parameters of the seedling. There was better seedling establishment along with higher endogenous sugar, starch content as well as alpha-amylase activity at the early stages of plant development. A positive effect of seed soaking was observed in all traits through all treatments. Overall results predicted that the combination of Ferrous sulfate (0.2%) along with Zinc sulfate (0.5%) shows the best results followed by Ferrous sulfate (0.2%) along with Zinc sulfate (0.2%).