Growth Of Tomato Seedlings Research Articles

Fungal Antagonism and Plant Growth Promoting Efficacy of Aspergillus oryzaeAVNF4 isolated from the Rhizome of Curcuma longa on Lycopersicum esculantum L. (tomato)

The present study aimed to develop liquid bioformulation of Aspergillus oryzae AVNF4, a Curcuma longa rhizome endophytic fungus with antagonistic activity against Fusarium oxysporum causing tomato wilt and plant growth promotion of Lycopersicum esculantum. Fungal antagonism, Indole 3- acetic acid production, ammonia and inorganic phosphate solubilisation and GC-MS analysis of antifungal metabolites of A. oryzae AVNF4 were analysed. Liquid bio formulation of A. oryzae AVNF4 (LBF) with enhanced production of IAA, ammonia and inorganic phosphate solubilisation has developed by optimising the culture medium. Seed bacterisation of tomato seeds with LBF for 48h followed by foliar application from the second week onwards showed a significant increase in germination percentage (Gp) and germination index (GI) along with biomass, plant height, shoot length, root length, root/shoot ratio, number of leaves, and soluble protein and reduced sugars in LBF treated plants compared to untreated control. Presence of 1,3-Dioxolane, 2-(1-propenyl)-, L-Prolinamide, 5-oxo-L-prolyl-L-phenylalanyl-4-hydroxy-, Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-, dl-Mevalonic acid lactone, Hydro cinnamic acid, Oleic acid, 9-Octadecenoic acid (Z)-, Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(phenylmethyl)-, 1-Allylazetidine, 4H-Pyran-4-one, 2,3-dihydro-3,5-dihydroxy-6-methyl-, 5-Pyrrolidino-2-pyrrolidone, Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methyl propyl)-, 9-Octadecenoic acid (Z)-, hexyl ester, Dehydromevalonic lactone, Acetaldehyde, (3,3-dimethyl cyclohexylidene)-, (Z)- in ethyl acetate extract of AVNF4 reported to be the pivotal compounds responsible for fungal antibiosis and to promote growth in tomato seedlings. The field performance of LBF of AVNF4 indicated that A. oryzae AVNF4 is a promising plant growth-promoting endophyte with fungal antagonism against Fusarium wilt.

Chitooligosaccharides promoted growth of tomato seedlings by shaping the structure and metabolism of rhizosphere microbial communities

Chitooligosaccharides promoted growth of tomato seedlings by shaping the structure and metabolism of rhizosphere microbial communities

Effect of different germination media on seed germination and seedling growth of tomato (Solanum lycopersicum L.) in Bhojpur, Nepal

The research was conducted following a Complete Randomized Design (CRD) under plastic tunnel with three replications to investigate the effects of different germination media on seed germination and seedling growth of tomato in Bhojpur Nepal. Nine different compositions of growing media are soil, cocopeat, vermicompost, soil + FYM (1:1), soil + cocopeat (1:1), soil + vermicompost (1:1), cocopeat + vermicompost (1:1), soil + cocopeat + vermicompost (1:1:1) and soil+ cocopeat + vermicompost + FYM (1:1:1:1). Seeds of tomato variety (Srijana) was sown in Plastic tray. Germination parameters such as germination percentage, germination speed, germination energy, and vigor index were recorded for seven consecutive days. Growth parameters including root length, shoot length, number of leaves, stem diameter, fresh seedling weight and dry seedling weight were measured at 20, 25 and 30 days after sowing. There were significant differences in the germination parameters and growth parameters. The maximum germination percentage (100%), maximum seedling vigor index (2329), root length (10.967cm), number of leaves (20.87cm) was recorded in soil + cocopeat + vermicompost + FYM (1:1:1:1) as a growing media. However maximum shoot length (12.847cm), maximum stem diameter (0.310cm) and maximum fresh weight (1.540g) was recorded in soil + cocopeat + vermicompost (1:1:1) as a growing media. Hence, optimum growth of tomato seedlings was observed when soil, cocopeat, vermicompost and FYM were used in equal proportions.

Exogenous Sucrose Enhances Growth and Physiological Performance of Tomato Seedlings Under Suboptimal Light Conditions in Passive Greenhouses

Exogenous Sucrose Enhances Growth and Physiological Performance of Tomato Seedlings Under Suboptimal Light Conditions in Passive Greenhouses

Influence of Plant Growth Regulators and Magnetic Field on Development of Nutritionally Important Tomato Plant

Plant hormones are signaling molecules and growth substances that occur naturally in plants. Growth regulators such as auxin and cytokinins play significant roles by controlling plant growth, development, flowering, fruiting, aging, leaf fall, etc. Alongside, the geomagnetic field is a natural element of earth’s environment which influences the response of plants to gravity, different wavelengths of light, electrical signals, etc. Based on the type of plant used, growth and proliferation of plant organs heavily depends on the presence of nutrients and growth regulators in the growth medium, and by magnetic influence in the environment. In our present study, we have found a definite positive correlation between the two external factors i.e., magnetic field and phytohormones (NAA and BAP) upon plant growth. It was clearly observed that the growth of the experimental crop - tomato (Solanum lycopersicum) was positively influenced by phytohormones and magnetic field when the seedlings were grown in presence of 0.5 mg NAA and 1.0 mg BAP and kept under magnetic field of 100 and 150 Gauss. Vegetative growth of tomato seedlings was significantly increased upon treatment with magnetic field in presence of plant hormones, as compared to the control plants. The current research is a pioneer endeavour in studying the role of plant growth regulators together with magnetic fields by evaluating the seedling growth responses to MF values higher than those of earth’s magnetic field.

Photoperiodic Effect on Growth, Photosynthesis, Mineral Elements, and Metabolome of Tomato Seedlings in a Plant Factory.

The duration of light exposure is a crucial environmental factor that regulates various physiological processes in plants, with optimal timing differing between species and varieties. To assess the effect of photoperiods on the growth and metabolites of a specific truss tomato cultivar, three photoperiods (12 h, 16 h, and 20 h) were tested in a plant factory. Growth parameters, including plant height, stem diameter, fresh and dry weights of shoots and roots, photosynthetic characteristics, mineral content, and metabolome profiles, were analyzed under these conditions. The results indicated that prolonged light exposure enhanced plant growth, with the highest photosynthesis and chlorophyll content observed under a 20 h photoperiod. However, no significant correlation was observed between the photoperiod and the mineral element content, particularly for macro minerals. Metabolome analysis revealed that different photoperiods influenced the accumulation of metabolites, particularly in the lipid metabolism, amino acid metabolism, and membrane transport pathways. Long periods of light would enhance photosynthesis and metabolism, improving the rapid growth of tomato seedlings. Overall, this study provides a theoretical basis for understanding the responses of truss tomato cultivars to varying photoperiods in plant factories and proposes an optimizable method for accelerating the progress of tomato seedling cultivation.

Effects of different LED light spectra and nutrient solution strength on the growth, photosynthetic parameters, and nutrients uptake in tomato seedlings

Light-emitting diode (LED) lighting is currently the most energy-efficient lighting technology, and its use in agriculture is rapidly increasing. This research aimed to investigate the interaction effect of nutrient solution concentration and light quality on tomato seedlings growth. The tested factors included two nutrient solution concentrations (50% and 33% Hoagland solution) and four ratios of blue (440 nm) to red (660 nm) light in LED lighting at a constant light intensity (B2R1, B1R1, B1R2, and B1R3). Height growth was greatest in the 33% nutrient solution × B1R2 light treatment and smallest in the 33% nutrient solution × B2R1 light treatment. Regardless of the nutrient solution concentration, total chlorophyll and carotenoid concentrations decreased with an increase in the proportion of blue light. Plant absorption of sulfur was highest in the 50% nutrient solution × B1R2 light treatment, significantly higher than all other treatments. Although the 50% nutrient solution × B1R2 light treatment also showed the greatest magnesium absorption, it did not differ significantly from most of the other treatments. In general, for growing tomato seedlings, a high ratio of blue light regime (B2R1) with a dilute nutrient solution, enriched with magnesium and sulfur, can be recommended to prevent elongation disorder and have no negative impact on various growth and physiological indicators.

Obtaining Lignin from Nutshells under Mild Extraction Conditions and Its Use as a Biostimulant in Tomato Seedlings

Biostimulants are an important alternative to improve and promote higher efficiency in cropping systems. Although the biostimulant industry has been developing for several years, there are still areas of opportunity for new sources of biostimulants as well as new ecofriendly extraction techniques that allow for a circular economy and the reuse of waste. Lignin is a heteropolymer that constitutes about 40% of the plant cell wall. A great source of lignin is agrowastes, giving it added value. Recently, its use has been tested in agronomy as a carrier of nutrients and pesticides. Walnuts are produced on a large scale in Northern Mexico, and the shell represents between 15 and 40% of its total weight. However, to obtain this biopolymer, to date, non-environmentally friendly techniques have been used; for this reason, it is necessary to find extraction alternatives to make this proposal sustainable. In this work, the obtaining and characterization of lignin through mild extraction conditions from nutshells and its evaluation as a biostimulant on the growth of tomato seedlings are reported. Lignin was extracted by hydrolysis with a mixture of acetic acid and distilled water (65:35 v/v). The results showed that it was possible to obtain 15% (w/w) lignin using mild solvents, evidenced by thermogravimetric analysis (TGA), proton magnetic nuclear resonance (H-RMN), and infrared (IR). Subsequently, lignin solutions were prepared at different concentrations, 0, 10, 50, and 100 ppm, and applied via foliar weekly to tomato seedlings. A greater fresh weight of the stem was found with 10 and 50 ppm, and the height and the fresh biomass increased with the three concentrations (10, 50, and 100 ppm), concluding that lignin extracted from nutshells using mild conditions can act as a plant biostimulant.

An Enhanced Interaction of Graft and Exogenous SA on Photosynthesis, Phytohormone, and Transcriptome Analysis in Tomato under Salinity Stress.

Salt stress can adversely affect global agricultural productivity, necessitating innovative strategies to mitigate its adverse effects on plant growth and yield. This study investigated the effects of exogenous salicylic acid (SA), grafting (G), and their combined application (GSA) on various parameters in tomato plants subjected to salt stress. The analysis focused on growth characteristics, photosynthesis, osmotic stress substances, antioxidant enzyme activity, plant hormones, ion content, and transcriptome profiles. Salt stress severely inhibits the growth of tomato seedlings. However, SA, G, and GSA improved the plant height by 22.5%, 26.5%, and 40.2%; the stem diameter by 11.0%, 26.0%, and 23.7%; the shoot fresh weight by 76.3%, 113.2%, and 247.4%; the root fresh weight by 150.9%, 238.6%, and 286.0%; the shoot dry weight by 53.5%, 65.1%, and 162.8%; the root dry weight by 150.0%, 150.0%, and 166.7%, and photosynthesis by 4.0%, 16.3%, and 32.7%, with GSA presenting the most pronounced positive effect. Regarding the osmotic stress substances, the proline content increased significantly by more than 259.2% in all treatments, with the highest levels in GSA. Under salt stress, the tomato seedlings accumulated high Na+ levels; the SA, G, and GSA treatments enhanced the K+ and Ca2+ absorption while reducing the Na+ and Al3+ levels, thereby alleviating the ion toxicity. The transcriptome analysis indicated that SA, G, and GSA influenced tomato growth under salt stress by regulating specific signaling pathways, including the phytohormone and MAPK pathways, which were characterized by increased endogenous SA and decreased ABA content. The combined application of grafting and exogenous SA could be a promising strategy for enhancing plant tolerance to salt stress, offering potential solutions for sustainable agriculture in saline environments.

Effects of Light Intensity, Water Content, and the Application of Biochar Nanoparticles on the Growth and Development of Tomato Seedlings

This study investigates the effects of light intensity, water content, and the application of biochar nanoparticles (BNPs) on the growth and development of tomato seedlings to provide valuable insight into tomato cultivation. BNPs were prepared using rice straw. In this experiment, the light intensity was set at 350 μmol ·m−2 · s−1 (L1), 300 μmol ·m−2 · s−1 (L2), and 250 μmol ·m−2 · s−1 (L3). The irrigation amount was set at 150 mL/plant (W1) and 100 mL/plant (W2). The contents of BNPs were set at 0% BNPs (N1) and 5% BNPs (N2). L2W2N2 was used as the control. A total of 12 groups were included in the study. Groups D, E, F, J, K, and L did not use BNPs, while the remaining six groups used 5% BNPs. We found that BNPs exhibit significant aggregation with spherical morphology. As the pH increased, the particle size of BNPs showed a trend of initial increase, followed by a decrease and subsequent increase. Carbon elements existed in three different forms and possessed distinct chemical bonds, resulting in different relative contents. The relative content of C═O accounted for 26.40%, which was significantly higher than that of C—O by approximately 15%. Under the W1 treatment, the height of the tomato plant in L1N2 was 31.7 cm, which is higher by 0.4 cm than that in L1N1. Under L2W1N1 treatment, the net photosynthetic rate, transpiration rate, stomatal conductivity, and intercellular CO2 concentration of tomatoes were 9.68 μmoL ·m2 · s−1, 1.223 mmoL ·m2 · s−1, 0.071 μmoL ·m2 · s−1, and 626 ppm, respectively, which are significantly higher than the control. In conclusion, this research provides a foundation for growing tomatoes.

Influence of Aloe Vera Gel on Germination and Early Growth of Tomato (Solanum lycopersicum) Seedlings in the Nursery

Tomato (Solanum lycopersicum L.) nursery production often relies heavily on chemical inputs to ensure vigorous seedling growth, which may have environmental and economic drawbacks. This study aimed to evaluate the efficacy of Aloe vera gel as a natural alternative to chemical treatments for improving germination and early seedling growth of Cobra 26 tomato seeds. The study used a factorial block design to compare the effects of seed treatments (Aloe vera gel coating, mancozeb, and untreated control) and substrate types (unfertilised topsoil, NPK-fertilised topsoil, and Aloe vera gel mixed with topsoil) on seed germination and seedling growth over three nursery cycles. Seeds coated with Aloe vera gel demonstrated the highest germination rate (90.53%) and fastest germination time (3 days), outperforming both mancozeb-treated and control seeds in germination kinetics. Growth parameters such as seedling height and leaf number were significantly influenced by substrate type (p<0.03), with no notable differences between NPK and Aloe vera-treated substrates. The study suggests that Aloe vera gel, both as a seed coating and soil additive, offers a promising, eco-friendly alternative to chemical treatments, enhancing seed germination and early seedling growth in tomatoes

Effects of different straw breeding substrates on the growth of tomato seedlings and transcriptome analysis.

Traditional substrate cultivation is now a routine practice in vegetable facility breeding. However, finding renewable substrates that can replace traditional substrates is urgent in today's production. In this study, we used the 'Pindstrup' substrate as control and two types of composite substrates made from fermented corn straw (i.e. 0-3 and 3-5mm) to identify appropriate substrate conditions for tomato seedling growth under winter greenhouse conditions. Seedling growth potential related data and substrate water content related data were tested to carry out data-oriented support. Since the single physiological data cannot well explain the mechanism of tomato seedlings under winter greenhouse condition, transcriptomic analysis of tomato root and leaf tissues were conducted to provide theoretical basis. The physiological data of tomato seedlings and substrate showed that compared with 0-3mm and Pindstrup substrate, tomato seedlings planted in 3-5mm had stronger growth potential and stronger water retention, and were more suitable for planting tomato seedlings. Transcriptome analysis revealed a greater number of DEGs between the Pindstrup and the 3-5mm. The genes in this group contribute to tomato growth as well as tomato stress response mechanisms, such as ABA-related genes, hormone-related genes and some TFs. The simulation network mechanism diagram adds evidence to the above conclusions. Overall, these results demonstrate the potential benefits of using the fermented corn straw of 3-5mm for growing tomato seedlings and present a novel method of utilizing corn straw.

α-costic acid, the main sesquiterpenoid isolated from Dittrichia viscosa (L) Greuter, induces oxidative stress and autophagy in tomato.

Dittrichia viscosa (L.) Greuter, a perennial plant in the Asteraceae, has strong allelopathic activity due to the high content of various secondary metabolites. The bicyclic sesquiterpenoid α-costic acid is the most abundant secondary metabolite of D. viscosa. Its remarkable insecticidal, antiparasitic, and phytotoxic activities point to its potential use as a natural herbicide, but information on its mode of action is lacking. To shed light on the mechanism of action of α-costic acid in plant cells, we investigated the phytotoxicity of α-costic acid in tomato plants (Solanum lycopersicum L.) through in vivo assays, the underlying cellular effects using biochemical assays, and the effect on subcellular organelles using confocal microscopy on tomato protoplasts incubated with organelle-specific fluorescent probes. In vivo tests showed that α-costic acid inhibited the growth of tomato seedlings and induced chlorosis and spot lesions in leaves. Biochemical assays demonstrated that α-costic acid caused ion leakage, chlorophyll depletion, H2O2 overproduction, callose deposition, and membrane lipid peroxidation. Confocal microscopy demonstrated that α-costic acid determined ROS overproduction and network disruption in mitochondria, singlet oxygen overproduction in chloroplasts, vacuole disintegration, and autophagosome formation. Overall, our data are consistent with a model according to which α-costic acid phytotoxicity is related to oxidative stress in mitochondria and chloroplasts that induces extensive membrane damage, ultimately resulting in cell death associated with autophagy.

Identification of Stutzerimonas stutzeri volatile organic compounds that enhance the colonization and promote tomato seedling growth.

Volatile organic compounds (VOCs) have an important function in plant growth-promoting rhizobacteria (PGPR) development and plant growth. This study aimed to identify VOCs of the PGPR strain, Stutzerimonas stutzeri NRCB010, and investigate their effects on NRCB010 biofilm formation, swarming motility, colonization, and tomato seedling growth. Solid-phase microextraction and gas chromatography-mass spectrometry were performed to identify the VOCs produced during NRCB010 fermentation. A total of 28 VOCs were identified. Among them, seven (e.g. γ-valerolactone, 3-octanone, mandelic acid, 2-heptanone, methyl palmitate, S-methyl thioacetate, and 2,3-heptanedione), which smell well, are beneficial for plant, or as food additives, and without serious toxicities were selected to evaluate their effects on NRCB010 and tomato seedling growth. It was found that most of these VOCs positively influenced NRCB010 swarming motility, biofilm formation, and colonization, and the tomato seedling growth. Notably, γ-valerolactone and S-methyl thioacetate exhibited the most positive performances. The seven NRCB010 VOCs, essential for PGPR and crop growth, are potential bioactive ingredients within microbial fertilizer formulations. Nevertheless, the long-term sustainability and replicability of the positive effects of these compounds across different soil and crop types, particularly under field conditions, require further investigation.

Mutual intercropping affects the growth and selenium content of cherry tomato seedlings

Intercropping can increase the utilization rate of light and water and can also improve plant growth. The objective of this study was to investigate the growth and selenium (Se) content in seedlings of three genotypes of cherry tomato under intercropping while applying Se. The pot experiment was conducted in a greenhouse. The monoculture of red, yellow and purple cherry tomato; among the three genotypes of cherry tomatoes, intercropping of two genotypes with each other, at the same time intercropping of three genotypes. These results show that the biomass increased under intercropping compared with monoculture. The chlorophyll b content of purple cherry tomato increased in different intercropping combinations. Furthermore, the net photosynthetic rate, stomatal conductance, and transpiration rate of purple were increased by intercropping with red and purple cherry tomatoes. The soluble protein and soluble sugar contents in yellow and purple cherry tomato increased by 49.13% and 8.37%, respectively, under mutual intercropping. Similarly, soluble sugar increased in purple cherry tomato by intercropping with yellow and red. The activities of superoxide and peroxidase in red and yellow cherry tomato seedlings were higher in all intercropping combinations than in monoculture, whereas free proline content and relative conductivity in all cherry tomatoes decreased. The Se content of roots, stem, and leaves in seedlings increased with intercropping. Therefore, intercropping can improve the growth and Se content of cherry tomatoes, and the combination of red, yellow and purple is better, which can be used to cultivate strong seedlings.

Combined application of myo-inositol and corn steep liquor enhances seedling growth and cold tolerance in cucumber and tomato.

Low temperatures pose a common challenge in the production of cucumbers and tomatoes, hindering plant growth and, in severe cases, leading to plant death. In our investigation, we observed a substantial improvement in the growth of cucumber and tomato seedlings through the application of corn steep liquor (CSL), myo-inositol (MI), and their combinations. When subjected to low-temperature stress, these treatments resulted in heightened levels of photosynthetic pigments, thereby fostering enhanced photosynthesis in both tomato and cucumber plants. Furthermore, it contributed to a decrease in malondialdehyde (MDA) levels and electrolyte leakage (REP). The effectiveness of the treatment was further validated through the analysis of key gene expressions (CBF1, COR, MIOX4, and MIPS1) in cucumber. Particularly, noteworthy positive outcomes were noted in the treatment involving 0.6 mL L-1 CSL combined with 72 mg L-1 MI. This study provides valuable technical insights into leveraging the synergistic effects of inositol and maize leachate to promote early crop growth and bolster resistance to low temperatures.

Aerial signaling by plant-associated Streptomyces setonii WY228 regulates plant growth and enhances salt stress tolerance

Plant-associated streptomycetes play important roles in plant growth and development. However, knowledge of volatile-mediated crosstalk between Streptomyces spp. and plants remains limited. In this study, we investigated the impact of volatiles from nine endophytic Streptomyces strains on the growth and development of plants. One versatile strain, Streptomyces setonii WY228, was found to significantly promote the growth of Arabidopsis thaliana and tomato seedlings, confer salt tolerance, and induce early flowering and increased fruit yield following volatile treatment. Analysis of plant growth-promoting traits revealed that S. setonii WY228 could produce indole-3-acetic acid, siderophores, ACC deaminase, fix nitrogen, and solubilize inorganic phosphate. These capabilities were further confirmed through genome sequencing and analysis. Volatilome analysis indicated that the volatile organic compounds emitted from ISP-2 medium predominantly comprised sesquiterpenes and 2-ethyl-5-methylpyrazine. Further investigations showed that 2-ethyl-5-methylpyrazine and sesquiterpenoid volatiles were the primary regulators promoting growth, as confirmed by experiments using the terpene synthesis inhibitor phosphomycin, pure compounds, and comparisons of volatile components. Transcriptome analysis, combined with mutant and inhibitor studies, demonstrated that WY228 volatiles promoted root growth by activating Arabidopsis auxin signaling and polar transport, and enhanced root hair development through ethylene signaling activation. Additionally, it was confirmed that volatiles can stimulate plant abscisic acid signaling and activate the MYB75 transcription factor, thereby promoting anthocyanin synthesis and enhancing plant salt stress tolerance. Our findings suggest that aerial signaling-mediated plant growth promotion and abiotic stress tolerance represent potentially overlooked mechanisms of Streptomyces-plant interactions. This study also provides an exciting strategy for the regulation of plant growth and the improvement of horticultural crop yields within sustainable agricultural practices.

Impact of Cadmium Contaminated Growing Medium on the Growth and Physiological Responses of Tomato Seedlings (Solanum lycopersicum L.)

Globally, urban areas are facing a rising issue of industrial pollution particularly due to heavy metals like Cadmium (Cd), which pose a threat to both plants and humans. However, plants response to Cd exposure varies based on factors like species, genetics, and growing conditions such as the type of soil and cultivation methods. This study focused on young tomato seedlings subjected to different Cd concentrations (0, 100, 200, and 300 ppm) through a pot experiment, aiming to understand the impact of Cd on various morpho-physiological traits of the "MAYAR F1" tomato cultivar. The results exhibited amazing findings that the chlorophyll contents (21.93 nmol/mg), relative water contents (0.84%), electrolyte leakage (135.5 uS/cm) and leaf area (6.37 cm2) were highest at 300 ppm followed by control. While the maximum number of leaves (11) were noticed in control. Consequently, the study suggests that cultivating tomatoes in urban agriculture soils contaminated with Cd could be a viable option. Nonetheless, it emphasizes the importance of exercising caution and conducting further research to fully comprehend the potential long-term implications and associated risks of Cd exposure in urban agriculture. Keywords: Heavy metal, cadmium; morphological traits, plant physiology, chlorophyll contents, electrolyte leakage.

Exogenous application of melatonin attenuates waterlogging stress through adopting quiescence adaptation technique in tomato seedlings

Waterlogging (WL) is a major limiting factor in global crop production and seriously limits growth and yield improvement in low-lying rainfed regions. Melatonin (MT) is a vital phytohormone that functions as a "master regulator" in multiple facets related to plant growth and development, in addition to maintaining a potential role in response to stresses. However, the pharmacological role of MT in attenuating waterlogging stress in tomato largely remains elucidated. The objective of the current investigation is to justify the physiological regulatory mechanism of tomato seedlings exposed to WL and the putative functions of MT to mitigate the adverse effects of WL. Tomato seedlings were grown on substrate (peat: vermiculite, 2:1, v/v) and at the 4th leaf stage subjected to waterlogging stress for 10 days and seedlings were foliar sprayed with melatonin during waterlogging stress. The results revealed that WL significantly arrested tomato seedlings growth, and reduced pigment content coincided with enhanced leaf senescence. MT supplementation attenuated WL-induced oxidative damage through increasing osmoprotectants activity, elevating antioxidant enzyme functioning synchronized with inhibiting excess reactive oxygen species (ROS) production. The concentrations of MT (28 %), abscisic acid (ABA, 170 %), and 1-aminocyclopropane-1-carboxylic acid (ACC, 129 %) were increased, while indole acetic acid (IAA, 15 %), jasmonic acid (JA, 55 %) and gibberellic acid (GA3, 26 %) content were decreased in only WL seedlings roots relative to control seedlings. The core anaerobic respiration enzyme alcohol dehydrogenase (ADH) and pyruvate decarboxylase (PDC) activity were elevated by 127 % and 163 %, respectively at day 10 in WL+MT received seedlings than control. WL treatment varyingly contributed on nutrient content, as evidenced that N+, K+, and Ca2+ content decreased, whereas Mn2+, Fe2+, and Mg2+ content increased and MT addition reversed their concentrations under similar stress conditions. Exogenous MT promoted WL-tolerance of tomato by positively suppressing respiratory burst oxidase homologs (RBOH)-regulating gene expression while up-regulating ethylene biosynthesis gene transcription. Most importantly, programmed cell death (PCD) regulated enzyme caspase-3 activity concurred with PCD-induced gene (caspase-3, pirin, TBN1) expression significantly inhibited by MT application. In general, these findings reveal that external supplementation with MT can improve plant tolerance to WL through complex processes and multifaceted mechanisms.

Vanadium toxicity was alleviated by supplementation of silicon in tomato seedlings: Upregulating antioxidative enzymes and glyoxalase system

The primary goal of this research is to investigate the mitigating effect of silicon (Si; 2 mM) on the growth of tomato seedlings under vanadium (V; 40 mg) stress. V stress caused higher V uptake in leaf, and enhanced concentration of leaf anthocyanin, H2O2, O2•−, and MDA, but a decreased in plant biomass, root architecture system, leaf pigments content, mineral elements, and Fv/Fm (PSII maximum efficiency). Si application increased the concentrations of crucial antioxidant molecules such as AsA and GSH, as well as the action of key antioxidant enzymes comprising APX, GR, DHAR, and MDHAR. Importantly, oxidative damage was remarkably alleviated by upregulation of these antioxidant enzymes genes. Moreover, Si application enhanced the accumulation of secondary metabolites as well as the expression their related-genes, and these secondary metabolites may restricted the excessive accumulation of H2O2. In addition, Si rescued tomato plants against the damaging effects of MG by boosting the Gly enzymes activity. The results confirmed that spraying Si to plants might diminish the V accessibility to plants, along with promotion of V stress resistance.