Tomato Seedlings Research Articles

Arbuscular Mycorrhizal Fungi Inducing Tomato Plant Resistance and Its Role in Control of Bemisia tabaci Under Greenhouse Conditions.

Arbuscular mycorrhizal fungi (AMF) are one of the environment-friendly organisms that enhance plant performance. AMF affect the herbivorous insect community by indirectly modifying host plant nutrient uptake, growth, and defense, also known as priming. In the current study, under greenhouse conditions, the effects of inoculating tomato seedlings with four species of AMF, i.e., Funneliformis mosseae, Rhizophagus intraradices, Rhizophagus irregularis, and Glomus iranicus, were studied in relation to tomato plant growth parameters, plant defense enzymes, and total phenol content, and additionally, the life table of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) feeding on these plants was determined. The results demonstrated that the growth parameters of tomato plants, including plant height, stem diameter, number of leaves, root volume, leaf surface area, weight of the root, and aerial organs (containing the leaves and stem), were greater and larger in the AMF-inoculated plants compared to the non-inoculated plants. Furthermore, there were higher defense enzyme activities, including peroxidase, phenylalanine ammonia lyase and polyphenol oxidase, and also higher total phenol contents in the AMF-inoculated plants. The whitefly life table characteristics were decreased in the group feeding on the AMF-inoculated plants. All together, the AMF colonization made the tomato plants more resistant against B. tabaci by improving plant growth and increasing defense enzymes. The degree of priming observed here suggests the potential of AMF to have expansive applications, including their implementation in sustainable agriculture.

Morphological characterization, phylogeny and pathogenesis of Setophoma terrestris causing corky and pink roots of tomato (Solanum lycopersicum) in Sinaloa, Mexico

Tomato (Solanum lycopersicum) is one of Mexico’s main crops. In the years 2017 and 2018, symptoms of corky and pink roots were observed with an incidence of 10 to 20% in Culiacan, Sinaloa, Mexico. In the foliage, plants presented a generalized chlorosis, with stunted growth and senescence in the leaves. In the roots, brown and pink lesions were formed, as well as a corky texture. The objective of this study was to morphologically and molecularly characterize fungal isolates associated to corky and pink root in tomato orchards in Culiacan, Sinaloa, as well as to evaluate their pathogenicity. Monoconidial isolates were obtained and they were identified as Setophoma terrestris, based on their morphological characteristics. To confirm the identity, the area of the internal transcribed spacers (ITS) of the rDNA was amplified and sequenced, along with a fragment of the gene 28S of the rRNA (LSU). Using the sequences obtained, a phylogenetic tree was created using the Bayesian Inference and it was found that the sequences were grouped with the ex–type sequences of Setophoma terrestris. The pathogenicity of the isolates was verified by inoculating mycelial discs into the root of 10 one-month-old tomato seedlings. The roots of the seedlings inoculated with PDA discs without mycelium served as a control. Thirty days after inoculation, corky and pink root symptoms appeared, whereas the roots of control plants remained healthy. According to the morphological characterization, the molecular identification and the pathogenicity tests, Setophoma terrestris was confirmed to be the causal agent of corky and pink root in agricultural tomato orchards in Culiacan, Sinaloa.

Carbon monoxide is involved in melatonin-enhanced drought resistance in tomato seedlings by enhancing chlorophyll synthesis pathway

BackgroundDrought is thought to be a major abiotic stress that dramatically limits tomato growth and production. As signal molecule, melatonin (MT) and carbon monoxide (CO) can enhance plant stress resistance. However, the effect and underlying mechanism of CO involving MT-mediated drought resistance in seedling growth remains unknown. In this study, tomato (Solanum lycopersicum L. ‘Micro-Tom’) seedlings were used to investigate the interaction and mechanism of MT and CO in response to drought stress.ResultsThe growth of tomato seedlings was inhibited significantly under drought stress. Exogenous MT or CO mitigated the drought-induced impairment in a dose-dependent manner, with the greatest efficiency provided by 100 and 500 µM, respectively. But application of hemoglobin (Hb, a CO scavenger) restrained the positive effects of MT on the growth of tomato seedlings under drought stress. MT and CO treatment promoted chlorophyll a (Chl a) and chlorophyll a (Chl b) accumulations. Under drought stress, the intermediate products of chlorophyll biosynthesis such as protoporphyrin IX (Proto IX), Mg-protoporphyrin IX (Mg-Proto IX), potochlorophyllide (Pchlide) and heme were increased by MT or CO, but uroporphyrinogen III (Uro III) content decreased in MT-treated or CO-treated tomato seedlings. Meanwhile, MT or CO up-regulated the expression of chlorophyll and heme synthetic-related genes SlUROD, SlPPOX, SlMGMT, SlFECH, SlPOR, SlChlS, and SlCAO. However, the effects of MT on chlorophyll biosynthesis were almost reversed by Hb.ConclusionThe results suggested that MT and CO can alleviate drought stress and facilitate the synthesis of Chl and heme in tomato seedlings. CO played an essential role in MT-enhanced drought resistance via facilitating chlorophyll biosynthesis pathway.

Tomato Seedling Performance in Commercial Organic Growing Media

Healthy transplants are critical to productivity in the field. For certified organic production in the United States, seedlings must be grown in media that meet the standards of the US Department of Agriculture’s National Organic Program. Many commercial organic media options are available, they vary substantially in composition, and it is unknown to what extent this influences seedling performance. This project compared tomato (Solanum lycopersicum L.) seedling emergence and growth in seven commercially available media for organic production and evaluated posttransplant performance. Tomato seedlings were grown in greenhouses at Wanatah, West Lafayette, and Vincennes, IN, USA. Chemical characteristics of the media measured in saturated media extract ranged as follows: pH 5.2–7.5; electrical conductivity (EC) 0.79–4.68 dS·m−1; 1–332 ppm nitrate-nitrogen, 5–69 ppm phosphorus, 41–451 ppm potassium, 78–714 ppm calcium, and 25–121 ppm magnesium. Higher media EC was associated with slower and less uniform seedling emergence and reduced total emergence. Seedling aboveground dry weights were significantly greater in media that contained compost. Relative performance in media containing compost varied across trials. The aboveground dry weight of tomato seedlings 4 weeks after transplanting did not differ for seedlings started in the five compost-based media, and those plants were significantly larger than plants started in the two media without compost. Larger plants tended to flower and set fruit earlier. Media testing protocols that predict nutrient supply over the production cycle could likely improve management in organic transplant production.

Strigolactone and nitric oxide collaborate synergistically to boost tomato seedling resilience to arsenic toxicity via modulating physiology and antioxidant system

Arsenic (As) poses a significant environmental threat as a metalloid toxin, adversely affecting the health of both plants and animals. Strigolactones (SL) and nitric oxide (NO) are known to play crucial roles in plant physiology. Therefore, the present experiment was designed to investigate the potential cumulative role of SL (GR24–0.20 μM) and NO (100 μM) in mitigating the adverse effect of AsV (53 μM) by modulating physiological mechanisms in two genotypes of tomato (Riogrand and Super Strain 8). A sample randomized design with four replicates was used to arrange the experimental pots in the growth chamber. 45-d old both tomato cultivars under AsV toxicity exhibited reduced morphological attributes (root and shoot length, root and shoot fresh weight, and root and shoot dry weight) and physiological and biochemical characteristics [chlorophyll (Chl) a and b content, activity of δ-aminolevulinic acid dehydratase activity (an enzyme responsible for Chl biosynthesis), and carbonic anhydrase activity (an enzyme responsible for photosynthesis), and enhanced Chl degradation, overproduction of reactive oxygen species (ROS) and lipid peroxidation due to enhanced malondialdehyde (MDA) content. However, the combined application of SL and NO was more effective in enhancing the tolerance of both varieties to AsV toxicity compared to individual application. The combined application of SL and NO improved growth parameters, biosynthesis of Chls, NO and proline. However, the combined application significantly suppressed cellular damage by inhibiting MDA and overproduction of ROS in leaves and roots, as confirmed by the fluorescent microscopy study and markedly upregulated the antioxidant enzymes (catalase, peroxidase, superoxide dismutase, ascorbate dismutase and glutathione reductase) activity. This study provides clear evidence that the combined application of SL and NO supplementation significantly improves the resilience of tomato seedlings against AsV toxicity. The synergistic effect of SL and NO was confirmed by the application of cPTIO (an NO scavenger) with SL and NO. However, further molecular studies could be imperative to conclusively validate the simultaneous role of SL and NO in enhancing plant tolerance to abiotic stress.

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.

Effect of Zinc Oxide Nanoparticle Based Seed Priming for Enhancing Seed Vigour and Physio-Biochemical Quality of Tomato Seedlings under Salinity Stress

Effect of Zinc Oxide Nanoparticle Based Seed Priming for Enhancing Seed Vigour and Physio-Biochemical Quality of Tomato Seedlings under Salinity Stress

Use of spent mushroom substrate for cherry tomato seedlings; a potential alternative to peat in horticulture

ABSTRACT This study aimed to assess the potential of using spent white button mushroom substrate (SMS) as replacement for peat for producing cherry tomato seedlings, considering different proportions of fresh and composted SMS. Phase I focused on testing the performance of seedlings raised in different growing media mixes and Phase II on the assessment of the subsequent yields of the tomatoes raised in selected treatments. Results showed that the use of fresh SMS as a replacement for the peat-based control substrate was limited to 20% (% w/v), due to its high salinity. However, the control substrate could be replaced completely with composted SMS (Composted SMS 100) without any significant differences in the growth of the seedlings. Based on the most promising results from Phase I, yields of plants raised in composted SMS (Composted SMS 40 and 100), fresh SMS (Fresh SMS 20), and peat-based control were compared. There were no significant differences in the total yield (mass) between the treatments, but the average total number of fruits of the five harvest dates was higher in the Composted SMS 100 and in the control than in the other treatments. Notably, Composted SMS 100 and control produced greater mass of tomatoes at the final harvest. In conclusion, SMS provided an effective alternative for production of cherry tomato seedlings, with composting of the SMS before use being a crucial step. It was recommended that no more than 20% fresh SMS should be used to replace peat to ensure optimal growth of cherry tomato seedlings.

A method to determine antifungal activity in seed exudates by nephelometry

BackgroundOne of the levers towards alternative solutions to pesticides is to improve seed defenses against pathogens, but a better understanding is needed on the type and regulation of existing pathways during germination. Dormant seeds are able to defend themselves against microorganisms during cycles of rehydration and dehydration in the soil. During imbibition, seeds leak copious amounts of exudates. Here, we developed a nephelometry method to assay antimicrobial activity (AA) in tomato seed exudates as a proxy to assess level of defenses.ResultsA protocol is described to determine the level of AA against the nonhost filamentous fungus Alternaria brassicicola in the exudates of tomato seeds and seedlings. The fungal and exudate concentrations can be adjusted to modulate the assay sensitivity, thereby providing a large window of AA detection. We established that AA in dormant seeds depends on the genotype. It ranged from very strong AA to complete absence of AA, even after prolonged imbibition. AA depends also on the stages of germination and seedling emergence. Exudates from germinated seeds and seedlings showed very strong AA, while those from dormant seeds exhibited less activity for the same imbibition time. The exudate AA did not impact the growth of a pathogenic fungus host of tomato, Alternaria alternata, illustrating the adaptation of this fungus to its host.ConclusionsWe demonstrate that our nephelometry method is a simple yet powerful bioassay to quantify AA in seed exudates. Different developmental stages from dormant seed to seedlings show different levels of AA in the exudate that vary between genotypes, highlighting a genetic diversity x developmental stage interaction in defense. These findings will be important to identify molecules in the exudates conferring antifungal properties and obtain a better understanding of the regulatory and biosynthetic pathways through the lifecycle of seeds, from dormant seeds until seedling emergence.

Effects of the synergistic treatments of arbuscular mycorrhizal fungi and trehalose on adaptability to salt stress in tomato seedlings.

AMF improve the plant adaptability to salt resistance by increasing mineral absorption and reducing the damage of saline soil. Trehalose plays an important role in plant response to salt damage by regulating osmotic pressure. Together, the use of AMF and trehalose in tomato seedlings proved efficient in regulating host substance synthesis, osmosis, and antioxidant enzymes. These synergistic effects significantly improved seedling adaptability to salt stress by enhancing cell osmotic protection and cell antioxidant capacity, ultimately reducing losses to crops grown on land where salinization has occurred.

SlSERK3B Promotes Tomato Seedling Growth and Development by Regulating Photosynthetic Capacity.

Brassinosteroids (BRs) are a group of polyhydroxylated steroids for plant growth and development, regulating numerous physiological and biochemical processes and participating in multi-pathway signaling in plants. 24-Epibrassinolide (EBR) is the most commonly used BR for the investigation of the effects of exogenous steroidal phytohormones on plant physiology. Although SlSERK3B is considered a gene involved in the brassinosteroid (BR) signaling pathway, its specific role in plant growth and development has not been reported in detail. In this study, tomato (Solanum lycopersicum L.) seedlings treated with 0.05 μmol L-1 EBR showed a significant increase in plant height, stem diameter, and fresh weight, demonstrating that BR promotes the growth of tomato seedlings. EBR treatment increased the expression of the BR receptor gene SlBRI1, the co-receptor gene SlSERK3A and its homologs SlSERK3B, and SlBZR1. The SlSERK3B gene was silenced by TRV-mediated virus-induced gene silencing (VIGS) technology. The results showed that both brassinolide (BL) content and BR synthesis genes were significantly up-regulated in TRV-SlSERK3B-infected seedlings compared to the control seedlings. In contrast, plant height, stem diameter, fresh weight, leaf area and total root length were significantly reduced in silenced plants. These results suggest that silencing SlSERK3B may affect BR synthesis and signaling, thereby affecting the growth of tomato seedlings. Furthermore, the photosynthetic capacity of TRV-SlSERK3B-infected tomato seedlings was reduced, accompanied by decreased photosynthetic pigment content chlorophyll fluorescence, and photosynthesis parameters. The expression levels of chlorophyll-degrading genes were significantly up-regulated, and carotenoid-synthesising genes were significantly down-regulated in TRV-SlSERK3B-infected seedlings. In conclusion, silencing of SlSERK3B inhibited BR signaling and reduced photosynthesis in tomato seedlings, and this correlation suggests that SlSERK3B may be related to BR signaling and photosynthesis enhancement.

The Effects of Mycorrhiza and Seaweed Applications on Seedling Growth Parameters: Tomato and Pepper

ABSTRACT The use of mycorrhiza and seaweed are becoming significant and complementary applications in different production systems because organisms increased quality of seedlings and crop yield. This study has been conducted under growth chamber conditions to determine some of the seedling growth parameters (length (cm), stem diameter (mm), fresh weight (g plant −1), dry weight (g plant −1), root fresh weight (g plant −1), root dry weight (g plant −1), leaf area (cm2 plant−1), SPAD, photosynthesis rate (%) and color parameters). As a plant material, Cuma F1 and Mert F1 genotype seeds were sown. Endo Roots Soluble (Mycorrhiza (ERS)) and MC-Extra (Seaweed) were applied in different doses (0, 250 and 500 mg kg−1) to seedling growing vessels at a rate of 10 ml per plant. Treatment effects in tomato were found statistically significant (p ≤.01**) on stem diameter, fresh weight, dry weight. Seedling length, leaf area and SPAD results were also statistically significant (p ≤.01**), and the results of these parameters were higher in ERS. ERS increases the leaf area and SPAD measurements in tomato seedlings. The results of pepper measurements were found to be statistically significant at p ≤.05* on root fresh weight, SPAD and photosynthesis rate. The highest values of root fresh weight, SPAD were obtained from 250 mg kg−1 doses of ERS; the highest value of photosynthesis rate was measured from 500 mg kg−1 doses of ERS on pepper. The effect of 500 mg kg−1 ERS on seedling growth was found statistically significant in pepper.

Chip Digital PCR (cdPCR) to Identify and Quantify Botrytis cinerea Infection in Tomatoes

Botrytis cinerea is a fungal pathogen present in almost any environment, able to cause a severe postharvest disease on a wide range of crops, resulting in significant economic losses. Furthermore, B. cinerea is frequently found in plant tissues as a latent, asymptomatic infection that, when stimulated by favorable alterations in the environment or the physiology of the host, can swiftly develop into a significant symptomatic infection. In greenhouses, fields, and on propagation materials, the principal strategy adopted to control infection is the use of chemical fungicides or eco-friendly alternative methods. For the optimal success of conventional and biocontrol treatments, it is crucial to monitor the disease development and the fungal infection entity. The aim of this work was to develop a fast new method based on chip digital PCR (cdPCR) to estimate the extent of the B. cinerea infection in tomatoes. To better evaluate the amount of plant infection, a duplex assay able to co-amplify both fungal and host plant DNA was fine-tuned. The cdPCR assays were applied to quantify B. cinerea in tomato seedling samples, both naturally and artificially contaminated. The developed method offers sensitive detection, reliable identification, and precise pathogen quantification. The method can be used for B. cinerea diagnostics along the tomato production chain, starting from the seeds and transplanting seedlings to plants and crop residues in open fields and greenhouses. To the best of our knowledge, this is the first study directed at applying cdPCR to B. cinerea diagnosis in tomatoes.

Antifungal activity of copper oxide nanoparticles derived from Zizyphus spina leaf extract against Fusarium root rot disease in tomato plants

Incorporating green chemistry concepts into nanotechnology is an important focus area in nanoscience. The demand for green metal oxide nanoparticle production has grown in recent years. The beneficial effects of using nanoparticles in agriculture have already been established. Here, we highlight some potential antifungal properties of Zizyphus spina leaf extract-derived copper oxide nanoparticles (CuO-Zs-NPs), produced with a spherical shape and defined a 13–30 nm particle size. Three different dosages of CuO-Zs-NPs were utilized and showed promising antifungal efficacy in vitro and in vivo against the selected fungal strain of F. solani causes tomato root rot disease, which was molecularly identified with accession number (OP824846). In vivo results indicated that, for all CuO-Zs-NPs concentrations, a significant reduction in Fusarium root rot disease occurred between 72.0 to 88.6% compared to 80.5% disease severity in the infected control. Although treatments with either the chemical fungicide (Kocide 2000) showed a better disease reduction and incidence with (18.33% and 6.67%) values, respectively, than CuO-Zs-NPs at conc. 50 mg/l, however CuO-Zs-NPs at 250 mg/l conc. showed the highest disease reduction (9.17 ± 2.89%) and lowest disease incidence (4.17 ± 3.80%). On the other hand, CuO-Zs-NPs at varied values elevated the beneficial effects of tomato seedling vigor at the initial stages and plant growth development compared to either treatment with the commercial fungicide or Trichoderma Biocide. Additionally, CuO-Zs-NPs treatments introduced beneficial results for tomato seedling development, with a significant increase in chlorophyll pigments and enzymatic activity for CuO-Zs-NPs treatments. Additionally, treatment with low concentrations of CuO-Zs-NPs led to a rise in the number of mature pollen grains compared to the immature ones. however the data showed that CuO-Zs-NPs have a unique antifungal mechanism against F. solani, they subsequently imply that CuO-Zs-NPs might be a useful environmentally friendly controlling agent for the Fusarium root rot disease that affects tomato plants.Graphical

Fungal endophytes from saline-adapted shrubs induce salinity stress tolerance in tomato seedlings.

To meet the food and feed demands of the growing population, global food production needs to double by 2050. Climate change-induced challenges to food crops, especially soil salinization, remain a major threat to food production. We hypothesize that endophytic fungi isolated from salt-adapted host plants can confer salinity stress tolerance to salt-sensitive crops. Therefore, we isolated fungal endophytes from shrubs along the shores of saline alkaline Lake Magadi and evaluated their ability to induce salinity stress tolerance in tomato seeds and seedlings. Of 60 endophytic fungal isolates, 95% and 5% were from Ascomycetes and Basidiomycetes phyla, respectively. The highest number of isolates (48.3%) were from the roots. Amylase, protease and cellulase were produced by 25, 30 and 27 isolates, respectively; and 32 isolates solubilized phosphate. Only eight isolates grew at 1.5M NaCl. Four fungal endophytes (Cephalotrichum cylindricum, Fusarium equiseti, Fusarium falciforme and Aspergilus puniceus) were tested under greenhouse conditions for their ability to induce salinity tolerance in tomato seedlings. All four endophytes successfully colonized tomato seedlings and grew in 1.5M NaCl. The germination of endophyte-inoculated seeds was enhanced by 23%, whereas seedlings showed increased chlorophyll and biomass content and decreased hydrogen peroxide content under salinity stress, compared with controls. The results suggest that the the four isolates can potentially be used to mitigate salinity stress in tomato plants in salt-affected soils.

Bioprospecting of endophytic fungi from medicinal plant Anisomeles indica L. for their diverse role in agricultural and industrial sectors

Endophytes are microorganisms that inhabit various plant parts and cause no damage to the host plants. During the last few years, a number of novel endophytic fungi have been isolated and identified from medicinal plants and were found to be utilized as bio-stimulants and bio fertilizers. In lieu of this, the present study aims to isolate and identify endophytic fungi associated with the leaves of Anisomeles indica L. an important medicinal plant of the Terai-Duars region of West Bengal. A total of ten endophytic fungi were isolated from the leaves of A. indica and five were identified using ITS1/ITS4 sequencing based on their ability for plant growth promotion, secondary metabolite production, and extracellular enzyme production. Endophytic fungal isolates were identified as Colletotrichum yulongense Ai1, Colletotrichum cobbittiense Ai2, Colletotrichum alienum Ai2.1, Colletotrichum cobbittiense Ai3, and Fusarium equiseti. Five isolates tested positive for their plant growth promotion potential, while isolates Ai4. Ai1, Ai2, and Ai2.1 showed significant production of secondary metabolites viz. alkaloids, phenolics, flavonoids, saponins, etc. Isolate Ai2 showed maximum total phenolic concentration (25.98 mg g−1), while isolate Ai4 showed maximum total flavonoid concentration (20.10 mg g−1). Significant results were observed for the production of extracellular enzymes such as cellulases, amylases, laccases, lipases, etc. The isolates significantly influenced the seed germination percentage of tomato seedlings and augmented their growth and development under in vitro assay. The present work comprehensively tested these isolates and ascertained their huge application for the commercial utilization of these isolates both in the agricultural and industrial sectors.

Green leaf volatiles co-opt proteins involved in molecular pattern signalling in plant cells.

The green leaf volatiles (GLVs) Z-3-hexen-1-ol (Z3-HOL) and Z-3-hexenyl acetate (Z3-HAC) are airborne infochemicals released from damaged plant tissues that induce defenses and developmental responses in receiver plants, but little is known about their mechanism of action. We found that Z3-HOL and Z3-HAC induce similar but distinctive physiological and signaling responses in tomato seedlings and cell cultures. In seedlings, Z3-HAC showed a stronger root growth inhibition effect than Z3-HOL. In cell cultures, the two GLVs induced distinct changes in MAP kinase (MAPK) activity and proton fluxes as well as rapid and massive changes in the phosphorylation status of proteins within 5 min. Many of these phosphoproteins are involved in reprogramming the proteome from cellular homoeostasis to stress and include pattern recognition receptors, a receptor-like cytoplasmic kinase, MAPK cascade components, calcium signaling proteinsand transcriptional regulators. These are well-known components of damage-associated molecular pattern (DAMP) signaling pathways. These rapid changes in the phosphoproteome may underly the activation of defense and developmental responses to GLVs. Our data provide further evidence that GLVs function like DAMPs and indicate that GLVs coopt DAMP signaling pathways.

Plant-on-a-chip: continuous, soilless electrochemical monitoring of salt uptake and tolerance among different genotypes of tomato.

Tomatoes (Solanum lycopersicum), a high-value crop, exhibit a unique relationship with salt, where increased levels of NaCl can enhance flavor, aroma and nutritional quality but can cause oxidative damage and reduce yields. A drive for larger, better-looking tomatoes has reduced the importance of salt sensitivity, a concern considering that the sodium content of agricultural land is increasing over time. Currently, there are no simple ways of comparing salt tolerance between plants, where a holistic approach looking at [Na+] throughout the plant typically involves destructive, single time point measurements or expensive imaging techniques. Finding methods that collect rapid information in real time could improve the understanding of salt resistance in the field. Here we investigate the uptake of NaCl by tomatoes using TETRIS (Time-resolved Electrochemical Technology for plant Root environment In situ chemical Sensing), a platform used to measure chemical signals in the root area of living plants. Low-cost, screen-printed electrochemical sensors were used to measure changes in salt concentration via electrical impedance measurements, facilitating the monitoring of the uptake of ions by roots. We not only demonstrated differences in the rate of uptake of NaCl between tomato seedlings under different growth conditions, but also showed differences in uptake between varieties of tomato with different NaCl sensitivities and the relatively salt-resistant "wild tomato" (Solanum pimpinellifolium) sister species. Our results suggest that TETRIS could be used to ascertain physiological traits of salt resistance found in adult plants but at the seedling stage of growth. This extrapolation, and the possibility to multiplex and change sensor configuration, could enable high-throughput screening of many hundreds or thousands of mutants or varieties.

Diâmetro do caule para enxertia do tomate italiano

ABSTRACT The adoption of grafting in vegetable production is an innovative technique that presents challenges to be overcome, which one of the main ones is the need to determine the appropriate diameter of the plant at the time of grafting. Therefore, the objective of this work was to evaluate the development of seedlings and production of tomato plants, grafted with different stem diameters, under protected environmental conditions. The experiment was divided into two phases, seedling development and field production. The experimental design was completely randomized with five treatments, composed of the following seedlings stem diameters at the time of grafting: 1.8; 2.0; 2.2; 2.5 and 2.8 mm. Morphophysiological and productive characteristics of the grafted plants were evaluated. The results demonstrated that Italian tomato seedlings, grafted with 2.2 mm stem diameter, showed better development. However, the production rates were similar for the different stem diameters (1.8 to 2.8 mm) adopted at the grafting moment. Estimated yields of around 200 t/ha, much higher than the national average, demonstrate the success of the grafting technique in Italian tomatoes, under protected environmental conditions.

Online diagnosis platform for tomato seedling diseases in greenhouse production

Online diagnosis platform for tomato seedling diseases in greenhouse production