Phytohormone profiling in relation to osmotic adjustment in NaCl-treated plants of the halophyte tomato wild relative species Solanum chilense comparatively to the cultivated glycophyte Solanum lycopersicum

Meta-QTL and Candidate Gene Analyses of Agronomic Salt Tolerance and Related Traits in an RIL Population Derived from Solanum pimpinellifolium

Breeding salt-tolerant crops is necessary to reduce food insecurity. Prebreeding populations are fundamental for uncovering tolerance alleles from wild germplasm. To obtain a physiological interpretation of the agronomic salt tolerance and better criteria to identify candidate genes, quantitative trait loci (QTLs) governing productivity-related traits in a population of recombinant inbred lines (RIL) derived from S. pimpinellifolium were reanalyzed using an SNP-saturated linkage map and clustered using QTL meta-analysis to synthesize QTL information. A total of 60 out of 85 QTLs were grouped into 12 productivity MQTLs. Ten of them were found to overlap with other tomato yield QTLs that were found using various mapping populations and cultivation conditions. The MQTL compositions showed that fruit yield was genetically associated with leaf water content. Additionally, leaf Cl- and K+ contents were related to tomato productivity under control and salinity conditions, respectively. More than one functional candidate was frequently found, explaining most productivity MQTLs, indicating that the co-regulation of more than one gene within those MQTLs might explain the clustering of agronomic and physiological QTLs. Moreover, MQTL1.2, MQTL3 and MQTL6 point to the root as the main organ involved in increasing productivity under salinity through the wild allele, suggesting that adequate rootstock/scion combinations could have a clear agronomic advantage under salinity.

Comparative Analysis of Organic Extracts Bioactivity from Two Limonium. Mill Species Growing Wild in Tunisian Salty Marshes

Limonium. Mill is a genus of flowering plants belonging to the Plumbaginaceae family. The present study aimed to compare two Limonium species (L. pruinosum Kuntze and L. tunetanum (Barratte & Bonnet) Maire) in terms of their chemical composition and bioactivity. Chemical profiling showed that the methanolic (MeOH) extracts of both species were the most enriched with total phenolic (TP) and total flavonoid (TF) contents. The TFC were higher in L. tunetanum compared to L. pruinosum. HPLC-DAD analysis showed that distinctly the gallic acid and L-tyrosine 7-amido-4-methylcoumarin were the main compounds for L. pruinosum and L. tunetanum, respectively. For both Limonium. Mil species, the MeOH extracts displayed the highest antioxidant with IC50 of 7.7 and 8.4 μg/mL for L. pruinosum and L. tunetanum, respectively. The highest anti-15-lipoxygnase activity was recorded in the ethyl acetate (IC50 =14.2 μg/mL) and Methanol (IC50 =15.6 μg/mL) extracts for L. pruinosum. However, for L. tunetanum the best activity was recorded for dichloromethane extract (IC50 =10.4 μg/mL). L. pruinosum extracts displayed the highest cytotoxic activity against MCF-7 and HCT-116 cell lines compared to L. tunetanum ones. The obtained bioactivity discrepancy between Limonium. Mill species was discussed in relation to the organic extract chemical richness.

Organ-specific responses during acclimation of mycorrhizal and non-mycorrhizal tomato plants to a mild water stress reveal differential local and systemic hormonal and nutritional adjustments

MAIN CONCLUSION

Tomato plant acclimation to a mild water stress implied tissue-specific hormonal and nutrient adjustments, being the root one of the main modulators of this response. Phytohormones are key regulators of plant acclimation to water stress. However, it is not yet clear if these hormonal responses follow specific patterns depending on the plant tissue. In this study, we evaluated the organ-specific physiological and hormonal responses to a 14 day-long mild water stress in tomato plants (Solanum lycopersicum cv. Moneymaker) in the presence or absence of the arbuscular mycorrhizal fungus Rhizoglomus irregulare, a frequently used microorganism in agriculture. Several physiological, production, and nutritional parameters were evaluated throughout the experiments. Additionally, endogenous hormone levels in roots, leaves, and fruits at different developmental stages were quantified by ultrahigh-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). Water deficit drastically reduced shoot growth, while it did not affect fruit production. In contrast, fruit production was enhanced by mycorrhization regardless of the water treatment. The main tissue affected by water stress was the root system, where huge rearrangements in different nutrients and stress-related and growth hormones took place. Abscisic acid content increased in every tissue and fruit developmental stage, suggesting a systemic response to drought. On the other hand, jasmonate and cytokinin levels were generally reduced upon water stress, although this response was dependent on the tissue and the hormonal form. Finally, mycorrhization improved plant nutritional status content of certain macro and microelements, specially at the roots and ripe fruits, while it affected jasmonate response in the roots. Altogether, our results suggest a complex response to drought that consists in systemic and local combined hormonal and nutrient responses.

Overexpression of the FERONIA receptor kinase MdMRLK2 enhances apple cold tolerance

Cold is one of the main abiotic stresses in temperate fruit crops, affecting the yield and fruit quality of apple in China and European countries. The plant receptor-like kinase FERONIA is widely reported to be involved in abiotic stresses. However, its function in apple cold resistance remains unknown. Modification of cell wall components and accumulation of soluble sugars and amino acids are important strategies by which plants cope with cold. In this study, expression of the apple FERONIA receptor-like kinase gene MdMRLK2 was rapidly induced by cold. Apple plants overexpressing MdMRLK2 (35S:MdMRLK2) showed enhanced cold resistance relative to the wild type. Under cold conditions, 35S:MdMRLK2 apple plants had higher amounts of water insoluble pectin, lignin, cellulose, and hemicellulose, which may have resulted from reduced activities of polygalacturonase, pectinate lyase, pectinesterase, and cellulase. More soluble sugars and free amino acids and less photosystem damage were also observed in 35S:MdMRLK2 apple plants. Intriguingly, MdMRLK2 interacted with the transcription factor MdMYBPA1 and promoted its binding to MdANS and MdUFGT promoters, leading to more anthocyanin biosynthesis, particularly under cold conditions. These findings complemented the function of apple FERONIA MdMRLK2 responding to cold resistance.

Tomato responses to salinity stress: From morphological traits to genetic changes

Tomato is an essential annual crop providing human food worldwide. It is estimated that by the year 2050 more than 50% of the arable land will become saline and, in this respect, in recent years, researchers have focused their attention on studying how tomato plants behave under various saline conditions. Plenty of research papers are available regarding the effects of salinity on tomato plant growth and development, that provide information on the behavior of different cultivars under various salt concentrations, or experimental protocols analyzing various parameters. This review gives a synthetic insight of the recent scientific advances relevant into the effects of salinity on the morphological, physiological, biochemical, yield, fruit quality parameters, and on gene expression of tomato plants. Notably, the works that assessed the salinity effects on tomatoes were firstly identified in Scopus, PubMed, and Web of Science databases, followed by their sifter according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline and with an emphasis on their results. The assessment of the selected studies pointed out that salinity is one of the factors significantly affecting tomato growth in all stages of plant development. Therefore, more research to find solutions to increase the tolerance of tomato plants to salinity stress is needed. Furthermore, the findings reported in this review are helpful to select, and apply appropriate cropping practices to sustain tomato market demand in a scenario of increasing salinity in arable lands due to soil water deficit, use of low-quality water in farming and intensive agronomic practices.

ROS scavenging and ion homeostasis is required for the adaptation of halophyte Karelinia caspia to high salinity

The halophyte Karelinia caspia has not only fodder and medical value but also can remediate saline-alkali soils. Our previous study showed that salt-secreting by salt glands is one of main adaptive strategies of K. caspia under high salinity. However, ROS scavenging, ion homeostasis, and photosynthetic characteristics responses to high salinity remain unclear in K. caspia. Here, physio-biochemical responses and gene expression associated with ROS scavenging and ions transport were tested in K. caspia subjected to 100-400 mM NaCl for 7 days. Results showed that both antioxidant enzymes (SOD, APX) activities and non-enzymatic antioxidants (chlorogenic acid, α-tocopherol, flavonoids, polyamines) contents were significantly enhanced, accompanied by up-regulating the related enzyme and non-enzymatic antioxidant synthesis gene (KcCu/Zn-SOD, KcAPX6, KcHCT, KcHPT1, Kcγ-TMT, KcF3H, KcSAMS and KcSMS) expression with increasing concentrations of NaCl. These responses are beneficial for removing excess ROS to maintain a stable level of H2O2 and O2 - without lipid peroxidation in the K. caspia response to high salt. Meanwhile, up-regulating expression of KcSOS1/2/3, KcNHX1, and KcAVP was linked to Na+ compartmentalization into vacuoles or excretion through salt glands in K. caspia. Notably, salt can improve the function of PSII that facilitate net photosynthetic rates, which is helpful to growing normally in high saline. Overall, the findings suggested that ROS scavenging systems and Na+/K+ transport synergistically contributed to redox equilibrium, ion homeostasis, and the enhancement of PSII function, thereby conferring high salt tolerance.

The anthocyanin-rich tomato genotype LA-1996 displays superior efficiency of mechanisms of tolerance to salinity and drought

Tomato cultivation is affected by high soil salinity and drought stress, which cause major yield losses worldwide. In this work, we compare the efficiency of mechanisms of tolerance to salinity, and osmotic stress applied as mannitol or drought, in three tomato genotypes: LA-2838 (Ailsa Craig), LA-2662 (Saladette), and LA-1996 (Anthocyanin fruit - Aft), a genotype known for high anthocyanin content. Exposure to salinity or drought induced stress in all three genotypes, but the LA-1996 plants displayed superior tolerance to stress compared with the other two genotypes. They were more efficient in anthocyanin and proline accumulation, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity, and leaf Na⁺, K⁺, and Ca²⁺ homeostasis. In addition, they suffered lesser oxidative damage as measured by chlorophyll (Chl) loss and malondialdehyde (MDA) accumulation, and bioassays showed that they were less affected in terms of seed germination and root elongation. Exposure to stress induced the upregulation of stress-related genes SlNCED1, SlAREB1, SlABF4, SlWRKY8, and SlDREB2A more efficiently in LA-1996 than in the two susceptible genotypes. Conversely, the upregulation of the NADPH oxidase gene SlRBOH1 was more pronounced in LA-2838 and LA-2662. Principal component analysis showed obvious distinction between the tolerant genotype LA-1996 and the susceptible LA-2838 and LA-2662 in response to stress, and association of leaf and stem anthocyanin content with major stress tolerance traits. We suggest that anthocyanin accumulation can be considered as a marker of stress tolerance in tomato, and that LA-1996 can be considered for cultivation in salinity- or drought-affected areas.

The Halophyte Species Solanum chilense Dun. Maintains Its Reproduction despite Sodium Accumulation in Its Floral Organs

Salinity is a growing global concern that affects the yield of crop species, including tomato (Solanum lycopersicum). Its wild relative Solanum chilense was reported to have halophyte properties. We compared salt resistance of both species during the reproductive phase, with a special focus on sodium localization in the flowers. Plants were exposed to NaCl from the seedling stage. Salinity decreased the number of inflorescences in both species but the number of flowers per inflorescence and sepal length only in S. lycopersicum. External salt supply decreased the stamen length in S. chilense, and it was associated with a decrease in pollen production and an increase in pollen viability. Although the fruit set was not affected by salinity, fruit weight and size decreased in S. lycopersicum. Concentrations and localization of Na, K, Mg, and Ca differed in reproductive structures of both species. Inflorescences and fruits of S. chilense accumulated more Na than S. lycopersicum. Sodium was mainly located in male floral organs of S. chilense but in non-reproductive floral organs in S. lycopersicum. The expression of Na transporter genes differed in flowers of both species. Overall, our results indicated that S. chilense was more salt-resistant than S. lycopersicum during the reproductive phase and that differences could be partly related to dissimilarities in element distribution and transport in flowers.

Salt tolerance mechanisms in the Lycopersicon clade and their trade-offs

Salt stress impairs growth and yield in tomato, which is mostly cultivated in arid and semi-arid areas of the world. A number of wild tomato relatives (Solanum pimpinellifolium, S. pennellii, S. cheesmaniae and S. peruvianum) are endemic to arid coastal areas and able to withstand higher concentration of soil salt concentrations, making them a good genetic resource for breeding efforts aimed at improving salt tolerance and overall crop improvement. However, the complexity of salt stress response makes it difficult to introgress tolerance traits from wild relatives that could effectively increase tomato productivity under high soil salt concentrations. Under commercial production, biomass accumulation is key for high fruit yields, and salt tolerance management strategies should aim to maintain a favourable plant water and nutrient status. In this review, we first compare the effects of salt stress on the physiology of the domesticated tomato and its wild relatives. We then discuss physiological and energetic trade-offs for the different salt tolerance mechanisms found within the Lycopersicon clade, with a focus on the importance of root traits to sustain crop productivity.

Phytohormone profiles in non-transformed and AtCKX transgenic centaury (Centaurium erythraea Rafn) shoots and roots in response to salinity stress in vitro

Plant hormones regulate numerous developmental and physiological processes. Abiotic stresses considerably affect production and distribution of phytohormones as the stress signal triggers. The homeostasis of plant hormones is controlled by their de novo synthesis and catabolism. The aim of this work was to analyse the contents of total and individual groups of endogenous cytokinins (CKs) as well as indole-3-acetic acid (IAA) in AtCKX overexpressing centaury plants grown in vitro on graded NaCl concentrations (0, 50, 100, 150, 200 mM). The levels of endogenous stress hormones including abscisic acid (ABA), salicylic acid (SA) and jasmonic acid (JA) were also detected. The elevated contents of total CKs were found in all analysed centaury shoots. Furthermore, increased amounts of all five CK groups, as well as enhanced total CKs were revealed on graded NaCl concentrations in non-transformed and AtCKX roots. All analysed AtCKX centaury lines exhibited decreased amounts of endogenous IAA in shoots and roots. Consequently, the IAA/bioactive CK forms ratios showed a significant variation in the shoots and roots of all AtCKX lines. In shoots and roots of both non-transformed and AtCKX transgenic centaury plants, salinity was associated with an increase of ABA and JA and a decrease of SA content.

Comparison of Drought and Heat Resistance Strategies among Six Populations of Solanum chilense and Two Cultivars of Solanum lycopersicum

Within the tomato clade, Solanum chilense is considered one of the most promising sources of genes for tomato (S. lycopersicum) selection to biotic and abiotic stresses. In this study, we compared the effects of drought, high temperature, and their combination in two cultivars of S. lycopersicum and six populations of S. chilense, differing in their local habitat. Plants were grown at 21/19 °C or 28/26 °C under well-watered and water-stressed conditions. Plant growth, physiological responses, and expression of stress-responsive genes were investigated. Our results demonstrated strong variability among accessions. Differences in plant growth parameters were even higher among S. chilense populations than between species. The effects of water stress, high temperature, and their combination also differed according to the accession, suggesting differences in stress resistance between species and populations. Overall, water stress affected plants more negatively than temperature from a morpho-physiological point of view, while the expression of stress-responsive genes was more affected by temperature than by water stress. Accessions clustered in two groups regarding resistance to water stress and high temperature. The sensitive group included the S. lycopersicum cultivars and the S. chilense populations LA2931 and LA1930, and the resistant group included the S. chilense populations LA1958, LA2880, LA2765, and LA4107. Our results suggested that resistance traits were not particularly related to the environmental conditions in the natural habitat of the populations. The expression of stress-responsive genes was more stable in resistant accessions than in sensitive ones in response to water stress and high temperature. Altogether, our results suggest that water stress and high temperature resistance in S. chilense did not depend on single traits but on a combination of morphological, physiological, and genetic traits.

Auxin alters sodium ion accumulation and nutrient accumulation by playing protective role in salinity challenged strawberry

High salinity in soil affects the strawberry production and fruit quality. Auxin-primed plants have enhanced responses to soil salinization. In this study, we report that exogenous application of IAA can partially relieve stress responses of strawberry seedlings. Cytological analysis showed that the ultrastructure of root tip and leaf cells in strawberry seedlings were altered under high salinity condition, which was partially recovered after the application of IAA. The study showed that the ultrastructure of root tip and leaf cells in strawberry seedlings were altered under salt stress condition, which was partially recovered after the application of IAA. Exogenous IAA ameliorated deleterious effects on seedling growth under salinity were attributed to accelerated Na⁺ fluxes, decreased the contents of Na⁺ to maintain the ion homeostasis, protect root growth, and promote the absorption of nutrients for improved photosynthetic efficiency in strawberry.

Transcriptional regulation-mediating ROS homeostasis and physio-biochemical changes in wild tomato (Solanum chilense) and cultivated tomato (Solanum lycopersicum) under high salinity

Salinity intrusion is one of the biggest problems in the context of sustainable agricultural practices. The major concern and challenge in developing salt-resistance in cultivated crops is the genetic complexity of the trait and lack of natural variability for stress-responsive traits. In this context, tomato wild relatives are important and have provided novel alleles for breeding abiotic stress tolerance including salt tolerance. We provide here a case study, involving tomato wild relative Solanum chilense and cultivated variety Solanum lycopersicum, carried out under high salt stress to investigate comparative transcriptional regulation mediating ROS homeostasis and other physiological attributes. Salt dependent oxidative stress in S. lycopersicum was characterized by a relatively higher H₂O₂ content, generation of O₂^•−, electrolytic leakage and lipid peroxidation whereas reduced content of both ascorbate and glutathione. On the contrary, the robust anti-oxidative system in the S. chilense particularly counteracted the salt-induced oxidative damages by a higher fold change in expression profile of defense-related salt-responsive genes along with the increased activities of anti-oxidative enzymes. We conclude that S. chilense harbours novel genes or alleles for salt stress-related traits that could be identified, characterized, and mapped for its possible introgression into cultivated tomato lines.

RNA-Seq analysis of Clerodendrum inerme (L.) roots in response to salt stress

Background

Clerodendrum inerme (L.) Gaertn, a halophyte, usually grows on coastal beaches as an important mangrove plant. The salt-tolerant mechanisms and related genes of this species that respond to short-term salinity stress are unknown for us. The de novo transcriptome of C. inerme roots was analyzed using next-generation sequencing technology to identify genes involved in salt tolerance and to better understand the response mechanisms of C. inerme to salt stress.

Results

Illumina RNA-sequencing was performed on root samples treated with 400 mM NaCl for 0 h, 6 h, 24 h, and 72 h to investigate changes in C. inerme in response to salt stress. The de novo assembly identified 98,968 unigenes. Among these unigenes, 46,085 unigenes were annotated in the NCBI non-redundant protein sequences (NR) database, 34,756 sequences in the Swiss-Prot database and 43,113 unigenes in the evolutionary genealogy of genes: Non-supervised Orthologous Groups (eggNOG) database. 52 Gene Ontology (GO) terms and 31 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were matched to those unigenes. Most differentially expressed genes (DEGs) related to the GO terms “single-organism process”, “membrane” and “catalytic activity” were significantly enriched while numerous DEGs related to the plant hormone signal transduction pathway were also significantly enriched. The detection of relative expression levels of 9 candidate DEGs by qRT-PCR were basically consistent with fold changes in RNA sequencing analysis, demonstrating that transcriptome data can accurately reflect the response of C. inerme roots to salt stress.

Conclusions

This work revealed that the response of C. inerme roots to saline condition included significant alteration in response of the genes related to plant hormone signaling. Besides, our findings provide numerous salt-tolerant genes for further research to improve the salt tolerance of functional plants and will enhance research on salt-tolerant mechanisms of halophytes.

Salinity-induced modifications on growth, physiology and 20-hydroxyecdysone levels in Brazilian-ginseng [Pfaffia glomerata (Spreng.) Pedersen]

- Salinity is a major threat to agriculture. However, depending on the concentration of soluble salts in soil, increased secondary metabolite levels can occur with no major damages to plant growth and development. The phytoecdysteroid (PE) 20-hydroxyecdysone (20E) is a secondary metabolite with biotechnological, medicinal, pharmaceutical and agrochemical applicability. Here, we characterize the responses (growth and physiology) of Pfaffia glomerata under different NaCl concentrations and examine the production of 20E as affected by salinity. Forty-day-old plants grown in greenhouse were exposed to 0, 120, 240, 360 or 480 mM of NaCl for 11 days. Moderate salinity (i.e., 120 mM of NaCl) led to increased 20E concentrations in leaves (47%) relative to the control with no significant effect on photosynthesis and biomass accumulation, thus allowing improved 20E contents on a per whole-plant basis. In contrast, plants under high salinity (i.e., 240-480 mM of NaCl) displayed similar 20E concentrations in leaves compared to the control, but with marked impairments to biomass accumulation and photosynthetic performance (coupled with decreased sucrose and starch levels) in parallel to nutritional imbalance. High salinity also strongly increased salicylic acid levels, antioxidant enzyme activities, and osmoregulatory status. Regardless of stress severity, 20E production was accompanied by the upregulation of Spook and Phantom genes. Our findings suggest that P. glomerata cultivation in moderate salinity soils can be considered as a suitable agricultural option to increase 20E levels, since metabolic and structural complexity that makes its artificial synthesis very difficult.

Early Brassica Crops Responses to Salinity Stress: A Comparative Analysis Between Chinese Cabbage, White Cabbage, and Kale

Soil salinity is severely affecting crop productivity in many countries, particularly in the Mediterranean area. To evaluate early plant responses to increased salinity and characterize tolerance markers, three important Brassica crops - Chinese cabbage (Brassica rapa ssp. pekinensis), white cabbage (B. oleracea var. capitata) and kale (B. oleracea var. acephala) were subjected to short-term (24 h) salt stress by exposing them to NaCl at concentrations of 50, 100, or 200 mM. Physiological (root growth, photosynthetic performance parameters, and Na+/K+ ratio) and biochemical parameters (proline content and lipid peroxidation as indicated by malondialdehyde, MDA, levels) in the plants' roots and leaves were then measured. Photosynthetic parameters such as the total performance index PItotal (describing the overall efficiency of PSI, PSII and the intersystem electron transport chain) appeared to be the most salinity-sensitive parameter and informative stress marker. This parameter was decreased more strongly in Chinese cabbage than in white cabbage and kale. It indicated that salinity reduced the capacity of the photosynthetic system for efficient energy conversion, particularly in Chinese cabbage. In parallel with the photosynthetic impairments, the Na+/K+ ratio was highest in Chinese cabbage leaves and lowest in kale leaves while kale root is able to keep high Na+/K+ ratio without a significant increase in MDA. Thus Na+/K+ ratio, high in root and low in leaves accompanying with low MDA level is an informative marker of salinity tolerance. The crops' tolerance was positively correlated with levels of the stress hormone abscisic acid (ABA) and negatively correlated with levels of jasmonic acid (JA), and jasmonoyl-L-isoleucine (JA-Ile). Furthermore, salinity induced contrasting changes in levels of the growth-promoting hormones brassinosteroids (BRs). The crop's tolerance was positively correlated with levels of BR precursor typhasterol while negatively with the active BR brassinolide. Principal Component Analysis revealed correlations in observed changes in phytohormones, biochemical, and physiological parameters. Overall, the results show that kale is the most tolerant of the three species and Chinese cabbage the most sensitive to salt stress, and provide holistic indications of the spectrum of tolerance mechanisms involved.

Comparison between the impacts of two different modes of salicylic acid application on tomato (Solanum lycopersicum) responses to salinity

Exogenous application of salicylic acid may improve tolerance to salinity. To investigate whether exogenous salicylic acid application had similar protective effects when applied as a priming agent or concomitantly with NaCl, tomato seedlings primed or not with 10 µM salicylic acid were further treated with 125 mM NaCl, 10 µM salicylic acid or combined treatments. Both priming and concomitant application of salicylic acid increased plant growth of salt-stressed plants but their positive impact was not additive. The endogenous salicylic acid concentration increased in the leaves after concomitant application but not in response to priming, suggesting that salicylic acid accumulated during priming was metabolized subsequently. Priming increased Na⁺ and K⁺ accumulation in leaves of salt-treated plants while concomitant application had no impact on shoot Na⁺ and K⁺ accumulation. Both priming and concomitant salicylic acid decreased osmotic potential values in salt-treated plants. Carbon isotope discrimination showed that combination of both salicylic acid application methods were required to maintain a good water use efficiency in salt-treated plants. Our work demonstrated that both procedures of salicylic acid application have positive impact on salt resistance but that the underlying properties sustaining these adaptations differ according to application methods.

Laboratory investigation of steam transmission in unsaturated clayey soil under osmotic potential

Liquids coming from different sources like wastewaters, agricultural and industrial activities and leakages of chemical substances often have high concentration of chemical compositions and the osmotic gradient generated around such sources causes a considerable transmission of the Contamination. The steam transmitted by non-polluted soils moves to polluted masses, causing an increase in the volume of pollution zone and movement of pollutants. Therefore, such physical and chemical processes should be taken into account in pollution transmission models. Using Crumb method, laboratory investigations were conducted on non-dispersive and dispersive clayey soil samples obtained from three areas in Zanjan Province of Iran. A simple experimental setup has been used and hereby introduced. The impact of osmotic force from salinities of 0.5, 1, and 1.5% on steam transmission in clayey soil was examined. Results indicate that for all samples between 5 to 15 days, the moisture content increased in the pollutant zone and decreased in the non-pollutant area. Also it was observed that for dispersive clayey soil, movement of steam among layers was observed to be orderly and its amount was higher than that of non-dispersive clayey soil.