Proper management of saline soils needs adequate information about the amount and SALT distribution in the root zone. Irrigation is one of the factors that control the distribution of SALT. This study investigated soil leaching simulation by using HYDRUS2D Software based on the evaporation of soil surface of a land without plant located at Shahid Chamran University, Ahwaz, Iran. Samples were taken from three distances of 0, 20, and 40 cm from the drip irrigation emitter and 0-20, 20-40, 40-60 and 60-80 cm depths. Among the measured depths, the 20- 40 cm layer was revealed as the best working depths with a SALT content of 5.7 mg/cm3, while the depth of 60-80 cm had an average salinity of 10.87 mg/cm3, the highest SALT content compared with the other depths. Soil salinity decreased with time and irrigation. At the last irrigation, soil salinity under the dripper reached a salinity of 2.13 mg/cm3 that was 1.15 of the initial amount. SALTs movement in soil and leaching simulation by HYDRUS2D software showed that this software simulated SALT distribution well.

In order to assess the effect of salinity on root traits and yield of two wheat cultivars, an experiment was conducted in Agricultural, Medical and Industrial Research School, Nuclear Science and Technology Research Institute, Karaj, Iran, using factorial experiment based on complete randomized design with 3 replications. The first factor included sensitive wheat cv. (Tajan) and tolerant cv. (Bam) and the second factor was salinity stress at four levels (6, 8, 10 and 12 dS/ m). In each treatment, 10 days after anthesis, the variation of root dry weight, shoot dry weight, root/stem ratio, and root area and volume were analyzed. The results showed significant reduction (P≤0.01) in root dry weight, root area and root volume per plant. Root/shoot dry weight ratio decreased 35.1% and 8.2% in Tajan and Bam cultivars, respectively, at 8 dS/m compared to 6 dS/m. Results revealed that grain yield per plant was affected by root dry weight, as the highest grain yield was observed in Bam cultivar. Increased grain yield in this cultivar was due to higher root dry weight. Also, Tajan cultivar had the lowest grain yield and root dry weight in 12 dS/m treatment. There were positive correlations among root surface and volume with root dry weight and therefore with grain yield. Therefore, based on the parameters studied in this experiment, it can be stated that a large part of the traits associated with sensitivity or tolerance of wheat cultivars to salinity could be attributed to their roots’ characteristics.

Mighan lake with the surface area of 112 km 2 is located eight kilometers northeast of Arak city, the main phytoplankton population and food chain of which include Dunaliella salina (Dunal) Teodoresco. The salinity of the lake ranges between 20-120 g/l depending on season and water input. The present study evaluated the effect of salinity and physicochemical factors on phytoplankton communities in the lake. To this end, sampling was performed monthly during March to December 2019. In addition, species and phytoplankton density were determined through inverted microscopy. Based on the results, 12 algal species were identified, among which D. salina was 87. 3% of phytoplankton composition. Indeed, salinity, as a major limiting factor, reduced phyto-plankton diversity in Mighan Lake.

Silicon(Si) is the second most abundant element in the earth’s crust and is regarded as a beneficial element for higher plants.In this study, the effect of Si supplementation (1 and 4 mM) was studied on wheat (Triticum aestivum cv. Homa) plants grown hydroponically under salinity stress (50 and 150 mM NaCl) for two weeks under controlled environmental conditions. Plant biomass was found to decrease at both salinity levels. Contrary to our expectation, Si supplementation failed to mitigate the SALT stress effects on dry matter production. However, the majority of biochemical parameters related to SALT tolerance showed improvements as a result of Si application, particularly at 1 mM. Under both control and salinity conditions, Si treatment resulted in higher leaf contents of chlorophyll and carotenoids, soluble sugars, proteins, and free amino acids, particularly proline. Osmotic potential, however, declined in the roots, suggesting that Si supplementation might contribute to plant’s higher water uptake capacity. Sitreatment diminished leaf concentration of Na+ in the cell sap but increased it in the cell wall-bound fraction, indicating a Na+ detoxification mechanism mediated by Si. Our results suggest that a short-term Si treatment affects biochemical indicators of SALT tolerance but that long-term exposure to Si is needed for a significantly alleviating effect on plant biomass.

Accumulation of anions and cations in soil solution prevents growth of plant. The main problem in saline soils is related to soluble SALTs. Saline soils have a large amount of SALTs; therefore the leaching from these soils is important. This study was conducted to evaluate the movement of solutes using soil columns picked from Azizabad of Bam. Leaching experiments were conducted on columns of five soil textures (clay loam, loam, sandy clay loam, sandy loam, loam sandy). The soils were filled in columns to achieve uniform bulk density of 1.5 g cm-3. The columns were leached with approximately 5 pore volumes (pv). Effluents from each leaching were collected for chemical analysis. Leachate samples were analyzed for soluble cations (Ca2+, Mg2+, Na+and K+). After completion of the leaching the soil columns were split open and cut into 3 sections, each 10 cm. Soil samples at different column depths were analyzed for EC, Na+, Ca2+and Mg+. The results showed using water in leaching experiments could reduce solutes concentration and it following saline soils and these soils do not need any amendant. Generally the effect of coarse textured soil on the ion movement is more than in the case of fine textured soil. The solute arrival in effluent solution is ahead when soil texture is coarse. The amount of clay plays an important role for retaining and ions removal from soil. The difference between the amounts of irrigation water needed for salinity removal depends on soil texture. The most common of such reactions is cation exchange.

Hybrid populations (F3) derived from cross between four moderate SALTresistant spring wheat (Triticum aestivum L.) were assessed for transgressive segregation of SALT-tolerant genotypes allowing germination and emergence at 350 mM NaCl for 30 days. The achieved Selection intensity was the order of 0.24- 0.27 in these segregation populations (22-25 seedlings from 9000 seeds). Assessment of transgrassive individuals (more SALT tolerant) and their parents was carried out in a hydroponics experiment applying six SALT concentrations of 150, 200, 225, 250, 275 and 300 Mm NaCl. Root lengths of two-week-old seedlings grown in the different concentrations were used as SALT-tolerant criteria. Root length of transgressive plants were longer than parents (except Tobari 66) showing more tolerance to NaCl. It may be assumed that the character in quantitative trait based, and the parents of such hybrids may contain different genes for SALT tolerance.  

Dissection of genetic architechture of salinity tolerance in different rice cultivars is a prerequisite of a breeding program for salinity stress. Therefore, to dissect genetics of salinity tolerance, 6 diverse rice genotypes such as Tarom mahalli, Gharib, Shahpasand, Dorfak, Sepidroud and IR28 were tested in a full diallel genetic design, 6×6, during 2007-08 at Rice Research Institute of Iran in Rasht, Iran. All cross combinations together with their parentss, totally 36 genotypes, were set in Randomized Complete Block Design with two replications.The plant materials were evaluated for salinity tolerance index, plant dry matter, sodium and potassium concentrations, Na+/K+ ratio at seedling stage and tiller number, grain weight, filled-grain, plant height and days to 50% flowering at reproductive stage in saline conditions with EC 10 and 12 ds/m, respectively. Analysis of variance for traits of interest among parents showed that they were significantly different for salinity tolerance index, plant dry matter, sodium uptake (%), tiller number, filled-grain.panicle-1, plant height and days to 50% flowering. Therefore, analysis of variance for combining ability was performed for this group of traits. Results of dissection of genetic variance to general, specific and cytoplasmic effects showed that for all these traits those components were highly significant. It’s revealed that both additive and non-additive components of genetic variance were important. Estimation of genetic parameters showed that both additive and dominance variances as well as maternal effect were important in controlling of the traits of interest. We also found that broad sense heritability (h2b) was rather high and ranged from 0.25 to 0.75 for different traits. According to results, cultivar Tarom was good combiner for increasing salinity tolerance index, lower sodium concentration and short duration for days to 50% flowering and Shahpasand was the second suitable parent and combiner for salinity tolerance index, but was the best parent for sodium uptake. Therefore, the mechanism of tolerance to salinity could be related to storage of high amount of sodium in the cell vacuoles.